The Coorong, Lower Lakes and Murray Mouth (CLLMM) region is quite biodiverse, due to highly variable environmental conditions over a relatively small area. The varying environmental conditions create a broad array of habitats due to physical (ie presence of structure), chemical (ie variations in water quality/salinity) and biological (ie presence of aquatic macrophytes) factors (Chapters 2.7 & 2.10). As such, the region is well known for the presence of a diverse array of biota, particularly bird and fish taxa. However, other biota such as plankton are also abundant and diverse in the region for the same reasons as higher trophic order animals. Plankton are a diverse group of microorganisms that live in water, ranging from unicellular organisms smaller than 0.2 µm (femtoplankton) to multicellular organisms up to 20 cm (macroplankton)(Table 3.1. 1).

Autotrophic planktonic organisms, such as Cyanobacteria and microalgae, photosynthesise like plants and produce their own food from inorganic compounds, such as nutrients and minerals, using energy captured from sunlight. The importance of nutrients, cyanobacteria and microalgae to aquatic ecosystems has been well documented in the literature, and consequently they have been monitored across the CLLMM region since the 1970s, although