Jellyfish
How Nutrient Pollution Might Help Sea Nettles to Thrive
Sea Nettles and Eutrophication?
Nitrogen Pollution may be Causing Their Populations to Rise
Sea Nettles (Chrysaora quinquecirrha) populations have been increasing throughout estuaries along the Eastern Seaboard and Barnegat Bay is no exception. Sea nettles become most abundant when water temperatures reach about 77°F, which is common during the summer months. Not only are these jellyfish a nuisance to bathers, they might also be an indicator of a dangerous ecological problem occurring in Barnegat Bay called eutrophication.
What are Sea Nettles?
These free swimming jellyfish are very unique creatures. They can be recognized by their bell shaped cap, sometimes called the top or head of the jelly. Extending down from the cap are tentacles. These long, string-like features can grow to more than a meter in length and are packed with stinging cells called nematocysts. As the sea nettle swims the tentacles trail behind acting as a net. When zooplankton comes in contact with the nematocysts, a poisoned barb extends from the tentacle spearing the prey. The tentacles then pull the plankton up into the sea nettles stomach where they are digested. Nematocysts are also the cause of the painful sting we associate with these jellyfish.
Sea Nettles and Eutrophication
Scientific evidence is beginning to link increasing sea nettle populations with eutrophication. Eutrophication decreases the amount of dissolved oxygen in the system. When oxygen levels are low, predator fish that would normally prey on Jellyfish swim to waters with more oxygen. Also, the fish would under normal circumstances compete for food with the sea nettles. Since there is less competition for food the sea nettles eat more and the population increases. Sea nettles are a very tolerant species, meaning that they can survive despite some changes to their environment. As long as the water remains warm enough, these jellies can “out compete” many species if dissolved oxygen in the water becomes too low. As their populations grow the ecosystems can be severely damaged.
Nitrogen Pollution may be Causing Their Populations to Rise
Sea Nettles (Chrysaora quinquecirrha) populations have been increasing throughout estuaries along the Eastern Seaboard and Barnegat Bay is no exception. Sea nettles become most abundant when water temperatures reach about 77°F, which is common during the summer months. Not only are these jellyfish a nuisance to bathers, they might also be an indicator of a dangerous ecological problem occurring in Barnegat Bay called eutrophication.
What are Sea Nettles?
These free swimming jellyfish are very unique creatures. They can be recognized by their bell shaped cap, sometimes called the top or head of the jelly. Extending down from the cap are tentacles. These long, string-like features can grow to more than a meter in length and are packed with stinging cells called nematocysts. As the sea nettle swims the tentacles trail behind acting as a net. When zooplankton comes in contact with the nematocysts, a poisoned barb extends from the tentacle spearing the prey. The tentacles then pull the plankton up into the sea nettles stomach where they are digested. Nematocysts are also the cause of the painful sting we associate with these jellyfish.
Sea Nettles and Eutrophication
Scientific evidence is beginning to link increasing sea nettle populations with eutrophication. Eutrophication decreases the amount of dissolved oxygen in the system. When oxygen levels are low, predator fish that would normally prey on Jellyfish swim to waters with more oxygen. Also, the fish would under normal circumstances compete for food with the sea nettles. Since there is less competition for food the sea nettles eat more and the population increases. Sea nettles are a very tolerant species, meaning that they can survive despite some changes to their environment. As long as the water remains warm enough, these jellies can “out compete” many species if dissolved oxygen in the water becomes too low. As their populations grow the ecosystems can be severely damaged.