HR: 1330h
AN: NB33Q-07    [Abstracts]
TI: Benthic Diatoms of an Alpine Stream/Lake Network in Switzerland
AU: * Rueegg, J
EM: janine.rueegg@eawag.ch
AF: Janine Rueegg, EAWAG Ueberlandstrasse 133, Duebendorf, ZH 8600 Switzerland
AU: Robinson, C T
EM: robinson@eawag.ch
AF: Christopher T. Robinson, EAWAG Ueberlandstrasse 133, Duebendorf, ZH 8600 Switzerland
AU: Kawecka, B
EM: kawecka@iop.krakow.pl
AF: Barbara Kawecka, Institute of Nature Conservation Polish Acadamy of Science Al.A. Mickiewicza 33, Krakow, 31-120 Poland
AB: We compared the benthic diatom composition of lakes, and lake inlet and outlet streams in a high elevation catchment (~2600 m a.s.l.). The catchment was separated in a southern and northern basin with different water sources. Streams in both basins flowed through a series of small lakes before converging into a lake with a primary outlet. The south basin had lower water temperatures and 2× higher nitrate-N levels (up to 300 μg/L) while the north basin had 2-4× higher levels of particulate-P, particulate-N, and particulate organic matter. 143 and 109 diatom species was identified in streams and lakes, respectively, with a similar number of species found in each basin. PCA showed a clear separation between basins. Of the 10 most common species, Psammothidium helveticum, Achnanthes helvetica var. minor, Achnanthes marginulata, Achnanthes subatomoides, and Diatoma mesodon were more abundant in south basin, whereas Achnanthidium minutissimum, Aulacoseira alpigena and Luticola goeppertiana were more abundant in the north. In general, lake outlet assemblages were similar to respective downstream lake inlet assemblages. Composition shifted along each basins longitudinal flow path. The spatial patterns in species composition reflected the hierarchical interaction of landscape features (geology, hydrology) on longitudinal gradients (lake position) in the stream/lake network.
DE: 1845 Limnology
DE: 1899 General or miscellaneous
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly