Well my 9yr old is doing a science experiment...she chose Oysters and their filtration abilities. One adult ouster can filter 50gals of water a day...the equivalent of a 200-300 Reverse Osmosis water filtration system. The oyster will live for 20yrs. An RO system will not last 20yrs, needs new filters, and uses electricity. From what ive researched so far...they filter everything a RO system filters out but they act as a ph balancer from calcium bicarbonate i believe plus produce excrement consisting of nitrogen, potassium and other valuable nutrients used in Growing. This is all new i fo to me and super early in my research so I wanted to know if anyone has used any of these like oysters, clams, or mussells for water filtration????
Published info re: oysters....
Nutrient cycling
Because they are filter feeders, oysters can greatly influence nutrient cycling in estuarine systems and
maintain the stability of the ecosystem. Oysters filter large amounts of phytoplankton and detritus (small
organic particles) from the water column. As grazers of phytoplankton and other particles, these filter
feeders couple, or join, the reef to the water column. The organic components resulting from metabolism
are returned, or "remineralized" to the water in the form of feces, pseudofeces (see Biology Section) or
excreted as urea, ammonium, nitrogen, phosphorus, and other inorganic nutrients. This flux or cycling of
carbon and other essential materials is vital for the continuity and stability of any living system and acts
to keep the system in balance.
On oyster reefs, the nutrients are moved from the water column to the benthos and back via the pumping
action of oysters and other bivalves. In this process, suspended particles are aggregated in the oysters'
guts and, when excreted, are used for food by deposit feeders and other organisms living in the
sediment. Organic matter contained in the particles filtered by the oysters is used for growth, resulting in
increased biomass, and some of the oysters are consumed by predators or degraded by bacteria and other
organisms when they die, cycling the nutrients once more (Dame 1996). The resulting inorganic
nutrients (e.g., dissolved carbon, nitrogen, and phosphorus) excreted by the bivalves, predators, and other
reef and benthic organisms back into the water column is used by primary producers (phytoplankton),
recycling these components through the system (Dame 1996; Dame et al 1984).
In systems with high ratios of oyster biomass to water volume, the removal of suspended organic
particles by the bivalves controls nutrient flow in an estuary, and therefore the amount of phytoplankton,
zooplankton, and other components of the ecosystem. For example, Chesapeake Bay was once
dominated by oyster reefs and bivalve filter feeders, and the loss of these reefs has resulted in the Bay's
shift from a benthic-pelagic system to a planktonic system.
Water quality
Oysters and some other bivalves (e.g., mussels) are suspension feeders that remove particles from the
water column by passing it over their gills and either using it for food or binding it into larger segments,
to be discharged from the gills and mantle cavity. Oysters are particularly efficient at filtering water and
may have significant effects on phytoplankton biomass in an area. This is especially true if the oyster
reef is dense and covers a relatively large area. Mussels, which also attach to oyster reefs, augment the
filtration rates carried out on the reefs. Filtration activity is defined in terms of clearance rate - i.e., the
olume of water cleared of particles per time unit. Clearance rates for Crassostrea virginica in
Chesapeake Bay have been estimated at 163 liters per gram (of oyster tissue) per day. The time needed
for oyster reefs to filter water depends on the biomass of the oysters, the concentration of phytoplankton,
retention time of water in the bay, and many other factors. Using historical densities of oysters in
Chesapeake Bay, one researcher estimated that the oyster population there in pre-colonial times could
filter all of the water in Chesapeake Bay in 3.3 days, but now, because of depletion of the reefs, it would
take 325 days (Newell 1988).
Encrusting, or fouling, organisms (e.g., tunicates, bryozoans, sponges, barnacles, and some polychaete
worms) on oyster reefs and in the surrounding benthos are also suspension feeders and contribute to the
overall filtering capacity of a reef. Because more oysters and associated animals can live where the
structure of reefs is three-dimensional (e.g., pyramid-shaped) rather than flat, reef construction should
reflect this consideration, especially if water quality is an important goal of the project.