Plants growing in Lake Okeechobee — both emergent marshes as well as submerged grasses — are a critical part of this ecosystem. In addition to providing habitat for fish and wildlife, these plants also help to take up nutrients that fuel algae blooms in the lake and the St. Lucie and Caloosahatchee estuaries.
After successive years of high water levels on Lake Okeechobee — which resulted in the loss of nearly 40,000 acres of submerged aquatic vegetation — a recent tour of the lake demonstrated that, with a little help, the underwater plants can make a comeback. Aquatic growth has surged throughout the lake, giving Audubon Florida a sense of optimism that newly emerging vegetation will be able to grow tall and strong enough to withstand the higher water levels that should come with Florida’s rainy season.
What made the difference? Favorable weather for one, but importantly, the U.S. Army Corps of Engineers took note of the decimated condition of the vegetation in the lake’s marsh areas. At the urging of Audubon Florida’s science and policy team, the Corps scheduled releases to achieve favorable water levels. The lake’s submerged aquatic vegetation provides the same nutrient absorption and water filtration services as stormwater treatment areas, which themselves cost billions of taxpayer dollars to construct and maintain. The underwater plants are free! A healthy submerged aquatic vegetation community not only improves water quality, but also provides critical marsh habitat for birds and fish. Downstream ecosystems continue to benefit from improvements in overall water quality.
Under normal conditions, the lake ecosystem can support a healthy marsh community when water levels fluctuate between 12 and 15 feet from dry to wet seasons. But the last few years have been anything but normal, with lake levels exceeding 16 feet in six of the last seven years.
To add insult to injury, in 2017 Hurricane Irma barreled across Florida and raised lake levels by three and a half feet in just one month, virtually wiping out the remaining aquatic community. The result? Churned, muddy water quality, the loss of important ecological services, and adverse impacts to wildlife, especially the world-famous, largemouthed bass fishery that relies on submerged aquatic vegetation to thrive.
By adapting lake management practices and allowing lake levels to recede to 11 feet in depth this year, the Army Corps gave Okeechobee a chance to recover: the lower lake level enabled sunlight to penetrate through the water column to seeds on the lake bottom, and they germinated and grew.