Long-term monitoring and analyses of physical factors regulating variability in coastal Antarctic phytoplankton biomass, in situ productivity and taxonomic composition over subseasonal, seasonal and interannual time scales

Abstract

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 145:143-160 (1996) - doi:10.3354/meps145143 Long-term monitoring and analyses of physical factors regulating variability in coastal Antarctic phytoplankton biomass, in situ productivity and taxonomic composition over subseasonal, seasonal and interannual time scales Moline MA, Prézelin BB A 3 yr high-resolution temporal data base related to phytoplankton dynamics was collected during the austral spring/summer periods of 1991 to 1994 in shelf waters adjacent to Palmer Station, Antarctica. Here, the data base is used (1) to quantify the variability in phytoplankton biomass, in situ productivity and taxonomic composition over subseasonal, seasonal and interannual time scales; (2) to elucidate environmental mechanisms controlling these temporal patterns; and (3) to ascertain which phytoplankton markers are most suitable for detecting longer-term (i.e. decadal) trends in phytoplankton dynamics in coastal waters of the Southern Ocean. The Long-Term Ecological Research (LTER) coastal study sites showed high interannual variability in peak phytoplankton biomass (75 to 494 mg chl a m-2) and integrated primary production (1.08 to 6.58 g C m-2 d-1). Seasonal and annual patterns in biomass and productivity were shown to be driven by shorter-time-scale physical forcing by local wind stress. Low daily wind speeds (<10 m s-1) were associated with water-column stabilization. However, extended periods (>1 wk) of low wind stress were required for increased phytoplankton growth and biomass accumulation. Temperature data supports the view that water masses can be replaced on time scales of a less than a day to a few days in these coastal waters. Such disruptions are associated with abrupt changes in local primary production and may lead to sudden shifts in local phytoplankton community structure. Despite the high seasonal and interannual variability in biomass and associated in situ productivity in this coastal environment, the replacement sequence of one dominant phytoplankton group by another was very similar on subseasonal time scales for all 3 years. We suggest that changes in phytoplankton successional patterns may be a more sensitive marker for detecting long-term trends in Southern Ocean ecosystems than either biomass or productivity indices, where short-term variability of the latter is as great or greater than interannual variations documented to date. Phytoplankton · Biomass · Primary production · Interannual variability · Seasonal variability · Taxonomic succession · Southern Ocean Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 145. Publication date: December 31, 1996 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1996 Inter-Research.