Types of Aquatic Ecosystems Freshwater: lakes, rivers Salt: oceans Estuaries: where fresh meets salt Provides variety of habitats, supporting diverse animal and plant communities  Migratory populations  Spawning grounds  Bay grass protects juvenile fish and crabs from predators Filtration system, prevent erosion Wetlands: Where land meets water Tidal vs non-tidal Emergent, shrubs, forested

Abiotic Factors affecting Aquatic Ecosystems Light  varies w/ depth, particulate matter  Photosynthetic organisms... Temperature  varies w/ depth and season  Convection Solubility of solids/liquids  Salinity  pollutants Solubility of gases CO 2  oceans as carbon sink, leads to acidification  Important component of carbonate shells  Food for autotrophs O 2 Acidity  Lower pH results in more metals soluble in water  Certain level for which organisms adapted

Aquatic Ecosystem Services Drinking water Food resources (fish, etc.) Irrigation Sanitation Fuels and raw materials Mining of minerals require water Processing of food Sport/Recreation Natural water filtration system Millennium Ecosystem Assessment These services are currently almost free, what will we do when there isn't enough water or its too polluted?

What is a watershed? Water flows downhill...Every water body uphill from the Chesapeake Bay is considered part of the watershed. Water flowing from New York, Maryland, Virginia, etc. will make its way, through rivers and streams, to the Chesapeake Bay. Any pollutants picked up along the way will accumulate in the bay US Fish and Wildlife Service Clean Water Act Legislation: What can you do? After the Storm

Eutrophication Eutrophication is the build up of nutrients in the water system. Nutrients support the growth of autotrophs (algae) Algae block sunlight from getting to lower levels of the ecosystem Algae die and as other organisms eat them, oxygen in the water is depleted Low levels of oxygen in the water result in hypoxic conditions where fish and other organisms that respire aerobically cannot live.

Wiseman IB Chemistry Biochemical Oxygen Demand Measure of amount of oxygen consumed by the biodegradable organic wastes and ammonia in a given amount of water over a time period (5 days at 20° C) Sample saturated with O 2 and put in closed container. After 5 days, dissolved O 2 lost is measured The more O 2 lost, the more organisms are in the water using up the oxygen BOD < 1 almost pure water BOD 5 Doubtful purity BOD 20 Unacceptable purity Units for BOD = mg / L

Pollutants Chemical Nutrients: N, P Toxins: organics, metals Heat Source  Energy (cooling towers)  Global warming Results:  Small range of temperatures over which aquatic organisms are adapted.  Changes metabolic rates  Removes dissolved gases (O2)  Coral bleaching Coral bleaching  April 2010: report: Potomac River showing statistically significant long-term warming. Lake Michigan

Water quality indicators (see also word document): Dissolved Oxygen This test is the most important of the nine water quality tests to measure water's ability to support plants and animals. There are many different factors that affect the amount of dissolved oxygen in water, the main one being temperature. As temperature rises, less gas will dissolve. Turbidity Turbidity measures water clarity, which allows sunlight to penetrate to a greater depth. The main sources of turbidity are erosion, living organisms, and those from human endeavors

Water quality indicators (continued): Total Solids Total solids measures both dissolved and suspended solids. There are six major types of total solids; silt, clay, soil runoff, plankton, industrial waste, and sewage. pH Level The pH of water is important to aquatic life. If the pH falls below 4 or climbs above 9 everything is dead.

Water quality indicators (continued): Temperature and Flow Rate Temperature is a very important part of a river's ecology. There are many natural and human factors that can affect a river's temperature. Human factors include industry, development, and dams. To measure temperature and flow rate you must find two places along the river that are about 1.6 kilometers apart that have the same conditions, then two people measure the temperature at approximately the same time. If the difference is greater than 2 degrees Celsius, then there is thermal pollution. To find flow rate you use a buoyant object, we used an orange, and float it down the river.

Water quality indicators (continued): Nitrates Nitrogen is necessary for plant and animal life. Water is tested for nitrates to monitor and control eutrofication, which causes more plant growth and decay. Fecal Coliform This nasty stuff is a certain bacteria that propagate in the digestive tracts of humans and animals. They coexist with other bacteria so they are often used as indicators of possible pathogenic contamination. There are many ways fecal coliform can enter a waterway such as animal waste, untreated sewage, combined sewage overflow, and septic tanks.

Water quality indicators (continued): Biochemical Oxygen Demand BOD is a measure of oxygen removed from an aquatic environment by aerobic microorganisms. It measures levels of organic pollution in lakes and streams. Phosphorous Phosphates is a nutrient needed in growth. The phosphate ion is found in shells, bones, and in animal teeth. By removing phosphorous from sewage the amount of phosphate ions in the water will be lowered.