Community structure and spatial distribution of phytoplankton in relation to hydrography in the Laptev Sea and the East Siberian Sea (autumn 2008)

Abstract

The Laptev Sea and the East Siberian Sea are remote areas of the Arctic region where detailed data on phytoplankton composition and spatial distribution remain limited. In the context of the ongoing environmental changes (increasing warming and ice melting) and prospective exploration activities (oil and gas production) on the Arctic shelves, understanding of the seasonal and interannual phytoplankton community dynamics is of critical importance. Our study provides new specifying data on species composition of phytoplankton over the vast area of the Laptev Sea shelf and the East Siberian Sea shelf. We found that the outer shelf of the Laptev and East Siberian seas was characterized by typical late spring diatom species (Chaetoceros furcellatus, Chaetoceros diadema, Chaetoceros debilis, Chaetoceros constrictus). On the inner shelf of the Laptev Sea, which is strongly affected by the Lena River water masses, the phytoplankton were characterized by the transition from the summer to an autumn stage of development. Local algal assemblages were composed by mixo-and heterotrophic dinoflagellates (Dinophysis and Protoperidinium genera) together with marine and brackish water-marine diatoms (Thalassiosira hyperborea, Thalassiosira baltica, Thalassiosira gravida, Thalassiosira nordenskioeldii) accompanied by sporadically occurring freshwater riverine planktonic diatom species (Aulacoseira granulata, Aulacoseira italica, Asterionella formosa). These variations in species composition over the Laptev Sea shelf were attributed to differences in the hydrography, marine chemical conditions, and the sea-ice regime.

Nutrient and Silicon Isotope Dynamics in the Laptev Sea and Implications for Nutrient Availability in the Transpolar Drift

“…(2016) therefore invoked seasonal DSi drawdown occurring in sea ice to explain the discrepancy between observed and expected 30 ε in the Canada Basin. In contrast, the Laptev Sea was essentially ice‐free during the sampling campaigns in September 2013 and 2014 and pelagic diatoms rather than sea ice diatoms processed all DSi, which can be inferred from the absence of the latter in preceding years with similar conditions (Polyakova et al., 2021).…”

Tight association between microbial eukaryote and giant virus communities in the Arctic Ocean

“…The representative sequence of the unclassified marine alveolate ASV was best hit to the dinoflagellate Heterocapsa rotundata in the NCBI Reference RNA sequences database (updated 07 July 2021) (100% sequence similarity). Although this dinoflagellate species has been detected typically in the temperate estuaries (Kyeong et al 2006; Millette et al 2015), it was also found to be common near the study area (Polyakova et al 2021).…”

Multi-Element Composition of Diatom Chaetoceros spp. from Natural Phytoplankton Assemblages of the Russian Arctic Seas

“…Overall, in the shelf seas of the Arctic Ocean, the productivity and composition of phytoplankton communities are jointly governed by strong seasonality in the light regime and sea-ice cover, as well as a strong freshwater signal originating from river runoff [43][44][45].…”

“…In general, the variation in the concentration of major elements in the Chaetoceros spp. diatoms in the Siberian Arctic seas was probably associated with the different functional states of microalga communities in the autumn period and with the stages of their cell cycles [37,43]. However, this assumption requires additional studies.…”