Ingestion rate and egg production of copepods collected in the upper 20m in the eastern Mediterranean Sea in Oktober 2008

This dataset based on samples taken during October 2008 in Dardanelles Straits, Marmara Sea and Bosporus Straits at the third priority stations. Copepods for the experiments were obtained with slow non-quantitative tows from the upper 50 m layer of the water column using 200 µm mesh size nets fitted with a large non-filtering cod end. For the grazing experiments we used the following copepod species: Oithona spp., Clausocalanus furcatus, Acartia clausi and Oncaea spp. and in one cladoceran species Penilia avirostris according to the relevant reference (Bamstedt et al. 2000). Copepod clearance rates on ciliates were calculated according to Frost equations (Frost 1972). Ingestion rates were calculated by multiplying clearance rates by the initial standing stocks (Bamstedt et al. 2000). Egg production rates of the dominant calanoid copepods were determined by incubation of fertilised females (eggs/female/day) collected in the 0-20m layer. Copepod egg production was measured for the copepods Clausocalanus furcatus, Paracalanus parvus,Acaria clausi. On board experiments for the estimation of copepod egg production were taken place. For the estimation of copepod production (mg/m**2/day), lengths (copepods and eggs) were converted to body carbon (Hopcroft et al., 1998) and production was estimated from biomass and weight-specific egg production rates, by assuming that those rates are representative for juvenile specific growth rates (Berggreen et al., 1988).

Vertical distribution of mesoplankton at the northern margin of the North Atlantic gyre in June-August 2001

Vertical distribution of mesoplankton was studied over a single season in 2001 at two sites in the western and eastern parts of the northern margin of the North Atlantic gyre. Plankton was sampled both with use of BR 113/140 net and observed from the Mir deep-sea manned submersible. In near-slope waters southeast of Newfoundland (Titanic Polygon) there occurred intensive interaction between subtropical and sub-polar waters and plankton communities. The subtropical gyre community being more mature from the succession viewpoint created a ''net'' of carnivores and scavengers (shrimp and smaller animals) feeding plankton supplied from the north and thus increasing their own biomass. Due to features of hydrological conditions in 2001 in contrast to other years, the plankton supplied from the north was dominated by small copepods, while abundance of larger Calanus hyperboreus was small. Perhaps due to this fact, abundance of macroplanktonic shrimp decreased, while abundance of mesoplanktonic carnivores (Themisto, Sagitta, and Pareuchaeta) increased. In East Atlantic, within the Porcupine abyssal plain (Bismark Polygon) contrasts in frontal boundaries decreased and community interaction became less expressed. While vertical distribution of plankton at Titanic Polygon was characterized by a series of extraordinary features, distribution at Bismark Polygon was much more ordinary.

Abundance of mesozooplankton from the S-IT4 cruise in the Western Mediterranean Sea in March and April 2008

The "SESAME_IT4_ZooAbundance_0-50-100m_SZN" dataset contains data of mesozooplankton species composition and abundance (ind./m**3) from samples collected in the Western Mediterranean in the early spring of 2008 (20 March-5 April) during the SESAME-WP2 cruise IT4. Samples were collected by vertical tows with a closing WP2 net (56 cm diameter, 200 µm mesh size) in the following depth layers: 100-200 m, 50-100 m, 0-50 m. Sampling was always performed in light hours. A flowmeter was applied to the mouth of the net, however, due to its malfunctioning, the volume of filtered seawater was calculated by multiplying the the area by the height of the sampled layer from winch readings. After collection, each sample was split in two halves (1/2) after careful mixing with graduated beakers. Half sample was immediately fixed and preserved in a formaldehyde-seawater solution (4% final concentration) for species composition and abundance. The other half sample was kept fresh for biomass measurements (data already submitted to SESAME database in different files). Here, only the zooplankton abundance of samples in the upper layers 0-50 m and 50-100 m are presented. The abundance data of the samples in the layer 50-100 m will be submitted later in a separate file. The volume of filtered seawater was estimated by multiplying the the area by the height of the sampled layer from winch readings. Identification and counts of specimens were performed on aliquots (1/20-1/5) of the fixed sample or on the total sample (half of the original sample) by using a graduate large-bore pipette. Copepods were identified to the species level and separated into females, males and juveniles (copepodites). All other taxa were identified at the species level when possible, or at higher taxonomic levels. Taxonomic identification was done according to the most relevant and updated taxonomic literature. Total mesozooplankton abundance was computed as sum of all specific abundances determined as explained above.