Lab Finds Differences between Port and Reef Sediments

Marine ports can be very busy places. From the vantage point of NSU’s Guy Harvey Oceanographic Research Center (GHOC), one can easily observe and be part of the boat traffic going in and out of Port Everglades Inlet (PEI). This includes small and large recreational vehicles, Coast Guard patrols, sleek and modern looking yachts, huge tankers, and cargo vessels, loaded with oil or other commodities, and of course cruise ships ferrying passengers to good times in the Caribbean.

All this activity contributes to PEI being one of the busiest ports in the SE United States, which started almost a century ago in 1928.  The human activities also set the port physically apart from nearby natural habitats, which our laboratory has corroborated by profiling the marine sediments from both port and nearby coral reef sites. Molecular microbiology analyses provide some stark contrasts.   “Although most of the sites are within a few kilometers from each other, and are connected by daily tidal flows, the port and reef microbial communities showed distinct characteristics which were statistically significant.”, says Jose (Joe) Lopez, Ph.D., a professor with a laboratory at the GHOC and the Department of Biological Sciences in Halmos College of Arts and Sciences and Guy Harvey Oceanographic Research Center (HCAS).

The study was analyzed and co-written by Lopez and affiliate NSU faculty, Lauren Krausfeldt, Ph.D., and published in the open access online journal PeerJ.  With the help of dedicated NSU students, like Catherine Bilodeau and Hyo Lee, and project initiation by former FL Dept of Environmental Protection manager, Shelby Casali, molecular microbiological methods, now routine in the field, were applied to uncover the details of which microbes live in nearshore or port sediments.  The universal gene used to identify bacteria, is called 16S rRNA, which has been previously used to characterize other samples ranging widely from shark and human teeth, octopus skin, sponge and anglerfish tissue in the GHOC molecular microbiology laboratory run by Lopez.

In the Port Everglades study, NSU researchers found that some photosynthetic cyanobacterial group abundances decreased in the reef sediments in 2021, which could indicate changing irradiance reaching sensitive corals and other symbiotic hosts that depend on sunlight.

The new PeerJ study on marine sediments has potential ramifications on local coral reef health, because routine dredging and other human activities can stir up port sediments that ultimately disperse and settle on nearby coral reef habitats.  This data, along with previous microbial research in the Lopez laboratory describing water quality provides useful baselines that can be used by local environmental managers.

Posted 04/23/23