Phytoplankton and pelagic primary productivity in Ovre Heimdalsvatn

• Published in: Holarctic ecology Vol. 1; no. 2/3; pp. 128 - 147
• Main Authors: Tangen, K, Brettum, P
• Format: Journal Article
• Language: English
• Published: Munksgaard International Booksellers and Publishers 1978
• Subjects: Biomass; Carbon; Ice; Irradiance; Lakes; Phytoplankton; Plankton; ponds; Primary productivity; Species; Summer; Norway
• ISSN: 0105-9327

A phytoplankton investigation was carried out in the subalpine, low-productive Norwegian lake Øvre Heimdalsvatn in 1969-70 and 1972. This paper describes the temporal and spatial distribution of the standing stock of phytoplankton, and phytoplankton primary productivity. The annual average primary productivity in 1972 was$4.0-4.9\ {\rm mg}\ {\rm C}\ {\rm m}^{-3}\ {\rm d}^{-1}$; the annual average standing stock varied from$120\ {\rm mg}\ {\rm m}^{-3}$(freshweight) in 1969-70, to$250\ {\rm mg}\ {\rm m}^{-3}$in 1972. Phytoplankton species composition and size distribution is discussed. Throughout the year the phytoplankton is dominated by small (ultraplankton) species; μ-algae (< 5 μm) showed cell concentrations up to 15 mill. cells l-1. The dominating group was chrysophytes; cryptophytes, dinoflagellates or green algae were at times abundant. A phytoplankton monthly budget and a diagram showing annual average carbon flow through the standing stock of phytoplankton are presented; the phytoplankton dynamics in Øvre Heimdalsvatn is compared to that of other low-productive lakes.