Coral reefs are diverse, productive, and economically valuable ecosystem, but are threatened by a variety of stressors in including land based sources of pollution, such as nutrients, pesticide, heavy metals and sedimentation. The island of Tinian (CNMI) has a unique land use history that includes military activities, tourism and low intensity agriculture. Understanding how pollution is affecting coral ecosystem health is critical information needed by coastal managers in order to effectively m
Why We Care
Previous studies have documented the prevalence of toxic contaminants (heavy metals, PCBs, pesticides, PAHs) in the coral reef environment, and have shown that corals incorporate many of these toxins into their tissues. While some ecosystem level correlations (e.g. coral species richness) have shown statistically significant relationships with pollutants, very little data exist on organism level responses to contaminants. It would be useful to coastal managers to have coral body burden thresholds (i.e. similar to sediment quality guidelines) to delineate at what point corals are being negatively impacted by pollution. This study, which will link pollutant information with genetic response variables, will be an important first step towards achieving that goal.
What We Are Doing
In August 2013, coral tissue samples were collected at twelve locations on the south shore of Tinian from Pocillopora damicornis. The coral tissue samples were analyzed for a broad suite of contaminant (PAHs, PCBs, pesticides, heavy metals). Coral stress will be measured using genetic techniques. Water samples were also collected for nutrient analysis.
What We Are Finding
Coral tissue concentrations are similar to what has been measured by NCCOS in other coral reef systems. Concentrations of are generally higher near the harbor area, as would be expected based on land use and boat traffic.
Benefits of Our Work
These data will serve as an environmental baseline and will allow coastal managers to detect future change in the ecosystem, e.g. as land use changes with proposed military activities.
Planned genetic analyses will allow us to directly related pollution stressor information with organism response. This is an important first step to developing tissue body burden thresholds for corals, which will help inform managers about the significance of observed pollution in coral reef ecosystems.