Data Series 711
1U.S. Geological Survey, St. Petersburg, FL 33701.
2University of South Florida, College of Marine Science, St. Petersburg, FL 33701
3Jacobs Technology, St. Petersburg, FL, 33701
U.S. Department of the
U.S. Geological Survey
St. Petersburg Coastal and Marine Science Center
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During January and February 2011 the U.S. Geological Survey (USGS), in cooperation with the University of South Florida (USF), conducted geochemical surveys on the west Florida Shelf. Data collected will allow USGS and USF scientists 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. This work is part of a larger USGS study on Climate and Environmental Variability (CEV). The first cruise was conducted from January 3 – 7 (11CEV01) and the second from February 17 - 27 (11CEV02). To view each cruise's survey lines, please see the Trackline page. Both cruises took place aboard the R/V Weatherbird II, a ship of opportunity led by Dr. Kendra Daly (USF), which departed and returned from Saint Petersburg, Florida.
Data collection included sampling of the surface and water column (referred to as station samples) with lab analysis of pH, dissolved inorganic carbon (DIC), and total alkalinity. Augmenting the lab analysis was a continuous flow-through system with a Conductivity-Temperature-Depth (CTD) sensor, which also recorded salinity, and pH. Corroborating the USGS data are the vertical CTD profiles collected by USF. The CTD casts measured continuous vertical profiles of oxygen, chlorophyll fluorescence, optical backscatter, and transmissometer. Discrete samples for nutrients, chlorophyll, and particulate organic carbon/nitrogen were also collected during the CTD casts.
As humans continue to burn fossil fuels, the partial pressure of carbon dioxide (pCO2) increases in the atmosphere and a large portion of this anthropogenic CO2 is absorbed by the oceans (Broecker et al., 1979; Sabine et al., 2002). As CO2 is absorbed by surface waters, it forms carbonic acid, which then titrates carbonate ions (CO32-) to reestablish chemical equilibrium. As a consequence, the chemistry of the ocean is changing, a phenomenon now commonly referred to as “ocean acidification.” This is a problem for marine organisms that precipitate calcium carbonate to form their skeletons, tests, and shells (Kleypas et al., 1999). For example, the effects of ocean acidification on corals, which produce aragonite, are not related to changes in pH per se but are instead related to corresponding changes in aragonite saturation state (Ωa) where Ωa is the ratio of the ion concentration product (Ca2+ x CO32-) to the stoichiometric aragonite solubility product (K*sp) (Langdon and Atkinson, 2005). Since pH and CO32- are strongly interdependent through the inorganic carbon system, the decrease in pH will cause a proportionally much greater decrease in CO32-. Experimental work has demonstrated decreases in calcification rates of corals, coralline algae, foraminifera, and other calcifying organisms in waters that are still supersaturated with respect to calcium carbonate minerals (Langdon and Atkinson, 2005; Orr et al., 2005). New research has recently confirmed that carbonate mineral saturation state has measurably decreased over the past two decades in the North Atlantic gyre (Bates, 2007). If the experimental data are directly applicable to the field, measurable decreases in calcification rates of important reef-building organisms should already be visible. It is critical to start measuring carbonate saturation state and calcification rates in a systematic way now, including subtropical latitudes where carbonate saturation states are already naturally low and fluctuate seasonally, in order to construct a baseline for the assessment of future changes.
As part of the USGS Climate Change project “Monitoring and modeling of Florida Shelf carbonate saturation state and calcification rates: setting a baseline for response of ocean acidification on marine habitats” and Coastal and Marine Geology Program project "Response of Florida Shelf Ecosystems to Climate Change" (PI: Dr. Lisa Robbins), data on surface ocean carbonate chemistry were collected along transects on the shallow inner west Florida shelf. The data collected will allow USGS, NOAA, and USF to map variations in ocean chemistry including carbonate saturation states along designated tracks. The USGS is also partnering with NOAA and NASA for the modeling of saturation state data.
This report is divided into seven sections: Acronyms and Abbreviations, Disc Contents, Methods, Data, Federal Geographic Data Committee (FGDC) Metadata, and Trackline. Links at the top and bottom of each page provide access to these sections. This report contains links to the USGS, collaborators, and other available resources if access to the Internet is available while viewing these documents. Geographic Information System (GIS) files, HyperText Markup Language (HTML) files, and images used to produce the Web pages are also included in this report. The Disc Contents page contains a listing with locations and links to all files and folders contained on this disc.
To access the information contained on this disc, use a Web browser to open the file index.html.
We would like to acknowledge Stephan Meylan and Matthew Gove for their contributions in preparing this Data Series for publication.
Bates, N.R., 2007, Interannual variability of the oceanic CO2 sink in the subtropical gyre of the North Atlantic Ocean over the last 2 decades: Journal of Geophysical Research, 112.
Broecker, W.S., Takahashi, T., Simpson, H.J., and Peng, T.H., 1979, Fate of fossil fuel carbon dioxide and the global carbon budget: Science, v. 206, no. 4417, p. 409-418.
Dickson, A.G., Sabine, C.L., and Christian, J.R., eds., 2007, Guide to best practices for ocean CO2 measurements. PICES Special Publication 3, 191 p., available online at http://cdiac.ornl.gov/oceans/Handbook_2007.html.
Langdon, C., and Atkinson, M.J., 2005, Effect of elevated pCO2 on photosynthesis and calcification of corals and interactions with seasonal change in temperature/irradiance and nutrient enrichment: Journal of Geophysical Research, v. 110, 16 p.
Orr, J.C., and 25 others, 2005, Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms: Nature, v. 437, p. 681-686.
Sabine, C.L. Feely, R.A., Key, R.M., Bullister, J.L., Millero, F.J., Lee, K., Peng, T.-H., Tilbrook, B., Ono, T., and Wong, C.S., 2002, Distribution of anthropogenic CO2 in the Pacific Ocean: Biogeochemical Cycles, v. 16, no. 4, p. 1083.
Yao, W., and Byrne, R.H., 1998, Simplified seawater alkalinity analysis: Use of linear array spectrometers: Deep-Sea Research Part I, v. 45, no. 8, p. 1383-1392.
Zhang, H., and Byrne, R.H., 1996, Spectrophotometric pH measurements of surface seawater at in-situ conditions: absorbance and protonation behavior of thymol blue: Marine Chemistry, v. 52, no. 1, p. 17-25.
Robbins, L.L., Knorr, P.O., Daly, K.L., Taylor, C.A., 2014, USGS Field Activities 11CEV01 and 11CEV02 on the West Florida Shelf, Gulf of Mexico, in January and February 2011: U.S. Geological Survey Data Series 711, 6 p., https://dx.doi.org/10.3133/ds711.
ISSN 2333–0481 (DVD)
ISSN 2327–638X (online)