My research concerns human impacts on freshwater wetland ecosystems. I have worked with several protocols in the field, all of which included indicators of ecosystem health such as presence/abundance of algae.
In particular, an abundance of filamentous algae is taken to indicate unnatural nutrient loading and hence unnaturally anaerobic conditions. But how much is too much? Is this a simple "field-crew friendly" indicator, or will it be necessary to learn a lot more about algae before using them as proxies for O2 depletion? Are some algae more "unnatural" than others? I have noticed non-filamentous types of algae (growing on underwater rocks or drying on shore) and wonder if they also indicate either nutrient loading and/or anaerobic conditions. It might also be important to determine suitable algae habitat before assuming that their absence indicates an absence of excess nutrients; some streams are just too turbulent, while others may be too dark, to support algae. Can anyone briefly describe (or point me to a resource describing) the habitat and functional importance of different freshwater algae?
