Sinking and floating rates of natural phytoplankton assemblages in Lake Erken

Rodrigo, M. A. and Pierson, D. C. and Pettersson, K. and Kaup, E. and Padisák, Judit (1998) Sinking and floating rates of natural phytoplankton assemblages in Lake Erken. In: Seminar on Lake Erken - 50 Years of Limnological Research, 1996. október, Uppsala University, Uppsala, Sweden.


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Sinking rates of the <120 mu m size phytoplankton fraction of water from Lake Erken were determined during the summer 1992 by following the increase of chlorophyll a in the 10 ml-bottom layer in replicate 100 ml settling cylinders. Changes in chlorophyll a concentrations as a function of incubation time allowed two fractions to be separated. Fast sinking rates varied between values of 1.9 m/day when pennate and centric diatoms and coccal cyanobacteria were dominant tin cell concentration) and values of 0.5 m/day when cryptophytes and chrysophytes dominated the <120 mu m size fraction. Slow sinking rates decreased from 0.04 m/day at the beginning of July to 0.02 m/day in late July. Photosynthesis-Irradiance parameters (P-max(B) light saturated photosynthesis and #alpha#(B), light limited photosynthesis) were lower in the fast sinking fraction (P-max(B) = 1.3 - 2.4 mu gC/mu gChl/h and #alpha#(B) = 0.01 - 0.04 mu gC/mu gChl/h/(mu E/m(2)/s) than in the slow or non-sinking one (P-max(B) = 3.9 - 6.4 mu gC/mu gChl/h and #alpha#(B) = 0.03 - 0.08 mu gC/mu gChl/h/(mu E/m(2)/s). P-max(B) and #alpha#B of the planktonic Gloeotrichia echinulata, a colonial broom-forming cyanobacterium, were similar to those found in the fast sinking fraction. Mean floating rates of G. echinulata were around 43 m/d from 15 to 27 July and increased by a factor of two afterwards. G. echinulata colonies migrating upwards from sediments and captured in inverted traps showed a mean floating rate of 104 m/d.

Item Type: Conference or Workshop Item (Paper)
Subjects: Q Science / természettudomány > QE Geology / földtudományok > QE08 Hydrosphere. Hydrology / hidroszféra, hidrológia
Q Science / természettudomány > QH Natural history / természetrajz > QH301 Biology / biológia
Q Science / természettudomány > QK Botany / növénytan
Depositing User: Erika Bilicsi
Date Deposited: 30 Oct 2012 14:43
Last Modified: 30 Oct 2012 14:43

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