s2ary
09-12-2007, 03:39 PM
The Coastal Ecology Cycle
Together the in-shore waters and the estuary work to create a mutually dependent relationship. Twice each day nutrient rich outgoing tides flow from the salt marshes across the mud flats and bring nutrients into the near-shore waters. Within these waters flow both dissolved nutrients and particulate plant and animal matter (detritus). As the outgoing tide crosses the mud flats, clams, muscles, and worms feed on the detritus supplied by this tide and excrete waste high in Nitrogen. As the tide continues its outbound journey, past the river mouth, filter feeding by invertebrates continues and the dissolved nutrients and high Nitrogen excrement take on the primary role of supplying nutrients for the near shore food web. As the dissolved nutrients mix in the water column, the phytoplankton community absorbs the nutrients for photosynthesis. In turn, the energy is transferred up the food chain to zooplankton and small fishes that feed on the phytoplankton.
Once the tide turns and begins to flow back into the estuary the nutrient rich waters flow back across the mudflats where the marine invertebrates again feed on the detritus and excrete more nitrogen into the water which flows directly into the salt marsh. Once in the marshes, the water is almost entirely stripped of nitrogen as the marsh grasses readily absorb all that they can. The waters in the marsh channels and rills provide nursery habitat for small fishes and grass shrimps. After cresting the cycle continues from the beginning. This cycle occurs twice each day and is essential for the health of our coastal fisheries.
Together the in-shore waters and the estuary work to create a mutually dependent relationship. Twice each day nutrient rich outgoing tides flow from the salt marshes across the mud flats and bring nutrients into the near-shore waters. Within these waters flow both dissolved nutrients and particulate plant and animal matter (detritus). As the outgoing tide crosses the mud flats, clams, muscles, and worms feed on the detritus supplied by this tide and excrete waste high in Nitrogen. As the tide continues its outbound journey, past the river mouth, filter feeding by invertebrates continues and the dissolved nutrients and high Nitrogen excrement take on the primary role of supplying nutrients for the near shore food web. As the dissolved nutrients mix in the water column, the phytoplankton community absorbs the nutrients for photosynthesis. In turn, the energy is transferred up the food chain to zooplankton and small fishes that feed on the phytoplankton.
Once the tide turns and begins to flow back into the estuary the nutrient rich waters flow back across the mudflats where the marine invertebrates again feed on the detritus and excrete more nitrogen into the water which flows directly into the salt marsh. Once in the marshes, the water is almost entirely stripped of nitrogen as the marsh grasses readily absorb all that they can. The waters in the marsh channels and rills provide nursery habitat for small fishes and grass shrimps. After cresting the cycle continues from the beginning. This cycle occurs twice each day and is essential for the health of our coastal fisheries.