Phytoplankton Composition and Geographical Distribution in the Eastern Laptev Sea in the Autumn 2008.

Kryukova, Irina (2011) Phytoplankton Composition and Geographical Distribution in the Eastern Laptev Sea in the Autumn 2008. (Master thesis), State University of St. Petersburg, Russia ; University of Hamburg, St. Petersburg, Russia ; Hamburg, 51 pp.

[img] Text
2011_Kryukova-Irina_MSc-Thesis.pdf - Accepted Version
Restricted to Registered users only
Available under License Creative Commons Attribution Non-commercial.

Download (2267Kb) | Contact

Abstract

Over the last decades the Arctic region is experiencing an intense climate change leading to the variability of the marine environments in the Siberian shelf seas. The changes of the thermal conditions, ice cover, water masses circulation and other key parameters of marine environment directly affect the productivity of phytoplankton, its seasonal dynamics and peculiarities of species composition. Long-term observations of the phytoplankton assemblages in the high latitudes will provide the background for the assessment of ecosystem changes connected with climate variability in the Arctic region.
This study is focused on the investigation of species composition and the peculiarities of spatial and temporal distribution of phytoplankton in the eastern Laptev Sea. Samples were collected during the TRANSDRIFT XIV expedition in September 2008. Phytoplankton abundances were determined by cell countings, which provided the basis for biomass calculations according to taxon-specific carbon values. The Shannon-Wiener index was used to estimate the species diversity. Special attention was paid to the ecological preferences and the phytogeographical distribution of identified species to reveal the influence of seasonal and abiotic factors (salinity, nutrient supply, riverine discharge etc.) on phytoplankton communities in the studied area.
The obtained results indicated that we observed a late stage of a seasonal succession pattern of the phytoplankton community. The algal standing stock consisted mainly of marine planktonic diatoms and dinoflagellates. The overall abundance of algae in the water column ranged from 190 to 5 040 cell × l-1. Total phytoplankton biomass in the water column ranged between 0.15 and 9.65 μg C × l-1. The highest values of algal abundance and biomass were observed in the vicinity of the Lena Delta. Diatoms were dominated by arctic-boreal marine and brakish water-marine species (Thalassiosira baltica, T. hyperborea, Chaetoceros diadema, C. socialis, C. wighamii). Dinoflagellates of a wide geographical distribution such as cosmopolitan and arctic-boreal-tropical species made up the most taxonomically diverse group (16 taxa) and were mainly represented by Dinophysis acuminata, D. rotundata, Gonyaulax spinifera, Preperidinium meunierii, Protoperidinium bipes, P. pallidum, P. pellucidum. Heterotrophic and mixotrophic forms were characteristic of dinoflagellate communities during the investigated period. The spatial pattern of the species distribution was affected by the Lena River discharge. Brackish water-marine euryhaline diatoms concentrated in the area north- and eastward of the Lena Delta, which was under the Lena River plume during September 2008. Marine neritic dinoflagellate and diatom species prevailed in the northern sampling area with higher salinity. The obtained results generally agree with previously published data on phytoplankton composition and its distribution in the eastern Laptev Sea during autumn.

Document Type: Thesis (Master thesis)
Thesis Advisors: Polyakova, Yelena I. and Dullo, Wolf-Christian
Keywords: Arctic region; Climate change; Siberian shelf seas; Lena Delta; Laptev Sea, East; Marine Environment; Phytoplankton; Diatoms; Dinoflagellates
Research affiliation: OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-P-OZ Paleo-Oceanography
Projects: POMOR
Expeditions/Models/Experiments:
Date Deposited: 17 Mar 2015 10:04
Last Modified: 17 Mar 2015 10:04
URI: http://oceanrep.geomar.de/id/eprint/28049

Actions (login required)

View Item View Item

Document Downloads

More statistics for this item...