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Seagrasses have been in decline in Tampa Bay for three years in a row. Here’s why

The loss of seagrass has been blamed on a variety of factors, including heavy rains that wash nutrients into the bay.

After decades of being on the mend, the amount of seagrasses in Tampa Bay has decreased for three years in a row. That's bad news for marine life, which depends on these grasses as a vital food source.

Between 2020 and 2022, seagrasses throughout Tampa Bay declined by more than 4,000 acres, or 12%. The bay has lost nearly 30% of its seagrasses since peak conditions were recorded in 2016.

The likely culprit is rain, which brings nutrients and sediments into the bay from rivers and storm drains. That clouds the water, preventing sunlight from reaching seagrasses.

"We're in a period of higher hydrologic inputs. That might just be higher rainfall conditions over the past decade, increasing the amount of storm water that's discharged into Tampa Bay," said Ed Sherwood, executive director of the Tampa Bay Estuary Program. "That could be tied to climate change impacts — definitely warmer water temperatures in the upper bay segments might also be adding stresses."

All that rain means nutrients from lawn clippings, fertilizer and street debris is swept into storm drains and empties into the bay.