WOceanic anoxic events or anoxic events (anoxia conditions) were intervals in the Earth's past where portions of oceans became depleted in oxygen (O2) over a large geographic areas. During some of these events, euxinia, waters that contain hydrogen sulfide, H2S, developed. Although anoxic events have not happened for millions of years, the geological record shows that they happened many times in the past. Anoxic events coincided with several mass extinctions and may have contributed to them. These mass extinctions include some that geobiologists use as time markers in biostratigraphic dating. Many geologists believe oceanic anoxic events are strongly linked to slowing of ocean circulation, climatic warming, and elevated levels of greenhouse gases. Researchers have proposed enhanced volcanism (the release of CO2) as the "central external trigger for euxinia".
WA bioindicator is any species or group of species whose function, population, or status can reveal the qualitative status of the environment. For example, copepods and other small water crustaceans that are present in many water bodies can be monitored for changes that may indicate a problem within their ecosystem. Bioindicators can tell us about the cumulative effects of different pollutants in the ecosystem and about how long a problem may have been present, which physical and chemical testing cannot.
WBiomagnification, also known as bioamplification or biological magnification, is any concentration of a toxin, such as pesticides, in the tissues of tolerant organisms at successively higher levels in a food chain. This increase can occur as a result of:Persistence – where the substance cannot be broken down by environmental processes Food chain energetics – where the substance's concentration increases progressively as it moves up a food chain Low or non-existent rate of internal degradation or excretion of the substance – mainly due to water-insolubility
WDead zones are hypoxic (low-oxygen) areas in the world's oceans and large lakes, which causes these bodies of water to fail to support the marine life living there. Historically, many of these sites were naturally occurring. However, in the 1970s, oceanographers began noting increased instances and expanses of dead zones. These occur near inhabited coastlines, where aquatic life is most concentrated.
WAn Ecotron is an experimental and instrumented device in ecology which makes possible in the same time to condition the environment of natural, simplified or completely artificial ecosystems and to measure the processes generated by living beings present in these ecosystems, in particular the flow of matter and energy. Its principle is to confine ecosystems in totally or partially waterproof enclosures capable of generating a range of physical and chemical conditions applied to terrestrial or aquatic ecosystems, continental or marine. Environmental control and real-time measurements are precise enough to test hypotheses or operating models. For this purpose, the enclosures are fitted with significant equipment allowing continuous measurement of fluxes, states or biological characteristics. Other specific measurements, in situ and ex situ, on samples taken complete these online measurements. A sufficient number of independent confinement chambers is necessary to study several interacting factors in a framework of statistical inference.
WEnvironmental assessment (EA) is the assessment of the environmental consequences of a plan, policy, program, or actual projects prior to the decision to move forward with the proposed action. In this context, the term "environmental impact assessment" (EIA) is usually used when applied to actual projects by individuals or companies and the term "strategic environmental assessment" (SEA) applies to policies, plans and programmes most often proposed by organs of state. It is a tool of environmental management forming a part of project approval and decision-making. Environmental assessments may be governed by rules of administrative procedure regarding public participation and documentation of decision making, and may be subject to judicial review.
WMarine debris, also known as marine litter, is human-created waste that has deliberately or accidentally been released in a sea or ocean. Floating oceanic debris tends to accumulate at the center of gyres and on coastlines, frequently washing aground, when it is known as beach litter or tidewrack. Deliberate disposal of wastes at sea is called ocean dumping. Naturally occurring debris, such as driftwood, are also present.
WMicrotox is an in vitro testing system which uses bioluminescent bacteria to detect toxic substances in different substrates such as water, air, soils and sediments. Allivibrio fischeri are non-pathogenic, marine, bacteria that luminesce as a natural part of their metabolism. When exposed to a toxic substance, the respiratory process of the bacteria is disrupted, reducing light output. Allivibrio fischeri have demonstrated high sensitivity across a wide variety of toxic substances. Response to toxicity is observed as a change in luminescence, which is a by-product of cellular respiration. This change can be used to calculate a percent inhibition of Allivibrio fischeri that directly correlates to toxicity.
WZearalenone (ZEN), also known as RAL and F-2 mycotoxin, is a potent estrogenic metabolite produced by some Fusarium and Gibberella species. Particularly, is produced by Fusarium graminearum, Fusarium culmorum, Fusarium cerealis, Fusarium equiseti, Fusarium verticillioides, and Fusarium incarnatum.
WThe Zone Rouge is a chain of non-contiguous areas throughout northeastern France that the French government isolated after the First World War. The land, which originally covered more than 1,200 square kilometres (460 sq mi), was deemed too physically and environmentally damaged by conflict for human habitation. Rather than attempt to immediately clean up the former battlefields, the land was allowed to return to nature. Restrictions within the Zone Rouge still exist today, although the control areas have been greatly reduced.