Unit 3 EcosystemsTopic 3, part 2: Aquatic Biomes

Abiotic FactorsWindNutrient availability pHDepthTemperature

Types of Aquatic Biomes

Streams and riversPonds and lakesWetlands

Streams and RiversFlowing fresh water that may originate from underground springs or as runoff from rain or melting snow.

Streams are typically narrow and carry relatively small amounts of water

Rivers are usually wider and carry larger amounts of water.

Biotic adaptations for moving waterRooted vegetationEncrusting algaeBenthic life stylesBurrowingHeavy or flat bodiesWebbing/netting

Nile RiverLongest river in the world (4,130 miles)At widest point, 4.7 miles

Amazon River2nd longest (3,977 miles), but greatest outputWatershed > 7 million sq miRiver mouth = 50 miles wideUnique fauna

Mississippi River4th longest (2,530 miles), 10th biggestWatershed includes 32 states (1,245,000 sqmi)

Lakes and PondsStanding water with areas too deep to support emergent vegetation.

Size and depth differentiate the two.

Lake and Pond Zonation

Seasonal turnover

The Great LakesTogether, 21% of unfrozen surface (fresh) waters

Lake BaikalOldest lake (25 million yrs)20% of unfrozen surface fresh waters

The Rift LakesVery diverse14% of all freshwater fish species in the worldStarted forming 40 million years ago on the divergent boundaryPeriods of drought

African Rift Lake Cichlids

Model of Cichlid Fish Diversification

Freshwater WetlandsSoils submerged or saturated by water for all or at least part of each year, but shallow enough to support emergent vegetation

Vegetation have adaptations that make them water tolerantSoils are hydric

Freshwater wetlands: SwampsWetlands with emergent trees

Freshwater wetlands: MarshesContain mostly reeds, sedges, grasses, and rushes for vegetation

Freshwater wetlands: BogsAcidic wetlands containing sphagnum moss, wild cranberry (New England), and spruce trees on the edges

Freshwater wetlands: Plants

Adapted to life in water-logged soilsAerenchyma

Freshwater wetlands: Ecosystem servicesRecreation/aesthetics

Absorption of excess water

Methane source

Water supply

Agriculture

Groundwater recharge

Freshwater wetlands: Ecosystem servicesWater filtrationNatural waste-water treatment

Freshwater wetlands: Human impactsDraining/filling to convert to land for other purposes

Urban runoff

Waste disposal

Water diversion

Invasive species (introductions)

20% of freshwater entering the ocean Arapaima grow up to 10 feet long and 400 lbs. They are air breathers and mouth brooders.

Littoral zone- the shallow area of soil and water near the shore where algae and emergent plants grow.Limnetic zone- open water, where rooted plants can no longer survive. Phytoplankton are the only photosynthetic organisms. This zone extends to as deep as sunlight can penetrate.Profundal zone- the zone where sunlight cannot penetrate and therefore producers cannot survive. Benthic zone- the muddy bottom of a lake or bond beneath the limnetic and profundal zone.From left: Superior, Michigan, Huron, Erie, Ontario*Lake Malawi

*Hydric soils are ones which have been saturated with water over long time periods. The soil is anoxic due to the saturation of all the porous spaces with water. This results in a community of anaerobic bacteria rather than aerobic bacteria. Dead organic matter tends to build up in the system due to low decomposition rates.Wetlands can provide revenue and jobs from ecotourism and from fishing and hunting permits and licensesDuring a storm or major snowmelt, wetlands can absorb flood waters from rivers and streams, reducing damage costs to properties, roads, crops, and commercial buildings. The presence or restoration of wetlands around a river can lower the cost of flood insurance.Anaerobic bacteria of the hydric soils produce methane. Some companies collect the gas and sell for a profit.During times of drought, wetlands can be a source of irrigation water for crops, thus maintaining a farmers profits. There are certain crops like wild rice and cranberries that originated and thrive in wetland ecosystems.Wetlands can recharge groundwater for private wells. Wetlands are a natural filtration system, so water treatment costs are reduced.In a wastewater treatment facility, the first step (Primary treatment) is the physical removal and trapping of sediments and solids. This is done in large settling tanks or with nets and screens. In a wetland that receives runoff from the land, sediments and solids are trapped in the vegetation and settle to the organic layer. In a wastewater treatment facility, secondary treatment consists of bacterial removal of waste by decomposition. In a wetland, anaerobic bacteria breakdown organic material.Some wastewater treatment facilities are adding a wetland component to their traditional approaches. Wetlands have long been viewed as wastelands. In many places wetlands have been drained or filled in to reclaim the land for housing and commercial developments or agriculture.Urban runoff from roads and storm drains carries lots of sediments, chemical pollutants (fertilizers, pesticides, heavy metals, oils), sewage, and litter. This degrades the natural environment.It is not uncommon for wetlands to be used as dumping areas for commercial animal feedlots, and in the past, as landfills for household and commercial waste.Water diversions such as dams to make reservoirs and canals for irrigation change the distribution patterns of water flow. This may lead to extreme changes in water levels such that wetland communities cannot be sustained. Invasive species can outcompete native flora or fauna, thus altering communities and sometimes reducing biodiversity.