The last time the earth was this hot — here's what the ocean did

Sea levels will rise — by metres, not centimetres — and the time to prepare is now. Drawing on ancient clues and the latest science, Johanna Wagstaffe explains what Earth's past reveals about our coastal future — and why smart planning today could protect millions in the decades and centuries to come.

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CBC

a day ago

• CBC

Researchers aim to fill data gaps about Dungeness crab amid concerns of declining population

If you've spent much time wandering along B.C.'s coast, chances are you've seen a Dungeness crab crawling sideways across the shoreline — or at least one of its colourful carcasses leftover in the sand. The cold water crustaceans are the second-most valuable invertebrate fishery on the West Coast of Canada and an important food source for coastal First Nations, but researchers warn they may now be facing some threats. Lauren Krzus, a research technician at the Hakai Institute, says they're hearing anecdotally that Dungeness crab stocks are declining, and says climate change is poised to further impact them. She's three years into a 10-year research project with Hakai coastal ecologist Heather Earle, studying the crab's populations from Prince Rupert down to the southern point of B.C.'s coastline. This year, they've recruited 300 data collection volunteers to help monitor 30 specialized traps that float at the surface of the water and use LED strips to draw young crabs in. In their last stage as larva, before they stop swimming and start crawling on the seabed, the creatures are attracted to the light. "When you haul the trap out of the water, everything drains into the bottom, you can unscrew that part and empty out your catch and take a look at what you've got," Earle told CBC's On The Island. Kruzus says they're catching the crabs in their larval stage because that's where one of their biggest knowledge gaps about the crustaceans exists. She says the project is interested in understanding what drives larval patterns and abundance from year to year, and that this data can be used to determine the health of fisheries along with potential future closures. One goal they're working toward is creating a harvesting forecasting tool. This has been researched south of the border, where University of Oregon biology professor Alan Shanks has used a single light trap to determine that an abundance of Dungeness crabs one year is a very good predictor of another abundance four years later. "It's been like a very powerful tool ... where that one light trap can predict the entire coast wide commercial catch for Oregon and even into Northern California," Earle said. "It's not something that we've done here yet in B.C. and it's a very different system, but it still holds a lot of potential. So it's something that we're looking into doing here as well." According to the Government of Canada, Dungeness crabs are the most important crab species harvested in B.C. and the second most valuable invertebrate fishery on the West Coast of Canada. Crabs accounts for approximately 34 per cent of the total wild shellfish landed value in B.C., and 12 per cent of the total landed value of all of B.C.'s wild fish species, according to Fisheries and Oceans Canada. Although Dungeness crabs are not on Canada's endangered list, Earle says people who live along the Salish Sea are saying similar things — that the abundance of crabs that were once there are slowly diminishing. It's an issue coastal First Nations in particular have raised. In 2014, the Heiltsuk, Kitasoo/Xai'Xais, Nuxalk and Wuikinuxv First Nations in B.C. launched a research project after noticing years of declining catch rates. They temporarily closed half of their commercial and recreational fisheries and found both the number and size of Dungeness crabs caught in those areas increased. More recently, in 2022, the Washington Department of Fish and Wildlife, alongside tribal and state managers, closed a fishery in South Puget Sound because of a large decline in Dungeness crab populations. According to a study conducted by University of Toronto in 2023, climate change is causing Dungeness crab to lose their sense of smell, which they need to survive. The study found that the crabs are impacted by ocean acidification, which is the result of the Earth's oceans becoming more acidic as they absorb increasing amounts of carbon dioxide from the atmosphere. Krzus says that "ultimately, we just want to learn more about Dungeness crab." "We're hearing anecdotally that stocks are declining throughout Puget Sound and the Salish Sea. They're impacted by climate change. So we want to gather as much information as we can about them in this larval stage, to fill in those knowledge gaps that we don't currently have." The project began in 2022, and data collection will be ongoing until 2032.

CBC

a day ago

• CBC

'It's not scary': Initiative to engage public with science finds new meaning post-COVID

Social Sharing The COVID-19 pandemic led to a lot of attacks on science. There were protests against public-health mandates, some people harassed health officials and others used social media to share scientific misinformation. But on Saturday, 10 scientists on the Halifax Waterfront put themselves in front of the public — standing on literal soapboxes — to discuss their work. "I think there's a little bit more skepticism with the public in general about science, so I think it's making these events even more important," said Kim Brewer, an associate professor at Dalhousie University's School of Biomedical Engineering who helped organize the Halifax Soapbox Science event. Soapbox Science is an international initiative that started in London, England, in 2011 and has hosted events across Canada since 2017. The events highlight the work of women and non-binary people in science while giving people "the opportunity to enjoy, learn from, heckle, question, probe [and] interact with" scientists, according to the group's website. The event has been held in Halifax before and returned last year for the first time since the start of the pandemic when science and scientists were constantly being challenged. "It's not scary," said Brewer. "It's not this weird thing that is done by strangers in labs far away." 'Fun challenge' to get people to understand science Sarah Martell was one of the researchers who took part of the event. She spoke about her work in hydrogen generation as a potential clean energy source. Martell, who works in a chemistry lab after recently finishing her PhD at Dalhousie University, said some of her environmental work has been subject to "wild" comments online. "I think that's what makes science communication and events like this really important," she said. Engaging with people in person is a lot easier than trying to get your point across to someone on the Internet, Martell said. She said people who stopped by the event Saturday seemed genuinely interested and asked good questions. As for how to communicate such complex topics to the average person, she said that's part of the job sometimes. "I think it's a fun challenge and, I think as a scientist, I sort of feel like it's my responsibility to take that challenge on."

CBC

a day ago

• CBC

Phytoplankton, key to ocean life, falling 2% per year in North Atlantic

Social Sharing Two main types of phytoplankton have been decreasing in biomass in the North Atlantic by two per cent each year for the past 60 years, a new study has found. Dalhousie University researchers analyzed data collected over more than half a century to assess how two types of phytoplankton — diatoms and dinoflagellates — are responding to climate change. The analysis found that while the makeup and distribution of phytoplankton varied in different parts of the North Atlantic, overall, there was a decrease over the period, from 1960 to 2017, except for the eastern and western continental shelves. "Changes are a concern," says Andrew Irwin, a professor in the department of mathematics and statistics at Dalhousie University and one of the authors of the study published this month in PLOS One, a peer-reviewed, open-access journal. "It's such an important part of our ecosystem that any change, especially a change we don't fully understand, is of concern." Phytoplankton are tiny but mighty. The microscopic organisms are the root of the ocean food web, feeding larger creatures such as zooplankton, which are then consumed by fish, which go on to feed mammals and birds. They also play a key role in the planet's carbon cycle, removing carbon dioxide from the atmosphere and sinking it to the bottom of the ocean when they die — thereby helping mitigate the effects of climate change. Irwin says the evidence points toward climate change as the cause of the decrease in phytoplankton. "It's not an experiment. We're observing things. So I can't say for certain that's the reason," he says. "But our models suggest that our changes to the atmosphere, changes to the temperature of the Earth, are leading to this decline in biomass." Continuous Plankton Recorder The data for the new study, conducted with colleagues in Dalhousie's math and oceanography departments, came from a fascinating project that began in 1931 and has continued virtually unchanged for decades. The Continuous Plankton Recorder is a sampler that is towed by ships in oceans around the world. Inside the torpedo-shaped casing is a roll of silk that slowly unwinds, capturing phytoplankton as the ship moves through the water. The rolls are preserved for the duration of the ship's journey and then sent to laboratories for analysis. The CPR has so far sampled more than seven million nautical miles. Douglas Campbell, the Canada Research Chair in Phytoplankton Ecophysiology at Mount Allison University, called the CPR a "fascinating old-school approach." "It's like steampunk technology," says Campbell, who is a professor of biology at Mount Allison and who was not involved in the study. "But because it goes back so far, it's this unparalleled window into what things were like over a long period of time and of course through a critical period of change." Study bucked expectations Irwin says one limitation of the study is that the CPR's silk is not able to grab smaller phytoplankton. "The smaller phytoplankton that don't get counted could be doing something very different," he says. "We don't know." Campbell says other research has found evidence that some smaller phytoplankton are becoming more abundant and dominant, which he says could be a concern over the long term, as they are not as high quality a food source and don't sink carbon as well as larger ones. Irwin says based on previous studies, he and his colleagues expected to find a shift toward dinoflagellates at the expense of diatoms. Dinoflagellates have lower nutritional concentrations and do not remove carbon from the atmosphere as efficiently as diatoms. However, the data showed that diatom biomass actually grew in proportion to dinoflagellate biomass everywhere except in the Arctic area of the North Atlantic. "The message there is that the ocean is complicated," Irwin says. "It's not just temperature, it's not just one factor that's going to tell us what's going to happen."