Octopus DNA predicts future West Antarctic ice sheet collapse

Sally Lau led a fantastic study published in Science which used octopus DNA to discover that the West Antarctic Ice Sheet (WAIS) likely collapsed during the Last Interglacial period around 125,000 years ago – when global temperatures were similar to today. This provides the first empirical evidence that the tipping point of this ice sheet could be reached even under the Paris Agreement targets of limiting warming to 1.5 – 2 degrees C.

This research solves a long-running mystery regarding whether or not the WAIS collapsed during the Last Interglacial. This was a period when global average temperatures were 0.5 – 1.5 oC warmer than preindustrial levels, but global sea level was 5 – 10 metres higher than today. What makes the WAIS important is that it’s also Antarctica’s current biggest contributor to global sea level rise. A complete collapse could raise global sea levels by somewhere between 3 and 5 metres.

In the study we employed a novel population genomic approach to answer this question. By employing demographic modelling and comparing the genetic profiles of Turquet’s octopus found in the Weddell, Amundsen, and Ross seas enabled detection of genetic connectivity dating back to the Last Interglacial. This would only be possible if a complete collapse of the WAIS occurred during the Last Interglacial, opening seaways linking the present-day Weddell, Amundsen and Ross seas. This would have allowed octopus to travel across the opened straits and exchange genetic material, which we can detect in the DNA of today’s populations.

This research was interdisciplinary, bringing together geneticists, physical scientists and geologists and was only possible through international collaboration and the use of samples collected over a 30 year time period. Our work was supported by the Australian Research Council, the Australian Academy of Science, an Antarctic Science International Bursary, the SCAR INSTANT programme, Ministry of Business Innovation & Employment, NZ, the Antarctic Science Foundation, Australasian eResearch Organisations and Suomen Akatemia.

Interdisciplinary team work makes the dream work! From L to R: Nick Golledge (Victoria University of Wellington), Nerida Wilson (University of Western Australia), Sally Lau (James Cook University), Tim Naish (Victoria University of Wellington) and Jan Strugnell (James Cook University).

We are delighted with the media attention our paper has received! Some of our favourites include First Dog on the Moon, The New York Times, The Washington Post and CNN. You can also read more about our research in an article we wrote for The Conversation.

There are many more blue-ringed octopuses than you think there are…..

Brooke Whitelaw led a fantastic study investigating species diversity in the iconic blue-ringed octopus genus, Hapalochlaena. Using genome-wide SNP data and mitochondrial loci, Brooke found 11 relevant taxonomic units – likely all species, suggesting MUCH greater diversity than is currently described! The origin of the genus Hapalochlaena was predicted to be in the Indo-Australian Archipelago and is older than you might thing ~30 mya.

The paper is published in Molecular Phylogenetics and Evolution and you can access it here.

Fig. 2. Delineation of Hapalochlanea species boundaries and genetic structure throughout the Indo Pacific using 10,346 SNPs: (a) SVDQuartet phylogeny of Hapalochlaena throughout the Indo Pacific generated using 10,346 SNPs, coloured branches represent putative taxonomic units A-K: brown (A/Southern coast of Australia), lilac (B/NSW), apple green (C/Taiwan lined), pink (D/Taiwan ringed), light orange (E/Darwin, NT & Kimberly & Exmouth, WA), red (F/Timor Leste), dark orange (G/G* Great Barrier Reef, QLD), purple (H/Cape York, QLD & Shark Bay, QLD) light blue (I/Deep water Yeppoon, QLD & North West, WA), dark blue (J/North West Shelf, WA) and light green (K/Ningaloo, WA). Posterior support values > 0.90 present on nodes. Bars at terminal branches indicate admixture of OTUs inferred using STRUCTURE, colours approximately correspond to OTUs. Lined box adjacent to OTU indicated lined markings while, OTUs without a box exhibit ringed markings. (b) Species delineation using the mitochondrial COI gene. Bayesian phylogeny (MrBayes) of Hapalochlaena throughout the Indo Pacific is coloured according to OTU with black used to represent taxa included from NCBI. Boxes represent putative species in accordance to sPTP, GYMC SC (strict clock) and GYMC RC (relaxed clock) methods. Boxes with diagonal lines represent specimens with lined markings as opposed to rings present in all other specimens. (c) Arrangement of samples according to the first two principal components of a PCoA based on SNP data generated using the dartR package. (d) Map of sample locations coloured by organisational taxonomic units A-K. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Securing Antarctica’s Environmental Future (SAEF) conference in Adelaide – Sally wins research prize!

Nikki, Sally, and Jan had a blast at the SAEF conference in Adelaide. Held at the National Library, it was the first time that many of the participants in SAEF had the opportunity to meet one another!

The ‘Connect’ dream team – from L to R, Sally, Jan, Nikki, and Nerida Wilson.

Biggest congratulations to Sally Lau, who together with Rachael Lappan, was the inaugural recipient of the SAEF biddable Research funding. Aimed at ECRs, it’s an initiative designed to support innovative, high-risk science. Go Sally!

Jan was delighted to meet Alun Thomas, Mawson’s grandson, who gave an inspiring speech about his Grandad. Alun now volunteers at the South Australian Museum where he works on accessioning his grandad’s valuable collections.

Sampling Marine Invertebrates at the Australian Antarctic Division

Nikki, Sally, Nerida, and Jan sampled Antarctic marine invertebrates at the Australian Antarctic Division (AAD). We collected tissue samples to investigate evolutionary processes in the Southern Ocean, and also prepared the samples to be accessioned at the Tasmanian Museum and Art Gallery (TMAG).

At the Australian Antarctic Division. Sunny, but nippy for Townsvillians!

Check out those invertebrates! (and our PPE).

Big thanks for all your work helping us accession these valuable samples Kirrily Moore at the Tasmanian Museum and Art Gallery (TMAG).

Big thanks to Glenn Johnstone, Jonny Stark and Kirrily Moore for all their help!

Emerging biological archives can reveal ecological and climatic change in Antarctica

Jan led a paper with co-authors from Securing Antarctica’s Environmental Future (SAEF) to highlight the utility and power of biological archives to understand past ecological and climatic change in Antarctica. Biological archives included extant moss beds and peat profiles, biological proxies in lake and marine sediments, vertebrate animal colonies, and extant terrestrial and benthic marine invertebrates. The paper highlights how emerging biological archives complement other Antarctic paleoclimate archives (e.g. ice cores) by recording the nature and rate of past ecological change, the paleoenvironmental drivers of that change, and constrain current ecosystem and climate models. Significant advances in analytical techniques (e.g., genomics, biogeochemical analyses) have led to new applications and greater power in elucidating the environmental records contained within biological archives. The paper highlights how these emerging biological archives will significantly expand our understanding of past, present, and future ecological change, alongside climate change in Antarctica and at the Southern Ocean.

A video about the article made by GCB: https://twitter.com/GlobalChangeBio/status/1561850857334923269

Link to SAEF article about the paper: https://arcsaef.com/story/accessing-earths-memories/

Link to paper: https://onlinelibrary.wiley.com/doi/10.1111/gcb.16356

Global drivers of recent diversification in a marine species complex

New paper by Catarina and Jan in Molecular Ecology, (full article here), investigates genome-wide divergence, introgression patterns and inferred demographic history between species pairs of all six extant rock lobster species within the genus Jasus – species with a larval duration of up to two years. Funded by the Australian Research Council, this work shows the important effect of habitat and demographic processes on the recent divergence of species in the genus.

Abalone sampling at Southern Ocean Mariculture

Jan and Phoebe visited Southern Ocean Mariculture (SOM) in Port Fairy, Victoria at the start of July to collect samples for Phoebe’s honours project. Phoebes project, supported by the Fisheries Research and Development Corporation and the Australian Abalone Growers Association, seeks to test established methods of early prediction of genetic merit in abalone broodstock. It was freezing in Port Fairy in comparison to sunny Townsville, but great to see the abalone growth and the impressive technology and set up at SOM! Thanks for hosting us!

Abalone = Yum!

8th International Barcode of Life Conference

Jan gave a plenary lecture at the 8th International Barcode of Life Conference in Trondheim, Norway on June 19. Jan spoke about “Dating the West Antarctic ice sheet collapse using molecular sequence data.” The conference was great – loads of metabarcoding presentations including monitoring freshwater and marine environments and also using barcoding to ascertain the ingredients in foods. Great to catch up with old friends and make new ones and see a little bit of beautiful Norway!

Jan delivering her lecture in Trondheim