Zooplankton oxygen consumption and nutrient release in relation to species composition, animals size and enviromental conditions in the Baltic Sea during May and August

[EN] Zooplankton metabolism in terms of oxygen consumption and ñutrient reléase (ammonia, phosphate) were measiu'ed in the Baltic Sea, a températe área with high envirormiental changes both in space and in time. Plankton of the surface layer were analysed with balance measurements in 4 size classes between 50 and 1000 nm during spring in 1988, 1990 and 1991, in summer 19^8 and 1990 as well. The use of electrón transport system (ETS), and the Glutamate Dehydrogenase (GDH) activity as indicators for respiration and ammonia reléase respectively, enlarged the data density and made a three dimensional resolution available (May 1990, 1991). Data are in the range of the latitudinal dependend magnitude. They reflect slight interannual, more seasonal and regional aspects. Animáis size, temperature, food concentration, and species composition influence the specific rates

Malaspina 2010: observaciones de R/ETS

[EN]Respiratory electron transport system (ETS) activities have been used, in the past, to study respiration in many marine organisms and many different environments. The methodology follows standard practices of enzymology, by attempting to measure the maximum velocity of the enzyme reaction (Vmax) sensu Michaelis-Menten. Under controlled conditions of nutritional state the ETS method is well correlated with in situ respiration. In the interdisciplinary Expedition MALASPINA 2010, that circumnavigated the planet, we had the chance in three of seven transects (Cape Town to Perth; Perth to Sydney and Cartagena de Indias to Cartagena) to take zooplankton samples from the southern Indian Ocean and from North Atlantic Ocean. From these samples we measured protein and 150 ratios between in vivo respiration and potential respiration (ETS activity) in three size-classes of zooplankton between 100?m to > 1000?m, in the upper 150 meters of the water column. Normally, the measurements were made on fresh naturally nourished zooplankton (in situ). When biomass permitted, measurements were also made on zooplankton starved for 24 h. With this data we are investigating the variations in the R/ETS ratio and Kleiber?s law under different nutritional conditions, different oceanographic conditions, and different oceanographic regions. This analysis will help our ongoing investigation of ETS activity as an index of both respiration and of living biomass. The information acquired will facilitate the calculation of zooplankton respiration for some relatively unexplored areas of the Indian and Atlantic oceans. This data will then be available for integration with results of other Malaspina research programs

Mesozooplankton community structure during summer months in the Bay of Cádiz

[EN] Mesozooplankton organisms (>250 μm) were sampled at two stations (inner and outer Bay) in the Bay of Cádiz between May and July 2008. Samples were analysed by means of a semi-automated technique in order to give a preliminary view of the mesoozooplankton community structure in the Bay, based on taxonomic diversity and biomass distribution among size classes. The abundance of organisms increased from May to July in accordance with the increase in temperature and Chlorophyll a (Chla) concentrations. Abundances were higher in the outer Bay station, where Chla concentrations are greater and the water column is more stable. The community changed from being meroplankton- to holoplankton-based due to an increase of Calanoida and especially Cladocera individuals (mainly Peniliaavirostris), which are known to peak acutely in the summer. The analysis of Normalised Biomass-Size spectra revealed fairly steep slopes (average -1.3) and relatively high departures from steady state (r2 = 0.8 – 0.94), expectable in a coastal system such as the Bay of Cádiz were disturbance factors are introduced from benthic and tidal processes, together with anthropogenic pressure.

The use of image analysis systems for the assesment of zooplankton physiological rates and carbon fluxes

Trabajo realizado por: Garijo, J. C., Hernández León, S.