Decomposition and Recycling in Aquatic Ecosystems

1095 words 5 pages
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.
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Eucalyptus had the second lowest with a total mean tissue loss of 3.67mg, differing between wetlands by 2.4mg. Salix had the lowest difference in mean loss between wetlands of .04mg, the lowest mean tissue loss of the three species between wetlands.

The aim of this experiment was to investigate and compare rates of decomposition of autochthonous and allochthonous leaf material immersed in different wetland types. The results indicate the native species being more resistant to decomposition than the introduced Salix. The results did not vary greatly between wetlands for the species. This large difference in mean tissue loss for Salix was possibly related to its susceptibility to native predators.
The structural weaknesses of Salix leave it susceptible to predation to a higher degree than Eucalyptus and Phragmite. Salix has a very thin cuticle and minimal schlerenchyma, which means that it has little support. The palisade close to the epidermal layer contains high degrees of protein, making them very attractive to herbivores.
Eucalyptus had a lower rate of tissue loss than the Salix. The structural differences between the Eucalyptus and the Salix mean that it is better defended against herbivory. The thicker cuticle and thicker epidermal layer slows the rate at which invertebrates can decompose the leaves. Cellulose covers the cell walls, due to its slow breakdown herbivores are less attracted to a leaf that burns more