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Project Manager

Dennis Hanisak, Ph.D.

Project Team

Paul Hargraves
Patrick Monaghan
Kristen Sanderson

Project Description

Harbor Branch is located on the Indian River Lagoon (IRL), a unique, highly diverse, shallow-water estuary of national significance. Water quality in the IRL has changed significantly over the past eight decades due to watershed alteration and land drainage patterns.

The Indian River Lagoon Research Initiative is focusing on the relationship of water quality in the IRL with seagrasses, macroalgae, and phytoplankton. Since May 2005, we have been conducting high-frequency water quality monitoring in the IRL near Vero Beach and Fort Pierce. We are identifying water quality gradients related to freshwater discharges in the IRL, which are recognized as the most significant human impacts on this estuary, and significant climate-related interannual variability in water quality.

We are determining relationships of water quality with seagrass and with algal communities (both benthic seaweeds and phytoplankton). Collectively, these photosynthetic organisms form the basis of the IRL’s food web, and any changes in them affect other organisms in the system (e.g., fish, shellfish, marine mammals). The major concerns of freshwater discharges to seagrasses (critical to the lagoon because of their importance to fish and other animals) are reduced salinity and water clarity, and elevated nutrients and suspended solids (or turbidity).

Management of the IRL requires a solid scientific foundation and reliable data. Our work is providing important baseline data to help determine long-term changes in the IRL, including documentation of expected positive improvements in estuarine health following the reduction of freshwater inputs due to several IRL-related projects underway in our local communities.