Project Summary Sheet

Project: Geochemical Monitoring of Restoration Progress

Web Sites: http://sofia.usgs.gov/; http://coastal.er.usgs.gov

Location (Subregions & Counties): Central Everglades, including Florida Bay; Monroe County

Funding (Source): USGS Place-Based Studies

Principal Investigator(s): Kimberly Yates, kyates@usgs.gov, 727-803-8747 x3059

Project Personnel: Robert B. Halley, rhalley@usgs.gov; Phillip Thompson, prthompson@usgs.gov; Nathan Smiley, nsmiley@usgs.gov; Iuri Herzfeld, iherzfeld@usgs.gov; Chris Dufore, cdufore@usgs.gov; Nancy Dewitt, ndewitt@usgs.gov; Keith Ludwig, kludwig@usgs.gov

Supporting Organizations: None

Associated / Linked Projects: Investigations of mud-bank seagrass die-off (Carlson); Synthesis of carbonate sedimentation in Florida Bay (Halley)

Overview & Status: This project monitors changes in critical biogeochemical processes and water quality parameters in Florida Bay as South Florida Restoration proceeds.  Fiscal year 2002 activities for Task 1 of this project have focused on continuing seasonal productivity monitoring of community calcification, photosynthesis, and respiration rates on representative substrate types (including seagrass beds, mud bottom, and hard bottom communities) located in regions of the bay that exhibit similar water quality properties.  Productivity monitoring has continued during March and September of each study year at Central Bay study sites including Russell Bank, Manatee Key Basin, and near Captain’s Key, and at Western Bay study sites including Buchanon Keys and Barnes Key.  In situ experimentation on the effects of elevated salinity on seagrass metabolism was performed in March of 2001 on seagrass beds near Captain’s Key. Productivity monitoring and salinity experimentation will resume in June 2002 and continue throughout the duration of the project. Bimonthly salinity surveys have continued throughout the project (Task 2). Instrumentation was acquired in 2001 for dissolved oxygen, pH, carbon speciation, and CO₂ gas flux measurements.  Carbon dioxide gas flux measurements have been performed simultaneously with bimonthly salinity surveys at 26 locations throughout Florida Bay since April of 2001. Dissolved oxygen, pH, total alkalinity, and total inorganic carbon measurements were added to the bimonthly geochemical surveys in April 2002 and will continue throughout the duration of the project.  Bimonthly salinity maps are posted on the SOFIA web site immediately after processing. Carbon dioxide gas flux maps, and newly acquired maps for dissolved oxygen, pH, total alkalinity, and total inorganic carbon from the April 2002 survey are currently being prepared, and will be posted on the SOFIA web site. 

Needs & Products:  Published products from 2000 to present: (1) Yates and Halley, 2001.  The Submersible Habitat for Analyzing Reef Quality (SHARQ): improved technology for benthic analyses and experimentation.  (2) Yates and Halley, 2001.  Geochemical productivity monitoring of Florida Bay.  (3) Halley and Yates, 2001.  Productivity measurements of benthic communities in Biscayne National Park as an indication of ecosystem health. (4) Yates and Halley, 2000.  Geochemical monitoring of Productivity in Florida Bay.  (5) Halley and Yates, 2000. Sea-level rise and the future of Florida Bay in the next century. (6) Yates and Halley,  2000.  Geochemical productivity monitoring in Florida Bay.  (7) Yates, 2000.  SHARQ Infested Waters.

Application to Everglades Restoration: Geochemical monitoring efforts establish baseline data from which to evaluate progress, provide a measure of the effects of restoration on environmental health and water quality, and complement biological monitoring of indicator species.  This information is critical for identifying when successful restoration has been accomplished.  Bimonthly geochemical surveys of critical water quality parameters such as salinity, dissolved oxygen, pH, total alkalinity, and carbon speciation serve as a monitoring system for identifying changes in environmental conditions that occur naturally and as alterations of the South Florida ecosystem continue.  This information has been posted on the SOFIA web site (and will continue to be) in a timely manner for use by resource managers and other scientists participating in Florida Bay research to aid in identification of ecological responses to environmental change. Bimonthly salinity surveys have been performed since 1994 and will provide a “recent” historical record of the impact of freshwater input to Florida Bay prior to restoration activities and as restoration proceeds.  Approximately 20,000 data points are collected during each survey.  This type of high-resolution data is critical for validation of circulation and water quality models. Seagrasses are critical ecological indicators for estuarine health due to their sensitivity to water quality change.  Benthic community metabolism (rates of photosynthesis, respiration, and calcification) is sensitive to changes in water quality and shows distinct rate changes before visual evidence of environmental disturbances such as seagrass die-off, algal blooms, and shifts in ecosystem success indicator species.  Therefore, measuring changes in these processes relative to changes in water quality (such as salinity, dissolved oxygen, etc.) provides a mechanism for early identification of stress to benthic communities.  In situ experimentation on the effects of salinity change on seagrass metabolism will provide insight into the potential impact of freshwater flow alteration to Florida Bay on seagrass communities.