Sea-grasses (Submerged Aquatic Vegetation) require light for photosynthesis. If the water is cloudy and light cannot penetrate to the bottom because of turbid water caused by tiny suspended plants (phytoplankton) and/or sediment, or the leaves of grasses are covered by “slime,” then SAV cannot grow. Surveying the area occupied by SAV is relatively inexpensive and is the best measure of water clarity because it yields a long term average. It is superior to expensive instantaneous measurements that can reflect sporadic events such as storms or algal blooms. We know that the area covered by SAV correlates with runoff into the Bay. In drought years, when runoff and groundwater deliver less nitrate and phosphate into the Bay, water clarity improves and the area occupied by SAV expands. Conversely, in wet years, when more nutrients are delivered to the Bay, the area occupied by SAV decreases. These variations prove that there are plenty of seeds to establish new grass beds if only we could improve water clarity permanently. Agencies like EPA and CBF joyously publicize short-time gains, when they occur. In fact, small annual improvements are just “noise” and no long-term improvement is yet evident. It is well known that beds of SAV are an extremely important habitat in the Bay ecosystem, providing food and sanctuary for a variety of organisms as well as producing oxygen. The ecology of the Bay would vastly improve automatically if significant and permanent increases in SAV can be realized by reducing the nutrient input into the Bay that is the cause of the turbid water.
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