How Will Climate Change Affect Water Quality and Biogeochemical Processes in the Delaware Estuary? David Velinsky Patrick Center for Environmental Research The Academy of Natural Sciences May 6, 2008 Climate Change in the Delaware Estuary: Impacts and Adaptation

Courtesy of Hans Paerl and Ashley Smyth Estuarine Processes and Climate Change What are the main driving forces? Temperature Sea Level

Sea Level Rise - Salt intrusion further up bay - Increase in vertical stratification - Loss of tidal marshes Changes in Precipitation and Freshwater Inflow - Nutrient and sediment loading (amount, timing and variability) - Water residence time Water and Air Temperature Changes - Timing of phytoplankton blooms - Algal community alterations (harmful algal blooms?) - Contaminant exchanges - Biogeochemical reaction kinetics Climate Change Affects Physical Factors that Impact Water Quality:

Salt Intrusion Salinity, at any given point, is a balance between freshwater inflow, tidal/wind mixing, shape and bathymetry, and sea level. - With a sea level rise of 0.7 to 2 m, the salt line could move up-bay by 3 to 30 mile, which would impact drinking water intakes, industrial intakes, groundwater recharge and mixing dynamics in the estuary. However…. Delaware River discharge is highly regulated via various reservoirs; management in the future will be a key issue in salt movement up bay, deepening of river bottom would allow salt water to move up bay, and some scenarios call for less rainfall in NE US. Taken from Hull and Titus, 1986 A “Prefect Storm” would be a rise in sea level, a deeper channel, drought conditions, and lower storage in the reservoirs >> salt front would move farther upstream.

Loading of Chemicals: Nutrient and Contaminants Three of the seven largest floods on record have occurred since Precipitation Changes (amount, intensity, and variability) - Land Use Changes are a factor There would be impacts to non-point source loads of nutrients, sediments and contaminants to the estuary. J. Sharp, UDEL (2007; MAC) Average Annual Discharge (CMS)

Biogeochemical Cycling Delaware Estuary, while receiving large loads of N and P, is not substantially impacted by eutrophication (e.g., algal blooms, low dissolved oxygen). Will climate change impacts make a difference? Courtesy of J. Sharp, UDEL DO (mg/L) Points of Interest: Loadings Primary Production Remineralization Oxygen Consumption Stratification Magnitude and Timing

Rain Deposition to Water and Land Urban Runoff Contaminant Inputs and Processes in Coastal Waters

Contaminants: Potential Impacts Relative to Climate Change Freshwater Inflows and Timing: - Increase or decrease of contaminants loads into the bay Air and Water Temperature, Salinity - Increase in the exchange between water and air - Changes in the partitioning between dissolved-colloidal-particulate forms Algal Productivity: - Changes in trophic transfer and bioaccumulation

Chemical Inputs and Processes in Coastal Waters Organic compounds, like PCBs, are volatile and can move between the air and water. The more chlorine groups the higher the molecular weight, and lower volatility. Research by Lisa Rodenburg (Rutgers Univ.) has shown that exchange is directed from the water to the air in Delaware estuary. (Env. Sci. Tech, 2007) Air-Water Exchange Atmospheric Deposition Tributary Inputs Air Water Sediment Dissolved PCBs Particulate PCBs Settling- Resuspension Porewater Transport Advection Dispersion Air-Water Exchange

Will the actual or predicted change in temperature and salinity make a difference? Various CC Models predict 1 to 5 o C increase PCB 52 (2,2',5,5'- tetrachlorobiphenyl) Starting temperature at 25 o C Henry’s Law transfer 4’ 5’ 2’ 6’ 3’(Cl) x The effect of increasing water temperatures on PCB 52 could increase the concentration in air by 20%. Movement of Volatile Organic Compounds (PCBs, PBDEs etc) Between Water and Air %Increase in PCB52 in air

Ecosystem “Services” of Tidal Marshes Primary nursery area for offshore winter-spawned fishes Finfish and shellfish habitat Recreation Aesthetic (property values - $$$$) Nutrient processing

Estuarine / Marsh Coastal Ecosystem Tidal Freshwater Marsh Salt Marsh River Ocean Estuary Courtesy of N. Weston (Villanova Univ.)

Burial MSL CO 2 Primary Production CO 2 & CH 4 Sediment Organic Matter (CNP) Microbial Respiration CO 2 & CH 4 Marshes Must Accrete to Keep Pace With Rising Sea-Levels Watershed Inputs (N,P & Seds) Export Carbon and Mass Balance in Tidal Marshes Marsh Accretion > Marsh Accretion: Plant growth/dieback, watershed and tidal water sediment inputs Courtesy of N. Weston (Villanova Univ.)

Estuarine / Marsh Coastal Ecosystem Salinity Intrusion River Ocean Changing Precipitation Rising Sea Level Courtesy of N. Weston (Villanova Univ.)

MSL Freshwater Marsh Undergoing Salinity Intrusion: Potential Impacts C and P Cycles CO 2 Primary Production CO 2 & CH 4 Sediment Organic Matter Microbial Respiration Methanogens CO 2 & CH 4 Sulfate Reducers Loss of Marsh? Plant Response Microbial Response Retention of P P Desorption PO 4 3- Courtesy of N. Weston (Villanova Univ.)

Future Concerns Some form of Climate Change will occur in the next 20 to 50 years Impacts: - Salinity Intrusion: reduced freshwater availability - Nutrient and Contaminant Loadings: changes due to precipitation - Water Quality: changes due to loadings, water stratification and impacts to dissolved oxygen - Tidal Marshes: loss of marshes will hurt filtering capacity for nutrients

Future Directions Monitor key ecosystem variables (e.g., DEWOOS) Improve communication and management of water flows among user groups Reduce nutrient, contaminant and sediment loads to estuary Land management to provide for marsh migration (natural adaptation) Plan for an adaptive management strategy

The End

Sharp (2007; MAC) From: Interlandi and Crockett, 2003 (NCDC; NOAA) R 2 = ; slope = 0.12 cm/yr; P =

Consequences of Coastal Shoreline Development and Marsh Removal

Delaware Estuary

Increased CO2 will lower pH in FW and increase chemical weathering. It will also decrease pH in seawater, but maybe less, but effects CaCO3 saturation (There is a big literature on ocean acidification; I'm working on a project with Whitman Miller on this here). CO2 increase may impact phytoplankton growth, both from lower pH and from more available CO2. CO2 tends to act as a limiting nutrient for plants. Higher CO2 certainly affects marsh grasses (and C4 plants different than C3, look up anything by Bert Drake. In terms of weather, it means different things in different places (changes in rain and average temp both plus and minus). Sea level rise will push salt water over freshwater marshes, and drown shallow land. Things that happen now, but they may speed up. Change in position of sed max in estuaries, and sedimentation pattern, estuarine circulation

Climate Change affects Physical Factors that Impact Water Quality: Sea Level Rise - Salt intrusion further up bay (also – water management & dredging) - Increase in vertical stratification - Loss of tidal marsh filtering capacity Changes in Precipitation Pattern and Freshwater Inflow - Water residence time - Nutrient and sediment loading Water and Air Temperature Changes -Timing of phytoplankton blooms - Algal species alterations (- harmful algal blooms?) - Alterations of contaminant exchanges

Impacts to Water Quality and Biogeochemical Processes : Contaminants Changes in freshwater inflow - - Vertical stratification and mixing patterns - Marsh-Bay exchange: salt and tidal freshwater systems Changes in Precipitation Pattern and Freshwater Inflow - Water residence time - Nutrient and sediment delivery Water and Air Temperature Changes -Timing of phytoplankton blooms - Algal species alterations

MSL CO 2 Primary Production CO 2 & CH 4 Sediment Organic Matter Microbial Respiration CO 2 & CH 4 Watershed Inputs Export How Does Salinity Intrusion Affect Tidal Freshwater Marshes?