Biotic Communities of Marsh Systems

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Biotic Communities of Marsh
Systems
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Fresh/Saltwater Systems

• Freshwater marsh?0.5-5.0 ppt (between oligohaline
  zone and non-tidal freshwater)
• Saltwater marsh?5.0-35.0 ppt or greater depending
  upon conditions

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Comparison

• Saltwater
• -lg. Tidal influence
• -sandy, lower OM
• -marine and estuarine macrophytes
• -low species diversity
• -moderate to high algal production

• Freshwater
• -riverine influence
• -silt and clay, high OM
• -freshwater macrophytes
• -high species diversity
• -very low algal production (lt1pp)

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Salt Marsh Ecology

• Complex systems
• Shaped by water,sediments, and vegetation
• Found on low energy coastlines and protected back
  barriers

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United States Salt Marshes
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Basic Characteristics

• Found in inter-tidal zones
• Fewer species present, occupying broader niches
  (recent geologic origin)
• Stressful environment
• Large gradients present for temperature,
  salinity, and pH

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Development

• Tidal sequence provides major source of sediment
  load
• Terrestrial runoff provides secondary source
• Salt tolerant plant species invade and thrive
  following deposition of sediments

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Atchafalaya Delta Region

• Recent studies prove importance of riverine input
• Delta receives 1/3 of Miss. River flow
• Wetland area actually increasing
• Surrounding areas are in rapid decline due to
  subsidence and sea level rise

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Global Variations

• North America
• Gulf Coast
• West Coast
• East Coast

• European
• Arctic (North and South)

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European Salt Marshes

• Found above low neap tide line
• Periodic inundation
• Different physiology due to tidal influence
• Salicornia, Suaeda maritima, Juncus maritimus

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Primary Production -Classical View

• Spartina alterniflora responsible for majority of
  production
• 3300 g/m/yr production
• Production influenced by tides

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Primary Production-Modern Approach

• Isotopic analysis
• C13/c12 ratio point towards other sources
• Algae, diatoms
• Ominvores complicate data

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Primary Consumers

• Trophic relationships begin with algae or
  Spartina detritus
• Rich benthic communities develop
• Bacteria rich detritus more valuable when
  compared to plant tissue
• Species of Uca, Callinectes, and Penaeus common
  in systems

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Primary Consumers cont.

• Deposit Feeders
• -take in bottom sediments
• -filter organic particles
• -oligochaetes,etc.

• Suspension Feeders
• -filter organic material and other nutrients out
  of water column
• -use siphons, internal filters
• -American oysters, mussels

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Value to Marsh System

• Macro-consumers provide an essential link in salt
  marsh energetics
• Take potentially harmful nutrients out of water
  column (phosphorus, etc.)
• Bioturbation aerates the soil, increasing algal
  productivity
• Feces provide new food source for microbial
  communities

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Secondary Consumers

• Birds, fish, and crabs compose a majority of the
  species for this trophic level
• Primary consumers provide valuable food source
  for juvenile populations
• May feed on organisms in sediments and water
  column

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Aerobic Zones

• Occur in top 2-3mm of soil
• High content of oxidized ions (Fe,Mn4,NO3-,
  SO4--)
• Vital source of energy for system
• Metals later reduced in anaerobic environment

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Anaerobic Zone

• Nitrate ?2 pathways
• Assimilatory nitrate reduction (plant uptake)
• Dissimilatory nitrate reduction (denitrification)
• Significant loss of N in salt marsh

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Nitrogen Cycling

• Complex interactions in both aerobic and
  anaerobic zones
• Mineralization ?production of ammonium ion from
  organic N
• Pulled upward (gradient change)?oxidized by
  chemoautotrophs
• Nitrification (nitrosomonas, nitrobacter)

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Mg and Fe reduction

• Follows dentrification
• Cause of grey/green coloration in soil
• Forms ferrous oxides which can inhibit nutrient
  uptake around plant roots

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Sulfur reduction

• Assimilatory S reduction? Desulfovibrio
• OM produced
• Combines with Fe to reduce H2S concentrations in
  sediments (limits toxicity)
• PS bacteria (purple sulfur)?create OM on surface
  of the salt marsh

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Methanogenesis

• Occurs in extremely reduced conditions
• After oxygen, nitrate, sulfate are used up
• Can be recycled by bacteria during droughts

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Conclusions

• Complex interactions regarding salt marsh
  energetics
• Algal growth and diatom formation provide basic
  primary production
• Nutrient cycling in anaerobic zones, rich
  bacterial communities
• Low species richness due to emphimeral nature and
  harsh environment

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Food Web Interactions
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Tidal freshwater Marshes
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Definition

• Tidal freshwater wetlands are a distinctive type
  of ecosystem located upstream from tidal saline
  wetlands (salt marshes) and downstream from
  non-tidal freshwater wetlands

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Characteristics

• Near freshwater conditions 0.5 ppt average annual
  salinity (more concen. during periods of drought
  )
• Plant and animal communities dominated by
  freshwater species
• A daily lunar tidal fluctuation

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Tidal Freshwater Wetlands

• lies between the oliogohaline zone and non-tidal
  freshwater

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Tidal Freshwater Marshes

• Are characterized by a large diverse group of
  broad-leafed plants, grasses, rushes, shrubs and
  herbacious plants.

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Grasses, rushes, shrubs
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Simplifying terminology

• Odum, et al (1984) identifies similar terminology
  in literature such as palustrine emergent
  wetland, freshwater tidal, transition marsh
  combined with arrow-arum and pickerelweed
  marshsimplified to tidal freshwater marsh for
  convenience and term is more widely used.

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Tidal Freshwater Marshes classified as either

• System palustrine
• Class emergent wetland
• Subclass persistent and non-persistent
• System riverine
• Class emergent wetland
• Subclass non-persistent

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Water regimes for either classification

• Permanently flooded tidal
• Regularly flooded
• Seasonally flooded tidal

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The system selected depends on the position of
the marsh with respect to the river channel

• High back marshes with persistent vegetation
  classified as palustrine
• Fringing low marshes along river edges
  classified as riverine

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Along United States East Coast

• Most extensive development of freshwater tidal
  marshes between Southern New England and Georgia

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Best developed in locations

• Major influx of freshwater
• Daily tidal amplitude of at least 0.5m (1.6ft.)
• A geomorphological structure which constricts
  magnifies the tidal wave in the upstream portion
  of the estuary

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In North Carolina estuaries lie behind Outer Banks

• reduced tidal amplitude
• Almost all coastal river systems have tidal
  and freshwater systems
• Slight tidal change
• Irregular tides and greatly affected by the
  wind

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North Carolina is unique

• Tidal plant communities present typically
  restricted in size
• Tidal swamps present
• Cape Fear River system, one exception
• One meter tide
• Extensive areas of typical tidal freshwater
  marshes

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Characteristics of freshwater wetlands by region

• Florida, tidal freshwater marshes are very
  restricted in size or very seasonal
• Gulf, Louisiana extensive tidal freshwater
  marshes
• Irregular
• Low amplitude
• Wind driven

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Continued

• Pacific Coast - relatively rare
• Alaska extensive
• California associated with large river systems,
  ex. Sacramento
• Washington and Oregon associated with Columbia
  River

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Geological History relatively recent

• Freshwater coastal marshes expanded rapidly as
  drowned river systems were inundated and filled
  with sediment
• Northern Gulf of Mexico coast, marshes are
  probably still expanding due to increased runoff
  associated with land clearing and human activities

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Soil and Water Chemistry

• Coastal Marsh sediments generally organic
• Sediments are anaerobic except for a thin
  surface layer
• Ammonium is present in the winter but reduced to
  lower levels in the summer due to plant uptake
• Nitrogen present in organic form
• Phosphorus levels vary
• High cation exchange capacity (CEC)
• Soil pH generally close to neutral (6.3 to 7.0)

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Decomposition 3 Factors

• Temperature, major factor in decay
• As temperatures increase, decay increases
• Oxygen and water availability
• Plants in anaerobic or dry environments decompose
  slowly
• Plant tissue
• broadleaf perennials (high concentrations of
  nitrogen, leaf tissue readily decays)
• high marsh grasses (low nitrogen concentrations
  and structural tissue resistant to decay)
• Litter tends to accumulate around persistent
  grasses
• Low erosion rates ( and low tidal energy)

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Organic Export

• Losses of organic carbon from marshes occur
  through respiration
• Peat forms below root zone
• Can convert to methane that escapes as a gas
• Exported in bodies of consumers that feed on the
  marsh
• In anaerobic freshwater, little sulfur available,
  carbon dioxide can be reduced to methane (which
  is lost to the atmosphere)

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General Model of N P Cycling
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Nutrient budgets

• Appears to be similar to salt water marshes
• Open systems
• Long-term sinks, sources or transformers of
  nutrients
• Most inputs are inorganic transformed chemically
  or biologically to organic forms
• Recycle most nutrients used within the system
  imports and exports are a small percentage of the
  total material cycled

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Tidal Wetland Ecosystem
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Marsh Vegetation Brackish to Fresh

• Marsh cord grass (Spartina cynosuroides)
• Narrow leaved cat-tail (Typha angustifolia)
• Coastal cat-tail (Typha domingensis)
• Marsh fleabane (Pluchea purpurascens)
• Arrow-arum (Peltandra virginica)
• Wild rice (Zizania aquatica
• Swamp rose (Rosa palustris)
• Mallows (Hibiscus spp.)

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Plants indicating Freshwater

• Wax myrtle (Myrica cerifera)
• Sedges (Carex spp.)
• Jewelweed (Impatiens capensis)
• Blue flag (Iris versicolor)
• Broadleaf cat-tail (Typha latifolia)
• Wild celery (Vallisneria spiralis)
• Red maple (Acer rubrum)
• Water tupelo (Nyssa aquatica)

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Algae Microscopic Organisms

• Algae
• Green (Chlorophytes)
• Blue-green (Cyanophytes)
• Plankton (non to poor swimmers)
• Protozoans (animal like w/flagella)
• dinoflagellates
• Diatoms (type of phytoplankton phyto green)
• Building block of food chain
• Forams (animal like, eat diatoms)
• Bacteria

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Larger Lower Animals

• Worms
• Small snails
• Jellyfish
• Shrimp (various spp.)
• Crab (various spp.)
• Sponges
• Mollusks
• Bivalve (oyster, bent mussel)
• Barnacles
• Sea squirt

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Fish and Shellfish Classification

• Anadromous (spawns in freshwater, lives in
  saltwater) Semiandromous (spawns in freshwater
  adults remain in lower estuaries) ex. Striped
  bass, Herring. Shad, Sturgeon Catadromous
  (spawns in saltwater, lives in freshwater) ex.
  ex. American eel
• Estuarine-Marine (a few species move into
  freshwater marshes to spawn) ex. Spot, Croaker,
  Brown Shrimp, Summer Flounder
• Estuarine (complete entire lifecycle in estuary,
  extend range into freshwater marshes) ex.
  Killifish, Bay Anchovy, Hogchoker
• Freshwater (spawn and complete lives in
  freshwater areas) ex. Bluegill, Sunfish,
  Largemouth Bass

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Amphibians and Reptiles

• Frogs, Toads
• Diamondback Terrapins
• American alligator
• Water snakes ex. Cottonmouth moccasins

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Birds 280 species reported

• Waterfowl (44 spp.)
• Wading birds (15 spp.)
• Rails and shorebirds (35 spp.)
• Birds of prey (23 spp.)
• Gulls, terns, kingfishers and crows (20 spp.)
• Arboreal birds (90 spp.)
• Ground and shrub birds (53 spp.)

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Mammals

• Muskrat
• Nutria
• Meadow mouse, white footed mouse
• Cottontail
• Fox
• Raccoon
• Otter
• Opossum
• Skunk
• Whitetail deer
• Manatee
• Beaver

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Freshwater Food Web
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Floating Marshes

• Usually associated with non-tidal systems
• Marsh substrate composed of a thick organic mat,
  entwined with living roots that rises and falls
  with the surrounding water levels
• Coastal Louisiana tidal marshes has the largest
  area of floating marshes in US
• The flora is diverse but dominated by ferns in
  spring and Panicum hemitomon in summer and fall

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Resources

• Alongi,D.M. 1998. Coastal Ecosystem Processes.
  Univ. of Minnesota, Minneapolis. pp. 419.
• Bertness, Mark D. 1999. The Ecology of Atlantic
  Shorelines, Sinauer Associates, Inc. Pbulishers
  Sunderland, Massachusetts, pp. 417.
• McLusky, D.S. 1981. The Estuarine Ecosystem.
  John Wiley Sons, New York. pp. 150.
• Mitsch, William J. and James G. Gosselink. 1993.
  Wetlands, 2d ed., Van Nostrand Reinhold, New
  York, pp. 722.
• Odum, W. E., T. J. Smith III, J.K. Hoover, C.C.
  McIvor. 1984. The Ecology of Tidal Freshwater
  Marshes of the United States East Coast A
  Community Profile, U.S. Fish and Wildlife
  Service, FWS/OBS-83/17,Washington, D.C., pp. 177.
• Pomeroy, L.R. and Weigert,R.G. 1981. The
  Ecology of a Salt Marsh. Springer-Verlag, New
  York. pp. 271
• Roberts, Mervin F. 1979. The Tidemarsh Guide,
  E.P. Dutton, a Division of Sequoia-Elsevier, New
  York, pp. 240.

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Resources

• Shabreck,R.H. 1988. Coastal Marsh Ecosystem and
  Wildlife Management. Univ. of Minnesota Press.
  pp.138
• Statler, Richard. 1993. Barrier Island Botany The
  Southern United States, Wm. C. Brown Dubuque,
  Iowa, pp. 164.
• Tiner, Ralph W. Jr.. 1987. A Field Guide to
  Coastal Wetland Plants of the Northeastern United
  States,The University of Massachusetts Press, pp.
  285.
• Wharton, Charles H.. 1978. The Natural
  Environments of Georgia, Geological and Water
  resources Division and Resource Planning Section,
  Office of Planning and Research Georgia
  Department of Natural Resources Atlanta, Georgia,
  pp. 227.
• www.epa.gov/owow/wetlands
• www.excite.com (photo gallery)
• www.uf.edu ( plant photo gallery)
• www.h20.denr.nc.state.gov

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Resources

• http//agen521.www.ecn.purdue.edu/AGEN521/epadir/w
  etlands/freshwtr_marsh.html
• http//www.mobilebaynep.com/habitats/fresh.htm
• http//www.uncwil.edu/people/hosier