Monthly eDNA Monitoring of an Invasive Bryozoan, Bugulina californica, in Seawater Using Species-Specific Markers

Environmental DNA (eDNA) method used by many ecologists as effective investigation tool can detect endangered species, rare species, and invasive species. In case of invasive species, eDNA method help to monitor the target species when the species was hard to detect through the traditional survey such as the early stage of invasion, low abundance, and larva or juvenile stage. The bryozoan, Bugulina californica, was known as a marine fouling invasive species in Korea since its first reported in 1978. This species expanded nationwide, and damages to ascidian aquaculture through attached on the ship hulls and artificial facilities. To monitor the distribution and biomass of invasive bryozoan, B. californica, the qPCR analysis of environmental DNA was performed on seawater samples from 12 harbors. In this study, we designed species-specific markers which can calculate the detected DNA copies of B. californica, and the presence and monitoring of this species can be more accurately estimated by environmental DNA analysis than by traditional survey, in which it is difficult to identify the species. Real-time PCR analysis using environmental DNA is an effective monitoring method that can determine both the distribution and the monthly change in biomass of B. californica in Korea.

Florida Inlets and Intertidal Biofouling Communities

This study reports on the identity and coverage of rocky intertidal species in the major inlets of Florida’s Atlantic coast. From north to south, these inlets are Fort George, St. Augustine, Ponce De Leon, Port Canaveral, Sebastian, Fort Pierce, Jupiter, Lake Worth, Boca Raton, Port Everglades, Baker’s Haulover, and Port of Miami. Dominant coverage in the southerly inlets included star corals (Siderastrea radians, 62% Port of Miami), ribbed barnacles (Tetraclita stalactifera, 18% Port Everglades), and zoanthid corals (Palythoa sp., 40% Baker’s Haulover). In the north, the community shifted and species absent in the south became common (e.g., eastern oysters Crassostrea virginica, 9% Fort George, 15% St. Augustine; the macroalga Enteromorpha lactuca, 10% Fort George, 17% Sebastian Inlet). The invasive bryozoan Bugula neritina was always present north of the Port of Miami and was a major community component north of Port Everglades (e.g., 27% Fort Pierce Inlet and 22% Ponce de Leon Inlet). Correlations between intertidal populations and environmental indicators included the oyster C. virginica with various sea surface temperature (SST) parameters (e.g., inverse correlations with max SST, R2 = 0.81, p = .038). Likewise, the coralline alga Pneophyllum fragile was correlated with various SST parameters (e.g., min SST, R2 = 0.51, p = .020). Bare rock and B. neritina both showed inverse correlations with the human population of inlet drainage basins (R2 = 0.28, p = .040 and R2 = 0.33, p = .026, respectively), the latter relationship an unexpected pattern for a notorious invader. These data show latitudinal patterns and provide baselines for future comparisons in the wake of projected climate change.