"That's a huge blow to a massively valuable industry," says Allott. "The marine species that are impacted can include everything from marine vegetation - kelp forests, coral, sea grass meadows - through to shellfish, fish and seabirds, and also marine mammals."ĭeaths, disease and population migration from heatwaves can also lead to knock-on disruptions in the economic sphere where supply chains and local economies rely on sea life.Īmber Allott, an environment reporter at The Press, tells The Detail about a marine heatwave last year that killed 40 percent of farmed salmon in the Marlborough Sounds, leading to a $73 million loss and over 100 staff being laid off. That can come about through factors including marine heatwaves pushing species above their thermal tolerance, or through reducing their food availability or quality. "They can trigger widespread die-offs of marine species. While it's normal for the ocean's temperature to change from season to season and location to location - the waters off the South Island in October might sit at around 13 degrees, whereas the upper North Island would be 18 waters around Papua New Guinea could easily hit 30 degrees - marine heatwaves represent dramatic changes that can disrupt and harm local ecosystems. On a local scale, a build up of heat from ocean currents, the warming of the ocean's surface from the atmosphere, and reduced wind speeds inhibiting the mixing of cooler waters towards the ocean surface can all cause marine heatwaves.īut Smith says on a national scale, heatwaves are also caused by extreme weather events - the likes of which are becoming more common as climate change progresses. "This is more than a nice warm day at the beach." ![]() Heatwaves can last for several months and stretch over thousands of kilometres of ocean. ![]() Smith says a heatwave is defined as when the ocean temperature at a given location sits at the top ten percent of temperatures typically recorded during that time of year for five days or more. The report says marine heatwaves are becoming both more common and more severe. "But knowledge is power, and knowing what is coming up gives us as scientists and communities around New Zealand a chance to respond positively to that." "It's quite confronting when you see some of the projections of ocean temperature for the coming century," says University of Otago marine scientist Rob Smith. ![]() Now, a new report from the Ministry for the Environment lays out the threat posed by marine heatwaves in plain terms - existential, economic and cultural. But the more detrimental effects of shifting sea temperatures are starting to show themselves.Įarlier this year, we caught a hint of the devastation when millions of Fiordland native sea sponges were found to have been bleached bone white in the wake of a marine heatwave, the largest event of its kind reported anywhere in the world. And maybe this sounds like good news if you're a beach-lover or an ocean swimmer.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |