Coastal Systems and Wetlands

Extent of Coastal ecosystems and wetlands

  • Distribution: Continental margins - interface of land and water

  • Climate varies widely depending on latitude and atmospheric circulation

  • Organisms: Many wetland species

  • Typically low-lying, undulating micro-topography

  • 620,000 km of coastline, over 1/3 of the population lives within 100km of the coast

  • Ecosystem services: Filters pollutants, storm buffering, nurseries for marine species and waterfowl, recreation, economic development, tourism, fishing industries, etc.

North Carolina has diverse coastal systems - saltwater, freshwater, estuaries, etc.

Protection of human communities is an important service of coastal ecosystems.

Insurance is strained - ex. FEMA

Coastal ecosystems are important components of global Carbon cycles

  • Wetland soils contain globally significant carbon reserves.

  • 2-3% of land area but hold 18-30% of total global soil organic carbon

  • Soil carbon residence time is thousands of years

Wetlands are also important for the global methane budget - they create a lot.

Drivers of coastal change

  • Human related or climate related - building houses or sea level rise

  • Sea level rise (SLR): expected to rise as much as 6 meters in 500 years

Coastal ecosystem responses

  • Risks to human settlements/human health, risks to rocky coasts/beaches/coral reefs/etc.

Rocky Coasts - form ¾ of the world’s coasts, soft-rock and hard-rock systems may respond differently to ocean acidification or other climate changes. Biodiversity will decline or change. Environmental gradients lead to high sensitivity to change ex. inter-tidal zone.

Beaches, barriers, and sand dunes - less common than rocky coasts, valued for recreation and economic development. Lots of erosion and hardening of shorelines, “sand starvation”. Beach renourishment sucks for everyone.

Wetlands and Sea grass Beds - Vegetated shorelines have declined globally due to SLR, wave action, and human land use. *Loss of habitat and loss of carbon stored in soil sediments* Marshes may move upland, rising temperature is causing species migration to higher latitude. Interior wetlands are being drowned. Elevated atmospheric CO2 or ocean acidification may increase productivity of terrestrial and aquatic plants.

Coral reefs - Mass coral bleaching, some coral species migrating poleward. Ocean acidification is additional stress.

Estuaries and Lagoons - Sensitive to changes in sediment inputs. Changes in storms, wave energy, SLR, freshwater inputs(drought), and sedimentation/nutrient inputs threaten.

Deltas - Naturally influenced by river flow, tides, wind, and waves - highly sensitive. Highly degraded globally, mostly human-caused.