Geology topics

Kira E. Barrera

Publications and source records attributed to Kira E. Barrera.

4 recordsLinked to original sources

USGS2017

Historical patterns of acidification and increasing CO2 flux associated with Florida springs

Florida has one of the highest concentrations of springs in the world, with many discharging into rivers and predominantly into eastern Gulf of Mexico coast, and they likely influence the hydrochemistry of these adjacent waters; however, temporal and spatial trends have not been well studied. We present over 20 yr of hydrochemical, seasonally sampled data to identify temporal and spatial trends of pH, alkalinity, partial pressure of carbon dioxide (pCO 2 ), and CO 2 flux from five first-order-magnitude (springs that discharge greater than 2.83 m 3 s −1 ) coastal spring groups fed by the Floridan Aquifer System that ultimately discharge into the Gulf of Mexico. All spring groups had pCO 2 levels (averages 3174.3–6773.2 μatm) that were much higher than atmospheric levels of CO 2 and demonstrated statistically significant temporal decreases in pH and increases in CO 2 flux, pCO 2 , and alkalinity. Total carbon flux emissions increased from each of the spring groups by between 3.48 × 10 7 and 2.856 × 10 8 kg C yr −1 over the time period. By 2013 the Springs Groups in total emitted more than 1.1739 × 10 9 kg C yr −1 . Increases in alkalinity and pCO 2 varied from 90.9 to 347.6 μmol kg −1 and 1262.3 to 2666.7 μatm, respectively. Coastal data show higher CO 2 evasion than the open Gulf of Mexico, which suggests spring water influences nearshore waters. The results of this study have important implications for spring water quality, dissolution of the Florida carbonate platform, and identification of the effect and partitioning of carbon fluxes to and within coastal and marine ecosystems.

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USGS2014

USGS field activities 11BHM01 and 11BHM02 on the west Florida shelf, Gulf of Mexico, May and June 2011

During May and June 2011 the (USGS), in cooperation with (USF), conducted geochemical surveys on the west Florida Shelf to investigate the effects of climate change on ocean acidification within the northern Gulf of Mexico, specifically, the effect of ocean acidification on marine organisms and habitats. The first cruise was conducted from May 3 to 9 (11BHM01) and the second was from June 25 to 30 (11BHM02). To view each cruise's survey lines, please see the Trackline page. Each cruise took place aboard the Research Vessel (R/V) Weatherbird II, a ship of opportunity led by Dr. Kendra Daly (USF), which departed from and returned to Saint Petersburg, Florida. Data collection included sampling of the surface and water column with lab analysis of pH, dissolved inorganic carbon (DIC) or total carbon dioxide (TCO 2 ), and total alkalinity (TA). lLb analysis was augmented with a continuous flow-through system (referred to as sonde data) with a conductivity-temperature-depth (CTD) sensor, which also recorded salinity and pH. Corroborating the USGS data are the vertical CTD profiles (referred to as station samples) collected by USF. The CTD casts measured continuous vertical profiles of oxygen, chlorophyll fluorescence and optical backscatter. Discrete samples for nutrients, chlorophyll, and particulate organic carbon/nitrogen were also collected during the CTD casts. Two autonomous flow-through (AFT) instruments recorded pH and CO2 every 3-5 minutes on each cruise (referred to as AFT data).

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USGS2014

USGS field activities 11BHM03 and 11BHM04 on the west Florida shelf, Gulf of Mexico, September and November 2011

During September and November 2011 the (USGS), in cooperation with (USF), conducted geochemical surveys on the west Florida Shelf to investigate the effects of climate change on ocean acidification within the northern Gulf of Mexico, specifically, the effect of ocean acidification on marine organisms and habitats. The first cruise was conducted from September 20 to 28 (11BHM03) and the second was from November 2 to 4 (11BHM04). To view each cruise's survey lines, please see the Trackline page. Each cruise took place aboard the Research Vessel (R/V) Weatherbird II, a ship of opportunity led by Dr. Kendra Daly (USF), which departed from and returned to Saint Petersburg, Florida. Data collection included sampling of the surface and water column with lab analysis of pH, dissolved inorganic carbon (DIC) or total carbon dioxide (TCO 2 ), and total alkalinity (TA). lLb analysis was augmented with a continuous flow-through system (referred to as sonde data) with a conductivity-temperature-depth (CTD) sensor, which also recorded salinity and pH. Corroborating the USGS data are the vertical CTD profiles (referred to as station samples) collected by USF. The CTD casts measured continuous vertical profiles of oxygen, chlorophyll fluorescence and optical backscatter. Discrete samples for nutrients, chlorophyll, and particulate organic carbon/nitrogen were also collected during the CTD casts. Two autonomous flow-through (AFT) instruments recorded pH and CO 2 every 3-5 minutes on each cruise (referred to as AFT data).

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USGS2014

USGS Field Activities 12BHM01, 12BHM02, 12BHM03, 12BHM04, and 12BHM05 on the West Florida Shelf, in February, April, May, June, and August 2012

Atmospheric carbon dioxide (CO 2 ) is absorbed by the ocean’s surface where it combines with seawater to form a weak, naturally occurring acid called carbonic acid (H 2 CO 3 ). Increasing carbon dioxide in the atmosphere results in the absorption of more CO 2 by the ocean and, therefore, increases in the acidity of seawater. This process, known as ocean acidification, has the potential to elicit change in ecosystems and organisms by disrupting biological processes. For example, ocean acidification is a problem for marine organisms such as corals, foraminifera, and algae that precipitate calcium carbonate to form their skeletons and shells (Kleypas and others, 2006). The effects are related to corresponding changes in the carbonate saturation state (Ω), where Ω is the ratio of the ion concentration product (Ca 2+ x CO 3 2- ) to the stoichiometric aragonite solubility product (K*sp) (Langdon and Atkinson, 2005). Because pH and CO 3 2- are strongly interdependent through the inorganic carbon system, the decrease in pH will cause a proportionally greater decrease in CO 3 2- . Globally, ocean acidification is occurring faster than at any time in the last 300 million years (Broeker and others, 1979). Recent evidence indicates that individual oceans are responding at different rates, depending on physical and biological processes. For example in the Arctic Ocean, the rate of saturation state decrease was 2.1 percent per year between 1997 and 2010 (Robbins and others., 2013) in an area as large as Montana, largely because of increases in melt of ice, versus the average rate observed for the Pacific Ocean (0.36 percent per year) (Feely and others, 2012). Unfortunately, comparative data sets over multiyear time frames are often not available because time series baseline carbon information has not been collected in many oceans. Data are needed in subtropical latitudes where carbonate saturation states are already naturally low and fluctuate seasonally. These data will help construct a baseline for the assessment of future changes. As part of the U.S. Geological Survey (USGS) Coastal and Marine Geology Program project "R esponse of Florida Shelf Ecosystems to Climate Change " and in partnership with Kendra Daly, University of South Florida ( USF ), data on surface ocean carbonate chemistry were collected on five cruises along transects on the shallow inner west Florida shelf and northern Gulf of Mexico in 2012. Data from the 2011 cruises were also published (Robbins and others., 2013). The data collected allows the USGS, National Oceanic and Atmospheric Administration ( NOAA ), and USF scientists to map variations in ocean chemistry including carbonate saturation states along designated tracks. The USGS also partners with NOAA and the National Aeronautics and Space Administration ( NASA ) to model air-sea flux as part of a Gulf of Mexico Carbon Synthesis project led by NASA.

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