Journal of Marine Science and Engineering Article Impacts of Hurricane Disturbance on Water Quality across the Aquatic Continuum of a Blackwater River to Estuary Complex Tracey Schafer 1,2,*, Nicholas Ward 3,4 , Paul Julian 1 , K. Ramesh Reddy 2 and Todd Z. Osborne 1,2 1 Whitney Marine Lab for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA; pjulian@ufl.edu (P.J.); osbornet@ufl.edu (T.Z.O.) 2 Wetland Biogeochemistry Laboratory, Soil and Water Sciences Department, University of Florida, Gainesville, FL 32611, USA; krr@ufl.edu 3 Marine Sciences Laboratory, Pacific Northwest National Laboratory, Sequim, WA 98382, USA;
[email protected] 4 School of Oceanography, University of Washington, Seattle, WA 98195, USA * Correspondence: tschafer25@ufl.edu Received: 20 May 2020; Accepted: 3 June 2020; Published: 5 June 2020 Abstract: Hurricanes cause landscape-scale disturbances that affect biogeochemical cycling and water quality in coastal ecosystems. During Hurricane Irma’s passage through northern Florida, water 1 movements driven by wind velocities up to 105 km h− caused a salinity peak in an estuary/blackwater river complex. Water quality was monitored across the 15 km site to detect the magnitude and duration of disturbance. Saline water intruded 15 km inland into a freshwater portion of the river that peaked at a salinity of 2 psu. Due to the volume of precipitation from the hurricane, significant runoff of freshwater and dissolved organic matter (DOM) caused a decrease in salinity, dissolved oxygen (DO), and Chlorophyll-a concentrations while increasing turbidity and fluorescent dissolved organic matter (fDOM). The disturbance caused rapid changes observed by in-situ water quality monitors over a 3-week period, but some effects persisted for longer periods as shown by 3-month weekly water sampling.