Sediment biogeochemistry and variability of CH4 in mud volcanoes of the Gulf of Cádiz

  1. D. Jiménez-López 1
  2. A. Sierra 1
  3. S. Manzano 1
  4. J.A. Sanabria 1
  5. T. Ortega 1
  6. V. Amaral 13
  7. M.C. Fernández-Puga 2
  8. N. López-González 4
  9. J.T. Vázquez 4
  10. R. Ponce 1
  11. A. Gómez-Parra 1
  12. J. Forja 1
  1. 1 Dpto. Química-Física, INMAR, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, Campus Universitario Río San Pedro, 11510 - Puerto Real, Cádiz, Andalucía, España.
  2. 2 Dpto. Geología, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, Campus Universitario Río San Pedro, 11510 - Puerto Real, Cádiz, Andalucía, España.
  3. 3 Ecología Funcional de Sistemas Acuáticos, Centro Universitario Regional Este, Universidad de la Republica, Rocha, Uruguay.
  4. 4 Instituto Español de Oceanografía, Centro Oceanográfico de Málaga, Puerto Pesquero s/n, 29640, Fuengirola, Málaga, Andalucía, España.
Mostrar afiliaciones +
Actas:
XIX Seminario Ibérico de Química Marina. COMUNICACION ORAL

Editorial: Universidad de Vigo

ISBN: 978-84-8158-790-6

Año de publicación: 2018

Páginas: 35-36

Tipo: Aportación congreso

GOOGLE SCHOLAR

Resumen

Samplings of sediment cores were realised with a gravity core in three mud volcanoes (Anastasya, Pipoca and San Petersburgo) of the Gulf of Cadiz, during two cruises in June and December 2016 on board the R/V’s Angeles Alvariño and Ramon Margalef. In the sediment has been determined the vertical variation of porosity and content of C, N, S and CH4 and, on the other hand, in the pore water, CID, COD, nutrients and majority elements concentrations have been defined to different depths. The observed variations in the vertical profiles of the species analysed in the sediment and pore water have been associated with the own existence of diagenetic processes of the organic matter (Emerson et al., 1980, Moreland Hering, 1993). In turn, diffusive fluxes were determined in the surface area of the sediments, although changes in the concentration gradients at intermediate depths have been observed, which suggest variations in the transport mechanisms of the volcanic flow and/or the irrigation of the benthic macrofauna associated to the mud volcanoes (e.g. Mau et al., 2006). The CH4 concentrations analysed in the sediment for Anastasya (0.5 - 115.3 µM) and San Petersburgo (0.03 - 126.1 µM) were much higher than for Pipoca (0.03 - 0.8 nM), what it could be associated with a certain volcanic activity in these volcanoes. In addition, the CH4 concentration in the water column above the volcanoes has studied also; it showed a behaviour practically constant, except for Anastasya with concentrations of 120 nM in the bottom water. Finally, it has estimated that this area acts as a source of CH4 to the atmosphere, with fluxes contain between 15.2 and 33.8 μmol m⁻2 d⁻1, similar to other zones affected by submarine volcanism (Jayakumar et al., 2001; Amouroux et al., 2002).