RT journal article
T1 Methane dynamics in the coastal–Continental shelf transition zone of the Gulf of Cadiz
A1 Sierra Padilla, Ana
A1 Jiménez López, María Dolores
A1 Ortega Díaz, Teodora
A1 Fernández Puga, María del Carmen
A1 Delgado Huertas, Antonio
A1 Forja Pajares, Jesús
A2 Biología
A2 Ciencias de la Tierra
A2 Química Física
K1 Methane
K1 Stable carbon isotope
K1 Sea - atmosphere exchange
K1 Coastal zone
K1 Mud volcanoes
K1 Gulf of Cadiz
AB The concentration of CH4 in water was measured along five transects in the Gulf of Cadiz (Trafalgar, Sancti Petri, Guadalquivir, Tinto - Odiel and Guadiana) during four cruises throughout the months of March, June, September and December 2016. For two of the cruises water overlying three mud volcanoes situated in the Gulf of Cadiz were also sampled (San Petersburgo, 860 m; Pipoca, 460 m; and Anastasya, 500 m. In addition, the stable carbon isotopic compositions of dissolved CH4 (δ13C) were measured in the study area in June and December 2016. The mean CH4 value for the whole water column was 10.5 ± 4.3 nmol L−1, with large spatial and temporal variations. The highest values were found in June 2016 and the lowest in March 2016. In surface waters, the mean dissolved methane concentration was of 9.6 ± 2.6 nmol L−1. In most of the sampling area, high concentrations of CH4 were found in subsurface waters at depths close to the thermocline and at the coastal stations. The highest concentrations were obtained from the bottom waters above the Anastasya mud volcano (125 nmol L−1). The stable carbon isotope compositions ranged between - 29.2 and - 58.4‰, and the least negative values were associated with the highest CH4 concentrations in samples from above the mud volcanoes, related to thermogenic values. The sea-air fluxes of CH4 ranged from 12.4 to 37.7 μmol m−2 d−1, showing that the study area acts as a source of CH4 to the atmosphere.
PB Academic Press LTD - Elsevier Science LTD
SN 0272-7714
YR 2020
FD 2020-05-05
LK http://hdl.handle.net/10498/30506
UL http://hdl.handle.net/10498/30506
LA eng
DS Repositorio Institucional de la Universidad de Cádiz
RD 07-nov-2026