In 2016, five of the eight locations with fixed intertidal transects were sampled as part of a long-term effort to monitor changes in the abundance of macroalgae in the Great Bay Estuary. Since 2013, the abundance and taxa of intertidal macroalgae have been assessed at fixed locations to serve as an indicator of ecological changes in the Estuary. Changes in the algae may reflect changes associated with excess nutrient loading, termed eutrophication, and may be especially informative of algal impacts to eelgrass meadows in the Estuary.
Macroalgae collections over the past four years have resulted in the accumulation of two years of data for six locations, three years of data for a seventh location and four years of data for an eighth location. Based upon this short-term data set we found significant cover and biomass of nuisance algae, some of these are recognized as introduced, invasive species. Monitoring results from 2016 show high levels of cover of nuisance algae, either green or red (Ulva and Gracilaria, respectively) at all sites sampled, but especially at the lowest elevations, nearest to the subtidal habitats. Visual examination of our intertidal transect data along with anecdotal observations suggest that algal populations are changing, but long-term collections will be needed to determine whether significant differences in intertidal macroalgal populations are occurring over time.
Burdick, D.M., A.C. Mathieson, S. Nick, M. McGovern and C.R. Peter. 2017. Monitoring Macroalgae in the Great Bay Estuary for 2016. Final Report. The Piscataqua Region Estuaries Partnership. 15 pp.