Thirty-seven southern species never before spotted in northern sites, mark an unprecedented poleward migration. A recent survey shows poleward expansion of species brings new flora and fauna to historically unoccupied places as northern waters heat up.
Warm water events are brought on by strong El Niño events, ocean-atmosphere climate interactions which temporarily raise ocean temperatures. “Before our very eyes, we’re seeing the species composition shift to more warm-water southern animals in just the 14 years I have been at the Bodega Marine Laboratory,” Dr. Eric Sanford told UC Davis News, Environment.
Because of a strong El Nino in 2016, a warmer water event, affectionately dubbed the “Blob,” was pushed from the equator north into places like Bodega Bay. Along with it were the species that Sanford’s team recorded. Being able to see how species react to a more localized warming event will give scientists a better expectation of what is to come if waters continue to warm.
The sixty-seven species that Sanford and his team found outside of their historical range may become the new normal. Sanford explains, “It’s perhaps a glimpse of what Northern California’s coast might look like in the future as ocean temperatures continue to warm.”
Their study includes nudibranchs (sea slugs) to sea birds, showing this is a widespread occurrence in many groups of animals. Among them is the Striated Sea Butterfly, which has never been recorded north of Baja California.
The species’ response could hint to a necessary resilience, “Against the backdrop of climate change, we hope southern species will track northward because that’s necessary for their persistence and survival,” Sanford says.
While this may preserve stressed species from the south, this is will change the species that the casual observer used to seeing. Sanford told the Press Democrat, “We’re basically seeing these communities change before our eyes as more southern species become part of these communities… That’s pretty dramatic.” Looking forward, how will these new species interact with the existing marine community?
When the northern waters returned to normal, most of the southern species were not able to tolerate the cooler temperatures. However, if this was a sustained warming, we could see these species hang around for much longer, and maybe even become established.
While this paper points towards hope for some southern species. Other species may not be so lucky. In 1999 over a four day period, the New York Times reported that over 100 million dollars worth of lobster died in Long Island Sound due to an extreme water event. With overwhelming evidence, climate change is becoming harder to ignore marine habitat protection official for the State Department of Environmental Conservation, Karen Chytalo says, "Global warming is definitely happening, and it's happening in Long Island Sound,".
These kinds of pattern, are not exclusive to the animal kingdom. Research in mangroves
suggests that these forests are also moving north. As ecosystem engineers, mangrove forests are habitat to many organisms. Additionally, they are one of the largest carbon sinks. Unable to cope with the cold, mangroves are almost exclusively found in the tropics. However, as tropical waters become unbearably warm, mangroves are invading northern habitats. Lead author Kyle Cavanaugh told Grist, “The mangroves are expanding into and invading salt marsh, which also provides an important habitat for a variety of species.” Additionally, what is happening to the habitats they’re leaving?
As the planet continues to warm, consistent warm water has the potential to bring more species up from the equator and sustain them. Sanford and Cavanaugh’s work all point to shifts in the local flora and fauna of our coasts, which support greater implications on global warming.
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