Irukandji jellyfish polyps exhibit tolerance to interacting climate change stressors

Abstract

Increasing ocean temperatures and strengthening boundary currents have caused the poleward migration of many marine species. Cubozoan jellyfish known to cause Irukandji syndrome have historically been confined to tropical waters but may be expanding into subtropical regions. Here, we examine the interactive effects of warming and acidification on the population dynamics of polyps of an Irukandji jellyfish, Alatina nr mordens, and the formation of statoliths in newly metamorphosed medusae, to determine if this jellyfish could tolerate future conditions predicted for southeast Queensland (SEQ), Australia. Two experiments, examining the orthogonal factors of temperature and pH, were undertaken. Experiment 1 mimicked the current, ca. 2050 and ca. 2100 summer temperature and pH conditions predicted for SEQ using A1F1 scenarios (temperature: 25, 27, 29 °C; pH: 7.9, 7.8, 7.6) and Experiment 2 mimicked current and future winter conditions (18 and 22 °C, pH 7.9, 7.8, 7.6). All polyps in Experiment 1 survived and budded. Fewer polyps budded in the lower pH treatments; however, patterns varied slightly among temperature treatments. Statoliths at pH 7.6 were 24% narrower than those at pH 7.8 and 7.9. Most polyps survived the winter conditions mimicked by Experiment 2 but only polyps in the 22 °C, pH 7.9 treatment increased significantly. The current absence of A. nr mordens medusae in SEQ, despite the polyps' ability to tolerate the current temperature and pH conditions, suggests that ecological, rather than abiotic factors currently limit their distribution. Observations that budding was lower under low pH treatments suggest that rates of asexual reproduction will likely be much slower in the future. We consider that A. nr mordens polyps are likely to tolerate future conditions but are unlikely to thrive in the long term. However, if polyps can overcome potential ecological boundaries and acidification proceeds slowly A. nr mordens could expand polewards in the short term.

Comparative physiological, biochemical, and molecular thermal stress response profiles for two Unionid freshwater mussel species

“…Comparative studies related to climate change issues have been largely successful in identifying traits and response patterns useful for informing conservation and management strategies (Klein et al, 2014;Stillman and Somero, 2000;Worthington et al, 2014). Although rather common in marine bivalves, there has been very little comparative research on thermal stress for freshwater mussels.…”

Exposure to elevated pCO2 does not exacerbate reproductive suppression of Aurelia aurita jellyfish polyps in low oxygen environments

“…Asexual reproductive success is often used as the primary measure for determining the response of polyps to experimental treatments (Condon et al 2001, Winans & Purcell 2010, Miller & Graham 2012, Klein et al 2014, Schiariti et al 2015, but direct observations of state variables do not capture information on short-term metabolic processes, which are required to determine mechanisms of responses to environmental conditions. We found that the metabolic response of polyps in terms of aerobic respiration did not mirror the trends observed in asexual reproduction.…”

“…Some studies have determined the independent effects of hypoxia (Condon et al 2001, Decker et al 2004, Grove & Breitburg 2005, Miller & Graham 2012, and reduced pH (Klein et al 2014, Lesniowski et al 2015, Tills et al 2016 on gelatinous zooplankton, with the majority concluding that various gelatinous taxa are relatively tolerant to constant exposure to both stressors in isolation (but see Tills et al 2016). For example, consumption and digestion rates of the ctenophore Mnemiopsis leidyi on copepods were unaffected by hypoxia (Decker et al 2004), which benefits gelatinous organisms over other plankton when oxygen is low.…”

“…polyps can survive and asexually reproduce, albeit at reduced rates, during prolonged exposure to hypoxia (Condon et al 2001, Miller & Graham 2012. Polyps may equally adapt to reduced pH conditions, since polyps of the cubozoan Alatina nr mordens survived and asexually reproduced, although more slowly, in pH 7.61 (Klein et al 2014), and growth and carbon content of scyphozoan polyps Cyanea capillata and Chrysaora hysoscella were unaffected by increased CO 2 (Lesniowski et al 2015). Taken together, these studies suggest that gelatinous zooplankton are generally tolerant to hypoxia and acidification in isolation.…”

Bridging indigenous and scientific knowledge

“…The insights that can be gained from local indigenous knowledge are illustrated by a recent study by Klein et al (5). The authors show that local knowledge of climate and ecological change supports the hypothesis of delayed summers on the Tibetan Plateau.…”