MOLECULAR METHODS SURVEY OF HARMFUL ALGAE IN SHIPS’ BALLAST WATER

Abstract

Harmful algal blooms (HAB) are increasing in frequency and diversity in the Gulf of Mexico and along the Texas coast. In 2016, the U.S. EPA and U.S. Coast Guard will require monitoring of ballast water discharged from all foreign ships calling at ports U.S. territorial waters. Archived samples from ships’ ballast water and Texas bays and ports were screened with polymerase chain reaction (PCR) assays specific for several species causing harmful algal blooms. Previous analysis of these archived samples has detected 13 different genera and species of harmful algae known to be transported via ships’ ballast water. Thus far, Karenia brevis, Pfiesteria piscicida, and Microcystis spp. have been detected thus far in upper Galveston Bay and the Port of Texas City and in the Upper Laguna Madre and the Port of Brownsville. P. piscicida has been detected in 7 out of 14 ballast water samples and Alexandrium spp. in 9 samples from ships calling at the Port of Houston, the 2nd busiest port in the U.S. Hypotheses to be tested by this study: H1: Higher concentrations of HABs will be present in ballast water that is less than 10 days old, i.e. taken up or exchanged less than 10 days prior to discharge at the Port of Houston. Objective 1: To determine if age of ballast water influences the detectability of HABs with quantitative PCR. H2: Ports and bays receiving ballast water discharged from ships that have not conducted a ballast water exchange in the open ocean, i.e. containing ‘coastal water’ will contain a greater number or a higher diversity of potential HAB species. Objective 2: To use PCR assays specific for different species of HABs to determine if the potential diversity of HABs in Texas port and bay waters can be linked to sources of ships’ ballast water.