Estuaries and Coasts
Notes Series for Oceanography
John P. Wnek
Coastlines and Productivity
oceanworld.tamu.edu
Coastal diagram with the area of nearshore and offshore productivity
Beaches
http://www.usa-chamber.com/gulf-beaches/home.html
High Productivity Coastal Areas
from NASA (SeaWIFS)
Northeast Coast Habitats
/www.epa.gov/owow/estuaries/programs/se.htm
Estuary Types: Classified by Geology
• Lagoon – parallel to coast (i.e. Indian River
Lagoon, Florida) – Bar-Built Estuaries
• Coast Plain Estuary – erosion (i.e.
Chesapeake Bay and Pamlico Sound)
• Tectonic Estuary – faults (i.e. San
Francisco Bay)
• Fjord – glacier formation (i.e. Alaska, British
Columbia, Norway, Chile)\
• Delta- formed at mouth of a river (i.e. –
Mississippi Delta)
Coastal Types
Rocky Coasts
Western Coasts U.S.
Mountain Coasts
Northern Boreal Coasts
Barrier Island Coast
Sandy Hook, N.J.
San Francisco Bay Estuary – a tectonic estuary
Basic Definition of Estuary – A water body where salt &
freshwater mix
Technical Definition - “A standing water body within the
coastal region where there is a greater net inflow of
freshwater than an influx of sea water”
J Wnek
Factors influencing an estuary
• Temperature
• Salinity
• Nutrients
Anthropogenic effects
• Increased runoff
• Development causing habitat
fragmentation
• Global Climatic Changes
Temperature
• Highly subjected to seasonal variations
• Shallow estuaries are prone to wide
ranges in temperatures (i.e. Barnegat Bay)
with variations from below -2 to 30 oC
• Temperatures may change with shifting
tidal regimes
• There can be temperature inversions
during the evenings, especially in the fall
when cooler temperatures may be at the
surface.
http://waterdata.usgs.gov/usa/nwis/uv?site_no=01409125
Salinity
• Salinity can vary in estuaries based upon
the amount of salt water inflow and
freshwater inputs.
• Estuaries can be classified according to
the layering of salt water based on density
- well-mixed
- partially-mixed
- salt wedge (highly stratified)
Inverse Estuaries
• Some estuaries show an increase in
salinity over time, these are considered
“inverse estuaries” or “negative estuaries.”
• There is a net increase in salinity over time
mostly due to human impacts (i.e. dams
and loss of freshwater flow into the
system)
(Zedler et al. 2001)
Swan River Estuary, W.
Australia (Neira et al., 1992)
“Human activities have greatly increased the
delivery of plant nutrients to estuarine and
coastal waters throughout the world. Over
abundant nutrients fuel excessive algal
growth, which destroys critical habitats for
fish and shellfish by depleting oxygen in the
water and by blocking light from reaching sea
grasses.” - Smithsonian Environmental Research Center
Flushing Time?
• Considered the amount of time in which all
water is totally exchanged in an estuary
• Varies according to the estuary due to
ocean access, freshwater runoff (called
inflow) and depth of the estuary
tF = VF / R
tF is the flushing time
Vf is the freshwater volume
R is the river discharge rate
Flushing Time* Comparisons
Estuary
Minimum
Maximum
Mean
Chesapeake
Bay, MD-VA
210 days
(Guo)
Delaware
Bay, DE-NJ
100 days
(Delaware Estuary
Program)
Barnegat
Bay, NJ
24 days
(January
1995)
74 days
(June/July
1995)
49 days
(Guo)
North River,
MA
3 days
(Geyer)
9 days
(Geyer)
Not
determined
Estuaries as Habitats
• Estuaries provide multiple habitat types
including marshes, marsh pools, tidal
creeks, and shoreline deep water habitats
• Finfish can inhabit specific habitats with
fish being considered seasonal residents
(19%), residents (21%) , nursery (38%) or
strays (22%) in a study on Great Bay and
Little Egg Harbor (Able et al. 1996 in
Estuarine Shores).
Marsh Zonation
• High Marsh – Not flooded regularly with
predominant Spartina patens and Phragmites
– Series of marsh pools at higher elevations
• Low Marsh – Floods regularly with Spartina
alterniflora
– Creeks and ditches with sometimes tidal effects
– Support a higher density of finfish than SAV beds
(Sogard and Able 1991).
Marsh Zones (Jones and Strange 2006)
Submerged Aquatic Vegetation
•In some estuaries over 300 species of fish
reside all in which SAV is important:
•Provide habitat for juveniles
•Key source of oxygen production
•Important part of nutrient cycling
•Binds and stabilizes sediments
Data from the CRSS and Barnegat Bay Estuary Program 2001
Species and habitats
Sygnathus fuscus
Cyrpinodon variegatus
Three-spine stickleback
Gasterostreus aculeatus
Striped Bass (Morone saxatilis)
www.stripertracker.org
Anthropogenic Effects on Coastlines
Coastal erosion in Norfolk in 1997
Human Impacts and Changes in Estuaries
Delaware Bay and human impacts
In the past eighteen thousand years, sea level has risen one hundred meters
(three hundred feet), converting freshwater rivers into brackish estuaries (Donn,
Farrand, and Ewing 1962). The Delaware River is an Alluvial Plain
Delaware River Fluxes in Sea Level Rise
Hull, C.H.J. and J.G.Titus (eds). 1997. Greenhouse Effect, Sea Level Rise, and Salinity in the Delaware
Estuary.. Washington, D.C.: U.S. Environmental Protection Agency and Delaware River Basin Commission.
Marsh Systems
Hartig et al. 2002
Hartig et al. 2002
Proposed Bruun Model with
changing sea level
Shifting of dunes and berms in
response to sea level rise
Davidson-Arnott, R. 2005. Conceptual model of the effects of sea level rise on sandy
coasts. Journal of Coastal Research 21 (6): pp. 1166-1172.
Jones & Strange 2006
Jones & Strange 2006
Jones & Strange 2006
Habitat Alteration Models from Jones and Strange 2006
SAV model (blue 3 mm/ red 9 mm)
Phrag. model (blue 3 mm/ red 9 mm)
Based on the inundation model through 2195
Habitat Alteration Models from Jones and Strange 2006
S. alterniflora model (blue 3 mm/ red 9 mm)
S. patens model (blue 3 mm/ red 9 mm)
Based on the inundation model through 2195
References
Able, K, D.A. Witting, R. McBride, R. Rountree, and K.J. Smith. 1996. Fishes of polyhaline estuarine shores in
Great Bay-Little Egg Harbor, New Jersey: a case study of seasonal and habitat influences in Estuarine
Shores by K.F. Nordstrom and C.T. Roman (eds.). John Wiley and Sons, England: pp. 335-353.
Candolin, U., T. Salesto, and M. Evers. Changed environmental conditions weaken sexual selection in
sticklebacks. 2006. The Authors: Journal Compilation in the European Society for Evolutionary Biology 20:
pp. 233- 239.
Carlson, D.M., and R.A. Daniels. 2004. Status of Fishes in New York: Increases, Declines, and Homogenization
of Watersheds. American Midland Naturalist 152: pp. 104-139.
Davidson-Arnott, R. 2005. Conceptual model of the effects of sea level rise on sandy coasts. Journal of Coastal
Research 21 (6): pp. 1166-1172.
Diffenbaugh, N.S., M.A. Snyder, and L.C. Sloan. 2004. Could CO2- induced land cover feedbacks alter nearshore upwelling regimes. Proceeding of the Natural Academy of Science, 101 (1): pp. 27-32.
Dybas, C.L. 2006. On a Collision Course: Ocean Plankton and Climate Change. BioScience 56 (8): pp. 642646.
Galbraith, H., R. Jones, J. Clough, S. Herrod-Julius, B. Harrington, and G. Page. 2002. Global Climatic Change
and Sea Level Rise: Potential Losses of Intertidal Habitat for Shorebirds. Waterbirds 25 (2): pp. 173-183.
Guo, Q., N. P. Psuty, G.P. Lordi, S. Glenn, and M.R. Mund.1995. Hydrographic Study of
Barnegat Bay, Year 1: Volume 1 and 2. Prepared by the Rutgers the State University of New Jersey, New
Brunswick, NJ, for the New Jersey Department of Environmental Protection, Division of Science and
Research.
Guo, Q. and Valle-Levinson. 2007. Tidal effects on estuarine circulation and outflow
plume in the Chesapeake Bay. Continental Shelf Research 27: 20-42.
References (cont’d)
Gray, V.R., 1998. "The IPCC future projections: are they plausible". Climate Research 10 pp. 155-162
Green, R., J.E. Maldonado, S. Droege, and M.V. McDonald. 2006. Tidal Marshes: A Global Perspective on
the Evolution and Conservation of their Terrestrial Vertebrates. BioScience 56 (8): pp. 675 – 685.
Hartig, E.K., V. Gornitz, A. Kolker, F. Mushacke and D. Fallon. 2002. Athropogenic effects and climatechange impacts on salt marshes of Jamaica Bay, New York City. Wetlands 22 (1): pp. 71 – 89.
Hull, C.H.J. and J.G.Titus (eds). 1997. Greenhouse Effect, Sea Level Rise, and Salinity in the Delaware
Estuary.. Washington, D.C.: U.S. Environmental Protection Agency and Delaware River Basin
Commission.
Jones, R. and E. Strange. 2006. A Pilot Study of the Ecological Consequences of Human Responses to Sea
Level Rise. Stratus Consulting Inc., Boulder Colorado as part of a supporting document for the Barnegat
Bay National Estuary Program’s Conservation and Management Plan (item 4.1): pp. 1- 61.
Neira, F.J., I.C. Potter, and J.S. Bradley. 1992. Seasonal and spatial changes in the larval
fish fauna within a large, temperate Autralian estuary. Marine Biology 112: 1- 16.
Ogdon, J., S.M. Davis, T.K. Barnes, K.J. Jacobs, and J.H. Gentile. 2005. Total System Conceptual
Ecological Model. Wetlands 25 (4): 955-979.
Reed, D.J., D.A. Bishara, D.R. Cahoon, J. Donnelly, M. Kearney, A.S. Kolker, L.L. Leonard, R.A. Orson, and
J.C. Stevenson. 2006. Site-specific scenarios for wetlands accretion as sea level rises in Mid-Atlantic
Region. Supporting document for CCSP 4.1 to Climatic Change Division U.S. Environmental Protection
Agency: pp. 1- 54.
Zedler, J.B. 2005. Restoring wetland plant diversity: a comparison of existing and adaptive
approaches. Wetlands Ecology and Management 13: 5-14.