Ren, L.; Belton, T.J.; Schuster, R., and Enache, M., 2017. Phytoplankton index of biotic integrity and reference communities for Barnegat Bay–Little Egg Harbor, New Jersey: A pilot study. In: Buchanan, G.A.; Belton, T.J., and Paudel, B. (eds.), A Comprehensive Assessment of Barnegat Bay–Little Egg Harbor, New Jersey.
A pilot study was carried out to quantify season-salinity-specific phytoplankton reference communities and to develop a phytoplankton index of biotic integrity (P-IBI) for Barnegat Bay–Little Egg Harbor (BB-LEH) estuary, using approaches similar to those for the Chesapeake Bay. Synchronized phytoplankton and water-quality data collected between August 2011 and August 2013 from the Barnegat Bay Water Quality Monitoring Program were used as calibration data set. The results showed that one-fifth of samples were from the least-impaired habitat condition, with low turbidity and low concentrations of dissolved inorganic nitrogen and orthophosphate (PO4). Nearly 60% of samples were from undesirable conditions with poor water clarity and excess nutrients. Phytoplankton reference communities, in comparison with communities in impaired conditions, were characterized with low concentrations of chlorophyll a (Chl a), total nitrogen (TN), and total phosphorus (TP), low Chl a/C ratio, low summer picoplankton biomass, and high spring and summer dissolved oxygen. Thirty-four metrics were evaluated for their ability to discriminate between the least-impaired and impaired habitat conditions. Nine phytoplankton metrics and three physiological and chemical metrics, which showed strong discriminatory ability, were selected, and different combinations of these metrics were used to create phytoplankton indices for spring and summer mesohaline and polyhaline zones in BB-LEH. The current P-IBI was able to correctly classify 64–100% for spring samples and 68–88% for summer samples in the calibration data set. Our work is the first attempt to develop a P-IBI for this region. The calculated reference communities and P-IBI, though constrained because of limited data availability, were region specific and intended to facilitate water-quality assessment and management efforts in BB-LEH. The differences of TN and TP between the least-impaired and impaired conditions in most of season-salinity zones suggested that dual reduction of N and P are necessary to control eutrophication in BB-LEH. Further work on the refinement of the P-IBI is underway as additional phytoplankton and water-quality data are being collected and assessed.