A wide array of tiny marine critters are struggling to survive in Bellingham Bay, according to a recently released report from the Washington Department of Ecology.
The report synthesizes the findings of a 2010 bay-wide survey (part of Ecology’s ongoing marine sediment monitoring program) that found unusually low numbers of invertebrates such as clams, sea stars, crabs and shrimp.
Scientists sampled the top inch of sediment at 30 different locations throughout the bay and measured levels of chemicals and toxicity and identified and counted different types of invertebrates living there.
They found a large number of marine organisms in each of the samples, but the diversity of species was very low. Most highly impacted were the types of marine life that are particularly sensitive to harsh conditions, including clams, snails, crabs, shrimp and brittle stars. The only abundant organism found was a type of marine worm with a reputation for being able to survive in harsh conditions.
It’s unclear what’s causing the health of Bellingham Bay to decline. Scientists were unable to draw any direct links to chemical contamination. They did, however, analyze for concentrations of 263 potentially toxic chemicals, including metals, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, pharmaceuticals and personal care products, pesticides, and other organic compounds.
They found metals and PAHs in 98 percent of the samples. A type of antihistamine called diphenhydramine was detected at 28 of the 30 sample sites. A diuretic called triamterene was found in almost half the locations sampled. And an antibacterial agent in hand soaps was found in nine of the locations sampled.
One contaminant — bis(2-ethylhexyl) phthalate, a type of plasticizer often used in medical devices — was found in one location at levels that exceeded the state’s sediment quality standards.
Scientists say other environmental conditions are likely to be impacting invertebrate populations, including
- Changes in dissolved oxygen, pH, and levels of ammonia and sulfides in the water above and within the sediment.
- Natural population cycles of sediment-dwelling organisms influenced by oceanic cycles.
- Sediment movement and burial.
- Unmeasured contaminants, including contaminants of emerging concern and contaminants that may sicken but not kill marine life.
In comparing the Bellingham Bay results with past surveys from 2006 and 1997, scientists found a drop in both the species abundance and diversity. Bellingham Bay sediment quality was also found to be significantly lower than overall Strait of Georgia and the greater Puget Sound.