Eutrophication: The enrichment of a terrestrial or aquatic ECOSYSTEM by the addition of nutrients, especially nitrogen and phosphorus, that results in a superabundant growth of plants, ALGAE, or other primary producers. It can be a natural process or result from human activity such as agriculture runoff or sewage pollution. In aquatic ecosystems, an increase in the algae population is termed an algal bloom.Baltic States: The collective name for the republics of ESTONIA; LATVIA; and LITHUANIA on the eastern shore of the Baltic Sea. (Webster's New Geographical Dictionary, 1988, p111)Water Pollution, Chemical: Adverse effect upon bodies of water (LAKES; RIVERS; seas; groundwater etc.) caused by CHEMICAL WATER POLLUTANTS.Phytoplankton: Free-floating minute organisms that are photosynthetic. The term is non-taxonomic and refers to a lifestyle (energy utilization and motility), rather than a particular type of organism. Most, but not all, are unicellular algae. Important groups include DIATOMS; DINOFLAGELLATES; CYANOBACTERIA; CHLOROPHYTA; HAPTOPHYTA; CRYPTOMONADS; and silicoflagellates.Drainage, Sanitary: A system of artificial or natural drains, generally used for the disposal of liquid wastes.Lakes: Inland bodies of still or slowly moving FRESH WATER or salt water, larger than a pond, and supplied by RIVERS and streams.Fresh Water: Water containing no significant amounts of salts, such as water from RIVERS and LAKES.Zooplankton: Minute free-floating animal organisms which live in practically all natural waters.Oceans and Seas: A great expanse of continuous bodies of salt water which together cover more than 70 percent of the earth's surface. Seas may be partially or entirely enclosed by land, and are smaller than the five oceans (Atlantic, Pacific, Indian, Arctic, and Antarctic).Ecosystem: A functional system which includes the organisms of a natural community together with their environment. (McGraw Hill Dictionary of Scientific and Technical Terms, 4th ed)Phosphorus: A non-metal element that has the atomic symbol P, atomic number 15, and atomic weight 31. It is an essential element that takes part in a broad variety of biochemical reactions.Harmful Algal Bloom: An algal bloom where the algae produce powerful toxins that can kill fish, birds, and mammals, and ultimately cause illness in humans. The harmful bloom can also cause oxygen depletion in the water due to the death and decomposition of non-toxic algae species.Water Pollution: Contamination of bodies of water (such as LAKES; RIVERS; SEAS; and GROUNDWATER.)Human Activities: Activities performed by humans.Water Quality: A rating of a body of water based on measurable physical, chemical, and biological characteristics.Nitrogen: An element with the atomic symbol N, atomic number 7, and atomic weight [14.00643; 14.00728]. Nitrogen exists as a diatomic gas and makes up about 78% of the earth's atmosphere by volume. It is a constituent of proteins and nucleic acids and found in all living cells.Seaweed: Multicellular marine macroalgae including some members of red (RHODOPHYTA), green (CHLOROPHYTA), and brown (PHAEOPHYTA) algae. They are widely distributed in the ocean, occurring from the tide level to considerable depths, free-floating (planktonic) or anchored to the substratum (benthic). They lack a specialized vascular system but take up fluids, nutrients, and gases directly from the water. They contain CHLOROPHYLL and are photosynthetic, but some also contain other light-absorbing pigments. Many are of economic importance as FOOD, fertilizer, AGAR, potash, or source of IODINE.Fertilizers: Substances or mixtures that are added to the soil to supply nutrients or to make available nutrients already present in the soil, in order to increase plant growth and productivity.Climatic Processes: Characteristic events occurring in the ATMOSPHERE during the interactions and transformation of various atmospheric components and conditions.Zosteraceae: A plant family of the order Najadales, subclass ALISMATIDAE, class Liliopsida (monocotyledons). This is a group of perennial aquatic herbs with basal leaves.Biomass: Total mass of all the organisms of a given type and/or in a given area. (From Concise Dictionary of Biology, 1990) It includes the yield of vegetative mass produced from any given crop.Environmental Monitoring: The monitoring of the level of toxins, chemical pollutants, microbial contaminants, or other harmful substances in the environment (soil, air, and water), workplace, or in the bodies of people and animals present in that environment.Biodiversity: The variety of all native living organisms and their various forms and interrelationships.Water Movements: The flow of water in enviromental bodies of water such as rivers, oceans, water supplies, aquariums, etc. It includes currents, tides, and waves.Geologic Sediments: A mass of organic or inorganic solid fragmented material, or the solid fragment itself, that comes from the weathering of rock and is carried by, suspended in, or dropped by air, water, or ice. It refers also to a mass that is accumulated by any other natural agent and that forms in layers on the earth's surface, such as sand, gravel, silt, mud, fill, or loess. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1689)Nitrosomonadaceae: A family of gram-negative nitrifying bacteria, in the order Nitrosomonadales, class BETAPROTEOBACTERIA.Environment: The external elements and conditions which surround, influence, and affect the life and development of an organism or population.Water Pollutants, Chemical: Chemical compounds which pollute the water of rivers, streams, lakes, the sea, reservoirs, or other bodies of water.Anthozoa: A class in the phylum CNIDARIA, comprised mostly of corals and anemones. All members occur only as polyps; the medusa stage is completely absent.Seawater: The salinated water of OCEANS AND SEAS that provides habitat for marine organisms.Animal DiseasesRivers: Large natural streams of FRESH WATER formed by converging tributaries and which empty into a body of water (lake or ocean).Eukaryota: One of the three domains of life (the others being BACTERIA and ARCHAEA), also called Eukarya. These are organisms whose cells are enclosed in membranes and possess a nucleus. They comprise almost all multicellular and many unicellular organisms, and are traditionally divided into groups (sometimes called kingdoms) including ANIMALS; PLANTS; FUNGI; and various algae and other taxa that were previously part of the old kingdom Protista.Water Microbiology: The presence of bacteria, viruses, and fungi in water. This term is not restricted to pathogenic organisms.Food Chain: The sequence of transfers of matter and energy from organism to organism in the form of FOOD. Food chains intertwine locally into a food web because most organisms consume more than one type of animal or plant. PLANTS, which convert SOLAR ENERGY to food by PHOTOSYNTHESIS, are the primary food source. In a predator chain, a plant-eating animal is eaten by a larger animal. In a parasite chain, a smaller organism consumes part of a larger host and may itself be parasitized by smaller organisms. In a saprophytic chain, microorganisms live on dead organic matter.Agriculture: The science, art or practice of cultivating soil, producing crops, and raising livestock.Conservation of Natural Resources: The protection, preservation, restoration, and rational use of all resources in the total environment.Soil: The unconsolidated mineral or organic matter on the surface of the earth that serves as a natural medium for the growth of land plants.Population Dynamics: The pattern of any process, or the interrelationship of phenomena, which affects growth or change within a population.Climate Change: Any significant change in measures of climate (such as temperature, precipitation, or wind) lasting for an extended period (decades or longer). It may result from natural factors such as changes in the sun's intensity, natural processes within the climate system such as changes in ocean circulation, or human activities.Population Density: Number of individuals in a population relative to space.Water Supply: Means or process of supplying water (as for a community) usually including reservoirs, tunnels, and pipelines and often the watershed from which the water is ultimately drawn. (Webster, 3d ed)Ecology: The branch of science concerned with the interrelationship of organisms and their ENVIRONMENT, especially as manifested by natural cycles and rhythms, community development and structure, interactions between different kinds of organisms, geographic distributions, and population alterations. (Webster's, 3d ed)Water: A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Models, Theoretical: Theoretical representations that simulate the behavior or activity of systems, processes, or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.Encyclopedias as Topic: Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)Eichhornia: A plant genus of the family PONTEDERIACEAE that is used as a biological filter for treating wastewater.Estuaries: A partially enclosed body of water, and its surrounding coastal habitats, where saltwater from the ocean mixes with fresh water from rivers or streams. The resulting mixture of seawater and fresh water is called brackish water and its salinity can range from 0.5 to 35 ppt. (accessed Participation: Community or individual involvement in the decision-making process.Leeches: Annelids of the class Hirudinea. Some species, the bloodsuckers, may become temporarily parasitic upon animals, including man. Medicinal leeches (HIRUDO MEDICINALIS) have been used therapeutically for drawing blood since ancient times.EncyclopediasDictionaries, MedicalDictionaries as Topic: Lists of words, usually in alphabetical order, giving information about form, pronunciation, etymology, grammar, and meaning.

Dynamics of bacterial community composition and activity during a mesocosm diatom bloom. (1/248)

Bacterial community composition, enzymatic activities, and carbon dynamics were examined during diatom blooms in four 200-liter laboratory seawater mesocosms. The objective was to determine whether the dramatic shifts in growth rates and ectoenzyme activities, which are commonly observed during the course of phytoplankton blooms and their subsequent demise, could result from shifts in bacterial community composition. Nutrient enrichment of metazoan-free seawater resulted in diatom blooms dominated by a Thalassiosira sp., which peaked 9 days after enrichment ( approximately 24 microg of chlorophyll a liter(-1)). At this time bacterial abundance abruptly decreased from 2.8 x 10(6) to 0.75 x 10(6) ml(-1), and an analysis of bacterial community composition, by denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rRNA gene fragments, revealed the disappearance of three dominant phylotypes. Increased viral and flagellate abundances suggested that both lysis and grazing could have played a role in the observed phylotype-specific mortality. Subsequently, new phylotypes appeared and bacterial production, abundance, and enzyme activities shifted from being predominantly associated with the <1.0-microm size fraction towards the >1.0-microm size fraction, indicating a pronounced microbial colonization of particles. Sequencing of DGGE bands suggested that the observed rapid and extensive colonization of particulate matter was mainly by specialized alpha-Proteobacteria- and Cytophagales-related phylotypes. These particle-associated bacteria had high growth rates as well as high cell-specific aminopeptidase, beta-glucosidase, and lipase activities. Rate measurements as well as bacterial population dynamics were almost identical among the mesocosms indicating that the observed bacterial community dynamics were systematic and repeatable responses to the manipulated conditions.  (+info)

Forecasting agriculturally driven global environmental change. (2/248)

During the next 50 years, which is likely to be the final period of rapid agricultural expansion, demand for food by a wealthier and 50% larger global population will be a major driver of global environmental change. Should past dependences of the global environmental impacts of agriculture on human population and consumption continue, 10(9) hectares of natural ecosystems would be converted to agriculture by 2050. This would be accompanied by 2.4- to 2.7-fold increases in nitrogen- and phosphorus-driven eutrophication of terrestrial, freshwater, and near-shore marine ecosystems, and comparable increases in pesticide use. This eutrophication and habitat destruction would cause unprecedented ecosystem simplification, loss of ecosystem services, and species extinctions. Significant scientific advances and regulatory, technological, and policy changes are needed to control the environmental impacts of agricultural expansion.  (+info)

Possible estuary-associated syndrome: symptoms, vision, and treatment. (3/248)

The human illness designated as possible estuarine-associated syndrome (PEAS) by the Centers for Disease Control and Prevention (CDC) has been associated with exposure to estuaries inhabited by toxin-forming dinoflagellates, including members of the fish-killing toxic Pfiesteria complex (TPC), Pfiesteria piscicida and Pfiesteria shumwayae. Humans may be exposed through direct contact with estuarine water or by inhalation of aerosolized or volatilized toxin(s). The five cases reported here demonstrate the full spectrum of symptoms experienced during acute and chronic stages of this suspected neurotoxin-mediated illness. The nonspecific symptoms most commonly reported are cough, secretory diarrhea, headache, fatigue, memory impairment, rash, difficulty in concentrating, light sensitivity, burning skin upon water contact, muscle ache, and abdominal pain. Less frequently encountered symptoms are upper airway obstruction, shortness of breath, confusion, red or tearing eyes, weakness, and vertigo. Some patients experience as few as four of these symptoms. The discovery that an indicator of visual pattern-detection ability, visual contrast sensitivity (VCS), is sharply reduced in affected individuals has provided an objective indicator that is useful in diagnosing and monitoring PEAS. VCS deficits are present in both acute and chronic PEAS, and VCS recovers during cholestyramine treatment coincident with symptom abatement. Although PEAS cannot yet be definitively associated with TPC exposure, resolution with cholestyramine treatment suggests a neurotoxin-mediated illness.  (+info)

Pfiesteria-related educational products and information resources available to the public, health officials, and researchers. (4/248)

Public and political concerns about Pfiesteria from 1997 to the present vastly exceed the attention given to other harmful algal bloom (HAB) issues in the United States. To some extent, the intense focus on Pfiesteria has served to increase attention on HABs in general. Given the strong and continuing public, political, and research interests in Pfiesteria piscicida Steidinger & Burkholder and related organisms, there is a clear need for information and resources of many different types. This article provides information on Pfiesteria-related educational products and information resources available to the general public, health officials, and researchers. These resources are compiled into five categories: reports; website resources; state outreach and communication programs; fact sheets; and training manuals and documentaries. Over the last few years there has been rapid expansion in the amount of Pfiesteria-related information available, particularly on the Internet, and it is scattered among many different sources.  (+info)

The role of nutrient loading and eutrophication in estuarine ecology. (5/248)

Eutrophication is a process that can be defined as an increase in the rate of supply of organic matter (OM) to an ecosystem. We provide a general overview of the major features driving estuarine eutrophication and outline some of the consequences of that process. The main chemical constituent of OM is carbon (C), and therefore rates of eutrophication are expressed in units of C per area per unit time. OM occurs in both particulate and dissolved forms. Allochthonous OM originates outside the estuary, whereas autochthonous OM is generated within the system, mostly by primary producers or by benthic regeneration of OM. The supply rates of limiting nutrients regulate phytoplankton productivity that contributes to inputs of autochthonous OM. The trophic status of an estuary is often based on eutrophication rates and can be categorized as oligotrophic (<100 g C m(-2) y(-1), mesotrophic (100-300 g C m(-2) y(-1), eutrophic (300-500 g C m(-2) y(-1), or hypertrophic (>500 g C m(-2) y(-1). Ecosystem responses to eutrophication depend on both export rates (flushing, microbially mediated losses through respiration, and denitrification) and recycling/regeneration rates within the estuary. The mitigation of the effects of eutrophication involves the regulation of inorganic nutrient (primarily N and P) inputs into receiving waters. Appropriately scaled and parameterized nutrient and hydrologic controls are the only realistic options for controlling phytoplankton blooms, algal toxicity, and other symptoms of eutrophication in estuarine ecosystems.  (+info)

State monitoring activities related to Pfiesteria-like organisms. (6/248)

In response to potential threats to human health and fish populations, six states along the east coast of the United States initiated monitoring programs related to Pfiesteria-like organisms in 1998. These actions were taken in the wake of toxic outbreaks of Pfiesteria piscicida Steidinger & Burkholder in Maryland during 1997 and previous outbreaks in North Carolina. The monitoring programs have two major purposes. The first, rapid response, is to ensure public safety by responding immediately to conditions that may indicate the presence of Pfiesteria or related organisms in a toxic state. The second, comprehensive assessment, is to provide a more complete understanding of where Pfiesteria-like organisms may become a threat, to understand what factors may stimulate their growth and toxicity, and to evaluate the impacts of these organisms upon fish and other aquatic life. In states where human health studies are being conducted, the data from both types of monitoring are used to provide information on environmental exposure. The three elements included in each monitoring program are identification of Pfiesteria-like organisms, water quality measurements, and assessments of fish health. Identification of Pfiesteria-like organisms is a particularly difficult element of the monitoring programs, as these small species cannot be definitively identified using light microscopy; newly applied molecular techniques, however, are starting to provide alternatives to traditional methods. State monitoring programs also offer many opportunities for collaborations with research initiatives targeting both environmental and human health issues related to Pfiesteria-like organisms.  (+info)

Field ecology of toxic Pfiesteria complex species and a conservative analysis of their role in estuarine fish kills. (7/248)

Within the past decade, toxic Pfiesteria outbreaks have been documented in poorly flushed, eutrophic areas of the largest and second largest estuaries on the U.S. mainland. Here we summarize a decadal field effort in fish kill assessment, encompassing kills related to Pfiesteria (49 major kills in North Carolina estuaries since 1991 and 4 in Maryland estuaries in 1997) and to other factors such as low oxygen stress (79 major fish kills in North Carolina estuaries). The laboratory and field data considered in developing our protocols are described, including toxic Pfiesteria behavior, environmental conditions conducive to toxic Pfiesteria activity, and impacts of toxic clonal Pfiesteria on fish health. We outline the steps of the standardized fish bioassay procedure that has been used since 1991 to diagnose whether actively toxic Pfiesteria was present during estuarine fish kills. Detailed data are given for a 1998 toxic Pfiesteria outbreak in the Neuse Estuary in North Carolina to illustrate of the full suite of diagnostic steps completed. We demonstrate that our conservative approach in implicating toxic Pfiesteria involvement in fish kills has biased in favor of causes other than Pfiesteria. Data are summarized from experiments that have shown stimulation of toxic Pfiesteria strains by nutrient (N, P) enrichment, supporting field observations of highest abundance of toxic strains in eutrophic estuaries. On the basis of a decade of research on toxic Pfiesteria, we present a conceptual model of the seasonal dynamics of toxic strains as affected by changing food resources and weather patterns. We also recommend protocols and research approaches that will strengthen the science of fish kill assessment related to Pfiesteria and/or other causative factors.  (+info)

History and timing of human impact on Lake Victoria, East Africa. (8/248)

Lake Victoria, the largest tropical lake in the world, suffers from severe eutrophication and the probable extinction of up to half of its 500+ species of endemic cichlid fishes. The continuing degradation of Lake Victoria's ecological functions has serious long-term consequences for the ecosystem services it provides, and may threaten social welfare in the countries bordering its shores. Evaluation of recent ecological changes in the context of aquatic food-web alterations, catchment disturbance and natural ecosystem variability has been hampered by the scarcity of historical monitoring data. Here, we present high-resolution palaeolimnological data, which show that increases in phytoplankton production developed from the 1930s onwards, which parallels human-population growth and agricultural activity in the Lake Victoria drainage basin. Dominance of bloom-forming cyanobacteria since the late 1980s coincided with a relative decline in diatom growth, which can be attributed to the seasonal depletion of dissolved silica resulting from 50 years of enhanced diatom growth and burial. Eutrophication-induced loss of deep-water oxygen started in the early 1960s, and may have contributed to the 1980s collapse of indigenous fish stocks by eliminating suitable habitat for certain deep-water cichlids. Conservation of Lake Victoria as a functioning ecosystem is contingent upon large-scale implementation of improved land-use practices.  (+info)

  • Phosphorus is often regarded as the main culprit in cases of eutrophication in lakes subjected to "point source" pollution from sewage pipes. (
  • Policy changes to control point sources of phosphorus have resulted in rapid control of eutrophication. (
  • This study analyses the response of the carbon and nitrogen isotopic composition of sedimentary organic matter to rapid human-induced eutrophication and meromixis as well as subsequent restoration efforts [in-lake phosphorus (P)-Precipitation, P-remediation of the well inflow and multiannual destratification] in a 46-yr sediment core sequence (1963-2009) from Fischkaltersee, a small hard-water lake (S-Germany). (
  • Eutrophication (pronounced you-tro-fi-KAY-shun) is a natural process that occurs in an aging lake or pond as that body of water gradually builds up its concentration of plant nutrients. (
  • Cultural or artificial eutrophication occurs when human activity introduces increased amounts of these nutrients, which speed up plant growth and eventually choke the lake of all of its animal life. (
  • However, eutrophication can be speeded up artificially, and then the lake and its inhabitants eventually suffer as the input of nutrients increases far beyond what the natural capacity of the lake should be. (
  • However, artificial or human-caused eutrophication has become so common that the word eutrophication by itself has come to mean a very harmful increase and acceleration of nutrients. (
  • Eutrophication is a process in which the ecosystem is enriched by nutrients, encouraging excess plant growth. (
  • Although eutrophication is a natural form of succession which usually takes hundreds or thousands of years, it can be enhanced through human inputs of nutrients. (
  • Eutrophication" has become synonymous with "excessive fertilisation" or the input of sufficient amounts of aquatic plant nutrients to cause the growth of excessive amounts of algae and/or aquatic macrophytes in a water body such that beneficial uses of the water body (i.e., water quality) are impaired. (
  • As eutrophication progresses, phytoplankton species tend to shift from chlorphytes (green algae) to cyanophytes ( blue-gree algae , which are in fact prokaryotic and are sometimes classified as bacteria ). (
  • As noted above, if eutrophication is sufficiently severe, an algal bloom will occur (a solid mat of vegetation that covers the water's surface) and when these algae die, they will sink to the bottom. (
  • They also have a lot of plants and algae (more information on eutrophication) . (
  • Eutrophication is not necessarily harmful or bad, and the word itself is often translated from the Greek as meaning "well nourished" or "good food. (
  • Natural eutrophication is usually a fairly slow and gradual process, occurring over a period of many centuries. (
  • To evaluate the observations indicating the ongoing process of eutrophication of Lake Baikal, a field study in July 2012 in the two largest bays of Lake Baikal, Barguzinsky and Chivyrkuisky, was organized. (
  • To prevent further extensions of this process in unique ecosystem of Lake Baikal, the detailed study and monitoring of the coastal zone, the identification of the sources of eutrophication, and the development of measures to reduce nutrient inputs in the waters are urgently needed. (
  • Hence, we conclude that in Fischkaltersee δ 13 C SOM was controlled by photoautotrophic input only during an early phase in the eutrophication process. (
  • Change to algal community structure: eutrophication not only increases the absolute concentration of plant matter in the water, but also changes the species composition. (
  • Depending on the algal species that proliferate, eutrophication at times produces toxins that threaten drinking water supplies, recreational swimming and consumption of seafood. (
  • In addition, the sediment record was compared with detailed data on water column chemistry during almost (1977-2009) the recorded history of eutrophication and trophic recovery of the named lake. (
  • JONES LEE, A. LEE, G.F. (n.y): Eutrophication (Excessive Fertilization). (