Changes in water properties in two different macrophyte stands and in open water in a shallow freshwater in Turkey

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.