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May 30, 2020

This page last modified:
March 21, 2001

A Peek Into Florida Bay's Past

by Pam Wingrove

University of Florida/Monroe County Cooperative Extension

Florida Bay Education Project

Ah the good old days! How many times have you sat back and reminisced about a time in the past that made you smile, or cry, or do both. Perhaps it was twenty years ago on a day when the fish were really biting and you had the magic hook. Maybe it was last week when the kids cooperated, everyone was out of the door on time in the morning and you could do no wrong at work. The past is a standard that resource manager's are now trying to apply to Florida Bay and understanding what, if anything, has gone wrong there.

What constitutes a healthy bay? For those who make their living on the water in Florida Bay it may have been a time in the late seventies or early eighties before the algal blooms and seagrass dieoffs occurred changing the Bay for years to come. Some consider the days before the railroad was built and natural water flow was altered by dredging and filling of passes to be the hallmark of what was pristine in Florida Bay. Pinpointing that perfect time is very difficult, however, because our knowledge of the bay is limited by incomplete records of man's influence and a relatively short history of research and monitoring.

Florida Bay was not a bay at all 5500 years ago. At that point sea level began to rise covering Florida Bay. About 3200 years ago Florida Bay reached close to its present size and shape. The bay as well as the entire South Florida Ecosystem is a dynamic, natural area that has responded throughout the history of the earth to environmental changes. What are we doing currently to impact this system, however, and can Florida Bay take it?

The answers to these questions tell us how to manage the bay, if and what type of restoration is needed. We must also know what type of bay we want to have. Studying the history of Florida Bay, assessing its current health, and factoring in our needs as residents will define that bay.

Several studies underway in Florida Bay are trying to tell us something about its past. By looking at cores of sediment from Florida Bay, scientists can determine the animals and plants that lived there long ago. Knowing the types of plants and animals that existed in the past tells us something about the environmental conditions that also existed then such as salinity and nutrient levels.

Scientists have looked at sediment from as much as 150 years ago and see some interesting things. It appears that natural fluctuations in salinity were common in Florida Bay years ago. Those changes seemed to have been caused by events such as hurricanes and El Nino and showed certain patterns that can be related to the occurrence of these events. Beginning around 1900, the patterns began to change and around 1932 to 1940 evidence of decreased fresh water input to the bay is obvious. This evidence exists through sedimentary records of plants such as seagrasses, and animals like corals and mollusks. The period of time from 1900 to the 1940's corresponds to the building of canals in South Florida to channel fresh water flow and scientists suspect the two are connected.

It appears man has had an impact on Florida Bay. Our actions to make the southern tip of Florida inhabitable have resulted in altering a Bay that is 850 square miles in size and over 3,000 years old. The challenge we face now is deciding how we can match our need for space and water with the needs of Florida Bay. To find out more about research underway in Florida Bay contact the Florida Bay Education office.

For more information on this research, contact the Florida Bay Education Project at 305-852-3592. Additional information on a variety of topics is available from the University of Florida/Monroe County Cooperative Extension Service, 5100 College Road, Stock Island or call at 292-4501; fax: 292-4415; email: or visit our web site Our services are free and available to all without regard to race, color, sex, or national origin.

The Florida Bay Education Project is an archived site. For more information go to NOAA's South Florida Ecosystem Education Project at