Abstract:
Aquatic plants play an active role in structuring the
ecosystems of shallow lakes. However, the effects of dif ferent macrophyte species on the water column vary in
terms of hydrodynamics and sediment resuspension. This
study experimentally compared the effects of two different
macrophyte life-forms in a shallow semi-arid Mediterra nean Turkish freshwater lake: the floating-leaved plant
Polygonum amphibium L. and the submersed plant
Myriophyllum verticillatum L. During daylight hours
between 25th of June to 23th of July, 2009, water samples
were obtained from monospecific Polygonum amphibium
and Myriophyllum verticillatum stands with very occa sional Myriophyllum spicatum L. stands growing to the
surface in water approximately 0.5 m deep, with similar
densities across sites and in open water (three sites: two
with plant satands and one without plants). Samples were
collected from four locations for each plant species, and
the open-water samples were also collected from four
locations more than 5 m away from any aquatic plants. To
understand the vertical structure of the water chemistry,
samples were taken at depths of 0, 10 and 30 cm at each
stand and open-water sampling location. Oxygen and pH
varied among sites and depths in both the morning and
afternoon measurements. This study indicated that, simi larly to submersed macrophytes, floating-leaved plants
may play an active role in determining the water proper ties of a shallow Mediterranean lake.