A diverse group of simple plants that contain chlorophyll and can photosynthesize. An algal bloom is a dense spread of algae caused by changes in water chemistry and/or temperature; Shukla et al. (2008) Appl. Maths & Comput. 196, 2 find a positive correlation between increasing nutrients in water and algal density—leading to eutrophication. Moran et al. (2001) CSIRO Land & Water Tech. Rept. 20/01 question the proposed link between phosphorus entering channel systems and algal blooms.