Biogeochemical data

An example of data delivered from Southern Surveyor in near real time and available via the web. The cruise track is superimposed on an SST image and shows that the Southern Surveyor travelled down the east coast of Tasmania. The XCO2 value is bottom right and is the preliminary CO2 value before the final quality control procedures are applied. The blue dots in the panel near 381 microatmospheres are atmospheric CO2, with higher values (390) indicating possible contamination from air passing near Melbourne or from ship stack gas. The surface waters are between about 341 to 355 microatmospheres (micromol/mol) and show the region is a sink for atmospheric CO2. These data are transmitted every 6 hours and are available in near real time. Most of the quality control is performed following the cruise and the fully processed data are being made available in delayed mode through eMII.

The above figure shows the spatial distributions of both pCO2 and salinity throughout the Great Barrier Reef (GBR). These data were collected on the SS09 voyage of RV Southern Surveyor from July 24 to August 11 2008. A major aim of the voyage was to characterise the carbonate chemistry through the reef region and compare this to the carbonate chemistry of the offshore source waters in the Coral Sea. Inshore-offshore sections and stations along the length of the GBR lagoon and offshore were used to characterise gradients in carbonate chemistry. This is the first detailed data on CO2 chemistry collected through the reef region and these data will be used to assess changes in carbonate chemistry through the region. In particular the work is helping determine the vulnerability of the reef to acidification. The atmosphere is currently about 284 ppm and the whole region was shown to be a sink for CO2.  Elevated pCO2 occurs over the reef in response to a mix of calcification and production. The highest pCO2 values occur nearshore in low salinity waters indicating a signal associated with nearshore river inputs. This is providing much needed data on the CO2 system through the GBR and is required if we are to assess the risk of the GBR to acidification.

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