New NASA discovery reveals mystery beneath Arctic ice (+video)
New NASA discovery: Researchers funded by NASA were surprised to discover phytoplankton blooms flourishing under thick layers of Arctic ice, upending preconceptions about Arctic ecosystems.
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They discovered a massive under-ice bloom that extended for more than 60 miles (100 kilometers) into the ice pack on theChukchi Sea continental shelf. Based on their findings, productivity in the area they studied may be 10 times higher than current estimates of productivity there that are based solely on open-water measurements of Arctic phytoplankton.Skip to next paragraph
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"Our results show clearly that the Arctic Ocean is a much more biologically productive place than we previously thought," Arrigo said.
Thinning ice, more light
The reason that phytoplankton can flourish under the ice is because the Arctic ice pack has thinned in recent decades, riddling it with meltwater ponds at its surface. As such, "a lot more light can penetrate through the ice into the ocean below," Arrigo said. "It's not nearly as dim as it used to be."
Apparently, phytoplankton begins to grow beneath the Arctic ice in the late spring, as soon as there is ample light for photosynthesis. After a couple of weeks, the ice disappears and what is left is a remnant population of phytoplankton from that earlier under-ice bloom. The reason that relatively little phytoplankton is later seen in open waters is because most of the available nutrients were already consumed by their under-ice brethren. [6 Signs that Spring Has Sprung]
"Some have claimed that the bloom couldn't have developed under the ice — that it had to have begun in open water and drifted below the ice," Arrigo said. However, "given the currents and known ice motion, we have shown that this isn't possible."
Although one might assume that such productivity will be good for the Arctic, its specific impact remains unclear. For instance, phytoplankton blooms now seem to occur earlier than normal. Animals that fly or swim to the Arctic to depend on these blooms may have difficulty adjusting to an earlier season.
"It is often assumed that when it comes to biological food production, more is better," Arrigo said. "However, a more productive Arctic is not necessarily an improved Arctic or a better Arctic. If the Arctic becomes increasingly more productive, some members of the ecosystem will benefit while others will not. There will be both winners and losers. It's too early to tell who these winners and losers will be."
Now, researchers want to figure out how widespread under-ice blooms are and determine their impact on the polar marine ecosystems. However, "this will be difficult because the Arctic can be a pretty inhospitable place and sampling deep within the ice pack, which is what this research would require, is challenging, even for an icebreaker," Arrigo said.
The scientists detailed their findings online today (June 7) in the journal Science.
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