Carbon dioxide sequestration and heterotrophy in shallow lakes.

Abstract

Research has recently begun to show the importance of lakes in controlling global CO2 budgets, but this work has only been done on a few large lakes. Small, shallow lakes and wetlands are the most plentiful lake ecosystems in world, but the most ignored. Here, I explore their ability to sequester CO2 and in some cases release the greenhouse gas to atmosphere. I found that pristine shallow lakes where macrophytes (aquatic vegetation) dominated, the lakes sequestered much more CO2 than disturbed lakes where phytoplankton dominated. Furthermore, I found that heterotrophs in shallow lakes respired tremendous amounts of carbon of terrestrial origin, thus calling into question the net ability of terrestrial ecosystems to sequester carbon. Finally, I found that some of the underlying mechanisms, including the productivity of different autotrophs and growth efficiencies of bacteria, favor greater carbon sequestration by macrophyte-rich shallow lakes. All of my observations form a basis for future work into the ability of shallow lakes to sequester CO2 and stresses the importance of not only saving shallow lakes and wetlands, but preserving them in a macrophyte-rich state.