2Wetlands – lands covered with water all or part of a year Hydric (saturated) soils – saturated long enough to create an anaerobic state in the soil horizonHydrophytic plants – adapted to thrive in wetlands despite the stresses of an anaerobic and flooded environmentHydrologic regime – dynamic or dominant presence of water
3Wetland Classification Chart Major CategoriesGeneral LocationWetland typesCoastal Wetlands:Marine (undiluted salt water)Open coastShrub wetland, salt marsh, mangrove swampEstuarine (salt/freshwater mix)Estuaries (deltas, lagoons)Brackish marsh, shrub wetland, salt marsh, mangrove swampInland Wetlands:Riverine (associated w/ rivers and streams)River channels and floodplainsBottomlands, freshwater marsh, delta marshLacustrine (associated w/ lakes)Lakes and deltasFreshwater marsh, shrub and forest wetlandsPalustrine (shallow ponds, misc. freshwater wetlands)Ponds, peatlands, uplands, ground water seepsEphemeral ponds, tundra peatland, ground water spring oasis, bogs
4Physical/Hydrological Functions of Wetlands Flood ControlCorrelation between wetland loss and downstream floodingcan capture, store, and slowly release water over a period of timeCoastal ProtectionServe as storm buffersGround Water RechargeWater has more time to percolate through the soilSediment TrapsWetland plants help to remove sediment from flowing waterAtmospheric EquilibriumCan act as ‘sinks’ for excess carbon and sulfurCan return N back to the atmosphere (denitrification)
5Chemical Functions of Wetlands Pollution InterceptionNutrient uptake by plantsSettle in anaerobic soil and become reducedProcessed by bacterial actionToxic Residue ProcessingBuried and neutralized in soils, taken up by plants, reduced through ion exchangeLarge-scale / long-term additions can exceed a wetland’s capacitySome chemicals can become more dangerous in wetlands (Mercury)
6Mercury Chemistry Elememental mercury (Hg0) Mercurous Ion (Hg+) Most common form of environmental mercuryHigh vapor pressure, low solubility, does not combine with inorganic or organic ligands, not available for methylationMercurous Ion (Hg+)Combines with inorganic compounds onlyCan not be methylatedMercuric Ion (Hg++)Combines with inorganic and organic compoundsCan be methylated CH3HG
7Methylation Mono- and dimethylmercury can be formed Basically a biological process by microorganisms in both sediment and waterMono- and dimethylmercury can be formedDimethylmercury is highly volatile and is not persistent in aquatic environmentsInfluenced by environmnetal variables that affect both the availability of mercuric ions for methylation and the growth of the methylating microbial populations.Rates are higher in anoxic environments, freshwater, and low pHPresence of organic matter can stimulate growth of microbial populations, thus enhancing the formation of methylmercury (sounds like a swamp to me!)
8Methylmercury Bioaccumulation Mercury is accumulated by fish, invertebrates, mammals, and aquatic plants.Inorganic mercury is the dominate environmental form of mercury, it is depurated about as fast as it is taken up so it does not accumulate.Methylmercury can accumulate quickly but depurates slowly, so it accumulatesAlso biomagnifiesPercentage of methylmercury increases with organism’s age.
10Chemical Functions of Wetlands Waste TreatmentHigh rate of biological activityCan consume a lot of wasteHeavy deposition of sediments that bury wasteHigh level of bacterial activity that breaks down and neutralizes wasteSeveral cities have begun to use wetlands for waste treatment
11Biological Functions of Wetlands Biological Production6.4% of the Earth’s surface 24% of total global productivityDetritus based food websHabitat80% of all breeding bird populations along with >50% of the protected migratory bird species rely on wetlands at some point in their life95% of all U.S. commercial fish and shellfish species depends on wetlands to some extent
12Wetland Life – The Protists One celled organisms (algae, bacteria)Often have to deal with a lack of oxygenDesulfovibrio – genus of bacteria that can use sulfur, in place of oxygen, as a final electron acceptorProduces sulfides (rotten-egg smell)Other bacteria important in nutrient cyclingDenitrification
13Phytoplankton Single celled Base of aquatic food web Oxygen production Solar Energy + CO2 + H20 C6H12O2 + O2Photosynthesis:CO2 + H20 H2CO3 H+ + HCO3- 2H+ + CO3 2-As CO2 is removed from the water pH increases.
14General Types of Aquatic Macrophytes Submergent – Plants that grow entirely under water. Most are rooted at the bottom and some may have flowers that extend above the water surface.Floating-leaved – Plants rooted to the bottom with leaves that float on the water surface. Flowers are normally above water.Free Floating – Plants not rooted to the bottom and float on the surface.Emergent – herbaceous or woody plants that have the majority of their vegetative parts above the surface of the water.
20Wetland Trees Wide at the base Tupelo Called a buttress Cypress Previous StudentWetland TreesI won this boat
21Benefits of Aquatic Plants Primary ProductionWildlife FoodOxygen ProductionShelterProtection from predation for small fishFish SpawningSeveral fish attach eggs to aquatic macrophytesSome fish build nests in plant bedsWater TreatmentWetland plants are very effective at removing nitrogen and phosphorous from polluted waters
22Submerged macrophytes can provide shelter for young fish as well as house an abundant food supply.
23Some fish will attach their eggs to aquatic vegetation. Alligators also build nests from vegetation.
24Too many plants can sometimes be a bad thing! Block waterwaysDeplete Oxygen