The biodiversity of mud volcanoes in the Gulf of Cadiz could be over 1000 species after the latest expedition
Nine scientists from the Spanish Institute of Oceanography (IEO), in cooperation with the Naval Hydrographic Institute, spent two weeks on board the oceanographic vessel Ramón Margalef to gather as much scientific information as possible on the nature of the seabed in the Gulf of Cadiz and its biodiversity.
The recently concluded scientific study involved direct observation with robot submarines to determine the conservation status of the most vulnerable ecosystems in the Gulf of Cadiz, and related to eruptions of fluidized sediments containing methane gas.
Habitat 1180 in the Natura 2000 network, “Structures related to gas seepage”, is particularly interesting from the standpoint of science and nature conservation because it facilitates the formation of rocky substrates based on bacterial activity involved in the transformation of methane into compact layers. This fosters great diversity in types of habitats and associated species that considerably enriches the seabed in the Gulf of Cádiz.
The scientists worked with a modern Super Mohawk II remote observation vehicle (ROV) known as Liropus 2000. They also used a prototype towed observation vehicle called Aphia 2012, developed at the IEO’s Centro Oceanográfico de Málaga by the marine geoscience group, which can be used to obtain very-high-definition digital images simultaneously in video and photographic formats. The latest generation technology available on board the ship consists of very-high-resolution acoustic and seismic sounders to study different types of marine habitats using non-intrusive methods that do not disrupt the environment.
An immense volume of data was collected during the expedition: 16 hours of video recordings with the LIROPUS 2000 ROV; 21 hours of HD video recordings with the APHIA 2012 towed underwater vehicle; 36 box corer stations that provided 80 subsamples of fauna and microbiology, and 150 for sediments; and 1000 kilometers of bathymetric surveys with multibeam and TOPAS equipment.
The expedition revealed the presence of a large number of gas seeps, more than ever recorded up to now. A sharp increase was also observed in the number of species found, which could be as high as a thousand, some of very great natural value and never before mentioned in the area.
The use of robot submarines made it possible to obtain images of underwater life and of bacterial activity linked to gas emissions with unprecedented precision. This detailed information will provide a meticulous estimate of the natural values of interest to Natura 2000.
This is an initiative backed by the Spanish Institute of Oceanography (IEO) and is part of the LIFE+ INDEMARES project fostered by the European Commission. The purpose of the project is to gain excellent scientific knowledge that will facilitate the sustainable management of biodiversity in Spanish marine waters, using the criteria established by Natura 2000 as a benchmark.
Luis Miguel Fernández headed the scientific expedition and Víctor Díaz del Río is the project leader. Both are senior researchers in the GEMAR group in the IEO’s Centro Oceanográfico de Málaga.