NPRB funded researcher Russ Hopcroft was looking at warmer temperatures in the waters of the Gulf of Alaska this summer
Most Alaskans would comment on how unusual the summer weather has been during 2014. The same applies to the waters in the Gulf of Alaska – it’s been a hot one! Ocean surface temperatures there were a comfy 55-57°F. A team of scientists that have been studying the Alaskan shelf south of Seward, Alaska, found the upper 300 feet of the ocean to be from 1 to 5°F warmer than the September average they have measured over the past 17 years. “It was like working in a bath tub out there” said chief scientist Professor Russ Hopcroft, “except for the wind and 12 foot swell. This year was more than 1 degree warmer than any other year we have studied.”
The warm temperatures are partly a result of an unsual winter that left the distant offshore water of the Gulf far warmer than normal. A warm water anomaly in the tropical Pacific Ocean may have further added to the warming. Together, they have created warmer summer waters from Southeastern Alaska through the Bering Sea. While this might be great if you’re a swimmer, warmer temperatures can have large consequences to marine life that are accustomed to colder year-round temperatures. Some colder-water species experience hard times when water is too warm for them. Consequences may have been mixed for other species, for example, while some fish grow more quickly in warm water, they also burn more calories at warmer temperatures, so need to find much more food.
During warm years, coastal currents also tend to bring more warm water species northward. The team lead by University of Alaska researchers found unusually large numbers of warmer water plankton species during their survey. Months of laboratory work analyzing plankton samples will be required to know the extent of their invasion. NOAA partners studying ocean acidification have had a small armada of self-contained robotic devices out monitoring the physics and chemistry of the shelf and the nearby Prince William Sound since their last cruise in May. This will provide an unprecedented look at the seasonal progression during this unusual year.
The ability of scientists to keep their fingers on the pulse of the ocean has been increasing progressively over the past decades. An army of profiling drifters monitors temperature and salinity in the deep oceans beyond the continental shelf. Satellites have also been able to follow the development of these warm conditions at the ocean’s surface. But understanding the details of what is happening on the Alaskan shelf – and most importantly its biological consequences – requires regular ship-based surveys that are in place to capture extreme events such as 2014. The North Pacific Research Board, Alaska Ocean Observing System and the Exxon Valdez Oil Spill Trustee Council have formed a consortium to ensure such information is collected in Alaska and distribute that information to the public as soon as it becomes available.