Phytoplankton biomass and productivity in the marginal ice zone of the Fram Strait during summer 1984

Abstract

The biomass and primary productivity of phytoplankton assemblages from the marginal ice zone of the Fram Strait were investigated during June-July 1984 as part of the 1984 Marginal Ice Zone Experiment. The entire region was characterized by strong vertical stratification and reduced nutrient concentrations near the surface. Chlorophyll a levels were elevated at the ice edge and decreased both under the ice and away from the ice edge. Chlorophyll concentrations were greatest at the top of the pycnocline and averaged 2.9 #g L-• at 20 m. Primary productivity was also greatest at the ice edge, with daily integrated productivity averaging 426 mg C m -2 d -•. Small flagellates numerically dominated the assemblages. Growth rates, when corrected for detrital material, were close to their potential maximum for the temperatures encountered. Large differences between the water temperatures, nitrate concentrations, and chlorophyll a levels during similar periods in 1983 and 1984 were noted. These differences, in addition to the spatial and temporal variations in biological processes induced by mesoscale eddies, suggest that the interannual variability in marginal ice zones may have significant consequences to the region's food web dynamics.

Spring bloom dynamics in Kongsfjorden, Svalbard: nutrients, phytoplankton, protozoans and primary production

“…4a). The highest integrated primary production measured in this study (1.52-1.85 g C m -2 day -1 ) was much higher than what Rokkan Iversen and Seuthe (2010) (Smith et al 1987;Hirche et al 1991;Vernet et al 1998;Hodal and Kristiansen 2008). In the first 2 weeks of May, the primary production rates were relatively high even though only moderate concentrations of Chl-a were measured.…”

Summertime plankton ecology in Fram Strait—a compilation of long- and short-term observations

“…Phaeocystis pouchetii in high abundances in the marginal ice zone have also been reported during the 1980sÁ1990s (Smith et al 1987;. So Phaeocystis blooms are not a new feature in this region.…”

“…During the past decades, Fram Strait has been the investigation area of several studies, though detailed and continuous studies of the pelagic ecosystems are rare, particularly in the western part. Exceptions consist of the large interdisciplinary study Marginal Ice Zone Experiment in the mid-1980s (e.g., Smith et al 1987;Hirche et al 1991) and the Northeast Water polynya project as part of the International Arctic Polynya Programme in the 1990s (e.g., Bauerfeind et al 1997).…”

Variability of sea-ice conditions in the Fram Strait over the past 30,000 years

“…Enhanced marine organic carbon accumulation has also been observed in other cores from Fram Strait and adjacent areas 15,16 in the vicinity of the SBIS. As primary production is enhanced at the ice edge 17 , resulting in higher sedimentary concentrations of marine-derived biomarkers 18 , these elevated fluxes of IP 25 and brassicasterol probably reveal the occurrence of a stationary ice margin (about 81 • N;2 • E) during this otherwise perennially ice-covered interval (Fig. 3b).…”