Calcareous nannofossil abundance estimates and datums of ODP Leg 189 sites

A major objective of Leg 189 was to date the opening of the Australia-Antarctic Gateway to shallow-water circulation and subsequently to deepwater circulation in the Paleogene. Calcareous nannofossils are the most consistently present, although not necessarily the most abundant fossil group in Paleogene sections, and the shipboard study (Exon, Kennett, Malone, et al., 2001, doi:10.2973/odp.proc.ir.189.2001) showed that they generally provided the most useful age information. This report presents documentation of the stratigraphic distribution of nannofossils in the Paleogene and summarizes useful nannofossil datums, which should facilitate construction of age-depth curves and contribute to an integrated chronology for Leg 189 sediments. Previous Paleogene nannofossil study in this area is that of Edwards and Perch-Nielsen (1975, doi:10.2973/dsdp.proc.29.113.1975).

Abundance of diatoms and foraminifers in the surface sediment layer of the southeastern Laptev Sea shelf

The study of diatoms and benthic foraminifers from the southeastern shelf of the Laptev Sea shows that their most diverse and abundant recent assemblages populate the peripheral underwater part of the Lena River delta representing the marginal filter of the sea. This area is characterized by intense interaction between fresh waters of Siberian rivers and basin seawater, Atlantic one included. Local Late Holocene (~last 2300 years) environments reflect the main regional and global paleoclimatic changes, the Medieval Warm Period (~600-1100 years B.P.) and the Little Ice Age (~100-600 years B.P.) inclusive. In addition, composition and distribution of planktonic foraminifers implies strong influence of Atlantic water during the Holocene optimum ~5100-6200 years B.P.

Abundance and composition of Fe-Mn nodules and host sediments in the Pacific Ocean

Data on internal structure, distribution, and chemical composition of iron-manganese nodules from the central part of the South Pacific are reported. Nodules with relatively high contents of Fe, Ti, Co, and Pb were found. Formation of these nodules in pelagic regions of the ocean with low sedimentation rates is tentatively ascribed by the authors to leaching of Fe, Mn, and some minor elements during submarine lava outflow and to geochemical mobility of these elements. The role of diagenetic re-distribution of ore elements during formation of nodules is also discussed.

Abundance of mesozooplankton in the north-eastern Black Sea during SESRU01 cruise in April 2008

The SESRU01_mesozooplankton dataset contains data collected in April 2008 at 19 stations located between 37°E and 39.5°E and between 42.4°N and 44.5°N in the north-eastern Black Sea. Samples were collected with a Juday net (mesh size 180 ?m, mouth area 0.1 m**2). Integrated samples were taken from the lower boundary of the oxic zone to the surface, stratified samples were taken according to CTD-profiles: samples were taken from the following depth strata: 1) the upper mixed layer (UML); 2) the layer of high temperature gradients (from the upper boundary of thermocline to the depth of 8 deg C temperature); 3) cold Intermediate layer (CIL) - the layer with the T< 8 deg C; 4) from the depth of sigma theta = 15.8 (oxycline) to the lower boundary of CIL; 5) from the depth of sigma theta = 16.2 to the depth of sigma theta = 15.8. Samples were analysed for zooplankton species and stage composition and abundance. Juday net: Vertical tows of a closing Juday net, with mouth area 0.1 m**2, mesh size 180µm. Samples were taken from different layers. Towing speed: 1m/s. Samples were preserved by a 4% formaldehyde sea water buffered solution. Sampling volume was estimated by multiplying the mouth area by the wire length. The entire sample or an aliquot (1/2 to1/4) was analyzed under the binocular microscope. Mesozooplankton species and stages were identified and enumerated; meroplankton were identified and enumerated at higher taxonomic level. Taxonomic identification was done at Shirshov Institute of Oceanology using the relevant taxonomic literature (Rose, 1933, Brodsky, 1950, and Internet resources).

Diatom abundance in sediments from ODP Leg 167 sites

The Pliocene and Pleistocene periods are known for the onset and consequent amplification of glacial-interglacial cycles. The California margin, situated in the mid-latitudes of the northern Pacific Ocean, is expected to be one of the most interesting regions for Pliocene to Pleistocene paleoceanography because this area occupies a unique position in the ocean-atmosphere system over the region. In this study, we investigated paleoceanographic history, using fossil diatoms, since the Brunhes/Matuyama (B/M) paleomagnetic boundary in which glacial and interglacial periods began to alternate in 100-yr cycles. In Hole 1018A, to a depth corresponding to the beginning of Northern Hemisphere glaciation (late Pliocene), we investigated the responses of the ocean-atmosphere system to stepwise cooling in the California margin. Although the work is still continuing, this data report shows that fossil diatoms of Pliocene and Pleistocene sediments significantly changed both in quality and quantity and implies a possible relationship to global climatic changes.

Abundance of mesozooplankton during the long-tern mesozooplankton analysis in Sevastopol Bay from 1976 to 2003

The present dataset includes results of analysis of 227 zooplankton samples taken in and off the Sevastopol Bay in the Black Sea in 1976, 1979-1980, 1989-1990, 1995-1996 and 2002-2003. Exact coordinates for stations 1, 4, 5 and 6 are unknown and were calculated using Google-earth program. Data on Ctenophora Mnemiopsis leidyi and Beroe ovata are not included. Juday net: Vertical tows of a Juday net, with mouth area 0.1 m**2, mesh size 150µm. Tows were performed at layers. Towing speed: about 0.5 m/s. Samples were preserved by a 4% formaldehyde sea water buffered solution. Sampling volume was estimated by multiplying the mouth area with the wire length. The collected material was analysed using the method of portions (Yashnov, 1939). Samples were brought to volume of 50 - 100 ml depending upon zooplankton density and mixed intensively until all organisms were distributed randomly in the sample volume. After that 1 ml of sample was taken by calibrated Stempel-pipette. This operation was produced twice. If divergence between two examined subsamples was more than 30% one more subsample was examined. Large (> 1 mm body length) and not abundant species were calculated in 1/2, 1/4, 1/8, 1/16 or 1/32 part of sample. Counting and measuring of organisms were made in the Bogorov chamber under the stereomicroscope to the lowest taxon possible. Number of organisms per sample was calculated as simple average of two subsamples meanings multiplied on subsample volume. Total abundance of mesozooplankton was calculated as sum of taxon-specific abundances and total abundance of Copepods was calculated as sum of copepods taxon-specific abundances.

Mesozooplankton abundance data from Disko Bay, West Greenland, 2008

The study site was located in the Disko Bay off Qeqertarsuaq, western Greenland. Due to land-connected sea ice coverage during winter, 2 sampling sites were combined. At the first site in winter (21 February to 23 March 2008), sampling was conducted through a hole in the ice at ca. 65 to 160 m depth approximately 0.5 nautical mile (n mile) south of Qeqertarsuaq (69° 14' N, 53° 29' W). In spring and summer (9 April to 18 July), sampling was done at a monitoring station 1 n mile south from Qeqertarsuaq (69° 14' N, 53° 23' W) at 300 m depth. Sampling was carried out between 10:00 and 17:00 h. During sampling from the ice, mesozooplankton was collected using a modified WP-2 net (45 µm) equipped with a closing mechanism (Hydrobios). Samples were collected in 3 depth strata (0-50, 50-100, and 100-150 m). During ship-based sampling, mesozooplankton was collected with a multinet (50 µm) equipped with a flow meter (Multinet, Hydrobios type midi), and 2 additional depth strata (150-200m and 200-250 m) were included. In addition to the seasonal study one diurnal investigation with sampling every 6 h was conducted from 29 April at 12:00 h to 30 April 30 at 12:00 h. Samples were immediately preserved in buffered formalin (5% final concentration) for later analyses. Biomass values of the different copepod species were calculated based on measurements of prosome length, and length/weight relationships. Two regressions for Calanus spp. were established for biomass calculations: one applicable prior to and during the phytoplankton bloom until 4 May, and another from 9 May onwards.

Abundance and biomass of mesozooplankton from the Romanian littoral during DANUBS_2001 in spring and autumn 2001

The Danubs 2001 dataset contains zooplankton data collected in March, June, September and October 2001 in 11 station allong 5 transect in front of the Romanian littoral. Zooplankton sampling was undertaken at 11 stations where samples were collected using a Juday closing net in the 0-10, 10-25, and 25-50m layer (depending also on the water masses). The dataset includes samples analysed for mesozooplankton species composition and abundance. Sampling volume was estimated by multiplying the mouth area with the wire length. Taxon-specific mesozooplankton abundance was count under microscope. Total abundance is the sum of the counted individuals. Total biomass Fodder, Rotifera , Ctenophora and Noctiluca was estimated using a tabel with wet weight for each species an stage.