The classical understanding of what drives blooms of freshwater algae and phytoplankton – warm water and nutrients – probably stands. In fact a recent whole lake experimental study in the USA found that available phosphorous was still the main predictor for cyanobacterial biomass and could be detected in enough time to take preventative action (Pace et al. 2016). But water bodies are variable – especially in size and chemistry and whether this longstanding pattern is ubiquitous is not clear. Here in the south of England we have large eutrophic drinking water reservoirs but little catchment rainfall – so water bodies are often a mix of water sources pumped from what can be different catchments. Despite this an early look at long term data suggests Phosphorous availability is highly correlated with algal biomass.
The problem is long term data is bias – there is more of it in the past when some of the more recent multi-stressors on freshwater environments were not so prominent, especially temperature.
We at Essex – myself, Eteinne Low-Decarie & Graham Underwood – are investigating the control of algal production, algal community composition and the biochemical feedbacks from algae (e.g. gases) in reservoirs in southern England. We will be starting up a number of lab and field based projects over the coming months and one such project – characterising control of algal production in pelagic and littoral reservoir habitats – is starting this week spearheaded by PhD student Amie Parris. So look out for our updates on Twitter!