P. Dobrzyna, b, A. Taturc, and A. Keckd
a Nencki Institute of Experimental Biology, Pasteura 3, PL-02-093 Warszawa, Poland
b Institute of Biology, University of Bialystok, Swierkowa 20B, PL-15-950 Bialystok, Poland
c Department of Antarctic Biology, Polish Academy of Science, Ustrzycka 10, PL-02-141 Warszawa, Poland
d University Centre in Svalbard, P.B. 156, N-9171 Longyearbyen, Norway
e-mail: p.dobrzyn@nencki.gov.pl
Abstract—The study was carried out from April 30 until July 13 of 1997 in Adventfjorden (Spitsbergen). For-
mation of less saline and warmer surface water (~1 m thick) caused by melting of the fast ice was observed in
the fjord during the first days of May. In summer a less saline surface layer was about 3 m thick. Euphotic depth
measured under ice sheet reached 12 m, whereas load of mineral matter brought with riverine discharge in sum-
mer (the content of total particulate matter in the fjord reached 1.66 kg m–2) dramatically reduced euphotic zone
depth to 0.35 m. By pigment measurement three phases of phytoplankton development in Adventfjorden were
distinguished: (1) spring bloom that has started under fast ice and reached maximum in the mid of May,
(2)stagnation period in June, (3) increase of pigment concentration in July, what could indicate a start of the
next algae bloom. Analyses of chlorophylls and carotenoids revealed that diatoms (chl c, fucoxanthin), and
green algae (chl b, lutein) dominated phytoplankton community in the fjord. Moreover, the presence of peridi-
nin indicates the presence of Dinophyta and alloxanthin—the occurence of Cryptophyta. In May and June 1997
phytoplankton appeared mainly in the surface of water, while in July, as a result of inflow of turbulent riverine
waters into Adventfjorden, algae cells were pushed down and the highest numbers were observed at the depth
~20 m. Great phaeopigments to chl a ratio (= 0.54) found in the fjord seston in June and July probably shows
strong impact of zooplankton grazing on phytoplankton development. High contribution of chlorophyllide a in
porphyrin a poll in samples collected under fast ice (chlorophyllide a/chl a ratio = 0.18) reflects the final stage
of algal communitie succession in ice, just before spring ice melt and release of biota to oceanic water. Chlo-
ropyllide a content during summer was minor or not detectable, demonstrating that diatom cells were in good
physiological condition. High chl a allomer/chl a ratio (average = 0.11 for the period investigated) confirms
high oxygen concentration in environment of Adventfjorden.
DOI: 10.1134/S0001437009030096
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