Tampa Bay
Tampa Bay is a large natural harbor and shallow estuary connected to the Gulf of Mexico on the west-central coast of Florida, comprising Hillsborough Bay, McKay Bay, Old Tampa Bay, Middle Tampa Bay, and Lower Tampa Bay. The largest freshwater inflow into the bay is the Hillsborough River, which flows into Hillsborough Bay in downtown Tampa. Many other smaller rivers and streams also flow into Tampa Bay, resulting in a large watershed area.
The shores of Tampa Bay were home to the Weeden Island Culture and then the Safety Harbor culture for thousands of years. These cultures relied heavily on Tampa Bay for food, and the waters were rich enough that they were one of the few Native American cultures that did not have to farm. The Tocobaga was likely the dominant chiefdom in the area when Spanish explorers arrived in the early 1500s, but there were likely smaller chiefdoms on the eastern side of the bay which were not well documented. The indigenous population had been decimated by disease and warfare by the late 1600s, and there were no permanent human settlements in the area for over a century. The United States took possession of Florida in 1821 and established Fort Brooke at the mouth of the Hillsborough River in 1824.
The communities surrounding Tampa Bay grew tremendously during the 20th century. Today, the area is home to about 4 million residents, making Tampa Bay a heavily used commercial and recreational waterway and subjecting it to increasing amounts of pollutants from industry, agriculture, sewage, and surface runoff. The bay's water quality was seriously degraded by the early 1980s, resulting in a sharp decline in sea life and decreased availability for recreational use. Greater care has been taken in recent decades to mitigate the effects of human habitation on Tampa Bay, most notably upgraded sewage treatment facilities and several sea grass restoration projects, resulting in improved water quality over time. However, occasional red tide and other algae blooms have caused concern about the ongoing health of the estuary.
The term "Tampa Bay" is often used as shorthand to refer to all or parts of the Tampa Bay area, which comprises many towns and cities in several counties surrounding the large body of water. Local marketing and branding efforts commonly use the moniker "Tampa Bay", furthering the misconception that it is the name of a particular municipality when this is not the case.
Geography
Origin
Tampa Bay formed approximately 6,000 years ago as a brackish drowned river valley type estuary with a wide mouth connecting it to the Gulf of Mexico. Prior to that time, it was a large fresh water lake, possibly fed by the Floridan Aquifer through natural springs. Though the exact process of the lake-to-bay transformation is not completely understood, the leading theory is that rising sea levels following the last ice age coupled with the formation of a massive sink hole near the current mouth of the bay created a connection between the lake and the gulf.Ecology
Tampa Bay is Florida's largest open-water estuary, extending over and forming coastlines of Hillsborough, Manatee and Pinellas counties. The freshwater sources of the bay are distributed among over a hundred small tributaries, rather than a single river. The Hillsborough River is the largest such freshwater source, with the Alafia, Manatee, and Little Manatee rivers the next largest sources. Because of these many flows into the bay, its large watershed covers portions of five Florida counties and approximately.The bottom of Tampa Bay is silty and sandy, with an average water depth of only about. The relatively shallow water and tidal mud flats allow for large sea grass beds, and along with the surrounding mangrove-dominated wetlands, the bay provides habitat for a wide variety of wildlife. More than 200 species of fish are found in the waters of the bay, along with bottlenose dolphins and manatees, plus many types of marine invertebrates including oysters, scallops, clams, shrimp and crab. More than two dozen species of birds, including brown pelicans, several types of heron and egret, Roseate spoonbills, cormorants, and laughing gulls make their year-round home along its shores and small islands, with several other migratory species joining them in the winter. The cooler months are also when warm-water outfalls from power plants bordering the bay draw one out of every six West Indian manatees, an endangered species, to the area.
Environmental issues
Conservation
Tampa Bay was designated as an "estuary of national significance" by the United States Environmental Protection Agency in 1990. Two National Wildlife Refuges are located in Tampa Bay: Pinellas National Wildlife Refuge and the refuge on Egmont Key. Most of the islands and sandbars are off-limits to the public, due to their fragile ecology and their use as nesting sites by many species of birds. The Tampa Bay Estuary Program keeps watch over the Bay's health.Pollution
Tampa Bay was once teeming with fish and wildlife. People of the Safety Harbor culture lived almost entirely from mullet, shellfish, sea turtles, manatees, crabs, and other bounties harvested from the sea. As late as the early 20th century, visitors still reported huge schools of mullet swimming across the bay in such numbers that they "impeded the passage of boats".The establishment and rapid growth of surrounding communities during the 20th century caused serious damage to the bay's natural environment. Heavy harvesting of fish and other sea life, constant dredging of shipping channels, and the clearing of mangroves for shoreline development were important factors. Most damaging was the discharge of waste water and other pollutants into the bay, which drastically degraded water quality. The bay's health reached a low point in the 1970s. The water was so murky that sunlight could not reach the shallow bottom, reducing sea grass coverage by more than 80% compared to earlier in the century and severely impacting the marine ecosystem. Many previously common species became scarce, and bay beaches were regularly closed due to unsafe levels of bacteria and pollutants.
Beginning in the early 1980s after federal and state legislation to improve water quality, authorities installed improved water treatment plants and tightened regulation of industrial discharge, leading to slow but steady improvement in water quality and general ecological health. By 2010, measures of sea grass coverage, water clarity, and biodiversity had improved to levels last seen in the 1950s.
However, industrial and agricultural runoff along with runoff from developed areas pose a continuing threat to marine ecosystems in the bay, particularly by clouding the water with sediments and algae blooms, and seagrass coverage declined slightly in the late 2010s. Wastewater pollution from old phosphate plants near the shoreline has been a particular problem. For example, in 2004, a leak of 65 million gallons of acidic water from a Cargill phosphate plant on the bay's southern shore severely impacted wetlands in the vicinity of the spill.
On September 5, 2004, acidic process water was released from the Mosaic Fertilizer, LLC storage containment system during Hurricane Frances. By the following day, an estimated 65 million gallons had emptied into Archie Creek Canal, Hillsborough Bay, and surrounding wetlands.
And in April 2021, a breach of a wastewater reservoir at the long-closed Piney Point phosphate plant sent over 200 millions gallons of nutrient-rich mine tailings streaming into lower Tampa Bay. The resulting growth of red tide algae led to an ecocide and killed over 1000 tons of fish in the bay and along the nearby gulf coast and may lead to further damage to seagrass beds.
The effects of Hurricane Milton in October 2024 caused polluted waste from the fertilizer industry including products from Mosaic, which were retained after the production of phosphate, to enter into Tampa Bay. Both Hurricane Milton and Hurricane Helene caused disruption in the production of phosphate fertilizers from Tampa Bay.
Climate change
Tampa Bay, like other parts of Florida, is extremely vulnerable to sea level rise caused by climate change. The sea level has risen since 1946. Tampa Bay is also one of the areas in the US most at risk when hurricanes arrive because of its location, growing population, and the geography of the bay.The Tampa Bay Regional Resiliency Coalition coordinates the region's response to climate change. Communities throughout the Bay, including St. Petersburg and Tampa are adapting infrastructure and buildings to face changes in sea level.
Human habitation
Early inhabitants
Humans have lived in Florida for millennia, at least 14,000 years. Due to worldwide glaciation, sea levels were much lower at the time, and Florida's peninsula extended almost 60 miles west of today's coastline. Paleo-Indian sites have been found near rivers and lakes in northern Florida, leading to speculation that these first Floridians also lived on Tampa Bay when it was still a freshwater lake. Evidence of human habitation from this early period has been found at the Harney Flats site, which is approximately 10 miles east of the current location of Tampa's downtown waterfront.The earliest evidence of human habitation directly on the shores of Tampa Bay comes from the Manasota culture, a variant of the Weeden Island culture, who lived in the area beginning around 5,000–6,000 years ago, after sea levels had risen to near modern levels and the bay was connected to the Gulf of Mexico. This culture, which relied almost exclusively on the bay for food and other resources, was in turn replaced by the similar Safety Harbor culture by approximately 800 AD. The pre-contact Indigenous nation most associated with the Tampa Bay are the historic Tocobaga nation, who are known to be among the ancestors of the contemporary Seminole and Miccosukee Tribes of Florida.