A debilitating shell disease affecting lobsters from Long Island Sound to Maine may be caused by environmental alkyphenols, formed primarily by the breakdown of hard transparent plastics.
Hans Laufer is a visiting scientist at Marine Biological Laboratory (MBL). Laufer has been searching for the causes of a debilitating shell disease affecting lobsters from Long Island Sound to Maine. His search has led him to suspect environmental alkyphenols, formed primarily by the breakdown of hard transparent plastics.
Laufer’s preliminary evidence suggests that certain concentrations of alkyphenols may be interfering with the ability of lobsters to develop tough shells. The shells are weakened and this leaves affected lobsters susceptible to the microbial invasions characteristic of the illness.
"Lobsters 'know' when their shell is damaged, and that's probably the reason when they have shell disease, why they molt more quickly," says Laufer, a visiting investigator at the MBL for over 20 years and professor emeritus of molecular and cell biology at the University of Connecticut. "But ultimately, they still come down with the disease. And we think the presence of alkyphenols contributes to that."
Lobsters shed their shells multiple times in one lifetime. After molting, the outer skin of the soft and exposed lobster will begin to harden. It is during this phase that Laufer thinks the alkyphenols are doing their damage.
For it is here, a derivative of the amino acid tyrosine, whose function is to harden the developing shell, is incorporated. We know alkyphenols and tyrosine are similarly shaped and Laufer suspects that the toxin may be blocking tyrosine from its normal functions.
Laufer is visiting MBL this summer to measure the amount of competition between the two molecules. Alkyphenols are also known to act as endocrine disruptors.
Laufer discovered the presence of alkyphenols in lobsters when he was investigating a tremendous lobster die off at Long Island Sound in 1999, when shell disease, first observed in the mid-1990s, was noted to be on the rise.
It was an unusually hot summer, however, it was also the first time New York City sprayed mosquito populations to prevent the spread of West Nile virus. Laufer suspected the toxins from the sprayings may have contributed to the lobster die off; then in 2001, while searching for the mosquito toxins in lobsters, he instead found alkyphenols.
"It's a real problem," Laufer says. "Plastics last a long time, but breakdown products last even longer. Perhaps shell disease is only the tip of the iceberg of a more basic problem of endocrine disrupting chemicals in marine environments."
If Laufer is correct in his suspicions it will be another example of the effect that human society has on other creatures.