Tiny genetic \u2018breadcrumbs\u2019 left behind by marine organisms offer unprecedented insights into ocean biodiversity and how it changes over time and in response to our changing climate, new research at Curtin University, in collaboration with CSIRO,\u00a0has revealed.<\/p>\n
Researchers developed new environmental DNA (eDNA) biomonitoring methods using samples collected off the coast of Rottnest Island near Perth, Western Australia, as part of Australia\u2019s Integrated Marine Observing System (IMOS<\/a>).<\/p>\n IMOS scientists collected and froze filtered seawater samples over a five-year period. These \u2018time capsules\u2019 provided a unique opportunity to study changes in our oceans and marine life that occur seasonally and in response to climate anomalies such as the marine heatwave that struck WA in 2011.<\/p>\n The study, published in journal PLOS Genetics<\/em>, demonstrated how a zooplankton community – the larvae and eggs of fish – responds normally to seasonal change in contrast to heatwave conditions.<\/p>\n The study is the longest multi-year marine eDNA study yet conducted and showcases the power of eDNA technologies to monitor our ocean health.<\/p>\n PhD student Tina Berry and Professor Michael Bunce, from Curtin\u2019s School of Molecular and Life Sciences, led the research team.<\/p>\n \u201cIt is incredibly rare to find a series of samples from such a long time period that are also suitable for DNA analysis,\u201d Ms Berry said.<\/p>\n \u201cThe scientists at IMOS had the foresight to biobank a set of samples that allowed us to travel back through time and see how the ocean responded to a marine heatwave.<\/p>\n \u201cAfter some hard work in the lab to isolate and sequence the DNA, a significant and revealing story appeared. The end result was a holistic window into our marine life that would otherwise be impossible to see.\u201d<\/p>\n Professor Bunce said environmental DNA was fast emerging as an effective way to study our oceans and the technique hit the headlines in 2018 as researchers went searching for the Loch Ness Monster<\/a> using eDNA.<\/p>\n \u201cWe didn\u2019t find any monsters either, unless you count two samples with trace amount of humpback whale in them. But to be honest, it\u2019s the small creatures that live in our oceans that provide the greatest clues to our ocean\u2019s wellbeing.\u201d<\/p>\n Professor Bunce said the eDNA signatures mapped out which marine organisms were present at different times of the year and identified those that first appeared when sea surface temperatures spiked during the heatwave.<\/p>\n \u201cBeing able to track thousands of marine species at a time using eDNA offers important clues regarding how our oceans are changing as they warm, it\u2019s a glimpse into the future that we can\u2019t see using other methods,\u201d Professor Bunce said.<\/p>\n \u201cAustralia has the Earth\u2019s third largest ocean territory and every year the nation derives an estimated $47.2 billion from its \u2018blue economy\u2019 so understanding how it is changing is of high national importance.<\/p>\n \u201cUsing eDNA, we are detecting sharks, corals, seahorses and marine mammals and the DNA toolkit we are developing in our wider research program is a road-map for long-term ocean monitoring around the world. We urgently need better ways to perform health-checks on our marine environments and eDNA is responding to this need.\u201d<\/p>\n