Feast and famine in Antarctica: seasonal physiology in the limpet Nacella concinna

Abstract

) in winter. Urea and primary amine excretion combined accounted for between 10 and 38% of total nitrogen excretion. O:N ratios ranged between 7 and 20 and demonstrated that although protein was the dominant respiratory substrate throughout the year, in late summer and early winter lipids and carbohydrates were also utilised for metabolism. N. concinna has a low degree of metabolic seasonality due to the maintenance of high winter metabolic rates. Although feeding during winter provides some energy, it is insufficient to offset the substantial utilisation of tissue energy stores to balance the metabolic budget. KEY WORDS: Limpet · O:N ratio · Nitrogen excretion · Oxygen consumption · Seasonal metabolismResale or republication not permitted without written consent of the publisher

Triggers of the HSP70 stress response: environmental responses and laboratory manipulation in an Antarctic marine invertebrate (Nacella concinna)

“…The Antarctic environment is highly seasonal with regard to food supply (Clarke 1988) with phytoplankton blooms occurring for brief periods in the water column in summer (Clarke and Leakey 1996). Whilst N. concinna feeds all year round, exhibiting a low degree of metabolic seasonality (Fraser et al 2002a), protein synthesis (and by extrapolation, gene expression) is reduced in winter (Fraser et al 2002b). There are also additional potential requirements, such as mucus production to guard against the effects of the cold (Hargens and Shabica 1973).…”

Extreme Phenotypic Plasticity in Metabolic Physiology of Antarctic Demosponges

“…Morphological plasticity is common in demosponges, as they have a leuconoid cell structure, which is believed to permit great diversity of shape, allowing plastic morphological responses FIGURE 6 | Factorial seasonal changes in oxygen consumption, modified from Obermüller et al (2010). Filled circles are polar herbivores: Nacella concinna (Fraser et al, 2002a), Laternula elliptica (Brockington and Peck, 2001), Adamussium colbecki (Heilmayer and Brey, 2003), Liothyrella uva (Peck et al, 1987(Peck et al, , 1997 Camptoplites bicornis, Isoseculiflustra tenuis, Kymella polaris (Barnes and Peck, 2005), Sterchinus neumayeri -1997 and 1998 (Brockington and Peck, 2001). Open diamonds are polar carnivores and scavengers: Orchomene plebs (m, male; f, female) (Rakusa-Suszczewski, 1982), Gammarus setosus (Weslawski and Opalinski, 1997), Glyptonotus antarcticus (Rakusa-Suszczewski, 1982), Notothenia coriiceps (Campbell et al, 2008), Harpagifer antarcticus, Parborlasia corregatus, Paracerodocus miersii, Ophionotus victoriae, and Doris Kerguelensis (Obermüller et al, 2010).…”

Growth in the slow lane: protein metabolism in the Antarctic limpetNacella concinna(Strebel 1908)

“…Stable (winter, Fig.·1B; -1.5 to 6.0°C temperature range) or linearly decreasing (summer, Fig.·1A) intracellular free-pools, significant and linear incorporation of radiolabelled Phe into protein in all experiments (Fig.·1C,D, Table·3), and the increase in intra-cellular free-pool Phe concentrations after injection, indicated that the criteria for the flooding dose technique (Houlihan et al, 1995;Fraser et al, 2002a;Fraser et al, 2004;Fraser and Rogers, 2007) had been fully met. in February and October, respectively (Fraser et al, 2002a;Fraser et al, 2002b). Although faecal egestion rates are not a direct measure of food consumption they do provide an indication that food consumption decreases in winter.…”

“…Protein synthesis rates in the current study were higher than those previously reported (Fraser et al, 2002a), probably as a result of inter-annual variability in food availability and consumption. Food consumption is known to have a significant effect on protein synthesis rates (Houlihan et al, 1989;Mente et al, 2001;Fraser et al, 2002a;Fraser et al, 2002b), and it is well established that both benthic and pelagic primary productivity show considerable inter-annual variability in the Antarctic (Clarke, 1988;Clarke et al, 1988;Gilbert, 1991;Fraser et al, 2004;Grange et al, 2004). Whole animal protein synthesis rates in N. concinna were very low in comparison to rates reported for temperate and tropical ectotherms, and a recent analysis (Fraser and Rogers, 2007) has suggested that protein synthesis rates decrease markedly below ~5°C (for reviews, see Houlihan, 1991;Houlihan et al, 1995;Carter and Houlihan, 2001).…”