There’s a whole world in Puget Sound that you can’t even see – kind of like Horton Hears a Who! Foraminifera, or forams for short, are tiny one-celled critters that may be small, but they help us learn a lot about the environment.
A team at the Burke Museum is turning to these tiny creatures to investigate and monitor the health of Puget Sound. The effort, known as the Puget Sound Foram Research Project, uses sediment samples that the Washington State Department of Ecology collects across Puget Sound—from the Canadian border to Olympia.
What are foraminifera?
Foraminifera are single-celled organisms, called protists, that live in marine habitats and can be indicators of environmental stresses, either through the presence or absence of certain species, or in their characteristics. Learn more about foraminifera
What can this tell us about Puget Sound?
Foraminifera can be very sensitive to their environments. Some can only live where the water is clean and unpolluted. Others are more tolerant and can live almost anywhere. Certain species move into polluted places where others cannot live, and there are even alien invaders, brought here on ships from other countries. By documenting what species are living in certain areas, we can assess whether the sediments are polluted or pristine.
How do we collect and study forams?
What have we learned so far?
In our initial study of Puget Sound, we found 46 species of foraminifera. The species that appeared most often was a highly pollution-tolerant species called Eggerrella advena, and is most commonly found in Bellingham Bay, the South Sound, and near Bremerton.
The density of foraminifera (number of individuals per gram of sediment) varied dramatically throughout the Sound, as did the diversity, or number of species in each sample, and how they were distributed. Our research found that no one environmental factor, such as water depth, salinity, temperature, was responsible for the complex distribution of the foraminifera in Puget Sound. So, we've turned our attention to individual embayments to better understand what factors influence them.
Currently, we're looking at the northern part of Puget Sound, particularly Bellingham Bay and nearby Semiahmoo, Boundary and Birch Bays. Bellingham Bay has a history of pollution from industrial and agricultural activities in the surrounding area. We've found the highly pollution-tolerant Eggerella advena foraminifera dominating most of the area. But in some parts of the Bay, there are no foraminifera at all, which we speculate is due to a lack of oxygen, caused by the degradation of large amounts of organic matter.
In addition, we noted a deterioriation in the foraminiferal assemblages between 2006 and 2010. We studied chemicals in the sediments and looked for metals such as mercury, cadmium, arsenic, zinc and polycyclic aromatic hydrocarbons in the water, but haven't pinpointed any single factor that could be causing this problem. Whatever the cause, it is clear that the foraminifera present indicate an unfriendly environment.
Other studies are underway in Hood Canal and Sinclair and Dyes Inlets near Bremerton, results of which will be published when they are completed.