Mesoscale eddies: Hotspots of prokaryotic activity and differential community structure in the ocean

14 pages, 9 figures, 2 tablesTo investigate the effects of mesoscale eddies on prokaryotic assemblage structure and activity, we sampled two cyclonic eddies (CEs) and two anticyclonic eddies (AEs) in the permanent eddy-field downstream the Canary Islands. The eddy stations were compared with two far-field (FF) stations located also in the Canary Current, but outside the influence of the eddy field. The distribution of prokaryotic abundance (PA), bulk prokaryotic heterotrophic activity (PHA), various indicators of single-cell activity (such as nucleic acid content, proportion of live cells, and fraction of cells actively incorporating leucine), as well as bacterial and archaeal community structure were determined from the surface to 2000 m depth. In the upper epipelagic layer (0-200 m), the effect of eddies on the prokaryotic community was more apparent, as indicated by the higher PA, PHA, fraction of living cells, and percentage of active cells incorporating leucine within eddies than at FF stations. Prokaryotic community composition differed also between eddy and FF stations in the epipelagic layer. In the mesopelagic layer (200-1000 m), there were also significant differences in PA and PHA between eddy and FF stations, although in general, there were no clear differences in community composition or single-cell activity. The effects on prokaryotic activity and community structure were stronger in AE than CE, decreasing with depth in both types of eddies. Overall, both types of eddies show distinct community compositions (as compared with FF in the epipelagic), and represent oceanic hotspots of prokaryotic activity (in the epi- and mesopelagic realms)This research was supported by two grants of the Spanish Ministry of Education and Science to JA (Oceanic Eddies and Atmospheric Deposition—RODA, CTM 2004-06842-C03/MAR, and Shelf–Ocean Exchanges in the Canaries– Iberian Large Marine Ecosystem-CAIBEX, CTM 2007- 66498-C02), a grant of the Earth and Life Science Division of the Dutch Science Foundation (ALW-NWO; ARCHIMEDES project, 835.20.023) to GJH, and a predoctoral Fellowship of the Spanish Ministry of Education and Science (AP2005-3932) to FB. IL and JMG were also supported by project MODIVUS (CTM2005-04795/MAR). The work was carried out within the frame of the EU ‘Networks of Excellence’ MarBef and EurOceansPeer Reviewe

Zooplankton biomass and indices of feeding and metabolism in relation to an upwelling filament off northwest Africa

Zooplankton biomass and indices of grazing (gut fluorescence), respiration (electron transfer system activity, ETS) and growth (aspartate transcarbamylase, ATC) were studied in relation to an upwelling filament off northwest Africa during August 1993. The filament extended 150 km offshore into the oligotrophic waters. It was generated by a trapped, quasi-permanent cyclonic eddy located between the Canary Islands and the African shelf. High biomass, specific gut fluorescence and electron transfer system activity in zooplankton were observed along the filament structure. In contrast, low values of biomass, gut fluorescence, ETS and ATC specific activities were found in the center of the trapped cyclonic eddy. Assuming a 50% of pigment destruction, the calculated grazing impact of zooplankton on primary production varied between 16 and 97%, a high range compared to other oceanic systems. Ingestion, estimated from indices of metabolism and growth, accounted for 47–296% of the primary production (assuming an herbivorous feeding). Mesozooplankton transported offshore into the oligotrophic area fulfilled their metabolic demands with nonpigmented food as observed from the increase of omnivory from the coastal waters to the open ocean. The progressive decay of grazing and metabolic indices along the filament suggests that advection, rather than local enrichment processes, is mostly responsible for the high biomass values in this physical structure

Mate preferences in Argentinean transgender people:An evolutionary perspective

Transgender people provide a unique opportunity to examine the effect of biological sex versus gender identity on mating preferences. This study aimed at identifying the mate characteristics that are most and least valued by transgender people and at examining to what extent their biological sex or their gender identity determined their mate preferences. A convenience sample of 134 male-to-female (MTF) and 94 female-to-male (FTM) individuals from Argentina rated Buss's list of 18 mate attributes. Compared to FTM, MTF individuals placed significantly more emphasis on attractiveness and socioeconomic status, whereas FTM, more than MTF individuals, valued partners with a dependable character. Although biological sex differences were present in both groups, providing support to the evolutionary theory, MTF individuals valued the same characteristics as both biological male and female individuals do.Fil: Aristegui, Ines. Universidad de Palermo. Facultad de Ciencias Sociales. Departamento de Psicología. Centro de Investigación y Posgrados; Argentina. University of Groningen; Países BajosFil: Castro Solano, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Palermo. Facultad de Ciencias Sociales. Departamento de Psicología. Centro de Investigación y Posgrados; ArgentinaFil: Buunk, Abraham P.. Universidad de Palermo. Facultad de Ciencias Sociales. Departamento de Psicología. Centro de Investigación y Posgrados; Argentin

Diapycnal Nutrient Fluxes in the Cape Ghir upwelling region

European Geosciences Union General Assembly 22-27 April 2012, Vienna, Austria.-- 1 pageAn oceanographic survey was carried out from 18 to 29 October 2010 in the Canary Basin (PROMECA project). Near Cape Ghir, in the Northwest Africa coastal upwelling, 17 CTD casts were made to obtain continuous records of conductivity and temperature with depth, and to collect waters samples for nutrients analyses. Additionally, free-fall turbulence profiles were obtained at each station. 14 Expandable bathythermographs (XBTs) were deployed between stations to increase the grid resolution of the temperature field. Velocity data were acquired with a vessel-mounted Acoustic Doppler Current Profiler (ADCP) with a vertical bin size of 8 m. Water samples for nutrients: nitrate + nitrite (N+N), phosphates and silicates, were collected from 12 depths (down to 2000 m or the maximum depth), with 12-l Niskin bottles mounted on the rosettes sampler. The first results show low to moderate concentrations of nutrients offshore, with average values in the upper 150 m of 2.45 ± 1.98, 0.37 ± 0.18 and 1.47 ± 0.94 μM for N+N, phosphate and silicate, respectively. However, for stations near the Cape Ghir upwelling filament or influenced by this feature, a significant increase in the concentration of nutrients (up to 10 µM of N+N at 200 m) was observed. We have estimated and compared the diapycnal nutrient flux in the region by using two different approaches. First, we used the dissipation rates of turbulent kinetic energy and thermal variance estimated from microstructure data acquired from turbulence profilers, and applied a model based on the dissipation ratio. This way we obtain net turbulence diffusivities in regions where there is an interaction of processes of double diffusion and turbulence induced by vertical shear of the flow. The second approach is based on obtaining diapycnal diffusivities with parameterizations of the gradient Richardson number and density ratioPeer Reviewe

Site fidelity and movement patterns of short-finned pilot whales within the Canary Islands : evidence for resident and transient populations

Funding: co-funded by the Canary Government (Consejería de Política Territorial, Sostenibilidad y Seguridad), the Spanish Government (Fundación Biodiversidad and Ministerio de Medio Ambiente, Medio Rural y Marino), Fundación La Caixa, and by a number of international projects funded by EU programmes MACETUS (FEDER/INTERREG III-B MAC/4.2/M10), EMECETUS (FEDER/INTERREG III-B56105/MAC/4.2/M10), LIFE (LIFE03NAT0062), INDEMARES LIFE+ (LIFE07/NAT/E/00732).1. The geographic location and oceanographic, physical, and chemical water properties make the Canary Islands one of the planet's biodiversity hotspots. The short‐finned pilot whale (Globicephala macrorhynchus) is one of the archipelago's most commonly encountered species and is potentially vulnerable to a range of anthropogenic pressures, including habitat degradation, acoustic pollution, fishing, whale‐watching operations, and shipping. Assessment of impact has not been possible because of a lack of even basic information about occurrence and distribution. 2. Spatial and temporal distributions, ranging behaviour, and residence patterns of short‐finned pilot whales were explored for the first time using survey and photo‐identification data collected in the Canary Islands between 1999 and 2012. In total, 1,081 pilot whale sightings were recorded during 70,620 km of search effort over 1,782 survey days. 3. Pilot whales were detected year round and distributed non‐uniformly within the archipelago, with greater densities concentrated in patchy areas mainly on the leeward side of the main islands. In total, 1,320 well‐marked individuals were identified, which exhibited a large degree of variability in site fidelity. 4. Different but not isolated subpopulations of pilot whales that share ranges and maintain social interactions were apparently present in the Canary Islands. Strong evidence of an island‐associated subpopulation was found, with a group of 50 ‘core resident’ individuals associated particularly with Tenerife. There were also ‘transient’ individuals or temporary migrants, which, probably driven by inter‐ and intra‐specific competition, may travel long distances whilst using the archipelago as part of a larger range. 5. These findings fill a major gap in the knowledge of this species’ occurrence, distribution, movements, and site fidelity in the archipelago and provide much needed data to allow the initiation of informed conservation assessments and management actions.PostprintPeer reviewe

Dissolved Organic Matter (DOM) in the open Mediterranean Sea. I. Basin-Wide distribution and drivers of chromophoric DOM

Original research articleChromophoric dissolved organic matter (CDOM) in the open Mediterranean Sea (MedSea) is barely documented, remaining the basin–wide patterns in intermediate and deep waters still enigmatic. Here, full–depth distributions of CDOM absorption coefficients and spectral slopes recorded during the HOTMIX 2014 cruise are presented and their respective environmental drivers resolved. General Additive Models (GAMs) in surface waters and Optimum MultiParameter (OMP) water mass analysis in deep waters were applied. In the surface, apparent oxygen utilisation (AOU), a proxy to cumulative net community respiration, explained most of the variability of dissolved organic carbon (DOC) and the absorption coefficient at 254 nm (a254), whereas the absorption coefficient at 325 nm (a325), and the spectral slopes were mostly explained by potential temperature, a proxy to stratification and solar radiation, indicating that both water column stability and photobleaching may drive the variability of the UV–A absorbing CDOM components. In deep waters, the effect of water mass mixing and basin–scale mineralization were discerned from local mineralization processes. Water mass mixing and basin–scale mineralization contributed more substantially to explain the variability of DOC, a254 and a325 (82–91%) than the variability of the spectral slopes (35–64%). Local mineralization processes indicate that DOC and CDOM play a more relevant role in the carbon cycle in the Eastern (EastMed) than in the Western (WestMed) Mediterranean: whereas DOC contributed to 66 ± 10% of the oxygen demand in the EastMed, it represented only 24 ± 4% in the WestMed. Independently of basins and layers, a254 revealed as an excellent proxy to the concentration of DOC in the MedSea. Also, the unexpected inverse relationship of a325 with AOU indicates that the consumption of the UV–A absorbing CDOM fraction prevails over their productionSpanish Ministry of Education and Culture, Spanish Ministry of Economy and Competitiviness, FEDER, CSIC, University of GranadaVersión del editor3,26

Microbial rhodopsins are major contributors to the solar energy captured in the sea

All known phototrophic metabolisms on Earth rely on one of three categories of energy-converting pigments: chlorophyll-a (rarely -d), bacteriochlorophyll-a (rarely -b), and retinal, which is the chromophore in rhodopsins. While the significance of chlorophylls in solar energy capture has been studied for decades, the contribution of retinal-based phototrophy to this process remains largely unexplored. We report the first vertical distributions of the three energy-converting pigments measured along a contrasting nutrient gradient through the Mediterranean Sea and the Atlantic Ocean. The highest rhodopsin concentrations were observed above the deep chlorophyll-a maxima, and their geographical distribution tended to be inversely related to that of chlorophyll-a. We further show that proton-pumping proteorhodopsins potentially absorb as much light energy as chlorophyll-a–based phototrophy and that this energy is sufficient to sustain bacterial basal metabolism. This suggests that proteorhodopsins are a major energy-transducing mechanism to harvest solar energy in the surface ocean

Dissolved organic matter (DOM) in the open Mediterranean Sea. II: Basin-wide distribution and drivers of fluorescent DOM

Research articleFluorescent dissolved organic matter (FDOM) in the Mediterranean Sea was analysed by excitation–emission matrix (EEM) spectroscopy and parallel factor (PARAFAC) analysis during the cruise HOTMIX 2014. A 4–component model, including 3 humic–like and 1 protein–like compounds, was obtained. To decipher the environmental factors that dictate the distributions of these components, we run generalized additive models (GAMs) in the epipelagic layer and an optimum multiparametric (OMP) water masses analysis in the meso– and bathypelagic layers. In the epipelagic layer, apparent oxygen utilization (AOU) and temperature presented the most significant effects on the variability of the marine humic-like peak M fluorescence, suggesting that its distribution was controlled by the net community respiration of organic matter and photobleaching. On the contrary, the variability of the soil humic-like peak E and the protein–like peak T fluorescence was explained mainly by the prokaryotic heterotrophic abundance, which decreased eastwards. In the meso– and bathypelagic layers, water mass mixing and basin–scale mineralization processes explained >72% and 63% of the humic–like and protein–like fluorescence variability, respectively. When analysing the two basins separately, the OMP model offered a better explanation of the distribution of fluorescence in the eastern Mediterranean Sea, as expected from the reduced biological activity in this ultra–oligotrophic basin. Furthermore, while western Mediterranean deep waters display the usual trend in the global ocean (increase of humic–like fluorescence and decrease of protein–like fluorescence with higher AOU values), the eastern Mediterranean deep waters presented an opposite trend. Different initial fluorescence intensities of the water masses that mix in the eastern basin, with Adriatic and Aegean origins, seem to be behind this contrasting pattern. The analysis of the transect–scale mineralization processes corroborate this hypothesis, suggesting a production of humic–like and a consumption of protein–like fluorescence in parallel with water mass ageing. Remarkably, the transect–scale variability of the chromophoric dissolved organic matter (CDOM) absorbing at the excitation wavelength of the humic–like peak M indicates an unexpected loss with increasing AOU, which suggests that the consumption of the non–fluorescent fraction of CDOM absorbing at that wavelength exceeded the production of the fluorescent fraction observed hereProject HOTMIX (reference CTM2011–30010–C02 01–MAR and 02–MAR), co–financed with FEDER funds (re ference BES–2012–056175) ; the project MODMED from CSIC (PIE, 201730E020) and the project FERMIO (MINECO, CTM2014–57334–JIN), co–financed with FEDER fundsVersión del editor3,26

Deep ocean prokaryotes and fluorescent dissolved organic matter reflect the history of the water masses across the Atlantic Ocean

Organic matter is known to influence community composition and metabolism of marine prokaryotes. However, few studies have addressed this linkage in the deep ocean. We studied the relationship between fluorescent dissolved organic matter and prokaryotic community composition in meso- and bathypelagic water masses along a surface productivity gradient crossing the subtropical and tropical Atlantic Ocean. Four fluorescence components were identified, three humic-like and one protein-like. The distributions of the humic-like components were significantly explained by water mass mixing, apparent oxygen utilisation (AOU) and epipelagic productivity proxies in varying degrees, while the protein-like component was explained only by water mass mixing and epipelagic productivity. The diversity and taxonomic composition of the prokaryotic community differed between water masses: the Nitrosopumilales order dominated in water masses with high AOU and humic-like fluorescence (notably, the SubPolar Mode Water), and tended to co-occur with Marine Group II archaea, the SAR324 clade and Thiomicrospirales, while bathypelagic water masses displayed greater abundances of members of Marinimicrobia, SAR202 and SAR324. Water mass mixing regression models suggested that the distribution of some taxa (e.g., Marinimicrobia, SAR202) was dominated by mixing and selection within the water masses during ageing, while others (chiefly, Alteromonadales) were mostly influenced by local processes. Our results suggest a link between the composition of the prokaryotic community, oxygen utilisation and the signal of fluorescent dissolved organic matter, and has implications for our understanding of the processes that shape carbon cycling and prokaryotic communities in the deep ocean.3,26