scholarly journals Global change and eutrophication of coastal waters

2009 ◽  
Vol 66 (7) ◽  
pp. 1528-1537 ◽  
Author(s):  
Nancy N. Rabalais ◽  
R. Eugene Turner ◽  
Robert J. Díaz ◽  
Dubravko Justić
Keyword(s):  
Water Quality ◽  
Global Change ◽  
Coastal Waters ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Nutrient Loading ◽  
Global Climate ◽  
Oxygen Depletion ◽  
Negative Consequences ◽  
Storm Activity

Abstract Rabalais, N. N., Turner, R. E., Díaz, R. J., and Justić, D. 2009. Global change and eutrophication of coastal waters. – ICES Journal of Marine Science, 66: 1528–1537. The cumulative effects of global change, including climate change, increased population, and more intense industrialization and agribusiness, will likely continue and intensify the course of eutrophication in estuarine and coastal waters. As a result, the symptoms of eutrophication, such as noxious and harmful algal blooms, reduced water quality, loss of habitat and natural resources, and severity of hypoxia (oxygen depletion) and its extent in estuaries and coastal waters will increase. Global climate changes will likely result in higher water temperatures, stronger stratification, and increased inflows of freshwater and nutrients to coastal waters in many areas of the globe. Both past experience and model forecasts suggest that these changes will result in enhanced primary production, higher phytoplankton and macroalgal standing stocks, and more frequent or severe hypoxia. The negative consequences of increased nutrient loading and stratification may be partly, but only temporarily, compensated by stronger or more frequent tropical storm activity in low and mid-latitudes. In anticipation of the negative effects of global change, nutrient loadings to coastal waters need to be reduced now, so that further water quality degradation is prevented.

Dead Zones

2021 ◽  
Author(s):  
David L. Kirchman
Keyword(s):  
Cover Crops ◽  
Precision Agriculture ◽  
Coastal Waters ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Biological Diversity ◽  
Oxygen Depletion ◽  
Waterborne Diseases ◽  
Buffer Zones ◽  
Dead Zones

This book explores the many rivers, lakes, and oceans that are losing oxygen. Aquatic habitats with little dissolved oxygen are called dead zones because nothing can live there except some microbes. The number and size of dead zones are increasing worldwide. The book shows that oxygen loss causes fish kills, devastates bottom-dwelling biota, reduces biological diversity, and rearranges aquatic food webs. In the 19th century in rich countries and in poor regions today, dead zones are accompanied by waterborne diseases that kill thousands of people. The open oceans are losing oxygen because of climate change, whereas dead zones in coastal waters and seas are caused by excessive nutrients, which promote excessive growth of algae and eventually oxygen depletion. Work by Gene Turner and Nancy Rabalais demonstrated that nutrients in the Gulf of Mexico come from fertilizers used in the US Midwest, home to the most productive cropland in the world. Agriculture is also the biggest source of nutrients fuelling dead zones in the Baltic Sea and other coastal waters. Today, fertilizers contaminate drinking water and kick-start harmful algal blooms in local lakes and reservoirs. Nutrient pollution in some regions has declined because of buffer zones, cover crops, and precision agriculture, but more needs to be done. The book concludes by arguing that each of us can do our part by changing our diet; eating less, especially eating less red meat, would improve our health and the health of the environment. A better diet could reduce the amount of greenhouse gas emitted by agriculture and shrink dead zones worldwide.

Predicting water quality variability in a Mediterranean hypereutrophic monomictic reservoir using Sentinel-2 MSI: the importance of model functional form

2021 ◽  
Author(s):  
Ibrahim Alameddine ◽  
Mohamad Abbas
Keyword(s):  
Water Quality ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Multivariate Adaptive Regression Splines ◽  
Support Vector ◽  
Negative Consequences ◽  
Significant Drop ◽  
Chl A ◽  
Spatio Temporal ◽  
Sentinel 2

<p>Anthropogenic eutrophication is a pressing global environmental problem that threatens the ecological functions of many inland freshwaters and diminishes their abilities to meet their designated uses. Water authorities worldwide are being pressed to manage the negative consequences of harmful algal blooms (HABs) based largely on data collected from conventional monitoring programs that lack the needed spatio-temporal resolution for effective lake/reservoir management. This study assesses the potential of using Sentinel 2 MSI to predict and assess the spatio-temporal variability in the water quality of the Qaraoun Reservoir, a poorly-monitored Mediterranean hypereutrophic monomictic reservoir that is subject to extensive HABs during the growing season. The performance and transferability of water quality models previously calibrated based on Landsat 7 and 8 surface reflectance to predict Chlorophyll-a (Chl-a), total suspended solids (TSS), Secchi Disk Depth (SDD), and Phycocyanin (PC) levels in the reservoir are first assessed. The results showed poor transferability between Landsat and Sentinel 2, with all models experiencing a significant drop in their predictive skill. Sentinel 2 specific models were then developed for the reservoir based on 153 water quality samples collected over two years. Different model functional forms were then tested, including multiple linear regressions (MR), multivariate adaptive regression splines (MARS), and support vector regressions (SVR). Our results showed that for Chl-a, the MARS model outperformed MR and SVR, with an R<sup>2</sup> of 60%. Meanwhile, the SVR-based models outperformed their MR and MARS counterparts for TSS, SDD and PC (R<sup>2</sup> = 59%, 94%, and 72% respectively).</p>

Harmful algal blooms as a sink for inorganic nutrients in a eutrophic estuary

2021 ◽  
Vol 663 ◽  
pp. 63-76
Author(s):  
DA Lemley ◽  
JB Adams ◽  
JL Largier
Keyword(s):  
Coastal Waters ◽  
Harmful Algal Blooms ◽  
Phytoplankton Biomass ◽  
Algal Blooms ◽  
Nutrient Dynamics ◽  
Nutrient Loading ◽  
Positive Association ◽  
Inorganic Nutrient ◽  
Study Objective ◽  
Hydrological Variability

Phytoplankton-mediated nutrient fluxes typically provide only pulsed relief to adjacent coastal waters during the productive period, with nutrient export increasing in the absence of substantial phytoplankton biomass. On the warm temperate coastline of South Africa, the Sundays Estuary is characterised by highly regulated freshwater inflow patterns, nutrient-enriched conditions, and resident harmful algal blooms (HABs). Given these attributes, the study objective was to investigate the effect of these phytoplankton blooms on fluvial inorganic nutrient dynamics. To assess uptake, we analysed inorganic nutrient (phosphate, ammonium, NOx) and phytoplankton concentrations in relation to salinity using data from 17 surveys. Property-salinity mixing diagrams and statistical analyses indicated a positive association between increasing phytoplankton biomass and decreasing NOx flux (p < 0.001), and to a lesser degree phosphate flux (p = 0.22), along the gradient from low-salinity inner estuary to high salinity outer estuary. High biomass HAB accumulations of Heterosigma akashiwo (>100 µg chl a l-1) represent significant removal of available NOx (~100%) and phosphate (>75%) during warmer conditions (>20°C). These events, together with continuous inorganic nutrient uptake during less severe bloom conditions, remove a substantial portion of annual NOx and phosphate loads (36.5 and 36.4% flux, respectively). Although this buffers inorganic nutrient loading to adjacent coastal waters, it also represents an emerging legacy pollution issue in the form of a benthic accumulation of organic material in bottom waters subject to recurrent hypoxia. Future management efforts should adopt an ecosystem-based approach centred around simultaneous restoration of hydrological variability and dual nutrient reduction strategies (N and P).

scholarly journals Nutrient Loading and Viral Memory Drive Accumulation of Restriction Modification Systems in Bloom-Forming Cyanobacteria

mBio ◽  
2021 ◽  
Author(s):  
Spiridon E. Papoulis ◽  
Steven W. Wilhelm ◽  
David Talmy ◽  
Erik R. Zinser
Keyword(s):  
Water Quality ◽  
Microcystis Aeruginosa ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Nutrient Loading ◽  
Major Contributor ◽  
Content Type ◽  
Global Threat ◽  
Restriction Modification ◽  
Restriction Modification Systems

Harmful algal blooms (HABs), caused by cyanobacteria like Microcystis aeruginosa , are a global threat to water quality and use across the planet. Researchers have agreed that nutrient loading is a major contributor to HAB persistence.

scholarly journals A global scan of how the issue of nutrient loading and harmful algal blooms is being addressed by governments, non-governmental organizations, and volunteers

2019 ◽  
Vol 55 (1) ◽  
pp. 1-23
Author(s):  
Étienne Foulon ◽  
Alain N. Rousseau ◽  
Glenn Benoy ◽  
Rebecca L. North
Keyword(s):  
Water Quality ◽  
Case Studies ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Nutrient Loading ◽  
Risk Mitigation ◽  
National Standards ◽  
Quality Issue ◽  
Non Governmental Organizations ◽  
The Usa

Abstract Harmful algal blooms (HABs) in aquatic ecosystems are of concern worldwide. This review deals with how jurisdictions around the world are addressing this water quality issue to inform recommendations regarding nutrient loading and HABs in Missisquoi Bay-Lake Champlain and Lake Memphremagog; transboundary lakes located in the USA and Canada that suffer from symptoms of eutrophication. A global scan of the literature resulted in the consideration of 12 case studies of large water bodies within large watersheds, excluding in-lake geoengineering approaches. Although all of the systems experience excessive nutrient loading, they vary in two key ways: sources of nutrients and manifestations of eutrophication ranging from HABs, to limited recreational uses, to the additional complexity of internal loadings and fish kills, up to drinking water shutdowns. The case studies were analyzed with respect to four categories of approaches, namely: (i) regulatory; (ii) incentive-based; (iii) risk mitigation; and (iv) outreach, engagement, and educational. We found that the management frameworks are based on integrated watershed management planning and national standards. National water quality standards, however, are not stringent enough to prevent HABs. Overall, identified case studies did not successfully remediate HABs, they simply managed them.

scholarly journals Effects of the Marine Biotoxins Okadaic Acid and Dinophysistoxins on Fish

2021 ◽  
Vol 9 (3) ◽  
pp. 293
Author(s):  
Mauro Corriere ◽  
Lucía Soliño ◽  
Pedro Reis Costa
Keyword(s):  
Okadaic Acid ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Current Knowledge ◽  
Global Climate ◽  
Scientific Evidence ◽  
Shellfish Poisoning ◽  
Morphological Alterations ◽  
The Impact ◽  
Dsp Toxins

Natural high proliferations of toxin-producing microorganisms in marine and freshwater environments result in dreadful consequences at the socioeconomically and environmental level due to water and seafood contamination. Monitoring programs and scientific evidence point to harmful algal blooms (HABs) increasing in frequency and intensity as a result of global climate alterations. Among marine toxins, the okadaic acid (OA) and the related dinophysistoxins (DTX) are the most frequently reported in EU waters, mainly in shellfish species. These toxins are responsible for human syndrome diarrhetic shellfish poisoning (DSP). Fish, like other marine species, are also exposed to HABs and their toxins. However, reduced attention has been given to exposure, accumulation, and effects on fish of DSP toxins, such as OA. The present review intends to summarize the current knowledge of the impact of DSP toxins and to identify the main issues needing further research. From data reviewed in this work, it is clear that exposure of fish to DSP toxins causes a range of negative effects, from behavioral and morphological alterations to death. However, there is still much to be investigated about the ecological and food safety risks related to contamination of fish with DSP toxins.

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