Publication Date:
2017-12-19
Description:
During RV Poseidon cruise POS469 (May 2014), the distribution of pCO2 in the
near field of submarine volcanic gas flares in shallow water depths down to 50 m
below sea level was continuously monitored using three different and independent
methodologies. In situ nondispersive infrared (NDIR) spectrometry, pH measurements,
and onboard membrane inlet mass spectrometry (MIMS) were used to determine
the fate of rising CO2 bubbles and the dissolved CO2 plume patterns in a 300 ×
400-m working area. The in situ sensor carrier platform, a towed video-controlled
water sampling rosette, equipped with CTD sensors, guaranteed excellent ground
truthing of seafloor characteristics and bubble discharge. Sensor data and nearseafloor
observations indicated that the gas bubbles (〈9 mm in diameter, 〉97 vol.%
of CO2) dissolved very rapidly within the first 10 m above seafloor. Bottom water
masses enriched with pCO2 (up to 1,100 μatm) show low pH values (up to 7.80) and
tend to spread rather downslope west than following the measured weak current in
SSE-SSW direction. The 3-D evaluation of pCO2 plume is a valuable tool to backtrace
the origin of CO2 leakage when compared with local current regimes, water
column CTD data, and seafloor bathymetry. Seep sites offshore Panarea can be
used for studying CO2 leakage behavior and testing measuring strategies in shallow
waters. Moreover, this area is a naturally designed laboratory to improve existing
physicochemical and oceanographic transport models for subsea CO2 leakage.
Type:
Article
,
PeerReviewed
,
info:eu-repo/semantics/article
Format:
text
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