RRS James Cook Cruise 62, 24 Jul-29 Aug 2011. Porcupine Abyssal Plain – sustained observatory research

Science rationale for the activities comes from the fact that during the EU Framework programme IV project BENGAL (1996 to 1999) radical changes were noted in fauna living on the abyssal seafloor (Progress in Oceanography, Billett 2001). The changes appeared to be related to changes in upper ocean productivity and the flux of organic matter to the abyss (Wigham et al., 2003). Various hypotheses have been created concerning the effect of total organic carbon input, shown by Lampitt et al (2010) to vary by an order of magnitude between years, the quality (organic geochemistry) of the organic material, and the timing (episodic or regular) of the inputs of organic matter. Large-scale changes in the abundance of the large epibenthic invertebrates by greater than two orders of magnitude, are now known to be mirrored by similar changes, but of a lower magnitude, in the protozoan meiofauna (c. 50 to 250 um in size) (Gooday et al. 2010), metazoan meiofauna (notably nematode and polychaete worms) (Kalogeropoulou et al. 2010) and macrofauna (250 to 1000 um in size) (Soto et al. 2010). The results have been brought together in a Special Volume in Deep-Sea Research II (Lampitt, Billett, and Martin 2010). The work below will help detail how deepsea ecosystems change naturally with time and space and in response to climate-change phenomena. It will be useful in predicting how deep-sea ecosystems will change under various climate change scenarios. In addition, coupled with other time series studies in the NE Pacific (e.g. Smith et al. 2009) and sampling around the Crozet Islands (Wolff et al. 2011), it will indicate how deep-sea ecosystems might change in relation to potential geo-engineering solutions for carbon sequestration by the oceans.