ALBERT

Beschreibung: Mesozooplankton have been widely used as a bioindicator of marine ecosystems due to their key position in ocean food webs, rapid response to environmental changes, and ubiquity. Here, we present the compilation of mesozooplankton biomass values in the Canary Current System over 50 years (1971-2021) in three different areas in relation to mesoscale activity: (1) scarcely affected by mesoscales structures (North of the Canary Islands), (2) affected by mesoscale activity and the presence of the islands (South and around the islands), and (3) close to the Northwest African coastal upwelling system (Upwelling influenced). This dataset contains the reference where mesozooplankton biomass values were obtained (indicated when not published), latitude, longitude, area, date, fraction, station number, net type and sampled period.

Beschreibung: Physical oceanography variables and carbon remineralisation (juveniles/adults of Cyclothone species and Argyropelecus hemigymnus) were analysed during the BATHYPELAGIC cruise (North Atlantic, June 2018). This dataset contains the depth, temperature, and conductivity which were recorded from surface to a maximum depth of 2000 m using a SeaBird SBE 25plus CTD equipped with a Seabird-43 Dissolved Oxygen sensor and a Seapoint Fluorometer. Values of numerical abundance, biomass, specific ETS activity, specific respiraton and respiration flux data analyzed from Northwest Africa (20° N, 20° W) to the South of Iceland are presented. A. hemigymnus specimens were collected using a ''Mesopelagos” net (5 x7 m mouth opening, 58 m total length) equipped with graded-mesh netting (starting with 30 mm and ending with 4 mm) and a multi-sampler for collecting samples from 5 different depth layers. However, Cyclothone specimens were collected using the Multiple Opening/Closing Net and Environmental Sensing System (MOCNESS-1 m²) zooplankton net with a 0.2 mm mesh size and with several nets for collecting samples from 8 different depth layers. The Mesopelagos catches were sorted out and identified on board to the lowest possible taxon, and specimens selected for Electron Transfer System (ETS) analyses were immediately frozen in liquid nitrogen for later analysis in the laboratory. MOCNESS samples were preserved in 5% buffered formalin, and specimens were sorted out later in the laboratory. Stomiiforms respiration in the meso- and bathypelagic zones of the ocean were estimated along the transect. Abundance, biomass, specific ETS activity, specific respiration and respiration are given by layer between e.g. 100 m and 1000 m depth (MOCNESS net, 1900–1600 m, 1600–1300 m, 1300–1000 m, 1000–700 m, 700–400 m, 400–200 m, 200–100 m and 100–0 m; Mesopelagos, 1900–1200 m, 1200–800 m, 800–500 m, 500–200 m and 200–0 m).

Beschreibung: Depth, temperature, and conductivity were recorded during the Bathypelagic cruise (from 24th May to 23rd June 2018,) using a SeaBird SBE 25plus CTD, the dissolved oxygen with a Seabird-43 sensor both attached to an oceanographic rosette from surface to a maximum depth of 2000 m, and the fluorometer with a Seapoint sensor in the upper 200 m depth.

Beschreibung: Otolith of mesopelagic fishes stranded in the Canary Islands during June 2021 were measured. This dataset contains the standard length (SL, mm) of each species, as well as the otolith length (OL, in mm) and width (OW, in mm), the aspect ratio (OAR = OW/OL) and the otolith relative length (ORL = (100*(OL/SL)) for each specimen. The species were identified using the external morphological identification and the otoliths analysis. We used the AFORO website for the identification of species using the otolith contour (Lombarte et al. 2006).

Beschreibung: The values of carbon remineralisation were measured in juveniles/adults of 5 non-migratory bristlemouth fishes (Cyclothone spp.) and partial migrator (Argyropelecus hemigymnus) sampled during the BATHYPELAGIC cruise (North Atlantic, June 2018). This dataset contains the values of numerical abundance, biomass, specific ETS activity, specific respiraton and respiration flux data analyzed from Northwest Africa (20° N, 20° W) to the South of Iceland. A. hemigymnus specimens were collected using a ''Mesopelagos” net (5 x7 m mouth opening, 58 m total length) equipped with graded-mesh netting (starting with 30 mm and ending with 4 mm) and a multi-sampler for collecting samples from 5 different depth layers (Olivar et al., 2017). However, Cyclothone specimens were collected using the Multiple Opening/Closing Net and Environmental Sensing System (MOCNESS-1 m²) zooplankton net (Wiebe et al., 1985) with a 0.2 mm mesh size and with several nets for collecting samples from 8 different depth layers. The Mesopelagos catches were sorted out and identified on board to the lowest possible taxon, and specimens selected for Electron Transfer System (ETS) analyses were immediately frozen in liquid nitrogen for later analysis in the laboratory. MOCNESS samples were preserved in 5% buffered formalin, and specimens were sorted out later in the laboratory. Stomiiforms respiration in the meso- and bathypelagic zones of the ocean were estimated along the transect. Abundance, biomass, specific ETS activity, specific respiration and respiration are given by layer.

Beschreibung: The biological carbon pump is the mechanism by which the organic matter is exported or sequestered in the deep ocean from years to millennia. This downward transport is performed through physical transport of dissolved and particulate organic carbon, the sinking of particles or passive flux, and the active transport by diel and seasonal vertical migrants. The latter mechanism is still poorly studied, and seasonality of this active flux is even less known. We studied active flux by zooplankton in two transects from the productive coastal transition zone off Northwest Africa to the warm oligotrophic ocean. We estimated the metabolic activity from the surface to 900 m depth using the enzymatic activity of the electron transfer system (ETS) as a proxy for respiration. We found zooplankton ETS activity significantly higher during spring than during fall in the mesopelagic zone. Even at similar migrant biomass values, respiratory flux was higher during spring compared to fall due to the important differences in respiration rates in the mesopelagic zone. These striking differences of respiration rates in the mesopelagic zone was mainly due to the smaller body size of zooplankton during the productive season (spring). These results should be considered in models of active carbon export in the ocean. Here, we provide the data compiled during both cruises (spring and fall).