Oxygen limited thermal tolerance and performance in the lugworm Arenicola marina: A latitudinal comparison

Abstract

Global warming trends in the marine environment currently lead to poleward shifts in the distribution of marine fauna along European coastlines indicating limited thermal tolerance of affected species and potential loss of their southernmost populations. The present study analyses the degree and limits of thermal specialisation in various populations of a key species of the intertidal zone, the lugworm Arenicola marina, which is exposed to highly fluctuating conditions in temperature, salinity, pH and oxygen levels during the seasonal as well as the tidal cycle. Thermal windows of tolerance and exercise performance were compared in three populations from the Russian White Sea, the German North Sea and the French Atlantic coast. Digging experiments in natural marine sediments quantified performance capacity and its optimum temperature. Temperature dependent ventilation and respiration were analysed in lugworms dwelling in artificial self-perfused burrows. Haemoglobin oxygen affinity was examined for an evaluation of population specific adaptations in the oxygen supply system. The results reflect a shift of both the thermal window and the thermal optimum towards higher temperatures with decreasing latitude. This shift was accompanied by a reduction of performance amplitude, i.e. the absolute number of digging periods, and a widening of the distance between critical temperatures, i.e. the total aerobic window of thermal tolerance.

Integrating climate-related stressor effects on marine organisms: unifying principles linking molecule to ecosystem-level changes

“…Wittmann et al (2008) and Schröer et al (2009) demonstrated such shifts in the intertidal lugworm Arenicola marina according to season and climate zone. Such acclimatization capacity is reflected in the up-regulation of metabolic capacity upon cold exposure and the down-regulation of metabolic costs in warm conditions, such that residual aerobic scope remains sufficiently high.…”

Energy homeostasis as an integrative tool for assessing limits of environmental stress tolerance in aquatic invertebrates

“…mitochondria, enzymes, ion and gas transport capacities as well as membrane composition (Hazel, 1995;Willmer et al, 2000;Hochachka and Somero, 2002). Thus, seasonal acclimatization or laboratory acclimation to different temperatures shifts the thermal tolerance windows in invertebrates and fish due to the readjustment of energy metabolism (Sommer et al, 1997;van Dijk et al, 1999;Pörtner, 2002;Sommer and Pörtner, 2002;Sokolova and Pörtner, 2003;Wittmann et al, 2008;Schröer et al, 2009). Similarly, long-term acclimation to changing salinity in aquatic invertebrates and fish often involves metabolic readjustments to reduce SMR and/or preserve the aerobic scope except when salinity change is extreme (Shumway and Koehn, 1982;Nelson et al, 1996;Sangiao-Alvarellos et al, 2005;Kidder et al, 2006).…”

A role for haemolymph oxygen capacity in heat tolerance of eurythermal crabs

“…Such levels decrease toward thermal extremes and can therefore be adopted as proxies of aerobic scope. Increased ventilation in vertebrates, like Gadus morhua (Sartoris et al, 2003) and Pachycara brachycephalum (Mark et al, 2002), and invertebrates, such as Maja squinado (Frederich and Pörtner, 2000), Sepia officinalis (Melzner et al, 2006a,b) and Arenicola marina (Schröer et al, 2009) contributes to sustain aerobic scope. Similarly, increased cardiac frequency in fish (Heath and Hughes, 1973; Mark et al, 2002; Farrell, 2009; Farrell et al, 2009) and, in combination with variations of stroke volume, in crustaceans (Spaargaren, 1974; Frederich and Pörtner, 2000; Walther et al, 2009), maintains oxygen delivery to tissues when demand increases but, in turn also contributes to the demand.…”