Super Clams = Cleaner Water
Super clams (credit: Florida Fish & Wildlife Foundation)
When folks typically refer to clams they think of seafood being served is a bowl of chowder or on a dish of pasta. They don't think of the bivalves as pollution control agents. One clam is showing how important these marine species really can be for maintaining clean water.
At the University of Florida, researchers provided a demonstration illustrating the potential for hard clams to be used as efficient water-filters. In a time-lapse video, they showed the clam’s water-cleaning ability by placing 24 littleneck clams in a small aquarium (2.5 gallons) that contained algae (phytoplankton) with a high concentration of nearly 400,000 cells per milliliter. In the 100 minute demo one aquarium contained the clams (right) while another only contained polluted water (left). The change in water clarity is obvious. The lab estimates that a single clam can filter 4.5 gallons of seawater per day if the natural technology can be scaled-up.
Scaling a lab experiment can be difficult to obtain similar results in a natural environment. In Florida and elsewhere, phytoplankton have produced 'dead zones' and toxic algal blooms that kill fish and other species. However, evolution by natural selection seems to have provided a potential pathway to success in a large Florida bay, the Indian River lagoon. A small population of 'super clams' was identified which can tolerate high levels of algal pollution in the bay. These tolerant clams were multiplied and the replanted them in the lagoon where they were extinct. This restoration project provided a 'real world' ecosystem-scale test. The early results were impressive and offer an ecological, practical, and economic solution to a serious pollution problem. Algal blooms and the water pollution they produce affects not only Florida's waterways but elsewhere in the USA and more widely on a global scale.
In certain situations, rewilding waterways with clams is showing the potential to produce cleaner water by using their filter-feeding capabilities. These restoration projects could produce an added benefit of providing more tasty clams being available for a hearty chowder as well.WHB