By K. P. Krishnan,* Rupesh Kumar Sinha**
and Kuldeep Attri*
*Scientist, National Centre for Antarctic and Ocean Research, Goa, India.
Email - firstname.lastname@example.org
**Junior Research Fellow, National Centre for Antarctic and Ocean Research, Goa, India.
***Research Scientist at National Centre for Antarctic and Ocean Research, Goa, India.
This paper presents a brief account of the inter-seasonal variability in the phytoplanktic community composition in the Kongsfjorden, an Arctic fjord. Ecologically, this Fjord represents a border area between the Atlantic and Arctic biogeographical zones. Even though records of oceanographic observations in the Kongsfjorden date back to 1905, a systematic monitoring programme for phytoplankton in conjunction with water exchange processes in the Fjord is yet to be undertaken. Hence, a programme was initiated in 2011 to study the response of the Fjord to the changing scenario in the Arctic. Water samples were collected using a Niskin sampler from predetermined depths along the major axis of the Fjord for estimation of various phytoplanktic pigments. Subsequent to preparation of pigment extracts, the samples were analysed on an Agilent 1200 series HPLC. In mid June (2011), the concentration of chlorophyll a ranged from levels of non detection to 0.5 µg/l while in early and late September the overall range was 0.01-1.3 µg/l. Diagnostic indices for diatoms, flagellates, prokaryotes and various planktic fractions were computed based on standard protocols. In mid June, the microplanktons clearly dominated the population with the diatoms and flagellate populations higher in the Fjord interior. An increase in the nanoplanktic abundance towards the Fjord interior could be attributed to the comparatively lesser concentration of chlorophyll a in the inner Fjord. In mid September, it was observed that the flagellate and prokaryotic factions showed close coupling and probably strongly influenced the Diagnostic Pigment Index. There was a significant rise in the diagnostic pigments index in late September compared to the other two periods and the abundance pattern of diatoms remained inversely related to the flagellate and prokaryotic fraction. Analysis of water column nutrients for this period indicated that the same may not be limiting (data not presented). However, in addition to the phytoplankton composition, the impact of turbidity on euphotic depth could also play a significant role on phytoplankton distribution.
Introduction The Kongsfjorden, a 25 km long and 5-10 km wide glacial fjord on the north-west coast of Svalbard is an established reference site for Arctic marine studies with great potential for international, multidisciplinary collaboration due to the presence of the international research platform in Ny-Ålesund (78o55' N, 11o56' E). Because Kongsfjorden receives variable Arctic/Atlantic climatic signals between years with measurable effects on the physical and biological systems, it functions as a climate indicator on a local scale. Kongsfjorden is...