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Term |
Meaning |
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| Anaerobic sediments | Aquatic sediments that have a high organic matter content. The organic matter is subject to a bacterial decay process that causes the oxygen level in sediments to sharply decline, producing anaeobic conditions. If this situation continues, hydrogen sulfide can form which combines with iron to give the sediments a black appearance. | ||||||||
| Aquatic ecosystem condition ratings (creeks and lakes in South Australia) |
Excellent: Natural or unaffected by human activity, with extensive areas of remnant native vegetation in the catchment area. It is possible some creeks and lakes in remote areas of the State may be given an Excellent rating, however the vast majority are likely to be affected by humans in some way. Very Good: Minimal changes in biological condition and the way the ecosystem functions as a result of human settlement. These sites continue to provide a healthy environment for a natural diversity of animal and plant life. Good: Often the best we can expect given significant changes to the natural landscape after more than 170 years of European settlement. Although changes to the environment and its animal and plant life are likely to be relatively minor, there will be clear, emerging signs of human impact, which could lead to further decline. Fair: Moderate changes to animal and plant life at the site, and some change to the way the ecosystem functions. The effects of nutrient enrichment are often evident. The condition of these creeks and lakes is unlikely to meet community expectations for a healthy aquatic ecosystem at least some of the time. Poor: These creeks or lakes are degraded, with evidence of major changes in the animal community and plant life, and moderate changes to the way the ecosystem functions. These sites typically have little native vegetation remaining and very high nutrient levels. Their condition is unlikely to meet community expectations for a healthy aquatic ecosystem most of the time. Very Poor: Major changes to both the animal and plant life are apparent with a significant breakdown in the way the ecosystem functions because of human impact. These creeks and lakes are unlikely to meet community expectations for a healthy aquatic ecosystem. |
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| Average | A measure of the mean, or middle-point, of a data set when there is more than one measurement taken. | ||||||||
| Baetid | A type of insect called a mayfly from the family Baetidae. | ||||||||
| Biological | Relating to any living organism either plant, animal, fungus or virus. | ||||||||
| Buffer zone | The band of vegetation that can reduce the amount of runoff entering a stream and provide vegetative corridors for the terrestrial life stages of aquatic organisms. Ideally a buffer zone should include tall trees, shrubs and grasses. These plants also bind together the sediment, preventing soil erosion. | ||||||||
| Cnidarians | Freshwater or marine invertebrate animals such as jellyfish and hydras, that belong to the phylum Cnidaria. | ||||||||
| Crustaceans | Aquatic organisms with a shell. These can vary from microcrustaceans, such as water fleas, and extend to shrimp and crayfish. Crustaceans occur in both fresh and marine environments. | ||||||||
| Cystophora | Type of robust brown algae found on reefs in South Australia. | ||||||||
| Detritus | Organic material derived from either instream vegetation, or riparian vegetation which has fallen into a stream. Detritus can include aquatic plants, leaves, bark, branches, gumnuts, etc. | ||||||||
| Ecklonia radiata | Is commonly known as kelp and is an example of robust brown algae. | ||||||||
| Ecosystem | A term that describes all the organisms living in a particular area, as well as all the non-living, physical components of the environment with which the organisms interact, such as air, soil and water. | ||||||||
| Emergent plants | Emergent vegetation includes aquatic plants which have roots in the sediment of a stream but stems which extend through and above the water. The leaves and flowers of these plants are above the water surface. | ||||||||
| Endocrine function | The endocrine system in an animal regulates hormone activity. Normal endocrine functions involve the secretion of hormones in response to environmental stimuli and to orchestrate developmental and reproductive changes. These systems work together to maintain the proper functioning of the organism through its entire life cycle. These functions can be disrupted by a variety of exogenus substances (endocrine disrupting chemicals), which can result in serious changes to development, reproduction and/or behaviour. | ||||||||
| Environmental values | Anything a community agrees a body of water should be protected for. This might include an ecosystem, industry, agriculture, recreation, and its spiritual and cultural uses/importance. >> More (120.9 KB PDF) | ||||||||
| Ephemeral | An ephemeral waterbody is a stream, lake or other type of wetland that only contains water for a short period following rainfall, typically for only a few weeks to several months. | ||||||||
| Epiphyte | A non-parasitic plant that grows upon another plant. | ||||||||
| Estuaries | Estuaries are regions where freshwater meets the sea. This most commonly occurs at a river mouth; however estuaries can also occur from fresh groundwater seeping into the sea. | ||||||||
| Eutrophic | Rich in mineral and organic nutrients that promote a proliferation of plant life, especially algae. | ||||||||
| Green filamentous algae | Hair-like filaments of algae often found floating on the surface of water or clumped on the stream bed. | ||||||||
| Groundwater | Groundwater is water that percolates down the soil profile. It is basically rainfall that falls on the surface and then infiltrates through the soil until it reaches a saturated and permeable zone known as an aquifer. | ||||||||
| Habitat | A part of the environment that has well-defined physical characteristics and is inhabited by a particular species or group of animals or plants. | ||||||||
| Headwaters | The source of a river or stream, ie the uppermost reaches of a catchment where a stream originates. | ||||||||
| Lakes | Inland water bodies that have little or no flow. Lakes usually occur at the end of large river systems (eg Lake Alexandrina), although some exist as a result of groundwater breaking the surface (eg the Blue Lake). | ||||||||
| Macroalgae | Large aquatic photosynthetic plants that can been seen without the aid of a microscope. | ||||||||
| Macroinvertebrates | Macroinvertebrates are aquatic animals without backbones that are large enough to be seen with the naked eye. They include insects, crustaceans, snails, worms, mites and sponges. | ||||||||
| Management responses | Aquatic ecosystem condition reports include management responses that are being coordinated by community, industry and government sectors. These are the sorts of plans and actions that address the pressures and will lead to maintenance or improvement in ecosystem condition. | ||||||||
| Marine waters | Marine waters include coastal environments such as beaches and bays. | ||||||||
| Metals | These are elements such as iron, manganese, copper, lead and zinc. They are found everywhere in the environment because they are naturally part of the earth's crust. They are sometimes called 'heavy metals'. They can become concentrated in urban environments (and end up in stormwater) because our society is based on many industrial activities which use them. They can also be found in at elevated levels in rural catchments where mining activities have occurred or because of unusual geology. | ||||||||
| Molluscs | Fresh and marine organisms which usually have a shell. Molluscs can be either snails (one coiled shell) or bivalves (two shells joined at a hinge), such as clams. | ||||||||
| National water quality guidelines | These are a set of documents that describe the process of assessing aquatic environments. The documents include water quality 'trigger' levels that have been set to protect the environmental values we place on waters. If water quality data at a monitoring site exceed these guidelines, there is a need to conduct further monitoring and/or consider other investigations and management strategies. >> More | ||||||||
| Natural Resources Management (NRM) | Natural Resources Management (NRM) is a framework to help us look after the environment with a balance between caring for our land, water, plants and animals and the needs of farmers and landowners. >> More | ||||||||
| Nearshore waters | Defined as coastal waters less than 15 m around the mainland or islands. In Southern Australia this depth is close to the limit that seagrasses can grow in. | ||||||||
| Nematodes | Also called round worms, they are thin, long worm-like animals with tapering ends that lack segments and appendages. | ||||||||
| Nitrogen |
Nitrogen is an important plant nutrient. It is found in water in various forms, which include dissolved nitrate and nitrite (oxidised nitrogen) and ammonia (or ammonium). Nitrogen can also be bound up in particulates, usually in the form of organic matter that results from plant and animal decay. The amount of organic nitrogen is usually expressed as total Kjeldahl nitrogen (TKN). The nature of the TKN analysis means that ammonia is included in the result. The total nitrogen is essentially the sum of the TKN and oxidised nitrogen forms. Inland surface waters based on Corbin and Goonan (2010)1:
1Corbin, TA and Goonan PM 2010, 'Habitat and water quality preferences of mayflies and stoneflies from South Australian streams', Transactions of the Royal Society of South Australia, 134(1): 5-18. |
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| Nutrient enrichment | A term that describes the addition of too much nutrient (nitrogen, phosphorus and carbon), to waterbodies from human actions and the resulting responses that typically leads to changes in plant and animal communities and degradation of water and sediment quality. | ||||||||
| Nutrients | Nutrients include several naturally occurring chemicals that animals and plants need to grow. In water quality, we usually refer to plant nutrients and these are different forms of nitrogen (eg nitrate or ammonia) and phosphorus. They can cause excessive growth of algae and other plants, which can generally degrade ecosystem condition by clogging creeks and lakes and smother seagrass habitat. | ||||||||
| Odonates | Insect groups such as dragonflies and damselflies. | ||||||||
| Oligotrophic | Lacking in plant nutrients and having a large amount of dissolved oxygen throughout. | ||||||||
| Opportunistic macroalgae | Large algae (eg Ulva, Hincksia, etc) that grow rapidly in marine waters when nutrients are high. | ||||||||
| Organic carbon | Refers to carbon that is bound to organic compounds, usually described as the amount of decaying natural organic matter in a water sample. | ||||||||
| Phosphorus |
Phosphorus is an essential nutrient for plants that can play a key role in stimulating algal growth in lakes and streams. Phosphorus is mainly bound to particulate matter rather than being dissolved in the water. Creeks and lakes based on Corbin and Goonan (2010)1:
1Corbin, TA and Goonan PM 2010, 'Habitat and water quality preferences of mayflies and stoneflies from South Australian streams', Transactions of the Royal Society of South Australia, 134(1): 5-18. |
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| Phytoplankton | Micro-organisms growing on submerged vegetation or substrate. Often single-cellular algae. Phytoplankton provides a source of food for many aquatic organisms. | ||||||||
| Pressures | Aquatic ecosystem condition reports include the pressures (ie issues that cause potential decline in ecosystem condition). These are addressed by application of management responses. | ||||||||
| Riffles | Sections of flowing water in a stream. Usually turbulent water flow over rocky substrate. | ||||||||
| Riparian zone | The band of vegetation located adjacent to a stream. Located between the banks of a stream and the terrestrial vegetation it comprises the flood zone. | ||||||||
| Robust brown algae | Large brown macroalgae (Phaeophyta) that are found in marine habitats with hard substrate where seagrasses cannot grow. Robust brown algae are considered to be the equivalent of seagrasses for hard substrates. | ||||||||
| Runoff | A general term for water that flows across the landscape after a significant rainfall event. Runoff and stormwater are often used interchangeably. | ||||||||
| Salinity | A measure of how much dissolved salt is in water. Salt is a natural part of the Australian landscape and a number of plants and animals inhabiting rivers and wetlands are adapted to it. Salt enters aquatic systems dissolved in rain and from a number of other sources such as groundwater, or erosion of sediments (eg weathering, microbial activity). Under natural flow conditions, periods of low flow result in salts being concentrated in wetland and riverine pool habitats. The plants and animals in these ecosystems survive increasing salinity by either tolerating or avoiding it. It is widely accepted that many of Australia's freshwater ecosystems are becoming degraded by increasing salinity; a result of rising saline groundwater and modifications to the water regime. Available data indicates that aquatic organisms are adversely affected when salinity exceeds 1,000 mg/L. Salinities between 1,000-5,000 mg/L reduce species richness and aquatic plant abundance, zooplankton and macroinvertebrate populations. Freshwater species are generally restricted to salt levels of less than 3,000 mg/L. It is now widely recognised that greater salinity will progressively lead to a reduction in diversity of wetlands and rivers, and see the dominance of saline tolerant animals and plants that can cope with high salt concentrations. | ||||||||
| Sampling | Sampling creeks and lakes to assess ecological condition involves visiting a site to count and identify macroinvertebrate species, observe the presence and extent of all major plant types, measure water clarity, assess sediment condition, and collect water samples for water quality assessment in a laboratory. | ||||||||
| Seagrass | Seagrasses are the 'grass meadows' of coastal waters. | ||||||||
| Sediment | Sediments are the material at the bottom of a waterbody. They are a mixture of solid particles such as gravel, sand, clay and organic matter with pore-water in between the sediment particles. The organic matter accumulate because of decaying plants and animals that settle to the bottom. Sediments are important habitat for numerous macroinvertebrates and provide substrate for aquatic plants. | ||||||||
| Standard deviation | A measure of how much variation there is from the average across a data set. | ||||||||
| Stormwater | Stormwater is the surface water runoff that occurs after rain. Urban stormwater is often polluted with many contaminants that are washed off urbanised areas. Urban stormwater flow is highly variable; it tends to rapidly runoff into creeks and drains because roads and concreted areas don't allow water to infiltrate. | ||||||||
| Sulfidic | Sediments that are typically blackened, lack oxygen and contain large amounts of sulfide; when exposed to air they usually give rise to a rotten egg smell. | ||||||||
| Suspended sediment | Refers to small solid particles which remain in suspension in the water column and cause poor water clarity. | ||||||||
| Terrestrial vegetation | Plants growing on land beyond the flood zone of a river or stream. | ||||||||
| Turbidity | A measure of water clarity. Low turbidity means the water is clear. | ||||||||
| Water pollution | An unusually high amount of a chemical in a water body that has the potential to cause an environmental impact. | ||||||||
| Water sensitive urban design | Water sensitive urban design provides for the sustainable use and reuse of water within developments from various sources, such as rainwater, stormwater, groundwater, mains water and wastewater (including greywater and blackwater). >> More | ||||||||
| Water quality | Water quality describes the condition of a water body and its related suitability for different purposes (also known as environmental values). In a healthy water body, the water quality supports a rich and varied community of organisms, sustains public health and/or agricultural applications. >> More | ||||||||
| Wave energy | The energy generated by coastal surface waves. | ||||||||
| Woody weeds | Introduced shrub like plants which can become pests, such as gorse and blackberries. | ||||||||
| Zooplankton | Small, free-floating or weakly swimming animals that are difficult to see with the naked eye. |
Last modified: 03/07/2012 01:30 pm
