Articles

Keywords: ETS; Modeling respiration; MTE; Oxygen consumption

Respiratory oxygen consumption is the result of a cell\'s biochemistry. It is caused by enzymatic activity of the respiratory electron transfer system (ETS). However, in spite of this understanding, respiration models continue to be based on allometric equations relating respiration to body size, body surface, or biomass. The Metabolic Theory of Ecology (MTE) is a current example. It is based on Kleiber\'s law relating respiration (R) and biomass (M) in the form, View the MathML source, where C is a constant, Ea is the Arrhenius activation energy, k is the Boltzmann constant for an atom or molecule, and T is the temperature in Kelvin. This law holds because biomass packages the ETS. In contrast, we bypass biomass and model respiration directly from its causal relationship with the ETS activity, R = f (ETS). We use a biochemical Enzyme Kinetic Model (EKM) of respiratory oxygen consumption based on the substrate control of the ETS. It postulates that the upper limit of R is set by the maximum velocity, Vmax, of complex I of the ETS and the temperature, and that the substrate availability, S, modulates R between zero and this upper limit. Kinetics of this thermal-substrate regulation is described by the Arrhenius and Michaelis–Menten equations. The EKM equation takes the form View the MathML source where Rg is the molar gas constant and K is the Michaelis–Menten constant. Here, we apply the EKM and the MTE to predict a respiration time-profile throughout the exponential, steady state, and nutrient-limited phases of the marine bacteria Pseudomonas nautica and Vibrio natriegens in acetate-based cultures. Both models were tested by comparing their output with the measured RO2 time-profile. The MTE predicted respiration accurately only in the exponential growth phase, but not during the nutrient limitation part of the stationary phase. In contrast, the EKM worked well throughout both physiological phases as long as the modeled substrates fall with the declining carbon source. Results support the theoretical bases of the EKM. We conclude that the EKM holds promise for predicting respiration at the different physiological states and time-scales important to microbiological studies.

Keywords: fish larvae; coastal zone; seasonality; environmental factors; western Mediterranean

The influence of coastal environmental conditions from winter-spring to summer on fish larvae assemblages in a temperate area has suggested a seasonal shift in ecosystem-level variation through which trophic pathways shift from the pelagic to the benthic system. This variation may be related to marked effects in the reproductive strategies in the fishes inhabiting the area and indirectly affect ichthyoplankton assemblages. Larval fish assemblages were sampled fortnightly at three stations located in coastal waters off southern Mallorca (Western Mediterranean) from March to August 2007, covering the main spawning period for the resident coastal fish in this region. The larval fish assemblage showed clear seasonality with higher specific abundance but lower diversity in the spring. Two main assemblages were identified: a spring assemblage, occurring at surface seawater temperatures <20 °C and dominated by species with relatively larger home ranges, such as Boops boops, Sardina pilchardus, Trachurus trachurus, and Spicara smaris, and a summer assemblage characterised by the presence of the benthopelagic Coris julis, Serranus hepatus, Serranus cabrilla and Mullus spp., among others. The shift between these ichthyoplankton communities occurred in early June, coinciding with the onset of summer hydrographical conditions and the local benthic productivity peak.

Keywords: Encystment; Excystment; Germination; Harmful algal bloom; Resting cyst

Knowledge of the specific life-cycle dynamics during harmful algal bloom (HAB) development is essential for understanding and forecasting the onset, evolution and future occurrence of these events. Life-cycle stages of the toxic dinoflagellate Alexandrium fundyense were monitored both in the water column and in the sediments from the onset to the decline of a bloom in Northport Harbor (New York, USA). Moreover, excystment and encystment were investigated in situ through the deployment of emergence and sediment traps, respectively. The bloom, the largest ever recorded on the east coast of the US south of Massachusetts, persisted for 6 weeks between April and June 2008, and reached maximum vegetative cell abundances of 1.3 × 106 cells l−1. Resting cysts in the surface sediments were quantified at the onset of the bloom, all of which germinated during the development of the bloom. Excystment of these resting cysts provided inoculum of vegetative cells for bloom development. In the water column, first detection of planozygotes occurred during the exponential phase of the bloom at vegetative cell abundances of ∼104 cells l−1. Nonmotile planozygotes and resting cysts were observed in the sediment traps before the first peak of vegetative cells, coinciding with the detection of planktonic planozygotes. The estimated encystment and planozygote percentages were relatively low, indicating that a small proportion of the vegetative cell population was involved in sexual reproduction. However, encystment was a crucial process for replenishing the cyst stock of the A. fundyense population in the sediments as cyst densities were low before the bloom but high after it. For the first time, formation of pellicle cysts in the field by A. fundyense was observed, which coincided with high vegetative cell abundances in the water column during the bloom.

Keywords: Bloom dynamics; Coastal zone; Encystment; Excystment; Harmful algal bloom; Resting cyst

Life-cycle transitions play a key role in the bloom dynamics of many dinoflagellates. In this study, in situ excystment and encystment were monitored during recurrent Alexandrium minutum blooms in Arenys de Mar harbor (NW Mediterranean Sea) from October 2005 to May 2008. In addition, the dynamics of vegetative cells in the water column and resting cysts in the sediments were assessed. Excystment occurred continuously during the period studied. The excystment fluxes and the estimated excystment percentages indicated a pattern of alternating reduced and active excystment periods. From July to November, excystment percentages were <0.1%, whereas from December to June the A. minutum population underwent active excystment, with excystment percentages of 0.3–45.7%. Periods of active excystment coincided with increases in irradiance and water temperature, conditions also favorable for bloom development. During vegetative cell blooms, resting cyst formation coincided with periods marked by vegetative cell abundances in the water column of >2 × 103 cells l−1. Resting cyst fluxes were higher when the abundance of vegetative cells in the overlying water column was greater. The excystment and encystment processes overlapped for 2 months during the extended blooms, indicating that newly formed resting cysts had overcome the mandatory dormancy period and were capable of germinating within the same bloom in which they were produced. Resting cysts in the surface sediment were rapidly depleted during periods of active excystment, but their production, although involving only a small fraction of the vegetative population, more than compensated for their loss. These results are discussed with respect to the role of frequent life-stage switches in determining the population dynamics and the maintenance of A. minutum blooms.

Keywords: L-band, microwave radiometry, ocean salinity, sea surface.

We validate Soil Moisture and Ocean Salinity (SMOS) sea surface salinity (SSS) retrieved during August 2010 from the European Space Agency SMOS processing. Biases appear close to land and ice and between ascending and descending orbits; they are linked to image reconstruction issues and instrument calibration and remain under study. We validate the SMOS SSS in conditions where these biases appear to be small. We compare SMOS and ARGO SSS over four regions far from land and ice using only ascending orbits. Four modelings of the impact of the wind on the sea surface emissivity have been tested. Results suggest that the L-band brightness temperature is not linearly related to the wind speed at high winds as expected in the presence of emissive foam, but that the foam effect is less than previously modeled. Given the large noise on individual SMOS measurements, a precision suitable for oceanographic studies can only be achieved after averaging SMOS SSS. Over selected regions and after mean bias removal, the precision on SSS retrieved from ascending orbits and averaged over 100 km × 100 km and 10 days is between 0.3 and 0.5 pss far from land and sea ice borders. These results have been obtained with forward models not fitted to satellite L-band measurements, and image reconstruction and instrument calibration are expected to improve. Hence, we anticipate that deducing, from SMOS measurements, SSS maps at 200 km × 200 km, 10 days resolution with an accuracy of 0.2 pss at a global scale is not out of reach.

Keywords: radiometry; interferometry; calibration; validation; imaging; radio frequency interference; ocean salinity; soil moisture; pixel disaggregation; GNSS-R; SMOS

This work summarizes the activities carried out by the SMOS (Soil Moisture and Ocean Salinity) Barcelona Expert Center (SMOS-BEC) team in conjunction with the CIALE/Universidad de Salamanca team, within the framework of the European Space Agency (ESA) CALIMAS project in preparation for the SMOS mission and during its first year of operation. Under these activities several studies were performed, ranging from Level 1 (calibration and image reconstruction) to Level 4 (land pixel disaggregation techniques, by means of data fusion with higher resolution data from optical/infrared sensors). Validation of SMOS salinity products by means of surface drifters developed ad-hoc, and soil moisture products over the REMEDHUS site (Zamora, Spain) are also presented. Results of other preparatory activities carried out to improve the performance of eventual SMOS follow-on missions are presented, including GNSS-R to infer the sea state correction needed for improved ocean salinity retrievals and land surface parameters. Results from CALIMAS show a satisfactory performance of the MIRAS instrument, the accuracy and efficiency of the algorithms implemented in the ground data processors, and explore the limits of spatial resolution of soil moisture products using data fusion, as well as the feasibility of GNSS-R techniques for sea state determination and soil moisture monitoring.

Keywords: Ebro Delta; foraging activity; foraging distribution; habitat use; marine birds; marine habitat; Mediterranean Sea; rice fields

A knowledge of the foraging strategies of marine predators is essential to understand the intrinsic factors controlling their distribution, abundance and their ecological function within the marine ecosystem. Here, we investigated for the first time the foraging movements and activity patterns of Audouin’s gull Larus audouinii by using satellite-tracking data from eight breeding adults in the main colony of the species worldwide (Ebro Delta, NW Mediterranean). Tagged gulls foraged in the marine area close to the breeding colony (62% of foraging locations) and in the terrestrial area of the Ebro Delta (mainly rice fields; 38% of foraging locations). The foraging activity patterns changed significantly throughout the day; lower from dusk through the first half of the night (19-1 h; 32% of active locations) and higher during the rest of the day (1–19 h; 75.5 ± 4.3% of active locations). These results confirm the foraging plasticity of this seabird and, based on previous information about the dietary habits of this species, we hypothesize how its time-dependent activity patterns and habitat use could be associated with variations in the availability of marine food resources (e.g. diel vertical migrations of pelagic fish) and the exploitation of terrestrial resources (e.g. American crayfish Procambarus clarkii).

Keywords: Ecological indicators; Ecopath with Ecosim; ecosystem approach; ecosystem traits; human impacts; Mediterranean Sea; trophic models

Ecological modelling tools are applied worldwide to support the ecosystem-based approach of marine resources (EAM). In the last decades, numerous applications were attempted in the Mediterranean Sea, mainly using the Ecopath with Ecosim (EwE) tool. These models were used to analyse a variety of complex environmental problems. Many applications analysed the ecosystem impacts of fishing and assessed management options. Other studies dealt with the accumulation of pollution through the food web, the impact of aquaculture or the ecosystem effects of climate change. They contributed to the scientific aspects of an ecosystem-based approach in the region because they integrated human activities within an ecosystem context and evaluated their impact on the marine food web, including environmental factors. These studies also gathered a significant amount of information at an ecosystem level. Thus, in the second part of this review, we used this information to quantify structural and functional traits of Mediterranean marine ecosystems at regional scales as the illustration of further potentialities of EwE for an EAM. Results highlighted differential traits between ecosystem types and a few between basins, which illustrate the environmental heterogeneity of the Mediterranean Sea. Moreover, our analysis evidenced the importance of top predators and small pelagic fish in Mediterranean ecosystems, in addition to the structural role of benthos and plankton organisms. The impact of fishing was high and of a similar intensity in the western, central and eastern regions and showed differences between ecosystem types. The keystone role of species was more prominent in protected environments.

Keywords: Microcosms – Food webs – Rock pools – Predator removal – Trophic cascade – Ecosystem functioning

Inverse trophic cascades are a well explored and common consequence of the local depletion or extinction of top predators in natural ecosystems. Despite a large body of research, the cascading effects of predator removal on ecosystem functions are not as well understood. Developing microcosm experiments, we explored food web changes in trophic structure and ecosystem functioning following biomass removal of top predators in representative temperate and tropical rock pool communities that contained similar assemblages of zooplankton and benthic invertebrates. We observed changes in species abundances following predator removal in both temperate and tropical communities, in line with expected inverse effects of a trophic cascade, where predation release benefits the predator’s preys and competitors and impacts the preys of the latter. We also observed several changes at the community and ecosystem levels including a decrease in total abundance and mean trophic level of the community, and changes in chlorophyll-a and total dissolved particles. Our results also showed an increase in variability of both community and ecosystem processes following the removal of predators. These results illustrate how predator removal can lead to inverse trophic cascades both in structural and functioning properties, and can increase variability of ecosystem processes. Although observed patterns were consistent between tropical and temperate communities following an inverse cascade pattern, changes were more pronounced in the temperate community. Therefore, aquatic food webs may have inherent traits that condition ecosystem responses to changes in top-down trophic control and render some aquatic ecosystems especially sensitive to the removals of top predators.

This thesis investigates physical-ecological and vortex-wave interactions through potential vorticity (PV) considering a stratified and oligotrophic ocean. To this end, a NPZ (Nutrients-Phytoplankton-Zooplankton) model is coupled to a physical one that conserves PV explicitly on isopycnals. The physical-ecological coupled model is initialized using stationary NPZ solutions numerically stable with the fluid at rest. These solutions are implemented homogeneous both on horizontal and isopycnals levels to quantify the effect of horizontal and vertical advection caused by mesoscale and submesoscale vortex structures, and isopycnal mixing. At the interior of the vortex separatrix, plankton and PV distributions translate in phase at vortex propagation speed. Within cyclones, isopycnal doming enhances plankton biomass at the vortex center in different trophic conditions. Furthermore, isopycnal mixing associated to small-scale motions maximizes the phytoplankton (P) biomass in cyclones through a resonant response between P and diffusive timescales. This P increase is significant in mesotrophic conditions and occurs where the vertical displacement of isopycnals is maximum, and hence where vertical gradients of PV are large. At the separatrix outer, horizontal and vertical advection are of the same order of magnitude than the ecological forcing and enhance P through different mechanisms. Firstly, vertical velocity w uplifts nutrients and P to better lit levels. P responds with some time lag to this perturbation and the associated increase in biomass occurs far from the upwelling location due to the action of horizontal advection. As a result, P correlates with w, and thus with horizontal gradients of PV, only at initial times. In the particular case of translating cyclones, this mechanism explains the development of a P trail at their wake. And secondly, the horizontal advection of a surface ecosystem patch by subsurface vortices decreases P self-shading at the patch front in benefit of P growth. Finally, interactions between vortex structures and pure inertial and gravity large amplitude waves are investigated. The advection of PV by waves causes vortices to be unsteady and modifies the upper and lower bounds of the wave frequency band. The advection of waves by vortices Doppler shifts the local wave frequency. When inertial waves are involved, a near-inertial right-handed helical wave is developed due to a non-linear interaction. As a result, total w increases one order of magnitude and correlates with horizontal gradients of PV. These results aim to shed further light on the ecological impact of long-lived coherent vortices in the open ocean.

Keywords: Arctic – Tipping points – Ecosystem – Non-linearity – Ice – Plankton

The Arctic marine ecosystem contains multiple elements that present alternative states. The most obvious of which is an Arctic Ocean largely covered by an ice sheet in summer versus one largely devoid of such cover. Ecosystems under pressure typically shift between such alternative states in an abrupt, rather than smooth manner, with the level of forcing required for shifting this status termed threshold or tipping point. Loss of Arctic ice due to anthropogenic climate change is accelerating, with the extent of Arctic sea ice displaying increased variance at present, a leading indicator of the proximity of a possible tipping point. Reduced ice extent is expected, in turn, to trigger a number of additional tipping elements, physical, chemical, and biological, in motion, with potentially large impacts on the Arctic marine ecosystem.

Keywords: Cory\'s shearwater feather corticosterone life history parental investment stress physiology trade-offs

Offspring of long-lived species should face costs of parental trade-offs that vary with overall energetic demands encountered by parents during breeding. If sex differences exist in how parents make the trade-off, sex-specific differences may exist in the contribution of each parent to those costs. Adaptations of offspring facing such costs are not well understood, but the hormone corticosterone probably plays a role. We manipulated breeding effort in Cory\'s shearwaters (Calonectris diomedea) to increase costs to offspring and used an integrated measure of corticosterone from chick feathers to investigate how experimental variation in parental investment influences offspring physiology. Average foraging trip duration and foraging efficiency (FE) of breeding pairs were not related to chick corticosterone, but sex biases in FE were. Adult male investment was more strongly related to chick corticosterone than was female investment. Importantly, we show for the first time suppression of adrenocortical activity in nestling Procellariiform seabirds, and explain how our results indicate an adaptive mechanism invoked by chicks facing increased costs of parental trade-offs.

Keywords: Northern-Central Adriatic Sea; trophic models; Ecopath with Ecosim; Ecospace; fisheries management; marine protected areas (MPA)

We examined various fishing management options to recover exploited marine resources and ecosystems of the Northern-Central Adriatic Sea. Dynamic simulations were based on a spatial ecological model previously calibrated with time series of data. Scenarios regarding spatial management were evaluated with the establishment of two marine protected areas, respectively, in the Pomo pit and the northern region. In addition, three temporal simulations of temporary closures and overall reduction of fishing effort of demersal and pelagic fleets (bottom, mid-water trawls and purse seines) were also considered. Simulations were run for 45 years (1975 – 2020), including the calibration period (1975–2002), and changes in biomass and catch of marine resources were analyzed. Our results confirm that current fishing management in the Adriatic Sea does not have clear beneficial impacts for the recovery of exploited resources, which will remain depleted in 2020 if “business as usual” continues. Simulations of alternative management suggest that both protected areas could be beneficial for fish population recovery predicting an increase in the biomass of commercial fish and predatory organisms. Simulations of temporary closures and overall reduction of fishing effort also show significant benefits for several commercial resources. We argue that both management measures may be effective tools to recover exploited ecosystems of the Northern-Central Adriatic Sea and halt the decline of marine resources.

Keywords: Microalgae – Dinoflagellates – Raphidophytes – Lipids – Biofuel – Triacylglycerols

Two different strains of microalgae, one raphidophyte and one dinoflagellate, were tested under different abiotic conditions with the goal of enhancing lipid production. Whereas aeration was crucial for biomass production, nitrogen deficiency and temperature were found to be the main abiotic parameters inducing the high-level cellular accumulation of neutral lipids. Net neutral lipid production and especially triacylglycerol (TAG) per cell were higher in microalgae (>200% in Alexandrium minutum, and 30% in Heterosigma akashiwo) under treatment conditions (25°C; 330 μM NaNO3) than under control conditions (20°C; 880 μM NaNO3). For both algal species, oil production (free fatty acids plus TAG fraction) was also higher under treatment conditions (57 mg L−1 in A. minutum and 323 mg L−1 in H. akashiwo). Despite the increased production and accumulation of lipids in microalgae, the different conditions did not significantly change the fatty acids profiles of the species analyzed. These profiles consisted of saturated fatty acids (SAFA) and polyunsaturated fatty acids (PUFA) in significant proportions. However, during the stationary phase, the concentrations per cell of some PUFAs, especially arachidonic acid (C20:4n6), were higher in treated than in control algae. These results suggest that the adjustment of abiotic parameters is a suitable and one of the cheapest alternatives to obtain sufficient quantities of microalgal biomass, with high oil content and minimal changes in the fatty acid profile of the strains under consideration.

Harmful algal blooms (HABs) are recurring events in Mediterranean coastal waters and can affect either large or smaller, more localized areas. HABs pose a threat to human health, marine ecosystems, and resources such as tourism, fisheries, and aquaculture. While some of the contributions of human activities to the recent increase in HAB incidence have been recognized, the exact causes of these blooms are still under debate. The present chapter provides an up-to-date and integrated perspective on harmful and toxic phytoplankton blooms in the Mediterranean Sea (MS), especially in relation to the human impacts and habitat changes that have occurred there during the past few decades. The earlier conceptual model of the MS described an oligotrophic sea with low values of phytoplankton biomass with a modest increase of biomass during seasonal phytoplankton blooms (late winter early spring) or in spatial structures as fronts, cyclonic gyres or in the deep chlorophyll maximum. Thus there was a low probability of high biomass bloom occurrence and maintenance in offshore waters. Based on our current knowledge of HABs, in coastal nearshore waters and in specific “hot spots,” the levels of nutrient availability, phytoplankton abundance, and harmful algal species are recognized as being much higher than in open waters. The contemporary conceptual model takes into account the frequent small-scale and localized proliferations of microalgae in the coastal nearshore waters. Coastal HABs in the MS are diverse, highly localized, and either recur annually or emerge in a seemingly arbitrary manner, without a defined pattern. They may be of short duration (2 or 3 weeks) or prolonged (up to 2 months) depending on several factors which, individually or collectively, influence bloom dynamics. Thus, blooms are diverse and in some cases non-predictable. Seasonality is not a constant feature; while most blooms occur in the summer they may also appear in winter. Both the damage caused by these blooms and the lack of a clear understanding of their occurrence underline the importance of establishing appropriate monitoring systems to gain the knowledge needed to implement preventative as well as prophylactic measures aimed at impeding these outbreaks. Finally, we discuss the possible causes of the blooms in relation the human activities and habitat changes that have occurred in the MS coastal areas during the last few decades. An anthropogenic forcing of bloom increase can be specifically related to the modification of the MS natural coastline and a subsequent increase in the number and size of areas of confined water. This has been occurred mainly in the northern basin. The information will contribute to a more thorough assessment of the impacts of HABs on the ecosystems of the MS and thus what, if anything, can be done to alleviate these impacts.

Keywords: Oceanographic discontinuities; Depth distribution; mtDNA; Glaciations; Population structure

Comparative multispecies studies allow contrasting the effect of past and present oceanographic processes on phylogeographic patterns. In the present study, a fragment of the COI gene was analyzed in seven decapod crustacean species from five families and with different bathymetric distributions. A total of 769 individuals were sampled along the Atlantic–Mediterranean transition area in order to test the effect of three putative barriers to gene flow: Strait of Gibraltar, Almeria–Oran Front and Ibiza Channel. A significant effect of the Strait of Gibraltar was found in the crabs Liocarcinus depurator and Macropipus tuberculatus. The Ibiza Channel had a significant effect for L. depurator. However, the Almeria–Oran front was not found to have a significant effect on any of the studied species. Higher levels of population structure were found in shallow-water species, although the number of species sampled should be increased to obtain a conclusive pattern. The haplotypes within the different species coalesced at times that could be related with past climatic events occurring before, during and after the last glacial maximum. Given the large diversity of phylogeographic patterns obtained within decapods, it is concluded that both historical and contemporary processes (marine current patterns, bathymetry and life-history traits) shape the phylogeographic patterns of these crustaceans.

A global alternative mix to fossil fuels is proposed,based on proven renewable energy technologies that do not use scarce materials. The mix consists of a combination of on shore and off shore wind turbines, concentrating solar power stations, hydroelectricity and wave power devices attached to the off shore turbines. Solar photo voltaic power could contribute to the mix if its dependence on scarce materials is solved. The most adequate deployment areas for the power stations are studied,as well as the required space. Material requirements are studied for the generation,power transport and for some future transport systems. The order of magnitude of copper, aluminium, neodymium, lithium, nickel, zincand platinum that may be required for the proposed solution is obtained and compared with available reserves.Overall,the proposed global alternative to fossil fuels seems technically feasible. However, lithium, nickel and platinum could be come limiting materials for future vehicles fleet if no global recycling systems were implemented and rechargeable zinc–air batteries would not be developed;60% of the current copper reserves would have to be employed in the implementation of the proposed solution. Altogether, they may become along-term physical constraint, preventing the continuation of the usual exponential growth of energy consumption

The gorgonian Eunicella singularis (Esper, 1794) is abundant on rocky bottoms at Cap de Creus (42°18′49″ N; 003°19′23″ E) in the western Mediterranean, and this study compared zooxanthellate colonies from relatively shallow depths with azooxanthellate colonies living at depths to 60 m. The goal was to determine the taxonomic status of a previously described subspecies, E. singularis aphyta. Sampling at 10-m intervals from 20 to 60 m using scuba or a remotely operated vehicle (ROV) in 2004 and 2010 allowed examination of colony shape, sclerite variability, genetic variability, and the presence/absence of zooxanthellae. Two morphotypes were identified: a shallow morphotype with candelabra-like colonies at 20–30 m has zooxanthellae, while a deep morphotype with more ramified colonies at 40–60 m lacks symbionts. Sclerite differences among colonies were also identified along the depth gradient. The mitochondrial marker msh1 did not discriminate between the two morphotypes and indeed did not discriminate among several Mediterranean species of Eunicella. Other genetic markers will be needed to firmly establish the taxonomic status of the two depth-related morphotypes. Electronic supplementary material The online version of this article (doi:10.1007/s00227-012-1928-3) contains supplementary material, which is available to authorized users.

The annual gonad development of a shallow (20 m depth) population of the Mediterranean gorgonian Eunicella singularis was found to be closely synchronized with that of a deep (60 m depth) population, but differences were observed in the gonadal output, with the shallow population producing more and larger sexual products. Lipid content in the shallow population showed a marked seasonality, peaking during summer. In contrast, lipid content remained persistently lower in the deep population. Fatty acids as well as C/N composition were also seasonal in the shallow population and more constant in the deep one. The isotopic composition (δ15N and δ13C) of the shallow colonies was similar to values observed for passive suspension feeders with symbiotic algae, whereas the deep colonies exhibited values similar to those of aposymbiotic passive suspension feeders that primarily feed on microzooplankton and particulate organic matter. These results highlight the importance of considering the depth-related variability among populations in order to achieve a better understanding of the ecology of sessile benthic suspension feeders. Electronic supplementary material The online version of this article (doi:10.1007/s00338-012-0904-1) contains supplementary material, which is available to authorized users.

Keywords: Error correction, interferometer, radiometer, remote sensing, sea surface salinity, Soil Moisture and Ocean Salinity (SMOS).

The Soil Moisture and Ocean Salinity (SMOS) mission was launched on November 2nd, 2009 aiming at providing sea surface salinity (SSS) estimates over the oceans with frequent temporal coverage. The detection and mitigation of residual instrumental systematic errors in the measured brightness temperatures are key steps prior to the SSS retrieval. For such purpose, the socalled ocean target transformation (OTT) technique is currently used in the SMOS operational SSS processor. In this paper, an assessment of the OTT is performed. It is found that, to compute a consistent and robust OTT, a large ensemble of measurements is required. Moreover, several effects are reported to significantly impact the OTT computation, namely, the apparent instrument (temporal) drift, forward model imperfections, auxiliary data (used by forward model) uncertainty and external error sources, such as galactic noise and Sun effects (among others). These effects have to be properly mitigated or filtered during the OTT computation, so as to successfully retrieve SSS from SMOS measurements.

Keywords: Microwave, radiometer, roughness, salinity, sea surface, Soil Moisture and Ocean Salinity (SMOS).

A prerequisite for the successful retrieval of geophysical parameters from remote sensing measurements is the development of an accurate forward model. The European Space Agency Soil Moisture and Ocean Salinity (SMOS), carrying onboard an L-band interferometric radiometer (Microwave Interferometric Radiometer using Aperture Synthesis), was launched on November 2009. Due to the lack of L-band passive ocean measurements from space, several prelaunch forward models were developed and initially used in the SMOS ocean salinity operational processor. In this paper, an update of the prelaunch semi-empirical forward model is presented, using for the first time, real SMOS data. In particular, the ocean surface emissivity modulation at L-band due to rough sea surface is reviewed and reanalyzed. A new model definition is provided with the help of a simple neural network. The improvement is quantified in terms of retrieved salinity accuracy compared with the climatology and concerns essentially the range of wind speeds higher than 12 m · s−1.

Keywords: Dimethylsulfide; DMS; Dimethylsulfoniopropionate; DMSP; Antarctic Peninsula; Palmer Station

The rate of gross biological dimethylsulfide (DMS) production at two coastal sites west of the Antarctic Peninsula, off Anvers Island, near Palmer Station, was estimated using a diagnostic approach that combined field measurements from 1 January 2006 through 1 March 2006 and a one-dimensional physical model of ocean mixing. The average DMS production rate in the upper water column (0–60 m) was estimated to be 3.1±0.6 nM d−1 at station B (closer to shore) and 2.7±0.6 nM d−1 at station E (further from shore). The estimated DMS replacement time was on the order of 1 d at both stations. DMS production was greater in the mixed layer than it was below the mixed layer. The average DMS production normalized to chlorophyll was 0.5±0.1 (nM d−1)/(mg m−3) at station B and 0.7±0.2 (nM d−1)/(mg m−3) at station E. When the diagnosed production rates were normalized to the observed concentrations of total dimethylsulfoniopropionate (DMSPt, the biogenic precursor of DMS), we found a remarkable similarity between our estimates at stations B and E (0.06±0.02 and 0.04±0.01 (nM DMS d−1)/(nM DMSP), respectively) and the results obtained in a previous study from a contrasting biogeochemical environment in the North Atlantic subtropical gyre (0.047±0.006 and 0.087±0.014 (nM DMS d−1)/(nM DMSP) in a cyclonic and anticyclonic eddy, respectively). We propose that gross biological DMS production normalized to DMSPt might be relatively independent of the biogeochemical environment, and place our average estimate at 0.06±0.01 (nM DMS d−1)/(nM DMSPt). The significance of this finding is that it can provide a means to use DMSPt measurements to extrapolate gross biological DMS production, which is extremely difficult to measure experimentally under realistic in situ conditions.

Ocean acidification may have severe consequences for marine ecosystems; however, assessing its future impact is difficult because laboratory experiments and field observations are limited by their reduced ecologic complexity and sample period, respectively. In contrast, the geological record contains long-term evidence for a variety of global environmental perturbations, including ocean acidification plus their associated biotic responses. We review events exhibiting evidence for elevated atmospheric CO2, global warming, and ocean acidification over the past ~300 million years of Earth’s history, some with contemporaneous extinction or evolutionary turnover among marine calcifiers. Although similarities exist, no past event perfectly parallels future projections in terms of disrupting the balance of ocean carbonate chemistry—a consequence of the unprecedented rapidity of CO2 release currently taking place.

Keywords: Alexandrium minutum; Karlodinium veneficum; Heterosigma akashiwo; Pilot plant photobioreactor; Life cycle assessment; Energy balance

A life cycle assessment (LCA) and an energy balance analysis of marine microalgal biomass production were conducted to determine the environmental impacts and the critical points of production for large scale planning. The artificial lighting and temperature conditions of an indoor bubble column photobioreactor (bcPBR) were compared to the natural conditions of an equivalent outdoor system. Marine microalgae, belonging to the dinoflagellate and raphidophyte groups, were cultured and the results were compared with published LCA data obtained from green microalgae (commonly freshwater algae). Among the species tested, Alexandrium minutum was chosen as the target marine microalgae for biomass production under outdoor conditions, although there were no substantial differences between any of the marine microalgae studied. Under indoor culture conditions, the total energy input for A. minutum was 923 MJ kg−1 vs. 139 MJ kg−1 for outdoor conditions. Therefore, a greater than 85% reduction in energy requirements was achieved using natural environmental conditions, demonstrating the feasibility of outdoor culture as an alternative method of bioenergy production from marine microalgae. The growth stage was identified as the principal source of energy consumption for all microalgae tested, due to the electricity requirements of the equipment, followed by the construction material of the bcPBR. The global warming category (GWP) was 6 times lower in outdoor than in indoor conditions. Although the energy balance was negative under both conditions, this study concludes with suggestions for improvements in the outdoor system that would allow up-scaling of this biomass production technology for outdoor conditions in the Mediterranean.

Keywords: Phagotrophy · Protists · Mixotrophic algae · Grazing rates · Wetland · Light ­attenuation

We examined the effect of light attenuation, due to floating plants, on the community structure of the main phagotrophic protists and their grazing rates in a wetland in the Lower Paraná Basin. Ingestion experiments (winter and summer) were conducted at 2 sites in the same shallow lake that had contrasting light scenarios: open waters (light) and under profuse macrophyte coverage (dark: light attenuation ~97%). We compared the rates at which protists ingested 3 types of tracer prey: fluorescently labelled heterotrophic bacteria (FLB), picocyanobacteria (FLC) and picoeukaryotic algae (FLA). Light influenced both the structure of the microbial communities and the protistan grazing rates. Heterotrophic flagellates (HF) were more abundant under the macrophytes, whereas mixotrophic algae (cryptophytes) and autotrophic and heterotrophic picoplankton populations attained higher abundances in open waters. Specific grazing rates (SGRs) of mixotrophs on heterotrophic bacteria (HB) were higher in the light (7.9 to 15.5 prey cells grazer−1 h−1), than in darkness (0.1 to 5.1 prey cells grazer−1 h−1); the same trend was observed on picocyanobacteria (Pcy) (1.1 and 0.2 prey cells grazer−1 h−1, light and dark). SGRs of HF were 1.0 to 7.3 cells grazer−1 h−1 (on HB) and 0.01 to 1.8 prey cells grazer−1 h−1 (on Pcy), with highest values in summer and no pattern in relation to light. SGRs of ciliates were higher in summer and in darkness. Clearance rates (CR) on Pcy were higher than on HB, for both HF and mixotrophic algae. In winter, cryptophytes contributed up to 93% of the microbial grazing in the light, whereas HF were more important in darkness; in summer, bacterivory was dominated by heterotrophs in both light scenarios. Our experimental results highlight the importance of light conditions in structuring bacterial grazing by protists.

Keywords: Inundation; Erosion; Vulnerability; Beaches

The temporal and spatial patterns of storm-induced damage along the Catalan coast (NW Mediterranean) during the last 50 years have been analyzed to identify main climatic and non-climatic forcings. In the absence of systematic data, a storm-induced damage database compiled from press news has been built, which together with an intensity scale has allowed us to characterize the frequency and intensity of damage. Although no temporal trend has been detected in storm-induced hazards, coastal damage has increased at a rate of about 40% per decade during the last 50 years along the Catalan coast. The main non-climatic factors identified controlling this trend were the urban growth along the coastal fringe and the generalized erosive behavior of beaches. The first one increased values at risk and the second one increased their exposure to storm-induced hazards. In spite of the importance of non-climatic factors to modulate coastal damage, an exponential dependence of damages on storm-induced inundation and erosion was detected. In addition to this, storm-induced geomorphic changes along the Ebro delta coast have also been analyzed. During the period analyzed, “harmful” storms seem to be clustered, with most of the events being present in the late 1990s and especially from 2001 to 2004, resulting in frequent events of intense beach/barrier breaching, massive overwash and flooding. They are mainly expressed in sensitive areas which are subject to long-term erosional processes and comprise a low-lying profile and a narrow beach. This reflects the role of coastal morphology in controlling the intensity of storm-induced hazards along the deltaic coast. Shoreline evolution rates calculated during this period were significantly larger than the previously recorded ones, reflecting a pulsating erosion behavior where large pulses occur during stormy periods and are reduced during post-storm periods. Under the present scenario of maximum coastal development, storm-induced damage has been reported almost every year which could indicate that the present overall beach configuration status along the Catalan coast has reached its limit for protecting the hinterland against storms

Keywords: Cytochrome P450 (CYP); Biotransformation; Polychlorobiphenyl (PCB); Bioaccumulation; Fish; Crustacea

Variations in cytochrome P450 enzyme (CYPs) distribution and function between animal groups could result in differential metabolism and elimination kinetics for certain contaminants. Although a number of studies have suggested that differences in polychlorobiphenyl (PCB) accumulation profiles between crustacea and fish might result from differential CYP patterns, the relationship between PCB bioaccumulation and CYP capacities has not been demonstrated in these organisms. In the present study we investigated the hepatic microsomal catalytic activities in three deep-sea fish species, Alepocephalus rostratus (Alepocephalidae), Coelorinchus mediterraneus (Macrouridae), and Lepidion lepidion (Moridae), and the decapod crustacean Aristeus antennatus (Decapoda), using six fluorescent CYP-mediated substrates, namely ER (7-ethoxyresorufin), PR (7-pentoxyresorufin), BR (7-benzyloxyresorufin), CEC (3-cyano-7-ethoxycoumarin), DBF (dibenzylfluorescein) and BFC (7-benzyloxy-4-trifluoromethylcoumarin). Furthermore, we related the metabolic activities to the accumulation patterns of 41 PCB congeners in the muscle of these organisms. The results indicated a marked difference in the presence and activities of CYP isoforms between fish and the crustacean A. antennatus. Liver microsomes of the three selected fish species were capable of metabolizing all six CYP-mediated substrates and enzymes were identified as primarily belonging to CYP1A and CYP3A subfamilies. In contrast, hepatopancreas microsomes from A. antennatus only showed activity for PR and DBF substrates, generally related to mammalian CYP2-like enzymes. Furthermore, a direct relationship between metabolic activities and PCB accumulation profiles could be established. Results revealed that A. antennatus accumulated significantly higher proportions of PCBs 28, 52, 118, 138, 158 and 169 than fish, which is in accordance with the previously observed lack of CYP1A-like biotransformation capacities. Moreover, A. antennatus exhibited lower levels of PCBs 87, 149, 153, 170, 180, 183, 194 and 206 indicating that this crustacean is able to metabolize congeners considered mammalian CYP2B inducers. Hence, the present findings highlight the role of CYP-mediated metabolism in the congener-specific accumulation of PCBs in aquatic organisms and stress the need to further investigate quantitative and qualitative differences in xenobiotic metabolism among animal groups.

Keywords: Corallium rubrum; marine protected areas; Mediterranean Sea; overfishing; poaching; scuba-diving effects

Although the rapid recovery of fishes after establishment of a marine reserve is well known, much less is known about the response of long-lived, sessile, benthic organisms to establishment of such reserves. Since antiquity, Mediterranean red coral (Corallium rubrum) has been harvested intensively for use in jewelry, and its distribution is currently smaller than its historical size throughout the Mediterranean Sea. To assess whether establishment of marine reserves is associated with a change in the size and number of red coral colonies that historically were not harvested sustainably, we analyzed temporal changes in mean colony diameter and density from 1992 to 2005 within red coral populations at different study sites in the Medes Islands Marine Reserve (established in 1992) and in adjacent unprotected areas. Moreover, we compared colony size in the Medes Islands Marine Reserve, where recreational diving is allowed and poaching has been observed after reserve establishment, with colony size in three other marine protected areas (Banyuls, Carry-le-Rouet, and Scandola) with the enforced prohibition of fishing and diving. At the end of the study, the size of red coral colonies at all sampling sites in the Medes Islands was significantly smaller than predicted by growth models and smaller than those in marine protected areas without fishing and diving. The annual number of recreational dives and the percent change in the basal diameter of red coral colonies were negatively correlated, which suggests that abrasion by divers may increase the mortality rates of the largest red coral colonies within this reserve. Our study is the first quantitative assessment of a poaching event, which was detected during our monitoring in 2002, inside the marine reserve. Poaching was associated with a loss of approximately 60% of the biomass of red coral colonies.

Keywords: quasi-extended optimum multiparameter analysis, water masses, oxygen minimum zone, Humboldt Current System.

The Humboldt-09 cruise covered a narrow meridional band along the Chilean continental slope (44–23º S). Here we use physical and biochemical data from a long meridional section (4000 km) and three short zonal sections (100 km) to describe the distribution of the different water masses found in this region. Six water masses were identified: Subantarctic Water (SAAW), Summer Subantarctic Water (SSAW), Subtropical Water (STW), Equatorial Subsurface Water (ESSW), Antarctic Intermediate Water (AAIW), and Pacific Deep Water (PDW). For the first time, a novel set of source water mass properties (or water types) is introduced for SSAW, and nutrient and dissolved oxygen water types are proposed for all the water masses. Optimum multiparameter (OMP) analysis was used through an iterative process to obtain a sound definition of the water types that minimizes the residuals of the method. Both the classic OMP and the quasi-extended OMP models reproduced the data rather well. Finally, the spatial distribution of the different water masses was calculated with the quasi-extended OMP, which is not influenced by the respiration of organic matter. The distribution of the different water masses is presented over the meridional and zonal transects and in property-property diagrams. A smooth meridional transition from subantarctic to tropical and equatorial water masses is observed in this area. This transition takes place in surface, central, and intermediate waters over distances of the order of 1000 km. The meridional transition contrasts with the abrupt zonal changes found in the cross-slope direction, which are of comparable magnitude but over distances of the order of 100 km. Both AAIW and SAAW (fresh and well oxygenated) partially mix with the hypoxic ESSW and, therefore, play an important role in the ventilation of the southern part of the oxygen minimum zone.

This study investigates the connections between climate fluctuations and sardine and anchovy production in the NW Mediterranean, taking the Western Mediterranean Oscillation index (WeMOi) as an indicator of climate variability. The basic working hypothesis is that sardine and anchovy productivity is influenced by the WeMOi, a proxy for the local environmental conditions such as sea surface temperature (SST) and river runoff. Sardine and anchovy landings (1974–2009) in the Catalan Coast and landings per unit of effort (LPUE) were used as proxy for recruitment. The results demonstrated a clear link between climate fluctuations and sardine and anchovy production. Positive WeMOi values were significantly correlated with low SST, high river runoff and high LPUE, that is, with better-than-average recruitment of sardine and anchovy. Conversely, negative WeMOi values were associated with high SST, low river runoff and low LPUE. During the negative WeMOi phases (such as that at the end of the analyzed period), environmental conditions are unfavourable for the overall biological productivity in the NW Mediterranean and would decrease the survival, growth, condition and reproduction of sardine and anchovy during their life cycle. Despite the evidences on the appropriateness of the NAOi as an indicator of the climate in Europe and its impact on some biological variables, we suggest that using a regional index, such as the WeMOi, can provide a more accurate representation of the environmental conditions affecting small pelagic fish production in the NW Mediterranean.

Carbon dioxide and coupled CO2 and O2-driven compromises to marine life were examined along the Chilean sector of the Humboldt Current System, a particularly vulnerable hypoxic and upwelling area, applying the Respiration index (RI = log10 pO2 pCO2 ) and the pH-dependent aragonite saturation () to delineate the water masses where aerobic and calcifying organisms are stressed. As expected, there was a strong negative relationship between oxygen concentration and pH or pCO2 in the studied area, with the subsurface hypoxic Equatorial Subsurface Waters extending from 100m to about 300m depth and supporting elevated pCO2 values. The lowest RI values, associated to aerobic stress, were found at about 200m depth and decreased towards the Equator. Increased pCO2 in the hypoxic water layer reduced the RI values by as much as 0.59 RI units, with the thickness of the upper water layer that presents conditions suitable for aerobic life (RI>0.7) declining by half between 42 S and 28 S. The intermediate waters hardly reached those stations closer to the equator so that the increased pCO2 lowered pH and the saturation of aragonite. A significant fraction of the water column along the Chilean sector of the Humboldt Current System suffers from CO2–driven compromises to biota, including waters corrosive to calcifying organisms, stress to aerobic organisms or both. The habitat free of CO2-driven stresses was restricted to the upper mixed layer and to small water parcels at about 1000m depth. Overall pCO2 acts as a hinge connecting respiratory and calcification challenges expected to increase in the future, resulting in a spread of the challenges to aerobic organisms.

Keywords: L-band radiometry, satellite remote sensing, sea surface salinity, soil moisture, Soil Moisture and Ocean Salinity (SMOS) mission.

The European Space Agency’s Soil Moisture and Ocean Salinity (SMOS) mission was launched on the 2nd of November 2009. The first six months after launch, the so-called commissioning phase, were dedicated to test the functionalities of the spacecraft, the instrument, and the ground segment including the data processors. This phase was successfully completed in May 2010, and SMOS has since been in the routine operations phase and providing data products to the science community for over a year. The performance of the instrument has been within specifications. A parallel processing chain has been providing brightness temperatures in near-real time to operational centers, e.g., the European Centre for Medium-Range Weather Forecasts. Data quality has been within specifications; however, radiofrequency interference (RFI) has been detected over large parts of Europe, China, Southern Asia, and the Middle East. Detecting and flagging contaminated observations remains a challenge as well as contacting national authorities to localize and eliminate RFI sources emitting in the protected band. The generation of Level 2 soil moisture and ocean salinity data is an ongoing activity with continuously improved processors. This article will summarize the mission status after one year of operations and present selected first results.

The ESA/SMOS (European Space Agency/Soil Moisture and Ocean Salinity) satellite mission provides new measurements of Sea Surface Salin-ity (SSS) using L-band radiometry. After correcting SMOS brightness temperatures from systematic biases, SMOS sea surface salinity (SSS) reproduces quite well large scale expected SSS variations *Font et al., 2012+. At L-band frequency, the skin depth is 1 centimetre while most in situ SSS measurements are taken at a few meters depth. A preliminary study based on ARGO vertical profiles *Henocq et al., 2010+ indicated that vertical salinity differences between 1m and 10m depth higher than 0.1 psu are observed in the 3 oceans, mainly between 0° and 15°N, coinciding with the average position of the Inter Tropical Conver-gence Zones characterized by high precipitation rates. In order to better document the variability of salinity near the sea surface, which is currently not often measured by other in situ observa-tions (current Argo uppermost data is between 5 and 10m depth, whereas TAO-type measurements are near 1 or 2m depth), surface drifters have been equipped with Conductivity-Temperature (C-T) cells near a depth of 50 cm, which proved reliable for mid-latitude deployments *Reverdin et al., 2007+. Since then, two manufacturers of SVP (Surface Velocity Program) drifters, Metocean and the Pacific Gyre have instru-mented SVP drifters with sensors measuring conductivity at 30-50cm depth. In addition, new light floats named SURPLAS have been built at LOCEAN laboratory to measure conductivity at 15cm depth for a duration of a few weeks to a few months. SURPLAS floats have been tied to SVP drifters allowing the study of the SSS and SST (Sea Surface Temperature) stratification between 15cm and 50cm depth. In addition, ICM/CSIC has buit slightly larger drifters with C-T cells also near 50 cm depth, but without an anti-fouling protection of the cell. The sampling char-acteristics of the different drifters are slightly different. The SURPLAS drifter provides a value (average over 8”) every 15 minutes of T (Temperature) and S (Salinity); the Pacificgyre SVP-BS drifter, a value every 30 minutes (average over 5 minutes), the Metocean SVP-BS drift-er, a value every hour (average of 7 values over 10 minutes), and the ICM/CISC provide values at the time of Argos transmissions (not aver-aged). Most of the drifters and floats transmit through Argos, although Metocean drifters since 2009 mostly transmit data (and a 3-hourly gps position) through iridium communication. Since 2007, we deployed 37 Metocean SVP-BS drifters, 29 Pacificgyre drifters, 21 ICM/CSIC drifters and 17 surplas floats. In 2010 and 2011, simultaneous to the first two years of SMOS measurements, 68 SVP drifters (49 Metocean and PacificGyre and 19 ICM drifters) and 13 SUR-PLAS floats have been deployed by the French and Spanish teams involved in the SMOS Cal/Val projects mostly in the North Atlantic, in the Bay of Biscay, in the equatorial and subtropical South Atlantic and in the western tropical and equatorial Pacific Ocean. Altogether in 2010-2011, they recorded measurements during 13500 days (Metocean+PacificGyre 8821, Surplas 472, ICM 4266). In this paper, we will first comment on the data return of these drifters, on our efforts to quality control and correct the data. Then, we will summarize results on tropical SSS freshening events linked to rain events as recorded at various depths by autonomous drifters and as de-duced from the SMOS radiometer measurements.

Keywords: Midwater fishes; Species assemblages; Diel vertical migration; Sound scattering layers; Myctophidae; Gonostomatidae; Sternoptichydae

The mesopelagic fish community of the western Mediterranean was studied during two cruises carried out in December 2009 and July 2010 in the shelf and slope zones around the Balearic Islands. Much of what was previously known about this deep water group of fishes in the Mediterranean Sea came from studies performed using planktonic and small midwater nets. This study was the first attempt to use large pelagic trawls and small nets combined with information about the main sound scattering layers to analyse mesopelagic fish composition, diversity and species assemblages. This community is characterised by a relatively low diversity compared to other oceanic regions of the world, with Myctophiformes and Stomiiformes being the main contributors. Bathymetry and the level of the water column were the most important factors structuring the investigated fish assemblages, and similar vertical patterns were observed for the different species collected during the two study periods. A shelf assemblage composed of a few species of myctophids, with Notoscopelus elongatus being the main contributor, was distinguished. The slope assemblage included both Myctophiformes and Stomiiformes that showed differences in their day–night main location along the water column. In terms of species behaviour, two important groups were detected. The first was non-migrant or weakly migrant species, with the paradigmatic example being the gonostomatid Cyclothone braueri, which occurred at a depth of 400–600 m; this species is partly responsible for the permanent acoustic (38 kHz) response at this depth. The second group, near-surface migrants at night, was represented by most of the juvenile and adult myctophids, exemplified by Ceratoscopelus maderensis, with the exception of just a few of the largest size classes of some species, such as Lampanyctus crocodilus and N. elongatus that remain near the bottom.

Keywords: Anchovy; Dispersion; Recruitment; Connectivity; IBM; Vertical migration; DVM; Schooling; Mediterranean; Gulf of Lions; Ebro Delta

Recruitment of European anchovy has been traditionally thought to largely depend on the passive transport and dispersion of eggs and larvae from spawning to nursery areas. Knowledge of the factors influencing the vertical distribution of fish early stages, and consequently influencing the transport, is a crucial issue in fisheries science. The aim of this study is to assess the relevance of diel vertical migration (DVM) as a mechanism involved in the transport of European anchovy larvae toward nursery areas taking into account age/stage-dependent vertical migration (i.e., the maximum migration). We developed a simplified vertical migration sub-model for anchovy larvae included in an Individual-based (IBM) hydrodynamic coupled model. Two types of simulation experiments were conducted: (1) ‘Pure’ Lagrangian (passive) transport experiments and (2) biological behavior transport experiments with a realistic scheme for egg-buoyancy, larval growth, and DVM scheme. We detected high variability in the trajectory and final position of larvae with 14 mm length between the passive and biological behavior experiments. The particles were less clustered in the passive transport experiment. In the biological experiment the particles were aggregated depending on the mesoscale oceanographic structures, evidencing a transport associated to filaments and meanders. The formation of schools was facilitated by the transport in filaments and larvae transported within filaments generally avoided the nucleus of the eddies and the central part of the North Current. Moreover, our results suggest that there is interconnectivity between all the anchovy sub-populations in the NW Mediterranean and that the Gulf of Lions and the shelf waters surrounding the Ebro River Delta are the most important areas for anchovy reproduction in this region. Additionally, we detected that the pre-recruitment is higher in those years when the larvae retention is favored. We underline that bottlenecks in larval transport modeling are related to the scarcity of knowledge in developmental biology and behavior of anchovy larvae and emergent mechanistic processes.

Keywords: Anchovy; Dispersion; Recruitment; Connectivity; IBM; Vertical migration; DVM; Schooling; Mediterranean; Gulf of Lions; Ebro Delta

Recruitment of European anchovy has been traditionally thought to largely depend on the passive transport and dispersion of eggs and larvae from spawning to nursery areas. Knowledge of the factors influencing the vertical distribution of fish early stages, and consequently influencing the transport, is a crucial issue in fisheries science. The aim of this study is to assess the relevance of diel vertical migration (DVM) as a mechanism involved in the transport of European anchovy larvae toward nursery areas taking into account age/stage-dependent vertical migration (i.e., the maximum migration). We developed a simplified vertical migration sub-model for anchovy larvae included in an Individual-based (IBM) hydrodynamic coupled model. Two types of simulation experiments were conducted: (1) ‘Pure’ Lagrangian (passive) transport experiments and (2) biological behavior transport experiments with a realistic scheme for egg-buoyancy, larval growth, and DVM scheme. We detected high variability in the trajectory and final position of larvae with 14 mm length between the passive and biological behavior experiments. The particles were less clustered in the passive transport experiment. In the biological experiment the particles were aggregated depending on the mesoscale oceanographic structures, evidencing a transport associated to filaments and meanders. The formation of schools was facilitated by the transport in filaments and larvae transported within filaments generally avoided the nucleus of the eddies and the central part of the North Current. Moreover, our results suggest that there is interconnectivity between all the anchovy sub-populations in the NW Mediterranean and that the Gulf of Lions and the shelf waters surrounding the Ebro River Delta are the most important areas for anchovy reproduction in this region. Additionally, we detected that the pre-recruitment is higher in those years when the larvae retention is favored. We underline that bottlenecks in larval transport modeling are related to the scarcity of knowledge in developmental biology and behavior of anchovy larvae and emergent mechanistic processes.

Keywords: European anchovy; Egg buoyancy; Egg density; Vertical distribution; Individual based model; IBM; CUFES

Small pelagic fish populations exhibit reproductive strategies resulting from past natural selection pressure, by which certain traits become more or less common in a population, allowing them to adapt and become better suited to certain habitats. One such adaptation is the buoyancy of eggs, which is observed as density changes during development. This is an important issue in fisheries and modeling science, as it affects the vertical distribution of eggs and, therefore, egg transport. Recently, individual-based models for anchovies in the Mediterranean have focused on developing adequate biological algorithms to simulate realistic spatial variations of eggs and larvae. Some models that include movements of particles according to Stokes’ law also assume a constant value of egg density during egg development. However, field observations show differences in the vertical distribution of eggs when egg density during development is considered. We address the problem of egg density and its vertical distribution within a biological context. In Mediterranean waters, the incubation time for anchovy eggs during peak spawning is approximately 48–70 h; during these first hours, egg density has an influence on the horizontal and vertical trajectories of eggs, as well as their routes and hatching zones. In this study, we introduce an algorithm describing the egg density of European anchovy eggs throughout development. Egg density measurements were carried out in a density gradient column (DGC). We fitted a polynomial model that estimated egg density, as a function of time from fertilization and that was dependent on temperature. Simulations to study the vertical transport of eggs in the Mediterranean were carried out using ICHTHYOP/MARS3D. The vertical distribution of pelagic eggs was determined by a set of interacting biological and physical parameters related to eggs (density, diameter) and ambient seawater (density, viscosity, turbulence), respectively. The egg buoyancy model introduced here was validated and will provide insight for the design of anchovy egg surveys, as the vertical position of the eggs in the water column during development can be inferred by the hydrographic structure of seawater.

Keywords: análisis multiparamétrico óptimo, Atlántico Subtropical Noreste, aguas centrales, aguas intermedias, aguas profundas

Se aplicó un análisis multiparamétrico óptimo a un set de datos en el margen oriental del giro subtropical del Atlántico Norte, recogido en noviembre de dos años consecutivos y que se extiende entre las latitudes 16 y 36º N. El set de datos cubre unos 20º de latitud y tiene una buena resolución meridional y zonal en toda la región de transición costera. La contribución de seis tipos de agua es resuelta en el intervalo de densidad entre 100 y 2000 m. Entre los 100 y 700 m de profundidad, las aguas centrales del Atlántico Norte y Sur se encuentran abruptamente en el frente de Cabo Verde. Tradicionalmente se ha descrito que la posición de este frente se alarga desde cabo Blanco, a unos 21.5º N, hasta las islas de Cabo Verde, pero nuestras observaciones muestran que penetra hasta 24º N cerca del talud continental. Al sur de 21º N se encuentra una variedad de Agua Central Sudatlántica menos salina y más oxigenada, que adscribimos a aguas ecuatoriales menos diluidas. Entre los 700 y los 1500 m de profundidad el tipo de agua dominante es un tipo diluido de Agua Antártica Intermedia (AAIW), cuya influencia desaparece suavemente al norte de las islas Canarias al ser reemplazada por Agua Mediterránea (MW); en las latitudes donde ambas masas de agua coexisten se aprecia que el MW se sitúa aguas afuera mientras que el AAIW se coloca cercana al talud. El Agua Profunda Noratlántica domina por debajo de los 1300/1700 m al sur/norte de las islas Canarias; este cambio abrupto en profundidad sugiere la existencia de caminos diferentes para las aguas profundas que llegan a cada lado del archipiélago.

Keywords: Gymnodinium catenatum, algal bloom, toxicity, upwelling.

Gymnodinium bloom events are of concern, since they produce toxins, which have unfavorable consequences to marine ecosystems, human health and the economy. This report describes the physico-chemical conditions that were present during the algal bloom event on May 2010 in Bahía Manzanillo and Bahía Santiago, Colima, Mexico. For this, seawater nutrient analysis, phytoplankton counts, identification, and toxicity tests were undertaken. Nutrients in seawater were determined using colorimetric techniques, the higher concentrations (8.88μM DIN, 0.78μM PO4 and 24.34μM SiO2) were related with upwelling waters that promoted the algal bloom that began after registering the year lowest sea-surface temperature, favoring the rapid growth of G. catenatum (up to 1.02 x107cells/L). Phytoplankton counting was carried out using sedimentation chambers and cells enumerated on appropriated area. The bloom persisted in the bays for approximately two weeks and was associated with toxicity (determined with HPLC) in local oysters (1525.8μg STXeq/100g), and in phytoplankton (10.9pg STXeq/cells) samples. Strong variations in cell toxicity (1.4 to 10.9pg STXeq/cells), most likely reflected the availability of inorganic nutrients. The toxin profile of the phytoplankton samples consisted of 11 toxins and resembled those recorded for several strains of G. catenatum isolated from other coastal areas of Mexico. Rev. Biol. Trop. 60 (1): 173-186. Epub 2012 March 01.

Most marine sponges establish a persistent association with a wide array of phylogenetically and physiologically diverse microbes. To date, the role of these symbiotic microbial communities in the metabolism and nutrient cycles of the sponge-microbe consortium remains largely unknown. We identified and quantified the microbial communities associated with three common Mediterranean sponge species, Dysidea avara, Agelas oroides and Chondrosia reniformis (Demospongiae) that cohabitate coralligenous community. For each sponge we quantified the uptake and release of dissolved organic carbon (DOC) and nitrogen (DON), inorganic nitrogen and phosphate. Low microbial abundance and no evidence for DOC uptake or nitrification were found for D. avara. In contrast A. oroides and C. reniformis showed high microbial abundance (30% and 70% of their tissue occupied by microbes respectively) and both species exhibited high nitrification and high DOC and NH4+ uptake. Surprisingly, these unique metabolic pathways were mediated in each sponge species by a different, and host specific, microbial community. The functional convergence of microbial consortia found in these two sympatric sponge species, suggest that these metabolic processes may be of special relevance to the success of the holobiont.

Gorgonian species may contribute to the three-dimensional seascape in soft bottom-gravel areas, but the information on their biology and ecology is very scarce. The biometry and secondary production of the Mediterranean soft bottom-gravel passive suspension feeder Leptogorgia sarmentosa (Cnidaria: Octocorallia) was studied using photographic monitoring of the primary branches from May 1998 to September 2000. The primary branches observed had a high density of polyps (2.2 ± 0.2 SD polyps mm−1) and a high organic matter content (63.2 ± 9.1 SD %). During the two-year sampling period, there was a net negative growth in 90% of the gorgonian population. The mean loss during the 27-month period was −2.9 ± 0.9 SD cm per branch (5.7 mg C branch−1). However, considering only the initial and final diameters and maximum height in the 27 months elapsed time, the gorgonians showed positive growth, which meant that photographic sampling of single branches was a more appropriate method for gorgonian secondary production monitoring. A water mass anomaly detected in 1999 in the north-western Mediterranean Sea may have been the cause of the net negative growth in L. sarmentosa in the studied area. Partial mortality due to different factors, such as strong currents, predation, disease, etc., could be a common strategy in sessile colonial benthic populations that would facilitate their maintenance even during very stressful circumstances.

Two diel cycle studies were conducted to determine the effect of day–night light changes on winter bacterial activity in the coastal Mediterranean (Blanes Bay Microbial Observatory). Bacterial abundances, bacterial heterotrophic activity, and flagellate grazing counts were determined at 4-h intervals during two 3-d periods separated by 2 d. Twice a day, the single-cell activity of major bacterial groups was further analyzed by applying microautoradiography combined with catalyzed reporter deposition-fluorescence in situ hybridization. During the first cycle, all the measured parameters (including the number of active cells in most groups) varied synchronously, with higher values at night and lower during the day. An episode of strong winds between the two studied periods disrupted this periodicity at the onset of the second cycle. The bulk incorporation of 3H-leucine recovered the diel pattern after 2 d, mostly driven by the activity of Gammaproteobacteria. Among the possibilities considered, the observed nighttime increases in the grazing activity of heterotrophic nanoflagellates appeared to partially drive the activity of all bacterial taxa through potential periodic release of dissolved organic matter.

Historical exploitation of the Mediterranean Sea and the absence of rigorous baselines makes it difficult to evaluate the current health of the marine ecosystems and the efficacy of conservation actions at the ecosystem level. Here we establish the first current baseline and gradient of ecosystem structure of nearshore rocky reefs at the Mediterranean scale. We conducted underwater surveys in 14 marine protected areas and 18 open access sites across the Mediterranean, and across a 31-fold range of fish biomass (from 3.8 to 118 g m−2). Our data showed remarkable variation in the structure of rocky reef ecosystems. Multivariate analysis showed three alternative community states: (1) large fish biomass and reefs dominated by non-canopy algae, (2) lower fish biomass but abundant native algal canopies and suspension feeders, and (3) low fish biomass and extensive barrens, with areas covered by turf algae. Our results suggest that the healthiest shallow rocky reef ecosystems in the Mediterranean have both large fish and algal biomass. Protection level and primary production were the only variables significantly correlated to community biomass structure. Fish biomass was significantly larger in well-enforced no-take marine reserves, but there were no significant differences between multi-use marine protected areas (which allow some fishing) and open access areas at the regional scale. The gradients reported here represent a trajectory of degradation that can be used to assess the health of any similar habitat in the Mediterranean, and to evaluate the efficacy of marine protected areas.

Keywords: Biochemistry; Sediments; Macrofauna; Antarctica

Lipid, protein and carbohydrate concentrations have been determined in sediment cores from the continental shelf in the South Eastern Weddell Sea (SEWS), where no ice shelves have been present at least for thousands of years, and the continental shelf off the Eastern Antarctic Peninsula (EAP), in the area where two ice shelf collapses occurred in 1995 and 2002. On one hand, SEWS presents an important flux of fresh organic matter to the seabed during summer, whereas on the other hand, the presence of ice shelves in EAP hampered photosynthesis restricting the input of organic matter to advected refractory material. In the present study, biochemical variables and benthic macrofauna abundance, biomass and diversity confirmed differences between the two regions. Lipid concentrations were higher in SEWS than in EAP, whereas carbohydrate concentrations were higher in the latter region. These differences were attributed to the higher concentration of labile and refractory material, respectively. Biomass, abundance and diversity of the macrofauna were higher in SEWS than in EAP, where benthic communities started receiving a fresh organic matter input only after the recent ice shelf collapses. As regards macrofauna composition, both regions presented macrobenthic communities associated to early stages of recolonization.

Keywords: Dyspanopeus sayi, alien species, Mediterranean, Ebro Delta, mtDNA sequences, zoea

The panopeid crab Dyspanopeus sayi (Smith, 1869) is reported here from the Ebro Delta (Mediterranean coast of the Iberian Peninsula). Originally endemic to the Atlantic coast of North America, D. sayi was involuntarily introduced into Britain, France and the Netherlands, and into the Adriatic and Black Sea within the last thirty years. Here we provide the first record of this species from the western Mediterranean Sea. Occurrences of ovigerous females at different localities of the delta and in different years provide evidence that the population is well established. Mitochondrial DNA confirms the identity of the species and indicates that the introduced population consists of at least three female lineages. The first zoeal stage of D. sayi was obtained in the laboratory from an ovigerous female captured in August 2010 with embryos in an advanced stage of development. The morphology of the zoea I is described here in detail and is similar to the one previously reported for native populations.

Keywords: stable isotope, water, agriculture, invertebrates, irrigation pond.

Different factors can affect the isotopic values of aquatic organisms. Nevertheless, water quality may be very important for aquatic organisms because they directly depend on it. In this article, we aimed to investigate if variations in the chemical and biological water characteristics affect the stable isotope values of aquatic organisms. We also wished to discuss alternative sources of isotopic variability. We analysed the water chemical characteristics, the input of extra nitrates from bird guano, and the δ15N and δ13C values for the macroinvertebrates and macrophytes present in freshwater irrigation ponds. Variability in the values of the analysed stable isotopes was high, even for the same species in different ponds. Water conductivity, nitrates, ammonium, organic nitrogen concentrations and COD (Chemical Oxygen Demand) directly correlated with the isotopic values. Besides, the input of extra nitrates from Larids’ (gulls and terns) guano might also increase the δ15N values at the ponds which these birds most intensively use. Nevertheless, the high δ15N values are difficult to explain in terms of water characteristics and excrements inputs and only general processes of denitrification could explain these values. Longer water residence times could cause extremely enriched isotopic values in both DIC (Dissolved Inorganic Carbon) and dissolved nitrates. This study shows different sources of isotopic variability which can prove useful to interpret stable isotopes studies.

Keywords: Microbial respiration – Southeastern U. S. continental shelf – Dissolved oxygen – Bacteria

Respiratory rates on the U. S. southeastern continental shelf have been estimated several times by different investigators, most recently by Jiang et al. (Biogeochemistry 98:101–113, 2010) who report lower mean rates than were found in earlier work and attribute the differences to analytical error in all methods used in earlier studies. The differences are, instead, attributable to the differences in the geographical scope of the studies. The lower estimates of regional organic carbon flux of Jiang et al. (Biogeochemistry 98:101–113, 2010) are a consequence of their extrapolation of data from a small portion of the shelf to the entire South Atlantic Bight. This comment examines the methodologies used as well as the variability of respiratory rates in this region over space and time.

Keywords: Indicator – Ecosystem approach to fisheries – Ecosystem model – Fisheries management – Global comparison

This report summarizes the outcomes of an IndiSeas workshop aimed at using ecosystem indicators to evaluate the status of the world’s exploited marine ecosystems in support of an ecosystem approach to fisheries, and global policy drivers such as the 2020 targets of the Convention on Biological Diversity. Key issues covered relate to the selection and integration of multi-disciplinary indicators, including climate, biodiversity and human dimension indicators, and to the development of data- and model-based methods to test the performance of ecosystem indicators in providing support for fisheries management. To enhance the robustness of our cross-system comparison, unprecedented effort was put in gathering regional experts from developed and developing countries, working together on multi-institutional survey datasets, and using the most up-to-date ecosystem models.

Keywords: Characterization; Cholinesterases; Carboxylesterases Solea senegalensis; CYPs; Fluorimetric substrates

In fish, the role that cholinesterases (ChEs) play in tissues other than those implicated in neural activity, as well as the involvement of carboxylesterases (CbEs) and cytochrome P450 isoenzymes (CYPs) in drug metabolism needs investigation. For that, Senegalese sole (Solea senegalensis) specimens were selected for characterization of several type B esterases and hepatic CYPs in order to further use this fish as sentinel. ChEs (acetylcholinesterase (AChE) and pseudocholinesterases (butyrylcholinesterase-BuChE and propionilcholinesterase-PrChE)) and CbEs were measured in brain, plasma, kidney, liver, gonad, muscle and gills. Moreover, seven fluorimetric substrates were selected to study CYP related activities in fish liver. The results showed that AChE was the dominant ChE form in brain whereas pseudocholinesterases were absent in most tissues, as demonstrated by low enzymatic activities using specific substrates and the lack of inhibition by iso-OMPA. Plasma exhibited trace activities of all the esterases assayed and no BuChE activity. CbEs were dominant in liver, but they were also present in kidney and brain. For CbE determination, α-naphtyl acetate (αNA) was seen as the most adequate substrate as it displayed higher enzymatic activities and showed more in vitro sensitivity to the carbamate eserine and the organophosphate pesticide dichlorvos. Alkoxyresorufin-O-dealkylase (EROD and BFCOD) activities, indicative in mammals of CYP1A and CYP3A subfamilies, respectively, were the highest microsomal CYP-related activities in liver. The results of this preliminary work allow us to select the most adequate esterase substrate, tissue and hepatic CYP substrate for further monitoring studies.

Keywords: Calibration, imaging, interferometer, radiometer, remote sensing, Soil Moisture and Ocean Salinity (SMOS).

SoilMoisture and Ocean Salinity (SMOS) brightness temperature synthesized images are obtained after a comprehensive error correction procedure that takes into account both on-ground and in-flight calibration measurements. However, the final images are still contaminated by small, although nonnegligible, spatial errors: the so-called pixel bias. Since spatial errors in the 2-D SMOS images are not zero mean along track, these errors produce clearly visible artifacts aligned to this direction. Fortunately, spatial errors have been found to be very stable and can be minimized once the image distortion pattern is properly measured by observing a target at a uniform brightness temperature distribution. This letter describes the procedure to compute a multiplicative mask that largely reduces spatial errors over the ocean. Preliminary results to assess the mask performance are also presented by computing the reduction of the rms spatial error for a number of targets selected to have significant temporal and geographical diversity.

Keywords: Cephalopoda; Teuthida; Gametes; Embryonic development; Paralarvae

In vitro fertilization of oceanic squid is a necessary step to develop their larval culture and creates new opportunities to study and understand cephalopod development, taxonomy and ecology. The techniques described here in the form of a laboratory guide represent an attempt to refine and standardize the general methodology by indicating suitable laboratory materials, sources and preservation of gametes, and methods for fertilization and egg incubation. Twelve oceanic squid species have been fertilized in vitro to date; we outline a generalized experimental protocol and suggest that the reader consider particular species-specific modifications. Inadequate egg chorion expansion and premature hatching are identified as major challenges for in vitro fertilization. Recommendations for future research include studies on optimal gamete concentration, gamete preservation and determination of the functions of female oviducal and nidamental glands. The greatest obstacles to improving fertilization success in squids are the lack of standard methodologies and the paucity of information on both endogenous and exogenous factors controlling the fertilization process. This review is a first step toward overcoming these challenges.

Keywords: geophysical and geological flows, rotating flows, vortex dynamics

Elliptic and hyperbolic geopotential solutions, for a homogeneous distribution of potential vorticity (PV), are obtained via PV inversion in geophysical vortices. The flow in the axisymmetrical three-dimensional vortices is steady and horizontal, where the centripetal acceleration plus the Coriolis acceleration equals the pressure anomaly gradient term (gradient wind or cyclo-geostrophic balance). It is found that the family of geopotential solutions in the vortex interior is completely parameterized by the PV density in the vortex and the squared aspect ratio between the horizontal and vertical semi-axes of the ellipsoidal or hyperbolic geopotential surfaces. Thus, the PV inversion task consists of obtaining, via solution of algebraic cubic equations, the absolute vertical vorticity and vertical stratification as a function of PV and aspect ratio. It is found that there is always a critical aspect ratio, which depends on PV, beyond which the PV inversion solutions are multi-valued. The complete vorticity and stratification solutions for the different regions in the PV and aspect ratio space are obtained and analysed with emphasis on the inertial and static instability of the vortex flow.