ESM 202 BIOGEOCHEMISTRY AND WETLANDS OUTLINE z z z z z Wetland distributions and classifications Wetland hydrographs Functions and processes Wetland threats and management Case study on local estuary Devereux Slough WETLAND CLASSIFICATION WETLAND CLASSIFICATION Wetlands distinguishing features Mitsch Gosselink 1993 z presence of water z unique soil conditions z Intermediate hydrology z biogeochemically active z hydrologic and chemical fluxes z z z Hydrophytes predominate at least periodically Substrate is predominantly undrained hydric soil Substrate is nonsoil and saturated covered with water at some time during the growing season Source Mitsch Gosselink 1993 Wetlands 2nd Ed WETLAND CLASSIFICATION MARSH TYPES z Marsh z Bog z Fen z Swamp z Vernal pool z Estuary BOG FEN SWAMP VERNAL POOL ESTUARY WETLAND CLASSIFICATION Source Mitsch Gosselink 1993 WETLAND HYDROGRAPH WETLAND HYDROGRAPH WETLAND HYDROGRAPH WETLAND HYDROGRAPH Shrubs Wet Meadow Marsh Aquatic Shrubs Aquatic Riparian Zones Riparian on the banks of a river the normally vegetated zone adjacent to streams and rivers saturated soils affect the processing of organic matter and nutrients biogeochemical hot spots in the landscape FUNCTIONS AND PROCESSES IMPORTANT FOR BIOGEOCHEMICAL PROCESSING FUNCTIONS AND PROCESSES External Exchange with Surroundings Position and abundance in the landscape Critical interface between uplands aquatic systems Wet soils different soil and water processes dominate sharp contrasts in environmental conditions FUNCTIONS AND PROCESSES Wetland Outlet Water Quality Different Sources source elements to wetland closely related to hydrology hydrology often primary vector of transport Different water sources Different Chemistry FUNCTIONS AND PROCESSES Chemistry of Different Flow Paths Time in soil or substrate primary source is precipitation dilute rain high Total Dissolved Solids TDS chemical weathering with TDS high nitrate lower nitrate or uptake during flow FUNCTIONS AND PROCESSES FUNCTIONS AND PROCESSES Type Soil and Parent Material Granite Bedrock low weathering low TDS higher Silica Limestone higher weathering higher P TDS Ca Mg Organic Soils higher Nitrogen N phosphorous P CO2 Mineral higher salts Ca Mg TDS Sand less TDS than clays weathering order of encounter important i e mineral into organic vs organic into mineral Chemistry of Different Flow Paths FUNCTIONS AND PROCESSES FUNCTIONS AND PROCESSES Outlet a mix of water sources often changes chemistry of water through a wetland reflect contrast chemistry of different source waters different sources mix combine to influence outflow chemistry FUNCTIONS AND PROCESSES Internal Processes Change in Storage in out In S Out S Retention S Source primarily driven by hydrologic condition water budget geologic setting hydroperiod etc Hydrological and Biogeochemical process influence the mass balances of nutrients Internal processes interacting with external exchange CYCLING NITROGEN CYCLING PHOSPHORUS CYCLING SULFUR CYCLING SULFUR CYCLING FUNCTIONS AND PROCESSES Controls on Nutrient Removal or Release Forms of Inputs particulate vs dissolved high sediment inputs large retention with high energy erosive inputs wetland detention and depression storage sedimentation entrainment FUNCTIONS AND PROCESSES Sedimentation rates Black Swamp Arkansas Retains nutrients in sediments in areas with lower velocity REDOX FUNCTIONS AND PROCESSES Redox potential dictates rates of transformations in wetland riparian soils Organic matter is very reduced so it can be oxidized by a number of different terminal electron acceptors O2 NO3 Mn4 Fe3 SO4 Decomposition oxidation rapid with O2 slower with other e acceptors like nitrate or sulfate ions FUNCTIONS AND PROCESSES Turn over Time uptake by vegetation and microbial assimilation take finite amount time volume of input in relation volume wetland storage Catchment wetland area larger the more closed influence the amount of wetland exchange with the surrounding area e g Bog 1year water residence time surface water swamp 30 days ground water swamp 1 day FUNCTIONS AND PROCESSES Open System high external exchange high flows pulsing hydroperiod high production high decomposition relies little on internal cycling most nutrients pass through e g Riverine wetlands Swamps Marshes FUNCTIONS AND PROCESSES z Closed System low exchange isolated Lower production Large reliance on internal cycling z Most inputs retained e g bogs poor fens FUNCTIONS AND PROCESSES Seasonality timing internal cycling magnitude inputs 1 Magnitude of inputs can vary seasonally ie snow melt z Case Study Devereux Slough 2 Seasonal growth plants in growing season fall winter die back and release microbes temperature control cold winters low activity Study Site DEVEREUX SLOUGH z z z Land use Watershed is approximately 9 7 sq km in size Devereux Creek is the only major stream in the Devereux watershed Seasonally open Canyon Mouth Estuary Study Site DEVEREUX SLOUGH HABITATS 1 Mud flats 1 2 Salicornia virginica slough flats 2 3 Slough Fingers 4 Eucalyptus forested wetlands 5 Slough basin permanently flooded 6 Dune swale basin 7 Snowy Plover habitat 4 6 5 7 3 Climatic Regime 250 Specifics Downtown Santa Barbara 30 m San Marcos Pass 671 m Annual Rainfall cm 200 150 Analyzing for Ammonium NH4 NO3 Total Dissolve Nitrogen Phosphate PO43 Total Particulate Carbon TPC Total Particulate Nitrogen TPN TPP Total Suspended Sediments TSS Frequency Regular sampling Once every 2 weeks during the dry season Once a week during the wet season Storm sampling Every hour on the rising limb of the hydrograph Every 2 4 hours on the falling limb of the hydrograph Project duration WY2003 WY2004 and WY2005 100 50 0 1965 1970 25 1975 1980 1985 1990 1995 2000 Downtown Santa Barbara 30 m San Marcos Pass 671 m 20 15 10 5 l ug A n Ju Ju A pr M ay b n M ar ec Fe Ja Se pt O ct N ov 0 D 1960 Avg Monthly Precipitation cm 1955 Nutrient Export WY2002 Carpinteria Cumulative Nutrient Loading 1 4 0 40 Chaparral Forest 0 35 WY2004 NO3 DON PO4 Devereux 100 0 35 0 30 NH4 0 25 0 20 0 15 10 Hourly time step Hydrology Pressure Transducer Observed stage HEC RAS Stream Chemistry 0 10 0 30 1 0 0 25 0 8 NH4 NO3 0 6 PO4 flow 0 4 0 20 0 15 3 1 0 40 Flow m s 1000 Cumulative Export kmols 1 2 Hourly time step Hydrology Pressure Transducer Observed stage HEC RAS 0 10 0 2 0 05 0 0 0 00 9 16 12 25 4 4 7 13 10 21 0 05 1 0 00 02 28 04 04 18 04 06 07 04 07 27 04 09 15 04 Percent of each nutrients for cumulative numbers for WY2004 100 80 60