Opportunity Title:

Influence of Saharan Dust on Seawater- and Coral-associated Vibrio spp

Research Area:

Water

EPA Lab/Center/Office:

National Exposure Research Laboratory (NERL)

Location:

Athens, GA

Duration:

12 months

Brief Summary:

Studying the influence of Saharan dust on the role and interactions of Vibrio spp. within the microbiome of a coral reef through the application of metagenomics and metatranscriptomics.

Opportunity Description:

The application of microbiome research has proven useful in understanding marine ecosystems’ health, especially because microbial interactions in the ocean are multifaceted. A disease state can be described as a dynamic interaction between the host, a pathogen or pathogenic community, and the environment – also known as the disease triangle. Few studies have used this comprehensive model to understand marine disease, particularly in the context of microbial ecology. At EPA, the intern will have access to tools not readily accessible at the intern’s home university to study the microbiome and health of a reef ecosystem experiencing episodic environmental stress.

A recent report described up to a 30-fold increase in seawater-associated Vibrio spp. abundance during Saharan dust events in Looe Key Reef, FL. Saharan dust provides a large portion of iron (Fe), which is a key micronutrient for heterotrophic Vibrio spp., to the ocean through atmospheric deposition. Vibrio is ubiquitous in seawater and a dominant member of the coral microbiome. Additionally, certain species of Vibrio spp. are well-known human pathogens, with a reported rate of infection reaching 100 deaths each year in the United States. Vibrio spp. have also been proposed as coral pathogens. Therefore, understanding Vibrio population dynamics in seawater is critical to assessing water quality not only in a human health context but also in a coral disease context, since the water column is a major avenue for coral pathogen transport.

The internship will involve applying the host-pathogen-environment triangle concept to investigate the influence of Saharan dust on both seawater- and coral-associated Vibrio. No other study has considered the effect of natural, episodic environmental events, such as dust pulses, on coral and human health simultaneously. This unique, interdisciplinary approach to studying ecosystem health will allow the intern to apply their research in a new scientific direction.

The goal of the project is to describe the influence of Saharan dust on both seawater- and coral-associated Vibrio by working in the EPA facility in Athens, GA to accomplish the following goals:

1. Knowing that dust events increase seawater-associated Vibrio, investigate if dust events also increase the abundance of coral-associated Vibrio.
   • Conduct a dosing experiment in the lab using the solar simulators available at the Athens EPA facility. This in-lab experiment will allow us to control for variables such as temperature, water contamination and light.
2. Investigate how Vibrio may be utilizing the nutrient input caused by the Saharan dust influx in seawater?
   • The intern will use EPA’s mass spectrometer to investigate microbial metabolites in the water column. Results will increase understanding of how Vibrio may be utilizing nutrients from Saharan dust and if its lifestyle could affect the marine microbial community as a whole.
3. A previous paper observed a boom-and-bust cycle of Vibrio during a Saharan dust event. Are viruses responsible for controlling Vibrio abundance during dust pulses?
   • The intern will utilize the ultrafiltration equipment and protocol developed by the EPA to sample large volumes of seawater in order to concentrate virus particles for both counting and sequencing.

Results may provide evidence for decreasing water quality during Saharan dust events, along with assessing the mechanism that increases coral susceptibility to disease.

Opportunities for Professional Development:

While accomplishing the above goals of the internship, the GRIP intern will have the opportunity to grow professionally by collaborating with EPA employees (i.e. training on new equipment and protocols). Intern will have access to resources available only at the Athens EPA facility. Within an interdisciplinary agency, the intern will be able to expand the scope of his/her research, develop new methodological skills, and share findings with a network of experienced, diverse scientists.

Point of Contact or Mentor:

Marirosa Molina, molina.marirosa@epa.gov