Lori J Morris, Lauren M Hall, Jan D Miller, Margaret A Lasi, Robert H Chamberlain, Robert W Virnstein, and Charles A Jacoby. “Diversity and distribution of seagrasses as related to salinity, temperature, and availability of light in the Indian River Lagoon, Florida”Proceedings of Indian River Lagoon Symposium. 2020. https://www.fau.edu/hboi/irlo/docs/MorrisetalDiversityanddistributionofseagrassesasrelatedtosalinitytemperatureandavailabilityoflightintheIndianRiverLagoon.pdf
Abstract
Seven species of seagrass have been found in the Indian River Lagoon (IRL), making it an
unusually diverse location at the global scale. From 1994 to 2019, the lagoon-wide distribution of
these species reflected variations in temperature, salinity, and the availability of light at depth, which
were related to latitudinal differences in hydrology and hydrodynamics along the IRL. In general,
species richness was higher near the four southern inlets, and fewer species were found in areas with
longer residence times for water. At a finer scale, the distribution of species varied among depths,
with the greatest number of species found at mid-depths (~0.4–0.9 m). Prior to 2011, these patterns
remained relatively consistent for ~ 40 years, but several, intense and prolonged phytoplankton
blooms disrupted them. The areal extent of all seagrasses decreased by over 50%, the offshore ends of canopies moved shoreward and shallower, distributions of species along gradients of latitude and
depth were disrupted, and mean percent cover decreased. Major changes in distribution and
abundance of seagrasses arose when salinity, temperature, and availability of light at depth exceeded
limits derived for each species. These substantial and widespread changes engendered concerns for
recovery or rehabilitation of seagrasses in the lagoon.
