Seasonal dynamics of primary production in the pelagic zone of southern Lake Baikal

Autor: Yoshida, T., Sekino, T., Genkai-Kato, M., Logacheva, N. P., Bondarenko, N. A., Kawabata, Z., Khodzher, T. V., Melnik, N. G., Hino, S., Nozaki, K., Nishimura, Y., Nagata, T., Higashi, M., Nakanishi, M.
Zdroj: Limnology; 20030401, Vol. 4 Issue: 1 p0053-0062, 10p
Abstrakt: Abstract:  We measured primary production by phytoplankton in the south basin of Lake Baikal, Russia, by in situ 13C-bicarbonate incubations within the period March–October in two consecutive years (1999 and 2000). Primary production was highest in the subsurface layer, possibly due to near-surface photoinhibition of photosynthesis, even under 0.8 m of ice cover in March. Areal primary production varied from 79 mg C m−2 day−1 (March) to 424 mg C m−2 day−1 (August), and annual primary production was roughly estimated as 75 g C m−2 year−1, both of which are within the lower range of previous estimates. Size fractionation measurements revealed that phytoplankton in the <20 μm fraction accounted for 72%, 96%, and 85% of total primary production in March, August, and October, respectively. The contribution of picophytoplankton (<2 μm) to total primary production ranged from 41% to 62%. A large fraction (82%–98%) of particulate organic carbon was associated with particles in the <20 μm fraction. These results suggest that nano- and picophytoplankton play an important role as primary producers in the pelagic ecosystem of Lake Baikal.
Databáze: Supplemental Index
Externí odkaz: