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Benthic Macroinvertebrates as bio-indicators in the Cache River Watershed. J. Fickenscher 503 B Scientific research methods for teachers Spring 2012. Why is water quality important?.
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Benthic Macroinvertebrates as bio-indicators in the Cache River Watershed J. Fickenscher 503 B Scientific research methods for teachers Spring 2012
Why is water quality important? • Clean water is essential to life itself. Adverse changes to the water quality of one stream can impact all the bodies of water downstream – rivers, lakes, or even the ocean. When water quality degrades, changes to plant, invertebrate, and fish communities may occur and affect the entire food chain. • Human health - drinking water • Fisheries (food) • Water for industry and agriculture • Aesthetic reasons • Species habitat • Water for recreation (swimming, fishing, boating)
Cache River • The Cache River Wetlands have been affected by varying levels of pollution from the surrounding areas. • There is a general feeling that surface water quality has declined due to man’s activities in the watershed. • Solution: Stop the pollution!
Pollution • Point Source • comes from a single source, such as a factory or wastewater treatment plant. The Clean Water Act of 1972 put restrictions on how much and what kind of pollutants industries can dispose of in rivers and lakes • Non-point source pollution • does not have one specific source, such as a factory; it originates from the cumulative effect of a region's residents going about their everyday activities, such as fertilizing a farm field. Non-point source pollution is much more difficult to regulate than point source pollution because it involves activities of private citizens on private land.
Non-Point Source Pollution • Nutrient Pollution • Oxygen Pollution
Nutrient Pollution • Plants and animals need nutrients • But…there can be too much of a good thing! • Too many nutrients results in…. There is both cultural (human) and natural eutrophication
Nutrient Pollution Too many nutrients can cause: Eutrophication Increase in nutrients Aquatic life suffers Increase in plant growth Dissolved oxygen declines as plants are decomposed
Dissolved Oxygen Pollution • The presence or absence of oxygen gas molecules (O2) in the water. • How does oxygen get into the water? • diffusion from the surrounding air • during the process of photosynthesis
DO Levels • Dissolved oxygen is often the most common, and most important, water quality test. It will give you an immediate indication of the health of the aquatic system at that moment. • Altitude • Temperature • Speed of water movement (dams as well as natural differences and tides) • Addition of wastes - POLLUTION • Vegetation
BenthicMacroinvertebrates • Used as bioindicator organisms • The presence or absence of these organisms in a stream can be used to reveal the overall ecological quality of the water. • Generally, unpolluted waters support a greater variety of freshwater macros than polluted water.
Why are macroinvertebrates biological indicators of stream health? • Spend up to one year in the stream • Have little mobility • Generally abundant • Primary food source for many fish • Good indicators of local conditions • Diversity = healthy stream • Easy to sample Caddis Fly
Water Quality Indicators • Each macroinvertebrate belongs in a Taxa - a group indicating the level of pollution tolerance • Group I – Pollution intolerant • Group II – Moderately intolerant • Group III – Fairly tolerant • Group IV – Pollution tolerant
River Continuum Concept • The River Continuum Concept (RCC) is a model for classifying and describing flowing water, in addition to the classification of individual sections of waters after the occurrence of indicator organisms
Functional Feeding Groups • Based on their feeding methods and adaptations • Shredders – break down larger organic material into smaller pieces • Collectors (Filterers) – feed on finer organic material • Grazers (Scrapers) – algae on rocks and plants • Predators – live prey (smaller collectors/shredders)
Functional Feeding Groups: The River Continuum(Vannote et al., 1980) • HEADWATERS: • Shredders abundant • Coarse POM CPOM STREAM ORDER FPOM • MID-REACHES: • Grazers abundant FPOM • LARGE RIVERS: • Collectors abundant • Fine-Ultra fine POM Relative Channel Width
Family Biotic Index • Each family given a tolerance value • Range of 0 – 10 • 0: Extremely intolerant of low dissolved oxygen • 10: Can survive great amounts of pollution / low dissolved oxygen
Family Biotic Index • FBI = Σ(xi*ti)/(n), where • xi = number of individuals within a taxonti = tolerance value of taxonn = total number of organisms in the sample (100)
Example 525/100 = FBI of 5.25 GOOD
Question • How much do man’s activities affect the overall health of a stream in the Cache River Watershed? • I plan on bio-assessing two streams in the Cache River Wetlands, 1 being near an agricultural field and the other not in order to see if the water quality has declined due to the local activities near and upstream of my test locations.
Hypothesis • My hypothesis is that the stream health will be significantly negatively impacted by the different agricultural factors affecting stream one, compared to the non agricultural field stream two.
Rapid Bioassessment Protocol • Site selection • Site assessment • Sample ten 1 m2 sections of stream reach with d-net • Subsample size: 100 organisms (or more) • Preserved and identified organisms in each subsample • Identify tolerance score for each family. • Calculate FBI