Abundance, biomass, production, grazing, and biometric measurements of prokaryotes, nanoflagellates, ciliates, and dinoflagellates in three areas close to the Antarctic Peninsula in spring and summer 1995/96

• Main Author: Vaqué, Dolors
• Format: Dataset
• Language: English
• Published: PANGAEA 2008
• Subjects: Bransfield Strait; CTD/Rosette; CTD-RO; Fruela95; Fruela95_142; Fruela95_15; Fruela95_169.3; Fruela95_39; Fruela95_79; Fruela96; Fruela96_193; Fruela96_210; he31_015; he31_040; he31_083; he31_150; he31_200; he31_243; he31_262; Hespérides; Antarctic; The Antarctic; Antarctic Peninsula; Austral; Bellingshausen Sea; Gerlache; Gerlache Strait; Antarc*
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.696287; https://doi.org/10.1594/PANGAEA.696287

Two cruises were carried out during the Austral spring-summer (November 1995 - January 1996: FRUELA 95, and January - February 1996: FRUELA 96), sampling in Bellingshausen Sea, western Bransfield Strait and Gerlache Strait. We investigated whether there were any spatial (among locations) or temporal (between cruises) differences in abundance and biomass of microbial heterotrophic and autotrophic assemblages. Changes in the concentration of chlorophyll a, prokaryotes, heterotrophic and phototrophic nanoflagellates abundance and biomass were followed in the above mentioned locations close to the Antarctic Peninsula. Parallel to these measurements we selected seven stations to determine grazing rates on prokaryotes by protists at a depth coincident with the depth of maximum chlorophyll a concentration. Measuring the disappearance of fluorescent minicells over 48 h assessed grazing by the protist community. From prokaryotes grazing rates, we estimated how much prokaryotic carbon was channeled to higher trophic levels (protists), and whether this prokaryotic carbon could maintain protists biomass and growth rates. In general higher values were reported for Gerlache Strait than for the other two areas. Differences between cruises were more evident for the oligotrophic areas in Bellingshausen Sea and Bransfield Strait than in Gerlache Strait (eutrophic area). Higher values for phototrophic (at least for chlorophyll a concentration) and abundance of all heterotrophic microbial populations were recorded in Bellingshausen Sea and Bransfield Strait during late spring - early summer (FRUELA 95) than in mid-summer (FRUELA 96). However, similar results for these variables were observed in Gerlache Strait as in spring-early summer as well as in mid-summer. Also, we found differences in grazing rates on prokaryotes among stations located in the three areas and between cruises. Thus, during late spring-early summer (FRUELA 95), the prokaryotic biomass consumed from the standing stock was higher in Bellingshausen Sea (26%/day) ...