HEAT WAVE KILLED MARINE WILDLIFE MASSE PATCH
HEAT WAVE KILLED MARINE WILDLIFE MASSE FULL

Next, though, Khangaonkar and his colleagues did a sensitivity test, removing the blob’s warming effect and running the model again.

So they ran the model, and with the blob’s conditions the model did indeed reproduce the increased zooplankton growth. “It seemed pretty straightforward, a clear temperature effect,” Khangaonkar says. Zooplankton are near the base of the food web, so organisms that feed on them, such as herring, benefited, their populations rising as well. During the blob years, first phytoplankton biomass and then zooplankton biomass increased substantially - up to 14% and 18%, respectively. One phenomenon they selected for scrutiny was zooplankton. What he and his colleagues found was that their model did not support some of the speculations about the blob’s effects on the Salish Sea. In a recent paper in Frontiers in Marine Science, Khangaonkar presented the model’s results. If it was able to reproduce observed conditions, they would perhaps have an idea of the physical mechanisms behind them. What this meant for Khangaonkar and his colleagues at the University of Washington and the Washington Department of Ecology was that they could parse the blob and the Salish Sea into a suite of main effects, include those effects or remove them in turn, and see how the model responded. “Over the years,” Khangaonkar says, “the model has grown to be a diagnostic tool that allows us to look at things we might not otherwise be able to test.” But its main focus is the major waterways that make up the Salish Sea: the Strait of Juan de Fuca, the Strait of Georgia, and Puget Sound. As a representation of the interior marine ecosystem, the model’s digitized spaces stretch from the tip of Vancouver Island to central Oregon, and extend west out into the Pacific about to the edge of the continental shelf. Khangaonkar had a way to test some of those speculations: the Salish Sea Model. So for extended period, a strong circulation regime was bringing in nutrients from the Pacific. All that extra freshwater flowing out pulled more oceanwater in. “Each of the blob years were marked by much higher-than-average river inputs,” Khangaonkar says. “I thought, How can you say that? It could have been a lot of things.” “People were blaming everything on higher water temperatures from the blob,” says Tarang Khangaonkar, the head of the Salish Sea Modeling Center at the University of Washington and a researcher with the Pacific Northwest National Laboratory. That hadn’t stopped people within the Salish Sea environment from speculating about the blob’s effects here. Not much had been written about the blob’s impacts on the Salish Sea, however. The known consequences for marine life in particular were spectacular and severe: tropical creatures showed up off the North American coast, marine birds and whales and sea lions starved and died by the thousands, and so on. (It would be displaced as the largest marine heatwave a few years later, in 2019.) In the years since it ended, many papers have come out exploring its impacts-physical, chemical, ecological-on the outer coast of North America. Sea surface temperatures at their peak were almost 3 ✬ above long-term averages.Īt the time, the blob was the largest and longest-lasting marine heatwave in recorded history.

HEAT WAVE KILLED MARINE WILDLIFE MASSE PATCH

At its greatest extent, this warm patch encompassed millions of square miles of ocean, from Alaska and British Columbia south to California. Take the marine heatwave now known colloquially as 'the blob.' Beginning in the late fall of 2013, and persisting until 2016, a large patch of the northeast Pacific Ocean began to warm (or, more precisely, failed to cool). Sometimes, though, it is perhaps less straightforward. Last summer, for example, when temperatures soared to triple-digit highs for three days throughout the Pacific Northwest, attributing the widespread baking of intertidal life to this so-called heat dome was fairly straightforward. Sometimes it’s easy to pin an outcome to its cause.

HEAT WAVE KILLED MARINE WILDLIFE MASSE FULL

One of the more challenging tasks for scientists can be to parse the full range of effects born of large events.

Heat wave killed marine wildlife masse