With the continuing threat of climate change and other anthropogenic disturbances, the future of Florida's coral reefs is uncertain. One way to gain insights into the future trajectories of Florida's coral reefs is to investigate how they responded to environmental disturbances in the past.
Coral Cores - A Climate History Archive
The coral reefs of the Florida Keys Reef Tract (FKRT) are an invaluable natural resource. They protect shorelines by reducing wave energy, provide critical habitat to associated marine life, and contribute nearly $3 billion annually to local economies. Over the last several decades, coral reefs around the world have declined as a result of a variety of local- to global-scale perturbations; the reefs along the FKRT are no exception to this trend (Toth and others, 2014). With the continuing threat of climate change and other anthropogenic disturbances, the future of Florida's coral reefs is uncertain. One way to gain insights into the future trajectories of Florida's coral reefs is to investigate how they responded to environmental disturbances in the past (Toth and others, 2012; Toth 2013).
Cores collected from coral reef frameworks (fig. 1) can provide valuable records of reef development across millennial timescales. Using underwater hydraulic drilling (fig. 2), USGS researchers have been collecting cores from the reefs of the Florida Keys since the early 1970s. As a result, USGS-Saint Petersburg has amassed an extensive archive of coral reef cores. We are synthesizing records of existing reef cores and new cores collected during the course of this study (Fig. 3), to better understand the spatial and temporal trends in the development of Florida's reefs during the Holocene. The study is divided into three main parts: reconstructions of Holocene reef accretion, coral-reef paleoecology, and paleoenvironmental reconstructions.
Holocene Reef Accretion
We are using a combination of radiocarbon and U-series dating techniques to determine whether the timing of reef decline differed across the FKRT as a result of environmental differences. We will also calculate reef-accretion rates during the Holocene epoch, the period since the last glacial time, from ~10,000 years ago to present. Reef accretion is a measure of the net vertical growth of the reef over time that incorporates both calcification and erosion. By better understanding how reef accretion changed in response to environmental changes in the past, we can make predictions about how Florida's reef may respond to changes in climate, water quality, and sea-level rise in the future. This work compliments other studies in CREST that are investigating calcification rates and reef-scape biogeochemical processes on today's reefs.
Coral-Reef Paleoecology
We are using core records to reconstruct the species composition of reefs during the Holocene to determine how modern reef assemblages compare to the assemblages of the past. We are also analyzing Holocene coral skeletons to determine if coral growth rates have changed through time. We will compare these paleoecological data with our records of reef accretion to determine what ecological changes may have characterized changes in reef growth in the past.
Paleoenvironmental Reconstructions
We are working with the Reef History and Climate Change team in CREST to reconstruct environmental conditions on Florida’s reefs during the Holocene using geochemical archives from coral skeletons. We are also using the dating records from the cores to develop a model of sea-level changes on the FKRT over the last 10,000 years. This will allow us to directly measure the impact of environmental variability on the history of Florida’s reefs.
This research is part of the Coral Reef Ecosystem Studies (CREST) project. That project and other related tasks are listed below.
Coral Reef Ecosystem Studies (CREST)
Reef History and Climate Change
Coral Reef Seafloor Erosion and Coastal Hazards
Measuring Coral Growth to Help Restore Reefs
- Overview
With the continuing threat of climate change and other anthropogenic disturbances, the future of Florida's coral reefs is uncertain. One way to gain insights into the future trajectories of Florida's coral reefs is to investigate how they responded to environmental disturbances in the past.
Coral Cores - A Climate History Archive
The coral reefs of the Florida Keys Reef Tract (FKRT) are an invaluable natural resource. They protect shorelines by reducing wave energy, provide critical habitat to associated marine life, and contribute nearly $3 billion annually to local economies. Over the last several decades, coral reefs around the world have declined as a result of a variety of local- to global-scale perturbations; the reefs along the FKRT are no exception to this trend (Toth and others, 2014). With the continuing threat of climate change and other anthropogenic disturbances, the future of Florida's coral reefs is uncertain. One way to gain insights into the future trajectories of Florida's coral reefs is to investigate how they responded to environmental disturbances in the past (Toth and others, 2012; Toth 2013).
Sources/Usage: Public Domain.Figure 1. A reef core collected from Dry Tortugas National Park. Numbers indicate the depth of penetration into the reef in feet. (Public domain.)
Sources/Usage: Public Domain.Figure 2. Lauren Toth operates an underwater hydraulic drill to collect a coral-reef core from Crocker Reef (this research was conducted under permit # FKNMS-2013-097). (Public domain.) Cores collected from coral reef frameworks (fig. 1) can provide valuable records of reef development across millennial timescales. Using underwater hydraulic drilling (fig. 2), USGS researchers have been collecting cores from the reefs of the Florida Keys since the early 1970s. As a result, USGS-Saint Petersburg has amassed an extensive archive of coral reef cores. We are synthesizing records of existing reef cores and new cores collected during the course of this study (Fig. 3), to better understand the spatial and temporal trends in the development of Florida's reefs during the Holocene. The study is divided into three main parts: reconstructions of Holocene reef accretion, coral-reef paleoecology, and paleoenvironmental reconstructions.
Holocene Reef Accretion
We are using a combination of radiocarbon and U-series dating techniques to determine whether the timing of reef decline differed across the FKRT as a result of environmental differences. We will also calculate reef-accretion rates during the Holocene epoch, the period since the last glacial time, from ~10,000 years ago to present. Reef accretion is a measure of the net vertical growth of the reef over time that incorporates both calcification and erosion. By better understanding how reef accretion changed in response to environmental changes in the past, we can make predictions about how Florida's reef may respond to changes in climate, water quality, and sea-level rise in the future. This work compliments other studies in CREST that are investigating calcification rates and reef-scape biogeochemical processes on today's reefs.
Coral-Reef Paleoecology
We are using core records to reconstruct the species composition of reefs during the Holocene to determine how modern reef assemblages compare to the assemblages of the past. We are also analyzing Holocene coral skeletons to determine if coral growth rates have changed through time. We will compare these paleoecological data with our records of reef accretion to determine what ecological changes may have characterized changes in reef growth in the past.
Paleoenvironmental Reconstructions
We are working with the Reef History and Climate Change team in CREST to reconstruct environmental conditions on Florida’s reefs during the Holocene using geochemical archives from coral skeletons. We are also using the dating records from the cores to develop a model of sea-level changes on the FKRT over the last 10,000 years. This will allow us to directly measure the impact of environmental variability on the history of Florida’s reefs.
Sources/Usage: Public Domain.Figure 3. Map of the Florida Keys Reef Tract (FKRT), which includes the Florida Keys National Marine Sanctuary (FKNMS; white boundary), Dry Tortugas National Park, and Biscayne National Park. The reef tract can be divided into 6 sectors based on geological and hydrographic variability (modified from Shinn et al. 1989). Points on the map indicate the sites that were previously cored by USGS researchers (yellow) and the new coring sites included in this study (red).(Public domain.) - Science
This research is part of the Coral Reef Ecosystem Studies (CREST) project. That project and other related tasks are listed below.
Coral Reef Ecosystem Studies (CREST)
The specific objectives of this project are to identify and describe the processes that are important in determining rates of coral-reef construction. How quickly the skeletons of calcifying organisms accumulate to form massive barrier-reef structure is determined by processes of both construction (how fast organisms grow and reproduce) and destruction (how fast reefs break down by mechanical...Reef History and Climate Change
Ecosystem-wide study of seafloor erosion, changing coastal water depths, and effects on coastal storm and wave impacts along the Florida Keys Coral Reef Tract in South Florida.Coral Reef Seafloor Erosion and Coastal Hazards
Synchronized field work focused on geochemistry, geology, and metabolic processes overlaid on a habitat map of an entire reef to produce a synoptic overview of reef processes that contribute to carbonate precipitation and dissolution.Measuring Coral Growth to Help Restore Reefs
It is critical to start measuring calcification rates in a systematic way now, particularly at subtropical latitudes where conditions fluctuate seasonally, so that we can understand how dynamic ocean conditions affect calcifying organisms today and predict possible changes in the future. We established a calcification monitoring network in the Florida Keys and have been measuring calcification... - Publications
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