Dynamics and attenuation characteristics of periphyton upon artificial substratum under various light conditions and some additional observations on periphyton upon Potamogeton pectinatus L.

Abstract

The seasonal variation in periphyton dynamics has been studied upon artificial substratum (microscopic glass slides) under various light conditions during the periods May-October 1986 and May-September 1987, in Lake Veluwe. Some additional observations on the periphyton development upon leaves of Potamogeton pectinatus L. have been made simultaneously. Four different light conditions were created in an experimental setup by manipulating the photon flux density through artificial shading.Periphyton upon artificial substratum exhibited a relatively high abundance with a distinct seasonal pattern. Periphyton accrual rates were highest at the beginning of June and in August and September upon slides which were incubated for two weeks. Periphyton mass increased during May and June, decreased or remained about the same during July and subsequently increased until an upper plateau was reached upon slides which were incubated from the beginning of May onwards.Generally, periphyton mass was lower upon slides than upon P. pectinatus. The seasonal variation in periphyton mass was more pronounced upon P. pectinatus leaves than upon the slides.Attenuation by periphyton upon slides ranged from 5 to 65 % after two weeks of incubation. Periphyton upon slides which had been incubated for more than two weeks demonstrated an attenuation of more than 85%.Water quality parameters other than photon flux density were probably more important in determining the periphyton dynamics, since only minor differences were observed in periphyton mass between the various light conditions. Chlorophyll-a content was higher with increased shading on various sampling dates.Periphyton, especially 'older' periphyton consisted largely of settled silt and clay particles and to a lesser extent of detrital matter on both substrata. Living epiphytes were only a relatively small fraction.It is concluded that a reduction of resuspension of sediment particles, giving less suspended matter in the water column, will result in lower periphytic mass. Consequently, the quantity of photosynthetically active radiation reaching the submerged macrophytes is expected to increase considerably. 144

The diurnal distribution of the zooplankton community of the littoral zone of Lake Wielkowiejskie (Wielkopolski National Park, Poland)

“…Furthermore, food availability may also influence the spatial distribution of zooplankton communities. In the littoral zone, apart from phytoplankton present in the interstem spaces, the nutritional source consists of periphytic algae, enriched by bacteria, protozoans and a large mass of detritus (Van Dijk 1993). Macrophytes, which differ in their architecture, in the fineness of leaves and also in the texture of the plant surface, influence the structure of epiphytic communities (Blindow 1987); hence zooplankton community structure may vary between particular plant species.…”

Potential for the development of submerged macrophytes in eutrophicated shallow peaty lakes after restoration measures

“…Light attenuation by periphyton Thin 1.5 cm 2 glass discs were used to measure shading by periphyton (Van Dijk, 1993). Ten glass discs were placed at a depth of 10 cm below the water level, and ten other plates at a depth of 50 cm.…”

Habitat requirements for submerged aquatic vegetation in Chesapeake Bay: Water quality, light regime, and physical-chemical factors

“…Studies in various estuarine habitats indicate that light attenuation by epiphytic material contributes an additional 15-50% shading on SAV (Bulthuis and Woelkerling 1983;Sand-Jensen and Borum 1983;van Dijk 1993;Vermaat and Hootsmans 1994). A recent detailed study of Thalassia testudinum beds in Florida coastal waters (Dixon 2000) showed that, while light levels at the maximum depth of seagrass colonization averaged about 22% of surface irradiance, epiphytic attenuation reduced this to approximately 15% of surface light actually available to the plants.…”