Mesozooplankton distribution, production and respiration in the global ocean.

Mesozooplankton biomass, abundance and mass-specific physiological rates as well as community production and respiration in the upper 2000 m were assessed from samples collected during the Malaspina circumnavigation expedition (~35ºN-40ºS) using an image-based analysis system (IBS). Equations relating metabolic rates, temperature, and body weight, were developed according to temperature ranges found at the different ocean regions and depth layers. High abundance and biomass were observed in the epipelagic zone and decreasing with depth as expected. However, high biomass was also found beyond 1000 m related to the colder and productive waters of the eastern regions of the Indian and Pacific Oceans. Specific growth and respiration rates followed a similar pattern and were highly correlated with temperature (r2=0.835 and 0.806 , respectively). Therefore, higher values were observed in the tropical and subtropical zones as the effect of higher temperature. Community production and respiration were considerably higher in the epipelagic layer, matching the distribution of biomass, with high values below 1000 m in the eastern Pacific/Indian Oceans. Global metabolism assessed through the IBS was similar to previous results based on data review.MALASPINA (CSD2008-00077

Nutrients, phytoplankton, bacterioplankton and particulated matter from the Alborán Sea, in July 1992.

Se presentan los resultados referentes a clorofila, fitopalncton, nutrientes, bacterioplancton y metabolismo, obtenidos en la totalidad de la cuenca del mar de Alborán, en el marco de la campaña 'Ictio.Alborán 0792'. La localización y análisis de los procesos que ocurren a nivel del máximo subsuperficial de clorofila ha constituido uno de los objetivos del trabajo. Los resultados ponen de manifiesto que el régimen hidrodinámico controla los patrones horizontales y verticales de productividad planctónica en el mar de Alborán.Abstract: Findings from the cruise 'Ictio.Alborán 0792' (regarding chlorophyll, phytoplankton, nutrients, bacterioplankton, and metabolism)are described. Special attention was paid to the subsurface chlorophyll maximum. These results ilustrate how hydrodynamics control the spatial patterns of productivity in the Alborán Sea.Postprin

Patterns in the size structure of phytoplankton in the deep fluorescence maximum of the Alborán sea (southwestern mediterranean)

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El ictioplancton y el medio marino en los sectores norte y sur del mar de Alborán, en julio de 1992. (Resultados de la campaña Ictio. Alborán 0792).

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Relations between icthyoplankton distribution, hydrology, phytoplankton, dissolved oxygen and nutrientes, in the Alborán Sea (July, 1992)

A la vista de los resultados obtenidos por los diferentes autores y expuestos en las páginas anteriores, se han elaborado las conclusiones generales seguidamente presentadas. (Para ampliar la visión que aquí se ofrece basta con consultar dichos trabajos.) Se ha comprobado cómo el particular régimen hidrodinámico de la zona determina claramente las distribuciones del ictioplancton y controla los patrones horizontales y verticales de productividad planctónica en el mar de Alborán.Abstract: In view of the results obtained by the different authors and discussed in the previous pages, final conclusions have been prepared and are presented below (in order to enlarge the view offered here, see the cited papers). It has been proved how the particular hydrodynamics of the area clearly determines ichthyoplankton distribution and controls the horizontal and vertical patterns of planktonic productivity in the Alborán Sea.Postprin

The structure of the pelagic ecosystem related to oceanographic and topographic features in the Gulf of Cadiz, Straits of Gibraltar and Alborán Sea during July 1995

Se analizan los resultados obtenidos en 59 estaciones muestreadas en el golfo de Cádiz, el estrecho de Gibraltar y el sector noroeste del mar de Alborán, en julio de 1995. Se presentan las principales características hidrológicas registradas durante la prospección y su posible relación con las composiciones y distribuciones planctónicas. En el golfo de Cádiz, con aguas más someras, cálidas y de menor salinidad, predominan los huevos y lavas de boquerón Engraulis encrasicolus (L., 1758) y de alacha Sardinella aurita Valenciennes, 1847 (tipicamente costeros), mientras que en mar de Alborán, con plataforma estrecha y un afloramiento activo, el ictioplancton oceánico de Maurolicus muelleri (Gmelin, 1788) es el mayoritario. Las diferentes características topográficas y oceanográficas de ambas zonas también se han reflejado en los análisis complementarios realizados. Así, las aguas atlánticas se caracterizan por presentar valores inferiores en concentraciones (actividad nitrato reductasa, material particulado, clorofila a y feopigmentos), mayores concentraciones de fosfatos y mayor abundancia de grupos planctónicos de pequeño tamaño (bacterioplacton, picoplancton autótrofo, flagelados, ciliados, cladóceros y copépodos).The results obtained from 59 stations sampled in the Gulf of Cadiz, Straits of Gibraltar and Alborán Sea (northwest sector) during July 1995 are analysed in this paper. The main hydrological characteristics recorded during the survey and their possible relationship with planktonic distribution and composition are presented. The eggs and larvae of anchovy Engraulis encrasicolus (L., 1758) and gilt sardine Sardinella aurita Valenciennes, 1847 (typically coastal) were the most abundant in the Gulf of Cadiz, where warmer, fresher and shallower waters are dominant. However, the Maurolicus muelleri (Gmelin, 1788) plankton components (oceanic) predominated in the Alborán Sea, characterised by a narrow continental shelf and active upwelling. The different topographic and hydrographic features of these geographic zones were also apparent in the complementary analyses that were carried out: Atlantic waters were characterised by lower concentration values of nitrate reductase activity, particulate matter, chlorophyll-a and phaeopigments, and higher values of phosphate concentrations and small planktonic organisms (bacterioplankton, autotrophic picoplankton, flagellates, ciliates, cladocerans and copepods).Postprint

Bathypelagic fauna as a main driver of carbon sequestration in the ocean

Sequestration, in contrast to export, is a mechanism of the biological pump occurring when carbon cannot return to the atmosphere in at least 100 years, normally the carbon transported below 1000 m depth. Pelagic fauna release carbon at depth through respiration, egestion, excretion, moulting, lipid consumption and mortality supporting deep-sea food webs. Knowledge about this transport in the mesopelagic layer is growing. However, the role of the pelagic fauna to fuel the bathypelagic zone, the layer where effective carbon sequestration occurs, is largely unknown. Here we report net zooplankton biomass in the meso- and bathypelagic zones showing significant relationships with primary production (PP) at a global scale during the Malaspina Circumnavigation Expedition. We also reviewed available data on zooplankton biomass at the different biogeographical provinces also showing significant correlations with large-scale estimates of PP, implying the transference of a significant fraction of PP from the epipelagic to the deep ocean. Carbon sequestration assessed only from conservative estimates of zooplankton mortality in the bathypelagic was 0.43 PgC y-1, in the order of recent estimates of gravitational carbon sequestration. These values and those recently reviewed due to lipid consumption almost triples ocean carbon sequestration estimates in Westerlies and Polar biomes. These results point at a pivotal role of the pelagic fauna in ocean carbon sequestration as, besides zooplankton, downward transport by macroplankton and micronekton should also be accounted for. Our results raises the question of whether we are severely underestimating carbon sequestration in the ocea

Large deep-sea zooplankton biomass mirrors primary productivity in the global ocean.

The biological pump transports organic carbon produced by photosynthesis to the meso- and bathypelagic zones, the latter removing carbon from exchanging with the atmosphere over centennial time scales. Organisms living in both zones are supported by a passive flux of particles, and carbon transported to the deep-sea through vertical zooplankton migrations. Here we report globally-coherent positive relationships between zooplankton biomass in the epi-, meso-, and bathypelagic layers and average net primary production (NPP). We do so based on a global assessment of available deep-sea zooplankton biomass data and largescale estimates of average NPP. The relationships obtained imply that increased NPP leads to enhanced transference of organic carbon to the deep ocean. Estimated remineralization from respiration rates by deep-sea zooplankton requires a minimum supply of 0.44 Pg C y−1 transported into the bathypelagic ocean, comparable to the passive carbon sequestration. We suggest that the global coupling between NPP and bathypelagic zooplankton biomass must be also supported by an active transport mechanism associated to vertical zooplankton migration