Underway measurements of dissolved gases along POLARSTERN cruise track ANT-XXVII/2


Autoria(s): Bittig, Henry; Körtzinger, Arne
Cobertura

MEDIAN LATITUDE: -61.712460 * MEDIAN LONGITUDE: -32.894457 * SOUTH-BOUND LATITUDE: -71.124200 * WEST-BOUND LONGITUDE: -75.334400 * NORTH-BOUND LATITUDE: -33.857600 * EAST-BOUND LONGITUDE: 18.438700 * DATE/TIME START: 2010-11-28T08:00:40 * DATE/TIME END: 2011-02-03T07:59:40 * MINIMUM DEPTH, water: 11 m * MAXIMUM DEPTH, water: 11 m

Data(s)

07/08/2015

Resumo

We present measurements of pCO2, O2 concentration, biological oxygen saturation (Delta O2/Ar) and N2 saturation (Delta N2) in Southern Ocean surface waters during austral summer, 2010-2011. Phytoplankton biomass varied strongly across distinct hydrographic zones, with high chlorophyll a (Chla) concentrations in regions of frontal mixing and sea-ice melt. pCO2 and Delta O2 /Ar exhibited large spatial gradients (range 90 to 450 µatm and -10 to 60%, respectively) and co-varied strongly with Chla. However, the ratio of biological O2 accumulation to dissolved inorganic carbon (DIC) drawdown was significantly lower than expected from photosynthetic stoichiometry, reflecting the differential time-scales of O2 and CO2 air-sea equilibration. We measured significant oceanic CO2 uptake, with a mean air-sea flux (~ -20 mmol m-2 d-1) that significantly exceeded regional climatological values. N2 was mostly supersaturated in surface waters (mean Delta N2 of +2.5 %), while physical processes resulted in both supersaturation and undersaturation of mixed layer O2 (mean Delta O2phys = 2.1 %). Box model calculations were able to reproduce much of the spatial variability of Delta N2 and Delta O2phys along the cruise track, demonstrating significant effects of air-sea exchange processes (e.g. atmospheric pressure changes and bubble injection) and mixed layer entrainment on surface gas disequilibria. Net community production (NCP) derived from entrainment-corrected surface Delta O2 /Ar data, ranged from ~ -40 to > 300 mmol O2 m-2 d-1 and showed good coherence with independent NCP estimates based on seasonal mixed layer DIC deficits. Elevated NCP was observed in hydrographic frontal zones and regions of sea-ice melt with shallow mixed layer depths, reflecting the importance of mixing in controlling surface water light and nutrient availability.

Formato

text/tab-separated-values, 796315 data points

Identificador

https://doi.pangaea.de/10.1594/PANGAEA.848615

doi:10.1594/PANGAEA.848615

Idioma(s)

en

Publicador

PANGAEA

Direitos

CC-BY: Creative Commons Attribution 3.0 Unported

Access constraints: unrestricted

Fonte

Supplement to: Tortell, Philippe Daniel; Bittig, Henry; Körtzinger, Arne; Jones, E M; Hoppema, Mario (2015): Biological and physical controls on N2, O2, and CO2 distributions in contrasting Southern Ocean surface waters. Global Biogeochemical Cycles, 29(7), 994-1013, doi:10.1002/2014GB004975

Palavras-Chave #ANT-XXVII/2; CT; DATE/TIME; DEPTH, water; derived; Gas Tension Device; LATITUDE; LONGITUDE; Nitrogen, partial pressure; Nitrogen, total dissolved; Nitrogen saturation; OCEANET; Oxygen; Oxygen, partial pressure; Oxygen optode, Aanderaa, type 3830; Oxygen saturation; Polarstern; Pressure, atmospheric; Pressure, total, dissolved gases; PS77; PS77/2-track; Salinity; Ships weather station; South Atlantic Ocean; Temperature, water; Thermosalinograph; Underway cruise track measurements
Tipo

Dataset