Author(s): David Hamilton
Linked Author(s): David Hamilton
Keywords: IAHR; Hydrolink; David Hamilton; biota; deep lakes; eutrophication; ozone layer; phosphorus; nitrogen
Abstract: Eutrophication and the resulting degradation of large lakes is usually pervasive and long-lasting. Symptoms of degradation are manifested as increased frequency of cyanobacterial harmful algal blooms (CyanoHABs), anoxia of bottom waters, reduced complexity of food webs and the attendant loss of biodiversity. Its causes – mostly from elevated external and internal loads of nutrients (phosphorus [P] and nitrogen [N])– have been described for many decades 29, 6. Other global environmental problems, such as synthetic pesticide disruption of food chains and destruction of the ozone layer by chlorofluorocarbons, were also described many years ago but have been at least partly remediated by coordinated global responses following scientific identification of their causal factors. Controls on nutrients still remain a ‘tragedy of the commons’; despite progress in addressing point sources, diffuse nutrient emissions remain a major problem and are dispersed among a few main actors who continue to impact the broader benefits provided by lakes, their services and their role as refugia for biota.