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Thesis - NSU Access Only
M.S. Marine Biology
Amy C. Hirons
Zooplankton samples and water mass measurements were conducted along a 10 km long, east-west transect off the coast of southeast Florida during 2007. Temperature and salinity measurements were recorded using a conductivity-temperature-depth (CTD) sensor, and current direction and magnitude measurements were recorded using an acoustic Doppler current profiler (ADCP). Daylight zooplankton samples were collected using a 335 μm mesh bongo net at surface 0-25 m and 0-150 m (nearshore) and 0-200 m (offshore), at three stations, for 5 nonconsecutive months along the transect. Chaetognatha were separated from bulk zooplankton samples and identified to species; fifteen different species were found. Flaccisagitta enflata had the highest densities over the entire sampling period, followed by Serratosagitta serratodentata, and Krohnitta pacifica. ADCP data revealed the existence of a Subsurface Counter Current in conjunction with an offshore meander of the Florida Current during May, July, and September 2007. Abiotic data confirmed the presence of Continental Edge Water and Yucatan Water occupying different spatial and temporal scales, and the boundary between these two water masses existed as the western boundary of the Florida Current. The densities of each species were compared to the collection site’s temperature and salinity data. Densities of several species (Flaccisagitta enflata, Ferosagitta hispida, M. minima, and Sagitta bipuctata) demonstrated a correlation to temperature and S. bipunctata and Ferosagitta hispida showed a correlation to salinity. These species were associated with the front and peripheries of the Florida Current.
Nicholas Brian Gadbois. 2013. Using Chaetognatha as Indicators of Water Masses in the Florida Current, Broward County, Florida. Master's thesis. Nova Southeastern University. Retrieved from NSUWorks, Oceanographic Center. (168)