Long-term acclimation and potential scope for thermal resilience in Southern Ocean bivalves

Reed, Adam J.; Thatje, Sven

doi:10.1007/s00227-015-2752-3

Cited by 31 publications

(5 citation statements)

References 52 publications

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“…Many Antarctic ectotherms have classically been considered to be specialized to an invariable environment, subsequently lacking phenotypic and physiological plasticity necessary for acclimatizing to environmental shifts on par with future climate change (Peck et al, 2004(Peck et al, , 2010(Peck et al, , 2014Beers and Jayasundara, 2015). A growing body of work is beginning to demonstrate, however, that physiological plasticity is retained and sufficient for metabolic recovery under a warmer and/or more acidic ocean in at least some Antarctic ectotherms (Seebacher et al, 2005;Peck et al, 2010;Enzor and Place, 2014;Reed and Thatje, 2015;Huth and Place, 2016a,b;Morley et al, 2016;Enzor et al, 2017;Davis et al, 2018;Hawkins et al, 2018). The responsiveness of DNA methylation in L. helicina antarctica to variation in pCO 2 may be linked to this species' environmental experience in situ.…”

Section: Resultsmentioning

confidence: 99%

Changes in Genome-Wide Methylation and Gene Expression in Response to Future pCO2 Extremes in the Antarctic Pteropod Limacina helicina antarctica

2020

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Epigenetic processes such as variation in DNA methylation may promote phenotypic plasticity and the rapid acclimatization of species to environmental change. The extent to which an organism can mount an epigenetic response to current and future climate extremes may influence its capacity to acclimatize or adapt to global change on ecological rather than evolutionary time scales. The thecosome pteropod Limacina helicina antarctica is an abundant macrozooplankton endemic to the Southern Ocean and is considered a bellwether of ocean acidification as it is highly sensitive to variation in carbonate chemistry. In this study, we quantified variation in DNA methylation and gene expression over time across different ocean acidification regimes. We exposed L. helicina antarctica to pCO 2 levels mimicking present-day norms in the coastal Southern Ocean of 255 µatm pCO 2 , present-day extremes of 530 µatm pCO 2 , and projected extremes of 918 µatm pCO 2 for up to 7 days before measuring global DNA methylation and sequencing transcriptomes in animals from each treatment across time. L. helicina antarctica significantly reduced DNA methylation by 29-56% after 1 day of exposure to 918 µatm pCO 2 before DNA methylation returned to control levels after 6 days. In addition, L. helicina antarctica exposed to 918 µatm pCO 2 exhibited drastically more differential expression compared to cultures replicating present-day pCO 2 extremes. Differentially expressed transcripts were predominantly downregulated. Furthermore, downregulated genes were enriched with signatures of gene body methylation. These findings support the potential role of DNA methylation in regulating transcriptomic responses by L. helicina antarctica to future ocean acidification and in situ variation in pCO 2 experienced seasonally or during vertical migration. More broadly, L. helicina antarctica was capable of mounting a substantial epigenetic response to ocean acidification despite little evidence of metabolic compensation or recovery of the cellular stress response in this species at future pCO 2 levels.

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Section: Resultsmentioning

confidence: 99%

Changes in Genome-Wide Methylation and Gene Expression in Response to Future pCO2 Extremes in the Antarctic Pteropod Limacina helicina antarctica

2020

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“…Many laboratory studies have focused on the effects of elevated temperature on Antarctic marine species. These include studies on fish [e.g., ( 126 , 127 )], molluscs [e.g., ( 128 – 131 )], echinoderms ( 132 , 133 ), amphipods ( 22 , 134 ), isopods [e.g., ( 135 , 136 )], and sponges ( 137 ). There have also been assessments of elevated temperature impacts using larger-scale approaches, aimed at quantifying multispecies, community, ecosystem, or overall biodiversity level responses [e.g., ( 24 , 138 , 139 )].…”

Section: Sensitivity To Environmental Changementioning

confidence: 99%

Antarctic environmental change and biological responses

2019

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Antarctica and the surrounding Southern Ocean are facing complex environmental change. Their native biota has adapted to the region's extreme conditions over many millions of years. This unique biota is now challenged by environmental change and the direct impacts of human activity. The terrestrial biota is characterized by considerable physiological and ecological flexibility and is expected to show increases in productivity, population sizes and ranges of individual species, and community complexity. However, the establishment of non-native organisms in both terrestrial and marine ecosystems may present an even greater threat than climate change itself. In the marine environment, much more limited response flexibility means that even small levels of warming are threatening. Changing sea ice has large impacts on ecosystem processes, while ocean acidification and coastal freshening are expected to have major impacts.

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“…There have been many studies of physiological capacities to respond to temperature stress in Antarctic marine species over recent decades on a very wide range of different taxa, including fish (e.g. Macdonald & Montgomery 1982, Hardewig et al 1999b, Hofmann et al 2000, Wilson et al 2001, Podrabsky & Somero 2006, Franklin et al 2007, Robinson & Davison 2008, Bilyk & DeVries 2011, Strobel et al 2012, Todgham et al 2017, molluscs (Peck 1989, Urban & Silva 1998, Clark et al 2008a,b, Morley et al 2010,b,c, Reed et al 2012, Reed & Thatje 2015, echinoderms (Stanwell-Smith & Peck 1998, Clark et al 2008b, Morley et al 2012b, amphipods (Young et al 2006a,b, Clark et al 2008b, Doyle et al 2012, Gomes et al 2013, Schram et al 2015b, isopods (Whiteley et al 1996, Robertson et al 2001, Young et al 2006a,b, Janecki et al 2010, brachiopods (Peck 1989, Peck et al 1997a, sponges (Fillinger et al 2013), and macroalgae or phytoplankton (Montes-Hugo et al 2009, Schloss et al 2012. There have also been many assessments of the effects of elevated temperature using a larger-scale approach, both experimentally and using field observations identifying multispecies response or evaluating community, ecosystem or overall biodiversity level responses (e.g.…”

Section: Rising Temperaturesmentioning

confidence: 99%

Oceanography and Marine Biology

Hawkins¹,

Evans²,

Dale³

et al. 2018

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Animals living in the Southern Ocean have evolved in a singular environment. It shares many of its attributes with the high Arctic, namely low, stable temperatures, the pervading effect of ice in its many forms and extreme seasonality of light and phytobiont productivity. Antarctica is, however, the most isolated continent on Earth and is the only one that lacks a continental shelf connection with another continent. This isolation, along with the many millions of years that these conditions have existed, has produced a fauna that is both diverse, with around 17,000 marine invertebrate species living there, and has the highest proportions of endemic species of any continent. The reasons for this are discussed. The isolation, history and unusual environmental conditions have resulted in the fauna producing a range and scale of adaptations to low temperature and seasonality that are unique. The best known such adaptations include channichthyid icefish that lack haemoglobin and transport oxygen around their bodies only in solution, or the absence, in some species, of what was only 20 years ago termed the universal heat shock response. Other adaptations include large size in some groups, a tendency to produce larger eggs than species at lower latitudes and very long gametogenic cycles, with egg development (vitellogenesis) taking 18-24 months in some species. The rates at which some cellular and physiological processes are conducted appear adapted to, or at least partially compensated for, low temperature such as microtubule assembly in cells, whereas other processes such as locomotion and metabolic rate are not compensated, and whole-animal growth, embryonic development, and limb regeneration in echinoderms proceed at rates even slower than would be predicted by the normal rules governing the effect of temperature on biological processes. This review describes the current state of knowledge on the biodiversity of the Southern Ocean fauna and on the majority of known ecophysiological adaptations of coldblooded marine species to Antarctic conditions. It further evaluates the impacts these adaptations have on capacities to resist, or respond to change in the environment, where resistance to raised temperatures seems poor, whereas exposure to acidified conditions to end-century levels has comparatively little impact. Zone Description Area (km 2) Length (km) Southern Ocean Total area (km 2)

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Long-term acclimation and potential scope for thermal resilience in Southern Ocean bivalves

Cited by 31 publications

References 52 publications

Changes in Genome-Wide Methylation and Gene Expression in Response to Future pCO2 Extremes in the Antarctic Pteropod Limacina helicina antarctica

Changes in Genome-Wide Methylation and Gene Expression in Response to Future pCO2 Extremes in the Antarctic Pteropod Limacina helicina antarctica

Antarctic environmental change and biological responses

Oceanography and Marine Biology

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