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.
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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