In Narragansett Bay, there have been great strides to improve water quality. This is evident in local sewage treatment plant upgrades designed to reduce nitrogen loads (e.g. Fields and Bucklin Point in Providence, RI). As we continue to work towards reducing anthropogenic nutrient loads to improve water quality, it is still very unclear what historical baseline we want to use as a goal. Often, we talk about restoring a system “back” to a prior state, but with little understanding of what that prior state might have been. The concept of a shifting baseline is often used to describe this issue, where changes are measured against baseline conditions that themselves reflect some alteration of the ecosystem from its original state. In ecosystem ecology, particularly in coastal ecosystems, there has been very little research done to look at how food webs have changed over time, particularly over longer time scales (thousands of years). It is essential to understand how an ecosystem has responded to prior impacts in order to make better decisions for its conservation and management in the future.
Nitrogen stable isotopes are frequently used as an indicator of anthropogenic nutrient impacts on coastal water bodies. While the Environmental Protection Agency has accumulated a substantial dataset of nitrogen stable isotope values in Narragansett Bay plants and animals over the past decade, we don't know what nitrogen stable isotopes values were prior to European colonization and, more significantly, the industrial revolution. We are looking to develop a method to measure nitrogen stable isotope values in Quahog shells from Native American middens. These middens were excavated and described as part of a prior research and the shells have been dated and span 4,000 years. These midden shells provide us with the pre-colonization outlook of the nitrogen in the Narragansett Bay. But in order to get data on the post-Industrial Revolution levels in the bay, we are on the hunt for other Quahog shells. Particularly ones that are dated from the 20th century.
The Tomaquag Museum was very generous and able to provide us with some shells. If you happen to have any or know of any shells that could be of use, please contact Bobbi Carter of the Environmental Protection Agency at 401-782-9619.