Seasonality in pH and temperature for shallow zones of the Bering Sea from measurements of coral Clathromorphum nereostratum

Increasing atmospheric CO2 concentrations are potentially affecting marine ecosystems twofold, by warming and acidification. The rising amount of CO2 taken up by the ocean lowers the saturation state of calcium carbonate, complicating the formation of this key biomineral used by many marine organisms to build hard parts like skeletons or shells. Reliable time-series data of seawater pH are needed to evaluate the ongoing change and compare long-term trends and natural variability. For the high-latitude ocean, the region facing the strongest CO2 uptake, such time-series data are so far entirely lacking. Our study provides, to our knowledge, the first reconstruction of seasonal cycle and long-term trend in pH for a high-latitude ocean obtained from 2D images of stable boron isotopes from a coralline alga.

Abundance and biomass of phytoplankton in the western part of the Black Sea during Parshin cruise BSRP in September and October 2005

The dataset is composed of 61 samples from 15 stations. The phytoplankton samples were collected by 5l Niskin bottles attached to the CTD system. The sampling depths were selected according to the CTD profile and the in situ fluorometer readings: surface, temperature, salinity and fluorescence gradients and 1 m above the bottom. At some stations phytoplankton net samples (20 µm mesh-size) were collected to assist species biodiversity examination. The samples (1l sea water) were preserved in 4% buffered to pH 8-8.2 with disodiumtetraborate formaldehyde solution and stored in plastic containers. On board at each station few live samples were qualitatively examined under microscope for preliminary analysis of taxonomic composition and dominant species. Taxon-specific phytoplankton abundance were concentrated down to 50 cm**3 by slow decantation after storage for 20 days in a cool and dark place. The species identification was done under light microscope OLIMPUS-BS41 connected to a video-interactive image analysis system at magnification of the ocular 10X and objective - 40X. A Sedgwick-Rafter camera (1ml) was used for counting. 400 specimen were counted for each sample, while rare and large species were checked in the whole sample (Manual of phytoplankton, 2005). Species identification was mainly after Carmelo T. (1997) and Fukuyo, Y. (2000). The cell biovolume of the taxon-specific phytoplankton biomass was determined based on morpho-metric measurement of phytoplankton units and the corresponding geometric shapes as described in detail in (Edier, 1979).