Acoustic multi-frequency indicator of four major groups on a spatial grid in the Bay of Biscay

The first data set contains the mean and cofficient of variation (standard deviation divided by mean) of a multi-frequency indicator I derived from ER60 acoustic information collected at five frequencies (18, 38, 70, 120, and 200 kHz) in the Bay of Biscay in May of the years 2006, 2008, 2009 and 2010 (Pelgas surveys). The multi-frequency indicator was first calculated per voxel (20 m long × 5 m deep sampling unit) and then averaged on a spatial grid (approx. 20 nm × 20 nm) for five 5-m depth layers in the surface waters (10-15m, 15-20m, 20-25m, 25-30m below sea surface); there are missing values in particular in the shallowest layer. The second data set provides for each grid cell and depth layer the proportion of voxels for which the multi-frequency indicator I was indicative of a certain group of organisms. For this the following interpretation was used: I < 0.39 swim bladder fish or large gas bubbles, I = 0.39-0.58 small resonant bubbles present in gas bearing organisms such as larval fish and phytoplankton, I = 0.7-0.8 fluidlike zooplankton such as copepods and euphausiids, and I > 0.8 mackerel. These proportions can be interpreted as a relative abundance index for each of the four organism groups.

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.

Analysis of Mn nodules from cruise GH72-2

The GH72-2 shipborne survey was carried out in the northwest Pacific during 31 days under the 'Basic investigations for exploration of deep sea mineral resources' program. The sediments encountered could be classified as follows: 1) Most of the brown clays occur on the abyssal plain of the basins at depth over 4500m. 2) Calcareous oozes are predominant at the top, slope and foot of seamounts and guyots. 3) Terrigeneous sediments are distributed near islands. The concentrated zone of ferromanganese nodules was located in the Magellan seamounts area. However, the metal contents in Mn, Cu, Ni and Co for these nodules are relatively poor, and these ferromanganese deposits occur at a depth over 5000m. It is interesting to note that the shape of the nodules is sometimes nearly spherical, and that the chemical composition of the nodules is characterized by the low ratio Mn/Fe and Co/Ni.