By: Hailey Robert
Rangia Clams, Rangia cuneate, are bivalve mollusks. These clams are non-selective filter-feeders. It consumes detritus, which is dead organic matter from plants, as well as phytoplankton (Rangia Clam). These clams are also the only clams capable of inhabiting oligohaline waters (salinity levels of 0 to 5 PSU). Lake Pontchartrain is an oligohaline estuary and Rangia Clams used to be everywhere, but not anymore. Humans have had a great impact on the Rangia Clam population ever since humans came to Pontchartrain basin area. Early on, many people ate Rangia Clam, which we know because middens (pile of left over parts of organisms that were eaten by other organisms) of clam shells from the time period. Around the mid-1700s, humans learned that Rangia Clams could be used to make lime cement, which is what Spanish Fort was made of (we do not use this method for building anymore because lime cement is slow to cure and cannot get wet until it dries). Then, during 1900s, humans dredged substrate and Rangia Clams out of Lake Pontchartrain to construct road ways, parking lots, levees, and even building up the land that UNO sits on today. Rangia Clams have been wiped out of Lake Pontchartrain, which has caused a long list of problems. Without these filter feeders, the water has become turbid in Lake Pontchartrain. This has had an effect on the Pontchartrain estuary. The turbid water has made Pontchartrain less habitual for plants, which has made the lake less habitual for detritivores (feed on dead plant matter), who also eat Aufwuchs (fungal/bacterial slime). This is why the lake’s water quality plummeted. Humans damaged the natural ecosystem and the organisms that kept it clean. Today, dredging has been banned and the clams are making a comeback, but it will take time for Lake Pontchartrain to recover fully (Rangia Clam).
Rangia Clams, Rangia cuneate, are bivalve mollusks. These clams are non-selective filter-feeders. It consumes detritus, which is dead organic matter from plants, as well as phytoplankton (Rangia Clam). These clams are also the only clams capable of inhabiting oligohaline waters (salinity levels of 0 to 5 PSU). Lake Pontchartrain is an oligohaline estuary and Rangia Clams used to be everywhere, but not anymore. Humans have had a great impact on the Rangia Clam population ever since humans came to Pontchartrain basin area. Early on, many people ate Rangia Clam, which we know because middens (pile of left over parts of organisms that were eaten by other organisms) of clam shells from the time period. Around the mid-1700s, humans learned that Rangia Clams could be used to make lime cement, which is what Spanish Fort was made of (we do not use this method for building anymore because lime cement is slow to cure and cannot get wet until it dries). Then, during 1900s, humans dredged substrate and Rangia Clams out of Lake Pontchartrain to construct road ways, parking lots, levees, and even building up the land that UNO sits on today. Rangia Clams have been wiped out of Lake Pontchartrain, which has caused a long list of problems. Without these filter feeders, the water has become turbid in Lake Pontchartrain. This has had an effect on the Pontchartrain estuary. The turbid water has made Pontchartrain less habitual for plants, which has made the lake less habitual for detritivores (feed on dead plant matter), who also eat Aufwuchs (fungal/bacterial slime). This is why the lake’s water quality plummeted. Humans damaged the natural ecosystem and the organisms that kept it clean. Today, dredging has been banned and the clams are making a comeback, but it will take time for Lake Pontchartrain to recover fully (Rangia Clam).
Sources
Rangia Clam: Rangia
Cuneata . South Eastern
University, www.southeastern.edu/acad_research/programs/turtle_cove/assets/boardwalk_pdf_files/rangia_clam.pdf.
Most information I
learned from my Estuarine Environmental Science class (EES 4520) by Dr. Martin
O’Connell
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