Estuary Systems

Estuary systems: Consequences of estuary contamination on crab heart and neurosecretory systems.

These studies  focus on a ubiquitous crustacean inhabitant of the San Juan Bay Estuary, the blue crab Callinectes sapidus, as an experimental model for assessing effects of anthropogenic factors on nervous system function.  This species is native to waters of the western Atlantic, ranging from northern Argentina to as far north as Nova Scotia and supports one of the largest fisheries industries in the United States, estimated at more than 100 million dollars in 2005.  However, alarming decreases in its populations have been documented in recent years. The central hypothesis of this project posits that pollutants can exert significant sub-lethal effects on nervous system structure and function. This project is comprised of three objectives that will explore this hypothesis: 1) develop bioprobes to monitor levels of contaminants in sediments, water and crab tissue samples in the SJBE; 2) assess the impact of contaminants and oxygen levels on the cardiac system of crabs obtained from distinct environmental condition; and finally, 3) assess the impact of contaminants and oxygen levels on the sinus gland neurosecretory system of crabs obtained from distinct environmental conditions.

We have begun testing several contaminants of emerging concern in the blue crab cardiac system, including dibutyl phthalate and dichlorobenze. For the priority list of hazardous substances from the Agency for Toxic Substances and Disease Registry, click here for a pdf version, or visit the ATSDR website at

Researchers: Mark Miller (Project leader), Liz Diaz, Loretta Roberson


What is an Estuary? (from the Environmental Protection Agency's Office of Wetlands, Oceans, and Watersheds)

An estuary is a body of water formed where freshwater from rivers and streams flows into the ocean, mixing with the seawater. Estuaries and the lands surrounding them are places of transition from land to sea, and from freshwater to saltwater. Although influenced by the tides, estuaries are protected from the full force of ocean waves, winds, and storms by the reefs, barrier islands, or fingers of land, mud, or sand that surround them.

Learn about estuaries and emerging contaminants:

Environmental Protection Agency's Office of Wetlands, Oceans, and Watersheds

National Estuarine Research Reserve System

Contaminants of Emerging Concern from the Environmental Protection Agency

Emerging Contaminants In the Environment from the US Geological Survey Toxic Substances Hydrology Program

Article: Assessing the exposure risk and impacts of pharmaceuticals in the environment on individuals and ecosystems. Arnold et al. 2013