Primary productivity, pulse amplitude modulated fluorometry and nutrient drawdown data from the marginal ice zone: BROKE-WEST survey 30o-80oE, 2006

• Other Authors: Australian Antarctic Division (isOwnedBy)
• Format: Dataset
• Language: unknown
• Published: data.gov.au
• Subjects: AMD; CEOS; NISKIN BOTTLES; SCINTILLATION COUNTERS; SHIPS; iron limitation; marginal ice zone; vertical mixing; Austral; Indian; Southern Ocean
• Online Access: https://researchdata.edu.au/primary-productivity-pulse-80oe-2006/1935678; http://data.gov.au/dataset/faec11ea-0505-41ed-9652-8278070bffbb

This data set contains primary productivity, pulse amplitude modulated fluorometry, and nutrient drawdown numbers associated with the abstract presented below.\n\n14C Primary Productivity\nGross column-integrated primary productivity determined through measurement of NaH14CO3 uptake by phytoplankton (1 hour incubations). Primary productivity was modelled from photosynthesis v irradiance curves, chlorophyll profiles, photosynthetically active radiation, and vertical light attenuation. Data for these parameters are also shown.\n\nNutrient Draw-down Data\nSeasonal depletion of oxidised inorganic nitrogen and silicate in the mixed layer, and production of oxygen. Data was calculated by the subtraction of mixed layer concentrations (uM) from values below the mixed layer. \n\nPulse Amplitude Modulated Fluorometry Data\nFv/Fm values determined using pulse amplitude modulated fluorometry (PAM). Samples were dark-adapted prior to measurement so that non-photochemical quenching was relaxed. Values provide an indication of cell health.\n\n\nAbstract\nPrimary productivity was measured in the Indian Sector of the Southern Ocean (30 degrees to 80 degrees E) as part of a multi-disciplinary study during austral summer; Baseline Research on Oceanography, Krill and the Environment, West (BROKE-West Survey, 2006). Gross integrated (0-150 m) productivity rates within the marginal ice zone (MIZ) were significantly higher than within the open ocean, with averages of 2110.2 plus or minus 1347.1 and 595.0 plus or minus 283.0 mg C m-2 d-1, respectively. In the MIZ, high productivity was associated with shallow mixed layer depths and increased Pmax up to 5.158 mg C (mg chl a)-1 h-1. High Si:N drawdown ratios in the open ocean (4.1 plus or minus 1.5) compared to the MIZ (2.2 plus or minus 0.79) also suggested that iron limitation was important for the control of productivity. This was supported by higher Fv/Fm ratios in the MIZ (0.50 plus or minus 0.11 above 40 m) compared to the open ocean (0.36 plus or minus 0.08). As well, in the open ...