Biotic Communities of
Marsh Systems
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
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 (<1%pp)
Salt Marsh Ecology
Complex systems
Shaped by water,sediments, and
vegetation
Found on low energy coastlines and
protected back barriers
United States Salt Marshes
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
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
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
Global Variations
North America
Gulf Coast
West Coast
East Coast
European
Arctic (North and
South)
European Salt Marshes
Found above low neap
tide line
Periodic inundation
Different physiology due
to tidal influence
Salicornia, Suaeda
maritima, Juncus
maritimus
Primary Production
-Classical View
Spartina alterniflora
responsible for
majority of
production
3300 g/m/yr
production
Production
influenced by tides
Primary Production
-Modern Approach
Isotopic analysis
C13/c12 ratio point
towards other
sources
Algae, diatoms
Ominvores
complicate data
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
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
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
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
Aerobic Zones
Occur in top 2-3mm of soil
High content of oxidized ions
(Fe+++,Mn+4,NO3-, SO4--)
Vital source of energy for system
Metals later reduced in anaerobic
environment
Anaerobic Zone
Nitrate 2 pathways
Assimilatory nitrate reduction (plant
uptake)
Dissimilatory nitrate reduction
(denitrification)
Significant loss of N in salt marsh
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)
Mg and Fe reduction
Follows dentrification
Cause of grey/green coloration in soil
Forms ferrous oxides which can inhibit
nutrient uptake around plant roots
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
Methanogenesis
Occurs in extremely reduced conditions
After oxygen, nitrate, sulfate are used
up
Can be recycled by bacteria during
droughts
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
Food Web Interactions
Tidal freshwater Marshes
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
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
Tidal Freshwater Wetlands
lies between the oliogohaline zone and nontidal freshwater
Tidal Freshwater Marshes
Are characterized by
a large diverse
group of broadleafed plants,
grasses, rushes,
shrubs and
herbacious plants.
Grasses, rushes, shrubs
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 marsh…simplified to tidal
freshwater marsh for convenience
and term is more widely used.
Tidal Freshwater Marshes
classified as either:
System: palustrine
Class:
emergent wetland
Subclass: persistent and non-persistent
System : riverine
Class:
emergent wetland
Subclass: non-persistent
Water regimes for either
classification:
Permanently flooded – tidal
Regularly flooded
Seasonally flooded – tidal
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
Along United States East Coast
Most extensive
development of
freshwater tidal
marshes between
Southern New
England and Georgia
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
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
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
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
Continued
Pacific Coast - relatively
rare
Alaska – extensive
California – associated
with large river
systems, ex.
Sacramento
Washington and
Oregon – associated
with Columbia River
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
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)
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)
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)
General Model of N & P Cycling
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
Tidal Wetland Ecosystem
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.)
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)
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
Larger Lower Animals
Worms
Small snails
Jellyfish
Shrimp (various spp.)
Crab (various spp.)
Sponges
Mollusks
Bivalve (oyster, bent
mussel)
Barnacles
Sea squirt
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
Amphibians and Reptiles
Frogs, Toads
Diamondback
Terrapins
American alligator
Water snakes ex.
Cottonmouth moccasins
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.)
Mammals
Muskrat
Nutria
Meadow mouse, white
footed mouse
Cottontail
Fox
Raccoon
Otter
Opossum
Skunk
Whitetail deer
Manatee
Beaver
Freshwater Food Web
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
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.
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
Resources
http://agen521.www.ecn.purdue.edu/AGEN521/epadir/wetlands/fre
shwtr_marsh.html
http://www.mobilebaynep.com/habitats/fresh.htm
http://www.uncwil.edu/people/hosier