//
you're reading...

Biodiversity

A transforming ecosystem: Chukchi and Bering Sea

Article: Huntington, H.P., Danielson, S.L., Wiese, F.K. et al. Evidence suggests potential transformation of the Pacific Arctic ecosystem is underway. Nat. Clim. Chang. (2020).

Even though we constantly hear about climate change, we still do not understand how exactly and to what extent it affects our ecosystems. That is because ecosystems do not respond in a simple fashion. Instead, various components interact in a sophisticated manner that is difficult to predict. Hence to get a complete picture, it is essential to look at how different elements react to a change instead of studying just a few.  In one such study, Huntington et al. looked at the effects of increasing temperature on various components such as phytoplankton, migratory birds, mammals, hunting communities of the Chukchi and Bering Sea Ecosystem.

Understanding the Chukchi and Bering Sea Ecosystem

 

Fig. 1 Satellite image showing northern Bering and Chukchi sea-ice conditions on 2 June 2017

Chukchi sea in the Pacific Arctic is one of the most productive regions in the world oceans (Fig. 1). During spring and summer, the ice melts and allows nutrient-rich waters from Bering Strait into the Chukchi Sea. Nutrient-rich waters result in phytoplankton blooms that form the base of the food web. Some of the phytoplankton escape grazing by zooplankton and fish in the water column and settles on the sea surface, serving as food for the organisms living on the seafloor like sea squirts and worms. The region is also home to nesting, migratory birds, and other marine mammals that support the indigenous coastal communities in the area. During autumn and winters, the ice formation reduces the flow of nutrient-rich waters to the Chukchi and limits the migratory birds, seals, Pacific walrus, and whales to the Bering Sea.

How is the ecosystem changing?

In recent years the Chukchi-Bearing Sea ecosystem has started to deviate from what we knew about it. Sea Ice is excellent at reflecting most of the sunlight falling on it and keeps the surroundings cool. Less sea ice means less reflection and greater absorption of sunlight which results in warming and accelerates the melting. In recent years warming has increased the amount of nutrient-rich waters flowing into the Chukchi Sea, as it remains ice-free for a good part of the year. Warming has also led the migratory birds and mammals to move northwards. For the hunting communities, the opportunities dependent on the presence of sea-ice have decreased or shifted in time. Arctic mammals such as seals and walruses use sea-ice as a platform to rest and nurse their young, this makes it easier for hunters to get them. But at the same time, the lack of sea ice in autumn and early winters has allowed additional whaling as less sea-ice opens up the Arctic to less ice adapted humpback, fin, and killer whales.

In addition to worldwide warming, the Arctic Pacific saw unusual warming in 2017. During the winter of 2017, the ice was observed only up to the Bering Strait, and the Bering Sea remained ice-free. The summer of 2017 also saw much warmer waters in the Bering Sea. Similar observations were made in 2018 and 2019. The authors of this study looked at the published and unpublished data on phytoplankton, migratory birds, fish catch, hunting communities, mammals, etc., from 2018 and 2019. To assess whether the changes in the ecosystem due to 2017 warming have persisted in 2018 and 2019.

Changes due to unusual warming

Bowhead whale (NOAA, Fisheries)

In the spring of 2018, phytoplankton bloom was delayed in the Bering Sea due to the lack of fresh water that comes from melting ice. But at the same time, the northern Bering Sea saw premature ice melt and hence an early bloom. Unfortunately, a bloom doesn’t always mean an excess of food. Due to the change in the timing and conditions of the bloom, the toxic phytoplankton species sometimes replace the usual phytoplankton species. Scientists found saxitoxin and domoic acid in the water samples and walruses harvested from the Bering Strait. These compounds are toxins released by some phytoplankton to protect themselves from grazing and have led to food safety concerns for the indigenous communities. The organisms, like copepods that feed on phytoplankton, also declined in numbers. The fishes and seabirds moved northwards into the Chukchi Sea due to the lack of sea-ice. The total numbers of seabirds declined in the Bering Sea as higher numbers were spotted in the Chukchi Sea.

 

Spotted seal pup (NOAA, Fisheries)

Now moving to the mammals, the scientists saw bowhead whales near Alaska, which is to the north of Chukchi Sea, nearly a month earlier than usual. These whales spent their winters in the Chukchi sea instead of their typical winter habitat in the Bering Sea. Smaller and weaker spotted seal pups were found during these years, and a lot of seal carcasses belonged to young and starved pups. The scientists attribute this mortality to lower food quality; even though fish like Salmon and Arctic Cod increased in numbers, they weren’t as nutritious.

 

Such changes may not be brief; instead, they may be a sign of what is to come.

The effects of the unusual warming persisted in 2018 and 2019. This interdisciplinary study points towards the opportunity to study the changes as they unfold rather than reconstructing them later. Even though the effects of unusual warming in 2017 may slowly wean off, they give us a glimpse into what is to come if the planet continues to warm. The authors point out that the Arctic ecosystem will most likely transform into a subarctic ecosystem; that is, the Chukchi Sea may resemble the Bering Sea though some differences will exist. As the sea-ice recedes some species will cling to their typical habitat while others will shift and severely affect the quality and the quantity of food. The major takeaway is to continuously monitor such ecosystems to stay ahead of the transformations rather than to react to them later.

 

 

 

Discussion

No comments yet.

Post a Comment

Instagram

  • by oceanbites 3 months ago
    Happy Earth Day! Take some time today to do something for the planet and appreciate the ocean, which covers 71% of the Earth’s surface.  #EarthDay   #OceanAppreciation   #Oceanbites   #CoastalVibes   #CoastalRI 
  • by oceanbites 4 months ago
    Not all outdoor science is fieldwork. Some of the best days in the lab can be setting up experiments, especially when you get to do it outdoors. It’s an exciting mix of problem solving, precision, preparation, and teamwork. Here is
  • by oceanbites 5 months ago
    Being on a research cruise is a unique experience with the open water, 12-hour working shifts, and close quarters, but there are some familiar practices too. Here Diana is filtering seawater to gather chlorophyll for analysis, the same process on
  • by oceanbites 6 months ago
    This week for  #WriterWednesday  on  #oceanbites  we are featuring Hannah Collins  @hannahh_irene  Hannah works with marine suspension feeding bivalves and microplastics, investigating whether ingesting microplastics causes changes to the gut microbial community or gut tissues. She hopes to keep working
  • by oceanbites 6 months ago
    Leveling up - did you know that crabs have a larval phase? These are both porcelain crabs, but the one on the right is the earlier stage. It’s massive spine makes it both difficult to eat and quite conspicuous in
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring Cierra Braga. Cierra works ultraviolet c (UVC) to discover how this light can be used to combat biofouling, or the growth of living things, on the hulls of ships. Here, you
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Elena Gadoutsis  @haysailor  These photos feature her “favorite marine research so far: From surveying tropical coral reefs, photographing dolphins and whales, and growing my own algae to expose it to different
  • by oceanbites 8 months ago
    This week for  #WriterWednesday  on Oceanbites we are featuring Eliza Oldach. According to Ellie, “I study coastal communities, and try to understand the policies and decisions and interactions and adaptations that communities use to navigate an ever-changing world. Most of
  • by oceanbites 8 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Jiwoon Park with a little photographic help from Ryan Tabata at the University of Hawaii. When asked about her research, Jiwoon wrote “Just like we need vitamins and minerals to stay
  • by oceanbites 8 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring  @riley_henning  According to Riley, ”I am interested in studying small things that make a big impact in the ocean. Right now for my master's research at the University of San Diego,
  • by oceanbites 8 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Gabby Stedman. Gabby is interested in interested in understanding how many species of small-bodied animals there are in the deep-sea and where they live so we can better protect them from
  • by oceanbites 8 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Shawn Wang! Shawn is “an oceanographer that studies ocean conditions of the past. I use everything from microfossils to complex computer models to understand how climate has changed in the past
  • by oceanbites 9 months ago
    Today we are highlighting some of our awesome new authors for  #WriterWednesday  Today we have Daniel Speer! He says, “I am driven to investigate the interface of biology, chemistry, and physics, asking questions about how organisms or biological systems respond
  • by oceanbites 9 months ago
    Here at Oceanbites we love long-term datasets. So much happens in the ocean that sometimes it can be hard to tell if a trend is a part of a natural cycle or actually an anomaly, but as we gather more
  • by oceanbites 10 months ago
    Have you ever seen a lobster molt? Because lobsters have exoskeletons, every time they grow they have to climb out of their old shell, leaving them soft and vulnerable for a few days until their new shell hardens. Young, small
  • by oceanbites 11 months ago
    A lot of zooplankton are translucent, making it much easier to hide from predators. This juvenile mantis shrimp was almost impossible to spot floating in the water, but under a dissecting scope it’s features really come into view. See the
  • by oceanbites 11 months ago
    This is a clump of Dead Man’s Fingers, scientific name Codium fragile. It’s native to the Pacific Ocean and is invasive where I found it on the east coast of the US. It’s a bit velvety, and the coolest thing
  • by oceanbites 11 months ago
    You’ve probably heard of jellyfish, but have you heard of salps? These gelatinous sea creatures band together to form long chains, but they can also fall apart and will wash up onshore like tiny gemstones that squish. Have you seen
  • by oceanbites 12 months ago
    Check out what’s happening on a cool summer research cruise! On the  #neslter  summer transect cruise, we deployed a tow sled called the In Situ Icthyoplankton Imaging System. This can take pictures of gelatinous zooplankton (like jellyfish) that would be
  • by oceanbites 1 year ago
    Did you know horseshoe crabs have more than just two eyes? In these juveniles you can see another set in the middle of the shell. Check out our website to learn about some awesome horseshoe crab research.  #oceanbites   #plankton   #horseshoecrabs 
WP2Social Auto Publish Powered By : XYZScripts.com