Shallow water hydrothermal vent field fluids and communities of the D. João de Castro Seamount (Azores)

Comparison of the community structure of the marine molluscs of the “Banco D. João de Castro” seamount (Azores, Portugal) with that of typical inshore habitats on the Azores archipelago

“…No specialized hydrothermal molluscs were found at DJC or RQT, similarly to what was reported from other locations with shallow-water vents (Tarasov et al 1986(Tarasov et al , 1990(Tarasov et al , 1999Kamenev et al 1993;Dando et al 1995). Nevertheless, physiological and ecotoxicological tests are needed to study the tolerance to the toxic compounds that are released by these vents, such as Cu, Pb, Ba, Fe, Mn, Co, and Cd (Cardigos et al 2005).…”

“…At shallow-water hydrothermal vents, bacteria constitute a more important food source than at typical coastal ecosystems (Tarasov and Zhirmunskaya 1989;Kharlamenko et al 1995). Rock samples collected from around the vent outlets at DJC were partially covered with bacterial mats, mainly an attached form of Beggiatoa (Cardigos et al 2005).…”

“…Recently, a second area with hydrothermal activity was discovered, in the depth range of 150 to more than 400 m, southeast of the shallowest part of the seamount (Pascoal et al 2000). For a discussion on the chemical characterization of the Xuids released by the vents at D. João de Castro Bank, see Cardigos et al (2005). The molluscan fauna at D. João de Castro Bank is still poorly known and has mainly been studied from a taxonomical point of view (Ávila 1997; Ávila et al 2004).…”

“…The gas is released within a small area (100 £ 50 m) at the bottom (16-45 m depth) in the western part of the volcanic cone. This gas, mainly CO 2 (90%) with lesser H 2 S, H 2 , and CH 4 (Cardigos et al 2005), has its source in a magmatic chamber located between 1 and 5 km under the seaXoor (Machado and Lemos 1998). Recently, a second area with hydrothermal activity was discovered, in the depth range of 150 to more than 400 m, southeast of the shallowest part of the seamount (Pascoal et al 2000).…”

Intertidal rocky shore seaweed communities subject to the influence of shallow water hydrothermal activity in São Miguel (Azores, Portugal)

“…There have been studies on the effects of shallow water hydrothermal activity on subtidal marine organisms in the Mediterranean (e.g., Dando et al 1991;Sartoni and De Biasi 1999;De Biasi and Aliani 2003;De Biasi et al 2004) and in the Azores (Cardigos et al 2005;Colaço et al 2006). Intertidal organisms affected by such conditions were first addressed by Wallenstein et al (2009) reporting increased accumulation of some heavy metals in seaweeds collected in the vicinity of hydrothermal venting near the shore, and by Couto et al (2010) who reported effects on the structure of calcareous coralline algae due to hydrothermal conditions.…”