Forams Highlight Pollution

On a previous web page Forams for Correlation, we discussed how scientists use forams to estimate geologic age and the water depths at which the forams lived. In this series of pages we are going to explore how scientists use benthic forams to study pollution.

Marine pollution comes in many forms including sewage from towns and cities, fertilizer and pesticide runoff from agriculture, chemicals and heavy metals from industries such as paper mills, chemical refineries, and power generation plants. All these different pollution types degrade the marine environment. How serious is this pollution?

Like many questions in science, the answer is "That depends". It depends on what type of pollution is present, how much is being added at any given time, and how long it has been polluted. Pollution-related changes range from relatively minor to completely toxic, where all marine life in an area is destroyed. Scientists can use benthic forams to study these questions.

Benthic forams can be used in several different ways, depending of what kind of pollution is suspected. For example, a scientist might look at species diversity, which means counting up how many different benthic foram species are present. He might also look at how many individuals of any single species are present (abundance). Or he might count up the number of deformed individuals or chemically analyze the foram test.

Let's look at two examples where benthic forams are being used to study the effects of pollution. The first example looks at foram test deformities in Biscayne Bay, Florida, and the second looks at sewage pollution in Long Island Sound.

Red Mangrove forest in Biscayne National Park, Biscayne Bay, Florida (Credit: Biscayne National Park, US Department of the Interior)
Falkner Island Lighthouse, Falkner Island, Long Island Sound (Credit: US Geologic Survey; US Department of the Interior)