Slide 1
Coastal Ecosystems: Salt Marshes and Mangroves
Marine Biology
Dr. Ouida Meier
Slide 2
Latitude
temperature
light, seasonality
Tidal cycles
amplitude
frequency
Wave energy
Degree of riverine input
freshwater input
alluvial sediments and deposition
turbidity
Slide 3
Factors Driving Coastal Ecosystems
Geological characteristics
rock
sand
sediment
Hydrological characteristics
nearshore currents
transport
Continental proximity
nutrient input
anthropogenic impacts
(cont.)
Slide 4
Our example (Pacific Northwest): high latitude, so
Cold Pacific waters, strong seasonality
Tidal cycle: high amplitude, semi-diurnal
Wave energy high
Freshwater input – riverine characteristics modified by bay / estuary
Geology: rocky cliffs, interspersed w/sandy beach
Hydrology: strong nearshore currents & transport
Continental edge, input via interaction with terrestrial systems
Slide 5
Our example (southeastern U.S.: Gulf and Atlantic coasts): moderate latitude, so
“Warm” Atlantic and warmer Gulf and Gulf stream waters, moderated seasonality
Tidal cycle: low amplitude
Wave energy low
Freshwater input often critical – deltaic riverine input can result in extensive marsh systems, abundant alluvial sediment input. Salt accumulation a challenge.
Geology: long-term alluvial sediment accumulation
Hydrology: nearshore currents & transport important
Continental edge, nutrient input via runoff, rivers
Slide 6
Salt marsh and tidal channels in coastal Georgia
Slide 7
Spartina alterniflora – marsh cordgrass
height depends on riverine or tidal flushing
export of dried mats during winter storms
exclude salt from roots
Salicornia – a succulent
Salt pans
Fresher water and soils / higher ground: other grasses (Spartina patens), rushes (Juncus romerianus), sedges
Zonation based on topography, inundation of freshwater, fresh/salt fluctuation, tidal flushing, relative stresses, anoxia of soils, latitudinal gradient (e.g., east coast U.S.).
Slide 8