Marine Education Resources ...

Water Quality -
Charlotte Harbor Water Quality ... the Good, Bad & Ugly

Maintaining good water quality is essential to maintaining the health of our harbor. Water quality refers to the condition of water relative to legal standards, social expectations or ecological health. In order to track water quality conditions in the harbor and identify specific areas of concern, long term water quality monitoring is a must. There are a number of organizations monitoring water quality in Charlotte Harbor and its adjacent tributaries. They include:

FDEP – Charlotte Harbor Aquatic Preserves Volunteers – Conduct monthly sunrise sampling at 40+ fixed locations from Lemon Bay to Estero Bay. Initiated in 1996, trained volunteers sample mostly near shore shallow waters. Sunrise sampling serves to identify Dissolved Oxygen levels (necessary for plant & animal survival) at their lowest levels. Data from Lemon Bay is available online at:
www.checflorida.org/index.php?option=com_content&task=view&id=18&itemid=59

Charlotte County Stormwater – Monitors water quality at 30 randomly selected locations monthly, by dividing the estuary into five distinct regions and then randomly selecting five points within each region (i.e., five in the Lemon Bay region, five in the Gasparilla Sound region, etc.). Initiated in 2001, the random design allows more of the harbor to be sampled, which over time produces more statistically valuable information. Data is available online at:
www.checflorida.org/index.php?option=com_content&task=view&id=18&itemid=59
Lee County waters are also sampled using the same monitoring approach.

Peace River Manasota Regional Water Supply Authority – Monitors water quality in the Peace River at fixed stations and moving isohaline (salinity) stations. Initiated in the 1970s, to ensure water withdrawals do not adversely affect downstream harbor health.

City of Punta Gorda – Monitors water quality in Shell Creek to ensure water withdrawals do not adversely affect downstream water quality.

Florida Department of Health – Monitors bacteria levels at public bathing beaches. Data is available online at:
http://esetappsdoh.doh.state.fl.us/irm00beachwater/default.aspx.

Information collected by each of these programs is used by State and Federal agencies to determine whether the water quality is meeting its designated use (drinking water, shellfish harvesting, or recreational). The water quality buzz word, IWR (impaired waters rule) refers to legal guidelines for specific water quality parameters (nutrients, bacteria, ect.). If a water body or water body segment does not meet the IWR then it receives a TMDL (total maximum daily load). A TMDL is essentially a plan which outlines actions that will be taken to get water quality back to meeting the IWR.

The three parameters which have exceeded the IWR most frequently in Charlotte Harbor are dissolved oxygen, nutrients, and bacteria (in shellfish).

Water quality impairments and potential impairments identified by FDEP for Charlotte Harbor and its tributaries, show dissolved oxygen (DO) impairments in the canals of Port Charlotte and Harbor Heights, for Alligator Creek (North Fork), Alligator Creek in Lemon Bay (Sarasota Co.), Gottfried Creek, Rock Creek, Oyster Creek, and Buck Creek. In addition, although not a legal impairment, declining DO trends have also been noted (CHNEP 2003) for much of Charlotte Harbor.

DO refers to the concentration of oxygen that is available for plant and animal survival. DO is produced by aquatic plants during photosynthesis. Because plants require sunlight to produce oxygen, levels are naturally highest during the daytime. At night, plants and animals still require DO; however it is no longer being created by plants, because of the lack of sunlight. Therefore by early morning DO levels are at their lowest.

In areas where excess nutrient (typically nitrogen or phosphorus) loads occur, increased amounts of algae will cause DO concentrations to decline. This is because although algae contribute to DO, their use of it, along with bacteria’s use of it when algae dies (bacteria degrades dead plant material), can use more DO than is produced. In these situations, low oxygen concentrations (hypoxia) or loss of all oxygen (anoxia) causes the death of invertebrates and fishes.

Nutrients [nitrogen (N) and phosphorus (P)] naturally occur in aquatic systems, where they largely control plant growth. When excess nutrients are added to the water, algae blooms occur. The result is less light available for the seagrasses and eventual seagrass loss. Phosphorus is often the ‘limiting’ nutrient in freshwater systems, meaning the addition of P stimulates plant growth. Nitrogen is more frequently limiting in the marine environment. Nitrogen, which is the limiting nutrient for Charlotte Harbor, is a key component in chlorophyll, the green pigment in plants. There are three primary sources of human-derived N, wastewater, fertilizer, and atmospheric pollution. FDEP shows nutrient impairments for Coral Creek (east branch), the lower Myakka River, Shell Creek, and upper Lemon Bay (Sarasota County).

High bacteria levels in shellfish are another concern, with most of Charlotte County estuary waters affected by impairment. Bacteria levels are typically highest in the summer months when the water is warm and frequent rains flush untreated stormwater into the harbor. Bacteria live in the guts of warm blooded animals. High bacteria levels are most often the result of failing septic systems and/or runoff of domestic and wild animal wastes. Because shellfish are filter feeders, bacteria present in water accumulate in the shellfish. When water column bacteria levels exceed state standards, shellfish harvesting areas are closed.

It’s not all grim, part of solving a problem is knowing one exists. Many coordinated Federal, State, and Local programs are underway to restore habitat and improve the quality of stormwater before it reaches the harbor. Hopefully each of us are doing our part to reduce our own personal stormwater runoff to the harbor.

Some simple do’s and don’ts that each of us can do to make a difference include:

• Do use plants to create a buffer between your yard and the water.

• Don’t overuse fertilizers, especially near the waters edge.

• Don’t throw grass clippings into the water.

• Do support efforts to improve our knowledge.