Microbial indicators of aquatic ecosystem change: current applications to eutrophication studies

Abstract

Human encroachment on aquatic ecosystems is increasing at an unprecedented rate. The impacts of human pollution and habitat alteration are most evident and of greatest concern at the microbial level, where a bulk of production and nutrient cycling takes place. Aquatic ecosystems are additionally affected by natural perturbations, including droughts, storms, and floods, the frequency and extent of which may be increasing. Distinguishing and integrating the impacts of natural and human stressors is essential for understanding environmentally driven change of microbial diversity and function. Microbial bioindicators play a major role in detecting and characterizing these changes. Complementary use of analytical and molecular indicator tools shows great promise in helping us clarify the processes underlying microbial population, community, and ecosystem change in response to environmental perturbations. This is illustrated in phytoplankton (microalgal and cyanobacterial) and bacterial community changes in a range of US estuarine and coastal ecosystems experiencing increasing development in their water- and airsheds as well as climatic changes (e.g., increasing hurricane frequency). Microbial indicators can be adapted to a range of monitoring programs, including ferries, moored instrumentation, and remote sensing, in order to evaluate environmental controls on microbial community structure and function over ecosystem to global scales.

Impacts of Mariculture on the Diversity of Bacterial Communities within Intertidal Sediments in the Northeast of China

“…Bacteria in surface sediment have massive diversity and rapid growth rate, and their populations are largely influenced by pollutants of water columns [7,8]. Recently, molecular method-based studies have indicated that bacterial diversity in sediment has been linked with impacts of anthropogenic activities, such as increase of eutrophication and chemical pollution [9][10][11][12][13], changes in species of phytoplankton or zooplankton [14][15][16], and operating a dredging, reclamation, or remediation project [17][18][19][20].…”

Palaeoecology: A tool to improve the management of Australian estuaries

“…Approximately 70% of the world's population and 85% of the Australian population is concentrated within 50 km of the coast (Paerl et al 2003. Many areas of the Australian coastline have been extensively modified and in some cases heavily degraded over a relatively short period of time since European settlement began over 200 years ago.…”

Flavobacterial response to organic pollution

“…Hypoxia/ anoxia may lead to the replacement of aerobic species with microaerophilic and anaerobic species and as a result alter ecosystem functions such as nutrient cycling (Paerl 1998). Overall, microbial activity in marine sediments is determined by geographic position, sedimentation rate, quality of the sedimenting material, temperature and sediment chemical conditions, but it is well established that sediment communities respond rapidly to altered nutrient input (Battersby & Brown 1982, Paerl 1998, Cloern 2001, Paerl et al 2003.…”