Decomposition and Recycling in Aquatic Ecosystems

Introduction
Biogeochemical cycles are important to the sustainability of all life. Chemical elements necessary for the growth and reproduction of all organisms have a limited quantity on earth at any one time, other than the occasional meteor that brings with it new matter. It is therefore important that the recycling of these chemical elements is efficient. Autotrophs are the basis of almost all ecosystems. The rate that autotrophs produce and transfer energy is vital to the capacity of organisms that can inhabit these ecosystems. To understand the rates in which certain species’ leaves decay and release the energy stored within them can demonstrate how quickly the energy becomes available to organisms in higher trophic levels.
Between plant species the rate of decomposition varies according to leaf structure, chemical or physical defence and whether the species is allochthonous or autochthonous. Native species adapt to the predators that feed upon them and the same applies for the predators, adapting to the plants defences. Allochthonous species have not evolved with the native predators in its introduced environment. In some cases this can result in the plant being more susceptible to predation.
The aim of this experiment was to investigate and compare rates of decomposition of different species of leaf material and examine if there is a difference in tissue loss between the same species immersed in different wetland types. By examining the rate of decomposition of three different leaf types we can determine the rate that energy becomes available to the inhabitants of the ecosystem. It is hypothesized that allochthonous Salix species will not have defence against native predators and will produce the highest rate of tissue loss. Eucalyptus will have the second highest rate of tissue loss due to its autochthony; while it has strong structural and chemical defences, predators have been able to adapt and successfully predate the Eucalyptus leaves. Phragmite