U.S. Department of the Interior
U.S. Geological Survey
FS-145-96



## Ecosystem History of Biscayne Bay and the Southeast Coast

Overview |
Biscayne Bay Ecosystem |
Project Goals |
Ecosystem Studies |
Collaborators and Results |

Overview



|map showing Biscayne Bay region, seagrass, hardbottom and barren bottom communities
|-----------------------------------------------------------------------------------

The U.S. Geological Survey is participating in a multi-institutional effort
 to assess, monitor, and restore the ecosystem of South Florida.  Federal, 
State and local agencies are collaborating to establish a firm scientific 
basis for land management and water policy issues.  Historical changes in 
South Florida related to rapid population growth in the early to middle 
1900's have led to significant alteration of the natural hydrocycles and 
water quality of Florida and Biscayne Bays.  These changes have affected 
the salinity and nutrient supply and introduced toxic components into
 Biscayne Bay.  The Biscayne Bay ecosystem shows increasing signs of 
distress: declines in fisheries, increased pollution, and dramatic changes 
in nearshore vegetation.  Northern and central Biscayne Bay are strongly
 affected by the urban development associated with the growth of Miami.
  Southern Biscayne Bay is influenced by drainage from the Everglades, 
which has been altered by canals and agricultural activities.  
Restoration and preservation of Biscayne Bay and Biscayne National Park 
are dependent on a comprehensive understanding of the linkages between 
the hydrologic system and the bay ecosystem, and of natural versus 
human-induced variability of the ecosystem.

Biscayne Bay EcosystemThe ecosystem of Biscayne Bay includes the marginal freshwater and saltwater
 wetlands, intertidal communities, and marine communities.  The health of 
each of these communities can be linked to their interaction with the 
hydrologic regime of South Florida.  Major factors that may affect these
 communities are:The alteration and control of freshwater flow entering Biscayne Bay.Urbanization of Dade County, thereby increasing storm runoff and pollutants 
into Biscayne Bay.Natural and artificial changes to vegetation associated with fires and 
urbanization.Natural disasters, including hurricanes, and prolonged wet or dry seasons.
The health of the Biscayne Bay ecosystem requires  that a critical balance be
maintained among the ecosystem communities.  Significant changes in one 
will ultimately affect the others.  Changes in the wetland communities 
(including vegetation) can alter surface water flow regimes and bird and 
fish behavior.  Alteration of seagrass distribution will affect mollusk, 
foraminifer, and ostracode distributions, among others.  Our ability to
interpret historical changes, as well as monitor future conditions, in the 
bay and surrounding area will allow us to improve or maintain the sensitive 
balance in freshwater quantity and quality necessary for the ecosystem 
components to continue to exist.
Project GoalsIn order for the restoration of Biscayne Bay to begin, it is necessary to 
have a comprehensive understanding of the evolution of the present ecosystem.
The goals of this project are as follows:Assess the modern distribution of the plants and animals (biota) of the 
Biscayne Bay ecosystem with respect to present environmental conditions.Interpret the historical record of environmental change within Biscayne Bay 
by using biotic indicators.Determine agents (natural and (or) human-induced) that may be responsible 
for changes in the ecosystem of Biscayne Bay.Make recommendations concerning approaches for Biscayne Bay restoration 
and monitoring.Ecosystem StudiesModern biotic distribution and environmental data are gathered from surficial
sediment and water samples collected throughout Biscayne Bay.  The sediments
are described and analyzed for animals (mollusks, foraminifera, ostracods) 
and plants (diatoms, pollen, and dinoflagellate cysts).  Data from the water
samples include  temperature, salinity, dissolved oxygen, clarity, nutrients,
and bacteria.  These data are statistically compared to determine
environmental conditions important to the distributions of the organisms.The historical record is interpreted from the examination of biotic components 
from sediment cores collected on mudbanks within the bay. The interpretation of 
these biotic data, based on their modern distributions,
allows us to reconstruct the ecosystem history of the bay.
Dating of the core sediments is vital to our understanding of cause and
 effect relationships between changing environments and the ecosystem.  
Dating is accomplished by using several radiometric techniques that include 
Lead-210 and Cesium-137.Collaborators and Results



The U.S. Geological Survey, through collaboration with the National Park Service, South Florida Water Management District, and Metropolitan Dade County Environmental Resources Management, will gain a more 
comprehensive understanding of the evolution of the Biscayne Bay 
ecosystem and its components.  This understanding will allow us to 
determine the impact of increasing human population and activities 
on the ecosystem and allow planners to make well founded decisions 
regarding restoration and land use policies for the future.PLANNED PRODUCTS

 ANTICIPATED SCHEDULEThe ecosystem history of Biscayne Bay and the Southeast Coast of Florida Project anticipates the following products:

 A distribution map of the major biotic, sedimentologic, and hydrologic components analyzed.Maps describing the changes in the ecosystem through time.A digital database describing the modern distribution of plants and animals in the bay.A synthesis document on the ecosystem history and evolution of Biscayne Bay.

 The project has the following schedule:

  Collect seasonal surficial sediments as assess core site localities.Collect short cores.Write a report on modern biotic distributions.Prepare time series analyses of ecosystem change.Compilation of historical ecosystem data into synoptic maps and electronic data.



FS-145-96

By Scott Ishman

For more information contact:Scott Ishman
			Geology DepartmentMail Code 4324Southern Illinois University
			Carbondale, Ill 62901
			Telephone: (618) 453-7377
			E-mail: sishman@geo.siu.edu

Related information:SOFIA Project: Ecosystem History of Biscayne Bay and the Southeast Coast
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							Last updated: 03 November, 2004 @ 02:22 PM(TJE)