The seagrass beds that carpet Sarasota Bay harbor a tremendous array of living creatures.

This critical and diverse ecosystem is generally out of sight except at extreme low tides. Sea grasses are actually underwater flowering plants that serve a number of important functions. They produce oxygen, bind sediments and baffle wave action while cleansing the water column. Seagrass roots, their leaves, and the epiphytes and microalgae that cling to them clean water by converting dissolved nutrients into plant matter. Besides giving us clean and clear water, seagrasses are home to the organisms that provide food and shelter for fish, crustaceans, shellfish and wading birds. They also are food source for manatees, sea turtles and various fish and crustaceans. Because they flower, sea grasses require sunlight and are limited to clear, shallow waters.

Of the 52 species of seagrasses worldwide, only seven are found in Florida. Three main species are found on Florida’s southwest coast. They include turtle grass (Thalassia testudinum), shoal grass (Halodule wrightii) and manatee grasses (Syringodium filiforme). The historical loss of these species has been extensive throughout Florida. Tampa Bay has lost 81 percent of its historical sea grasses, Sarasota Bay 35 percent and Charlotte Harbor 29 percent. Poor watershed management of stormwater run-off and sewage disposal, dredge and fill operations and scaring from boats have taken a heavy toll on Florida’s seagrasses.

Fortunately organizations like the Sarasota Bay Estuary Program, Tampa Bay Watch and the Tampa Bay Estuary Program have instituted programs to make citizens aware of the importance of seagrasses. Other improvements also have begun to turn the tide on water quality. The most important of these is the elimination of small, poorly maintained regional sewage systems.

From experience, anglers are aware of the importance of these prolific, shallow beds. They experience firsthand the myriad interactions that produce fertile fisheries. They may not understand the intricate web of existence that proceeds from the microscopic level to the fish on the end of their line, but they reap the benefits nonetheless. Government scientists consider sea grasses to be of such importance that they have adopted a no net loss policy to manage them. Despite this pronouncement sea grasses remain under assault.

Preventing the loss of valuable sea grasses must be a high priority. Watershed management, replanting, avoidance of direct impacts to existing grasses and mitigation are avenues to reach those goals.

Mitigation involves the replacement of seagrasses impacted by residential and commercial development. Unfortunately the literature reveals that the effectiveness of mitigating seagrass damage is considered, even among the leading wetland scientists, to be marginal at best.

In recent years, seagrass have rebounded in Sarasota Bay. It is a foregone conclusion that development will continue to impact coastal areas and their seagrass resources; and it vital that decisions are made that will allow needed development while protecting the quality of our most valuable local resources. Enlightened citizens, anglers and their interest groups must take part in this decision making process. Cost considerations often eclipse concerns for seagrasses, but research reveals the true value of these resources.

The Virnstein and Morris study conducted in 1996 in the Indian River Lagoon estimated the value of seagrass to be $12,500 per acre, per year, based solely on economic values derived from recreational and commercial fisheries.

To celebrate Earth Day, Sarasota County and local partners are inviting the public to volunteer in a seagrass survey on Saturday, April 25, at Ken Thompson Park in Sarasota. The fun, family-friendly, hands-on event will provide the public with an opportunity to learn about seagrass habitat up-close. Volunteers will take to the waters in and around Sarasota Bay to count and identify seagrass species, in an effort to collect data for the county's Seagrass Monitoring Program. The seagrass survey is open to the public, and snorkelers, waders, kayakers, boaters, and paddle boarders are invited to participate.

The seagrass survey celebrates Sarasota County's commitment to protecting its water resources and focuses on increasing awareness of the economic and environmental value of seagrass habitat. Seagrass is vital to maintaining healthy aquatic ecosystems, stabilizing shorelines and providing food and shelter for a variety of wildlife. Seventy percent of Florida's fisheries species, such as shrimp and trout, spend part of their life in seagrass. This year's survey theme, Seagrass: The Lawn That Doesn't Need Fertilizer, focuses on how stormwater pollution, like too much fertilizer placed on our lawns, harms seagrass habitat. Excess nutrients can result in algae blooms that block necessary light from reaching sea grasses. To participate, register by April 20 at seagrasssurvey.eventbrite.com. On-site training is required for all participants and will be conducted from 8 to 9 a.m. Data collection is scheduled from 9 a.m. until noon. There will be a volunteer appreciation luncheon after the event from noon until 1:00 p.m. Ken Thompson Park is located at 1700 Ken Thompson Parkway in Sarasota, just east of Mote Marine Laboratory.