Climate Change and Coastal Wetlands Presented by: Sidrotun Naim Susanna Pearlstein Valerie Herman Matt Carter
US Coastal and Marine Facts • 95,000 miles of coastlines • 3.4 million square miles of ocean • 53% of US population live on the 17% of land in the coastal zones • Global sea level rise: 4-8 inches in century • Estimation: additional 19 inches by 2100
Threats to Estuarine Health • Estuaries are extremely productive ecosystems • Increased run-off would deliver increased amounts of nutrients such as nitrogen and phosphorus • Decreased run-off would reduce flushing, decrease the size of nursery zones, allowing predators to penetrate
WetlandsChapter 11 • Methane, CH4, emitters • 20-25% global emissions • 50% of world wetlands LOST, methane emissions are increasing, anthropomorphic causes • 21 times more effective greenhouse gas than CO2 • Carbon sequestration • 20-30% stored in wetlands • Peat deposits • Permafrost • Restored & created wetlands
Mid Atlantic Coastal (MAC) Region • Poor water quality • Coastal Squeeze
Delaware Bay 1.6% of DE lost 21% of marsh land flooded But <1% of affected area Is developed
Chesapeake Bay Salt water marshes today lack Sediment Oxygen Organic matter accumulation Due to: Poor water quality Dams Farmland abandonment Now add climate change….
Most hypoxic estuary in MAC • Fresh water marshes have high river sediment influxes • Steep topography, sea level rise will increase erosion
Management & Warnings • Wetlands will be protected if they fall under socially significant areas • Repeating the inland floodplain experience • Federal subsides for dynamic & hazardous zones • Structures to control hazards & sea level rise • Increasing vulnerability
Chemical and Biological Changes • Extreme weather events and rising sea level alters: • Salinity • Ionic Exchanges • pH • Microbial Communities • Organic and Inorganic Content
Nutrient Exchanges • Earlier litterfall • 3 - 5 times as much N, Mg, P, K • Transported during runoff /flooding • Nutrient uptake is hindered by: • Uprooting • Swaying • Water logging
Damages to Plants/Animals • “Woody vegetation” is damaged more than “herbaceous vegetation” • Breakage increases infestation • Microbial community differs in aerobic and anaerobic conditions • Water quality directly affects food chain • Hypoxia Image from www.montgomerybotanical.org • Osmotic stress • Turbidity • Seed distribution • Biodiversity
Mitigation • Allow sediment to distribute naturally • Plan communities that allow coastal wetland migration • Project future outcomes using models: • Space-For-Time Substitution paired with long-term monitoring Image from soundbook.soundkeeper.org
Hurricanes lose their force dramatically as the system moves toward land, therefore wetlands around coast regions provide delicate buffer zones to slow the storm system down before it reaches more populated regions. The levees in New Orleans are causing dramatic wetland loss.
The levees built to prevent flooding in the cities also prevent recharge of coast wetlands of the Mississippi River Delta. The Delta is cut off from its life force and is being destroyed at a rate of 24 sq. miles a year. Over 1900 sq. miles have disappeared since the 1930s. As the wetlands decrease, the city becomes more and more vulnerable to hurricane without the precious buffer zone.
Fixing the problem is costly and time consuming. Old Christmas trees are strategically place around the delta to collect sediment, and 14 billion dollars is being used for manual sediment recharge and diversion of the Mississippi around the levees to recharge other areas of the delta.
Hurricanes are actually vital for wetland survival in that the storm surge washes and spreads all of the sediment, silt, and nutrients the wetlands of the delta could ever need. A hurricane of smaller proportions could easily do the work of all of the wetland projects.