TP21 Assessment in Tropical Ecosystems
Tuesday, 15 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(FOR-1117-836229) Synthetic organic chemicals, microorganisms, African and Asian dust, and coral reefs.

Garrison, V.¹, Carr, R.², Foreman, W.³, Griffin, D.¹, Kellogg, C.¹, Majewski, M.⁴, Shinn, E.¹, Simonich, S.⁵, Smith, G.⁶, ¹ U.S. Geological Survey, St. Petersburg, FL, U.S.A.² U.S. Geological Survey, Corpus Christi, TX, U.S.A.³ U.S. Geological Survey, Denver, CO, U.S.A.⁴ U.S. Geological Survey, Sacramento, CA, U.S.A.⁵ Oregon State University, Corvallis, OR, U.S.A.⁶ University of South Carolina, Aiken, SC

ABSTRACT- Coral reef declines worldwide are well documented, but the processes driving the increases in numbers and types of diseases, increased mortality from disease, and lack of recovery on damaged coral reefs remain elusive. In 1997, Shinn presented a new hypothesis to explain the widespread occurrence of apparently "new" diseases and the lack of recovery of damaged coral reefs close to and remote from human populations–that African and Asia dust systems transport nutrients and viable microorganisms that adversely affect coral reefs and human health. Shinn et al. (Geophys. Res. Letters, 2000) suggested that the composition of dust air masses changed over the past 30 years, coincident with increased quantities of dust transported. Dust may be linked with coral reef declines by: 1) widespread distribution of pathogens to downwind reefs; 2) deposition of limiting micronutrients, such as iron, or macronutrients that could spike pathogen reservoir populations or trigger microorganism pathogenicity; and 3) influx of chemical contaminants (toxins, carcinogens, mutagens, or endocrine disruptors) that can weaken the natural immunocompetency of coral reef organisms, adversely affect reproduction (at any stage including settlement of planula larvae) or invoke direct toxicity (Garrison et al., BioScience, 2003). Current research involves a large, international network of collaborating scientists from many disciplines. Our research shows that viable microorganisms appear to be transported in African dust, because air samples from dust events in the U.S. Virgin Islands (VI) contain significantly more microbes than from ambient, nondust conditions, and air samples from a dust source region (Mali) contain orders of magnitude more viable microorganisms than in the Caribbean. Preliminary results from analysis of chemical contaminants in air samples provide new information that adds to our knowledge of the global transport of persistent organic pollutants (POPs). Analysis of air samples collected in the VI during dust events and in the Sahel in Africa identified a nearly identical suite of POPs, with concentrations of POPs usually much higher (mid-to-sub ng/m³ range) in the African source region.

Key words: dust, air, contaminants, corals