Production and respiration of Antarctic ascidians

Role of suspension feeders in antarctic pelagic-benthic coupling: Trophic ecology and potential carbon sinks under climate change

“…In our energy budget, we were unable to directly measure filtration and respiration rates, and values were therefore computed from FPR and taken from the literature, respectively. Respiration were constrained to rates calculated for a seston diet (Kowalke et al 2001) or sediment concentrations similar to those used in this study (Torre et al 2012), but these rates were referred to body weight excluding the tunic. The tunic organic content certainly represents a significant part of the ascidian biomass (49.54±3.49 % in our study) and while our C sink potential would be underestimated, growth of body parts is much faster than the tunic growth (Petersen et al 1995).…”

“…Suspension feeders not only enhance PBC in shallow waters (Ahn 1993, but also develop complex three-dimensional biogenic structures particularly on soft bottoms (Tatián et al 1998, Gili et al 2006), where epibiosis is a common phenomenon especially over solitary ascidians (Rimondino et al 2015). In new ice-free areas of the WAP ascidians reach the higher abundances (Lagger et al 2017(Lagger et al , 2018, which could increase retention of a greater share of the productivity in their living structures for decades (Kowalke et al 2001). Nevertheless, these organisms of apparently great C sink potential in shallow waters (Petersen andRiisgård 1992, Coppari et al 2014) are generally neglected in the overall equation of C circulation in our changing world (Rossi et al 2015).…”

“…) is correct on the only assumption that inorganic matter is a conservative tracer in the gut (no absorption of inorganics would occur). The oxygen consumption of C. verrucosa wasobtained from published values for standard conditions(Kowalke et al 2001) and after sediment exposure to increased sediment loads(Torre et al 2012). All data were standardised to 1 g dry tissue weight.…”

Ascidians collected during the Spanish Antarctic expedition CIEMAR 99/00 in the Bransfield and Gerlache Straits

“…Among the most recent publications we may highlight those by Tatián et al (2005), Ramos-Esplá et al (2005) and Arntz et al (2006). However, the Antarctic Region has been unequally studied, the best sampled areas being the Antarctic Peninsula and the South Shetland Islands, with 75 species described so far (Primo 2006), and especially Potter Cove (Sahade et al 1998;Kowalke 1999;Kowalke et al 2001;Tatián et al 1988aTatián et al , 1998bTatián et al , 2002. During the Spanish CIEMAR 99/00 expedition on-board RV Hespérides, the macrobenthos was sampled from the Bransfield and Gerlache Straits.…”