AIMS eReefs
Dissolved oxygen & oxygen saturation percentage (GBR4 BGC v3.1 baseline)
Note: The near-real time GBR1 and GBR4 models (including hydro, river tracer and BGC) are currently paused at December 17th 2023 due to infrastructure damage from the recent flooding events around the Daintree River region (see here). These floods have damaged the real-time river temperature and flow sensors across surrounding catchments, and Queensland government is working to recover and restore these as quickly as possible. We will provide further updates when available.
Dissolved Oxygen
Concentration of oxygen.
Dissolved oxygen plays a pivotal role, driving multiple biogeochemical processes and influencing the balance of other elements like carbon, nitrogen, and phosphorus. The BGC model cycles carbon, nitrogen, phosphorous and oxygen through multiple phytoplankton, zooplankton, detritus and dissolved organic and inorganic forms in the water column and sediment layers.
The production (by photosynthesis) and consumption (by respiration and remineralisation) of dissolved oxygen is included in the model and, depending on prevailing concentrations, facilitates or inhibits the oxidation of ammonium to nitrate and its subsequent denitrification to dinitrogen gas which is then lost from the system.
More detail on how oxygen levels were modelled can be found in Baird et al. (2020).
Oxygen saturation percentage
The saturation state of oxygen [O2]sat is determined as a function of temperature and salinity following Weiss (1970). It represents the maximum amount of the dissolved oxygen that the water can hold. It is used to calculate the amount of oxygen exchange in the sea-air boundary. If the oxygen saturation percentage is below 100% then oxygen will be absorbed from the atmosphere. If it is above 100% then oxygen will be out gased from the sea into the atmosphere.
Reference
Baird, M. E., Wild-Allen, K. A., Parslow, J., Mongin, M., Robson, B., Skerratt, J., Rizwi, F., Soja-Woźniak, M., Jones, E., Herzfeld, M., Margvelashvili, N., Andrewartha, J., Langlais, C., Adams, M. P., Cherukuru, N., Gustafsson, M., Hadley, S., Ralph, P. J., Rosebrock, U., … Steven, A. D. L. (2020). CSIRO Environmental Modelling Suite (EMS): scientific description of the optical and biogeochemical models (vB3p0). Geoscientific Model Development, 13(9), 4503–4553. https://doi.org/10.5194/gmd-13-4503-2020
Weiss, R.: The solubility of nitrogen, oxygen and argon in water and seawater, Deep Sea Res., 17, 721–735, 1970.