Dominance of picophytoplankton in the newly open surface water of the central Arctic Ocean

Abstract

Picophytoplankton are the main primary producers in oligotrophic oceans. They account for more than 90 % of the phototrophic biomass. Investigations of picophytoplankton in the central Arctic Ocean region are rare because these waters used to be completely covered with sea ice. Large, newly exposed water areas, however, appeared in the sea ice zone during the summer of 2010. This provided the first opportunity to study the Arctic picophytoplankton community in these newly open surface waters. This study focuses on the picophytoplankton in the areas near the Alpha-Mendeleev Ridge and Makarov Basin. Here, HPLC pigment analysis with CHEMTAX was used to study community populations, and 454 pyrosequencing with bioinformatics analysis was used to identify the dominant genera (species). Both Pearson correlation analysis and canonical correlation analysis were used to study the relationships between the community and environmental factors. We found chlorophyll a concentrations were low (0.05-0.39 lg l -1 ), and picophytoplankton dominated these areas. The abundances of picophytoplankton were 1.58 9 10 6 -9.47 9 10 6 cells l -1 and made up 44-80 % of the total chlorophyll a. Prasinophytes made up 0-88 % of the picoplanktonic chlorophyll a with the following distributions: diatoms (2-80 %), cyanobacteria (0-20 %), haptophytes (4-14 %), and dinoflagellates (2-11 %). The dominant genera (species) in the picoeukaryotes were Pyramimonas (Pyramimonas gelidicola), Micromonas (Micromonas pusilla), and Phaeocystis. Salinity and latitude were the primary factors controlling the community structure of the picophytoplankton.

Carbon export fluxes and export efficiency in the central Arctic during the record sea‐ice minimum in 2012: a joint 234Th/238U and 210Po/210Pb study

“…Our finding is in line with recent observations that reveal that small cells are important contributors to POC export fluxes in diverse oceanic regimes [e.g., Richardson and Jackson , ; Lomas and Moran , ; Durkin et al ., ; Mackinson et al ., ; Puigcorbé et al ., ]. Prasinophytes, including Micromonas spp., are common in the central Arctic [ Booth and Horner , ; Sherr et al ., ; Zhang et al ., ], and are considered to be among the most abundant photosynthetic cells in pan‐Arctic waters [ Lovejoy et al ., ]. Genetic analyses in trap samples revealed that prasinophytes contributed to downward fluxes in the Sargasso Sea [ Amacher et al ., ], but to our knowledge, this has not been observed before in Arctic waters.…”

Functional Genomics Differentiate Inherent and Environmentally Influenced Traits in Dinoflagellate and Diatom Communities

“…Yet dinoflagellates include autotrophic, heterotrophic, parasitic and endosymbiotic species, thus encompassing diverse ecological niches. Differences in the life strategies and nutrition modes of these two groups should be detectable in their expressed genes, as identified for diatoms [22], dinoflagellates [23,24] or both groups [25,26]. However, microeukaryotes are regulated by the interplay of individual species traits, biotic interactions and the environment [15] and these interacting challenges render it difficult to identify specific trophic roles.…”

Seasonal patterns in Arctic prasinophytes and inferred ecology of Bathycoccus unveiled in an Arctic winter metagenome

“…While the heterokont Phaeocystis is reported in the picophytoeukaryote fraction of Atlantic influenced waters of Fram Straight in the European Arctic (Kilias et al, 2014), over the summer and autumn throughout much of the Arctic, including at the North Pole, a single mamiellophyte represented by the cultured strain Micromonas sp. CCMP2099 (Lovejoy et al, 2007;Balzano et al, 2012;Zhang et al, 2015) dominates picophytoeukaryotes. A second mamiellophyte, Bathycoccus prasinos, is also consistently reported from Arctic marine waters but as a minor community constituent (Lovejoy and Potvin, 2011;Balzano et al, 2012).…”