I am in Marineland, a town south of St. Augustine, covered in muck, standing on an oyster reef offshore. My dingy garage-sale kayak, which I have recently dubbed the “Oystercatcher” (potentially a tongue-in-cheek name amusing only to me) sits unceremoniously nearby, full to the brim with random pieces of equipment – muddy work gloves, needle nose pliers, zip ties, lengths of rebar and PVC pipe. I free the buckets I’ve lashed to the back of the boat with fluorescent green lengths of nylon rope. This is one of several trips I have taken to test the design of sediment traps, constructed from said buckets and netting, which I will use for my research. Over two weeks, I will relate what the oysters produce as faeces and pseudofaeces (rejected food particles), collectively called biodeposits, to inorganic matter in the surrounding waters. I will use this to reveal how much and how fast these bivalves filter feed.
|My boots after just two trips to the reef!|
|One of my sediment trap prototypes.|
But some of the more salient functions of oysters relate to their role as filter feeders. Their ability to positively affect water quality has been the impetus for many restoration projects. Through the use of my sediment traps, I am hoping to shed light on the local linkage between oyster filtration and the control of phytoplankton - masses of microscopic plants whose populations wax and wane with a variety of environmental factors, but whose growth can boom substantially when excess nutrients are present in a system. When phytoplankton abound in a region, less light is available for sea grasses and other submerged vegetation, and dissolved oxygen may become a scarcer commodity as well. In some regions, oysters may be a significant part of the components controlling this unchecked growth.
So while I pull off my work gloves and start to collect my things in expectation of the incoming tide, I pause. Delicate little shore birds nimbly navigate over the reefs, feeding between the crevices, while hints of silvery scales break the water’s surface nearby. I begin to remember why I love what I do and what a bastion of life these oysters are.
|Example of a fringing reef hugging the shoreline of a tidal creek.|