Estimation of phytoplankton biomass using HPLC pigment analysis in the southwestern Black Sea

The phytoplankton population of the southwestern Black Sea in May 2001 was studied by taxonomic analysis using microscopic examination and by pigment analyses using high-performance liquid chromatography (HPLC). Pigment data, which identified phytoplankton assemblages dominated by dinoflagellates, diatoms and coccolithophores in May 2001, were compared to phytoplankton cell counts and biomass. There were significant (p < 0.002-0.01, r=0.56-0.67) relationships between the taxon-specific pigment concentrations and the taxon-specific cell numbers during this sampling period. The ratios of chlorophyll-a to the dominant accessory pigments calculated by multiple linear regressions were 1.2 (chlorophyll-a: peridinin) in dinoflagellates, 1.8 (chlorophyll-a: fucoxanthin) in diatoms, and 2.66 (chlorophyll-a: 19'-hex on oyloxyfucoxanthin) in coccolithophores. HPLC-determined chlorophyll-a biomass correlated well with the sum of the group-specific pigment biomass (p < 0.001, r(2) = 0.95). The phytoplankton assemblage as revealed by the microscopic and HPLC analyses was thus made up of common Black Sea groups showing that HPLC pigment analysis can be used to quantify phytoplankton assemblages in the Black Sea based on simple ratios

Phytoplankton Distribution in the Caspian Sea During March 2001.

Abstract not availableJRC.H-Institute for environment and sustainability (Ispra

Phytoplankton distribution in the Caspian Sea during March 2001

Phytoplankton abundance, biomass and species composition of the Caspian Sea were evaluated by using samples collected from the Iranian (southern Caspian Sea) and southern Kazakhstan (eastern Caspian Sea) surface waters in March 2001. A total of 45 taxa were found in the samples (20 diatoms, 17 dinoflagellates and 8 others). Abundance and biomass of diatoms were high at the eastern stations, while dinoflagellates were dominant in terms of both biomass and abundance in the southern region. Average abundance and biomass were 40 000 +/- 35 000 cell l(-1) and 580 +/- 690 mu g l(-1). The mean biomass value found here for the Middle and southern Caspian Sea in March are difficult to compare with the past due to limited information, but seems higher than previously registered values. Higher chlorophyll values were also apparent from the Sea WIFS images in 2001 compared to those in 1998. This is suggested to be due to decreased grazing of phytoplankton by zooplankton which is voraciously preyed by the recent invasive ctenophore Mnemiopsis leidyi

On the linkages between equity markets in Latin America

This paper utilizes a VAR model to analyse the extent of interdependency of equity markets in Latin America. The results from estimating impulse response functions suggest that there are strong linkages between the equity markets of Mexico and the US, and weaker but significant linkages between the stock markets of Argentina, Brazil and Chile. These cross-country differences in transmission patterns may result from country-specific differences in both the financial market structure as well as economic fundamentals.