Leachates and elemental ratios of macrophytes and benthic algae of an Andean high altitude wetland

Abstract

In wetlands, macrophytes and filamentous algae constitute an important carbon source for the total content of Dissolved Organic Matter (DOM) of the environment. Mallín wetland meadows are highly diverse and rare habitats in Patagonia, that can be characterized as wet meadows with a dense cover mainly dominated by herbaceous plants. We carried out a field study comparing elemental composition (C:N:P) of benthic algae (Spirogyra sp. and Zygnema sp.) and the submerged macrophyte (Myriophyllum quitense) from a high latitude wetland (local name: mallín). Besides we performed laboratory experiments in order to study the effect of ultraviolet radiation (UVR) on the optical properties and nutrient release of DOM from leachates of these benthic algae and submerged macrophyte. The obtained results indicated that macrophyte leachates could contribute significantly to changes in the optical characteristics of the wetlands while benthic algae contribute with leachates with low photoreactivity. Finally, nutrient release differs among plant species and season: benthic algae leachates release more P in spring, while M. quitense releases more of this nutrient in autumn. These results suggested that the different colonization may contribute differentially to the chemical environment of the wetland.

Keywords

• high altitude wetlands, submerged macrophytes, dissolved organic matter, carbon nitrogen phosphorus, ultraviolet radiation