Benthic Ecology Blog Post by Morgan Ziegenhorn
When people think of the Arctic, the first thing that comes to mind is probably a polar bear sitting on a piece of ever-shrinking ice. News about polar regions is rarely good, especially when it comes to scientific discoveries—we hear that the ice is diminishing, that the animals are losing habitat, and that rapid change is occurring. While all of these are true, there’s more to our polar climates than meets the eye. The Arctic Ocean is home to the polar bear, but it’s also home to a rich diversity of species that live in deeper water and along the ocean bottom. A recent paper on the Canadian Arctic by Anni Makela and her colleagues at University of Aberdeen in the United Kingdom suggests that in some of these benthic habitats, diversity and productivity will be maintained and possibly even increase as the Arctic warms and sea ice is lost.
Map of the Canadian Arctic, showing the locations of satudy for Makela et al (5).
What’s a benthic habitat like?
Benthic habitats are those that sit along the ocean floor. The world of benthic organisms is very different from ours, but at a basic level they need the same thing we do to survive: food. Much of this food is provided via phytoplankton that live in the surface ocean and require sunlight and nutrients to create energy (termed ‘primary productivity’) through photosynthesis, like many of the land plants we’re more familiar with. When phytoplankton sink down to the ocean floor, they become food for benthic species.
Productivity, diversity, and food chains
The more food a habitat receives, the greater number of individuals and species it can support (one measure of biodiversity). And in general, the greater biodiversity of a system, the better the chance of its survival.
Systems with greater productivity also usually have shorter food chains. Most people are familiar with the idea of a food chain—the grass creates energy via sunlight and nutrients, the rabbit eats the grass, and the wolf eats the rabbit. What’s less familiar is that the energy transferred diminishes with each consumer (i.e. at each “trophic level”). The rabbit doesn’t receive all of the energy created by the grass; the wolf receives even less. For this reason, shorter food chains often mean more energy reaches the animals we usually think about, such as fish, mammals, and sea birds.
Open water and sea ice
In terms of benthic food sources, the Arctic ocean is a special case—here, much of the surface water is covered in ice, which limits the light phytoplankton receive. This makes it more difficult for them to create energy. For this reason, areas of open water (‘polynyas’) are particularly productive. But there is another piece to this puzzle, which has sparked debate over Arctic benthic systems. Sinking algae that lives on the bottom of the sea ice can also be an important source of food for benthic animals. This begs the question, which is more important for a diverse, productive benthic system? The open water, or the sea ice?
Algae vs. phytoplankton
In 2017, Anni Makaela and her colleagues published a paper focused on two open water polynyas in the Arctic Ocean: the North Water Polynya (NOW), which is the biggest and most productive polynya in the northern hemisphere, and the Lancaster Sound Polynya (LS), which is smaller and where sea ice (and associated algae) was previously supposed to contribute more to the diets of benthic species. Both polynyas occur in deep sea sites, which have not been studied as often as coastal/more shallow locations. In their study, these scientists found that benthic organisms in both systems depended mostly on phytoplankton for their food, and that sea ice algae was a prevalent food source only for very mobile organisms who could easily get to it (it falls irregularly to the ocean floor).
The NOW polynya supported a wider range of organisms and shorter trophic chains than the LS polynya, and both were more productive than expected. This suggests that, at least in some cases, deep benthic habitats can be even more productive than their shallow counterparts!
Photo of an Arctic benthic crusteacean, the snow crab (left) and an Arctic benthic bivalve, a mollusk (right) Photos adapted from the Arctic Ocean Diversity database. http://www.arcodiv.org/index.html
The study also found that the smaller polynya was dominated by bivalves (clams, mussels, mollusks) whereas the larger was dominated by crustaceans (crabs, lobsters). They predicted that this was mainly due to differences in current speed—bivalves feed by straining food out of the water, and faster currents aid this process. In some cases, species fed on different prey at each of the two polynyas, which suggests an ability to adjust to changes (i.e., resilience in the face of the changing Arctic Ocean).
What does it all mean?
With global warming, the Arctic Ocean is one of the fastest evolving environments on our planet. Some models predict it will be free of summer ice entirely as soon as 2040. Though this will have major negative impacts on many Arctic species, this study suggests that benthic organisms may reap a positive benefit from increased open water. Additionally, these deep water systems being even more productive than previous studies suggested may change our understanding of the relationship between ocean depth and productivity (it has generally been supposed that the deeper the benthic habitat, the less productive).
How do we study Arctic benthic habitats…
This study provided one of the first examinations of the benthic ecosystem structure for a deep ocean Arctic polynya—but how did the scientists manage it?
To determine what species were at their sites, the authors took large sediment cores. This is a process that involves the removal of a chunk of the ocean floor, which can then be brought back to the lab and examined to determine the number and species of animals present.
To study the food chains and dependence of the organisms on sea ice algae/phytoplankton, this study used stable isotope analysis. This complex process is not so difficult to understand as its name suggests. Essentially, it works through the idea of “you are what you eat” by using carbon and nitrogen to trace the path of food chains through organisms. The ratio of carbon isotopes (carbon atoms with different numbers of neutrons) remains consistent as you travel up a food chain and allows scientists to identify the original food source. In contrast, the ratio of nitrogen isotopes changes at each trophic level. Combining these two via a process called mixed modelling makes it possible to construct food chains and food webs (interconnected food chains) that show who eats who, and at what trophic level.
…and why do we care?
As nice as it is to hear a positive climate change effect, this story is, at its base, about an ocean that most of us will never go to, about organisms that we rarely think of, in depths that we couldn’t survive at. You might think, how could something so remote be connected to my life?
But it is. Many of the Arctic species whose survival we are invested in, such as gray whales and walruses, rely on food from benthic ecosystems like the ones studied in this paper. Arctic sea birds an
A general marine Arctic food web, courtesy of Darnis et al. (2)Facebook pages and laptop backgrounds, will be successful in their changing habitat, it at least may lighten some of their burden.
d seals dive to eat fish that feed on benthic crustaceans. The polar bears, on their thinning ice, hunt these seals. Because we care about the success and future of these species, we have to care about the future of their food.
And that’s how a story that at first seems interesting, but on the whole unimportant, can in fact have a great impact. As the sea ice melts, these polynyas grow larger and potentially more productive and diverse. In this way they provide a feasting ground for many of the species we’re invested in. As food chains shorten, more energy will reach higher trophic levels, where organisms such as the walrus and the polar bear sit. While this isn’t enough to suggest that the animals we care about, the ones whose videos fill our Facebook pages and laptop backgrounds, will be successful in their changing habitat, it at least may lighten some of their burden.
The ocean feeds us, too
Several Arctic fish species that people consume, especially Arctic peoples, rely on benthic production. As the ocean current changes, the LS polynya could no longer support bivalves and might instead support mostly crustaceans. It’s hard to say what the ramifications of this are but understanding them is important for marine Arctic species and the diets of people both in the Arctic and worldwide.
Hardly the end of the story
Makela and her colleagues made some interesting discoveries, but there’s still much that hasn’t been uncovered. Though I mentioned that the future may mean less bivalves (bad news for the organisms that eat them), this study hasn’t concluded whether shifts like this may occur. The authors focused on summer conditions, while in truth, conditions in other seasons are equally important—it’s possible sea ice may play a greater role in non-summer months. Studying the deep ocean remains difficult, and there are still questions about what we might see in other spots of the deep Arctic, especially ones that have been historically less productive. As nice as it is to hear that the Arctic benthos may be benefitting from the loss of sea ice, further study is required to say whether or not this is the case on a larger scale.
Other factors besides ice come into play as well. Temperature, salinity, and ocean mixing rates can all affect productivity levels. It’s important to get the whole story before we can make the claim that Arctic production may increase with climate change, and that some ecosystems will reap a positive benefit from global warming.
But they might.
For today, at least, I’ll take the win.
- Cochrane, Sabine KJ, et al. “Benthic macrofauna and productivity regimes in the Barents Sea—ecological implications in a changing Arctic.”Journal of Sea Research4 (2009): 222-233.
- Darnis, Gérald, et al. “Current state and trends in Canadian Arctic marine ecosystems: II. Heterotrophic food web, pelagic-benthic coupling, and biodiversity.”Climatic Change1 (2012): 179-205.
- Hobson, Keith A., William G. Ambrose Jr, and Paul E. Renaud. “Sources of primary production, benthic-pelagic coupling, and trophic relationships within the Northeast Water Polynya: insights from δ 13 C and δ 15 N analysis.”Marine Ecology Progress Series(1995): 1-10.
- Krupnik, Igor, and Dyanna Jolly.The Earth Is Faster Now: Indigenous Observations of Arctic Environmental Change. Frontiers in Polar Social Science. Arctic Research Consortium of the United States, 3535 College Road, Suite 101, Fairbanks, AK 99709, 2002.
- Mäkelä, Anni, Ursula Witte, and Philippe Archambault. “Benthic macroinfaunal community structure, resource utilisation and trophic relationships in two Canadian Arctic Archipelago polynyas.”PloS one8 (2017): e0183034.
- Moore, Sue E., Jacqueline M. Grebmeier, and Jeremy R. Davies. “Gray whale distribution relative to forage habitat in the northern Bering Sea: current conditions and retrospective summary.”Canadian Journal of Zoology4 (2003): 734-742.
- Odate, Tsuneo, et al. “Temporal and spatial patterns in the surface-water biomass of phytoplankton in the North Water.”Deep Sea Research Part II: Topical Studies in Oceanography22-23 (2002): 4947-4958.
- Overland, James E., and Muyin Wang. “When will the summer Arctic be nearly sea ice free?.”Geophysical Research Letters10 (2013): 2097-2101.
- Post, David M. “Using stable isotopes to estimate trophic position: models, methods, and assumptions.”Ecology3 (2002): 703-718.
- Welch, Harold E., et al. “Energy flow through the marine ecosystem of the Lancaster Sound region, arctic Canada.”Arctic(1992): 343-357.
Less ice means less reflected heat, meaning more intense heatwaves worldwide. But it also means more extreme winters: as the polar jet stream—a high-pressure wind that circles the Arctic region—is destabilized by warmer air, it can dip south, bringing bitter cold with it.
Changes in the amount of sea ice can disrupt normal ocean circulation, thereby leading to changes in global climate. Even a small increase in temperature can lead to greater warming over time, making the polar regions the most sensitive areas to climate change on Earth.Why is sea ice important to the Arctic ecosystem? ›
Sea ice plays an important role maintaining the Earth's energy balance while helping keep polar regions cool due to its ability to reflect more sunlight back to space. Sea ice also keeps air cool by forming an insulating barrier between the cold air above it and the warmer water below it.How does climate change affect Arctic ecosystems? ›
Recent research shows that climate change can potentially alter the transport of pollution to polar areas and exert an even greater burden in the form of environmental toxins on the arctic ecosystem. As climate change warms arctic waters, higher temperatures can increase the uptake of toxins in marine organisms.Will the Arctic be ice-free? ›
The Arctic could see ice-free summers by 2035, reshaping global shipping routes. Arctic sea lanes might be ice-free in the summertime by 2035, according to scientists. The Northern Sea Route may save almost 20 days off the shipping time now spent traveling through the Suez Canal, according to China.Can the Arctic ice Be Saved? ›
Rapidly slashing the world's methane emissions could help save our Arctic summer sea ice, slow climate change and protect countless animals that make sea ice home. The findings come in a powerful new study by EDF researchers Tianyi Sun, Ilissa Ocko, and Steven Hamburg.Why is climate change in the Arctic important? ›
Most prominently, snow and ice are melting at an increasing rate. This impacts both local ecosystems and the global climate system. It contributes to rising sea levels, and is likely to provoke extreme temperature events beyond the Arctic.How can we help climate change in the Arctic? ›
Reducing your carbon emissions and dependence on fossil fuels can help save the Arctic. Discover practical ways you can make a difference, from joining our campaigns to shopping greener at the supermarket and making your home energy efficient.Why Arctic sea ice is important to Earth's weather and climate? ›
Because sea ice is light-colored, it reflects more sunlight (solar energy) back to space than liquid water, thereby playing an important role in maintaining the Earth's energy balance and helping to keep polar regions cool.What is positive impact of the Arctic? ›
As the sea ice melts there's less to reflect the rays, and more heat is absorbed by the ocean, magnifying the warming effect. The Arctic also helps circulate the world's ocean currents, moving cold and warm water around the globe.
changes climate patterns by not keeping polar regions cool. Ice reflects sun (solar energy, or heat) more than liquid water does, and sea ice keeps air cool by separating warm ocean water from cooler air.Why is declining Arctic sea ice a problem? ›
Changes in Arctic sea ice can potentially affect other regions through altered weather patterns and ocean circulation. An ice-free Arctic is creating new business opportunities, political challenges, and threats to the ecosystems and local communities.Is the Arctic ecosystem changing? ›
The global climate is changing, and the Artic is on the front line. Satellite imagery illustrates the dramatic loss of sea ice over the last several decades as air and water temperatures in the Arctic have warmed – one of many documented changes being tracked and reported on annually.What is affecting the Arctic ecosystem? ›
Unless we reduce greenhouse gas emissions rapidly, we will lose the Arctic as we know it. VANISHING HABITATS. Climate change is triggering the rapid loss of entire Arctic habitats, most notably sea ice and glaciers, and is leading to the degradation of others.How does climate change in the Arctic affect the economy? ›
What economic activities are likely to expand in the Arctic due to climate change? In addition to the likely increase of seafood production activities, climate change could influence non-renewable resource extraction, marine transportation, and tourism.What year will the Arctic melt? ›
As a whole, in general, the climate models all agree that the Arctic will become ice-free by 2050. So that's, you know, 30 years.How long will the Arctic last? ›
A 2009 paper from Muyin Wang and James E. Overland applied observational constraints to the projections from six CMIP3 climate models and estimated nearly ice-free Arctic Ocean around September 2037, with a chance it could happen as early as 2028.
Anticipated warming will thaw permafrost over large areas of the Arctic leading to the release of more greenhouse gases to the atmosphere, adding to global warming. The report not only brings into view the impacts hitting the Arctic with full force, but also how they are changing the lives of those who live there.Is it too late to save the Arctic? ›
The UN-sponsored study has reached the conclusion that even if global emissions were suddenly halted right now, winter temperatures in the Arctic would still skyrocket by 4°C to 5°C by the year 2100 as compared to the temperate in the late 20th century.How do we save the Arctic ice? ›
Reduce emissions wherever possible. Gandhi said: be the change you want to see in the world. There is no better time than now to put that into action. Fly or drive less, buy green energy, turn your gadgets off rather than on standby, eat less meat and try slow food, the list goes on and on.
- reduce the consumption of natural resources,
- reduce the emissions of harmful substances into the atmosphere, and.
- preserve the purity of water and forests.
The Arctic—home to diverse wildlife and many cultures—is changing faster than any other part of the planet in the face of climate change. Melting sea ice is already contributing to rising ocean levels worldwide and opening up new areas of the ocean for risky oil drilling.What are the main solutions to climate change? ›
- Keep fossil fuels in the ground. ...
- Invest in renewable energy. ...
- Switch to sustainable transport. ...
- Help us keep our homes cosy. ...
- Improve farming and encourage vegan diets. ...
- Restore nature to absorb more carbon. ...
- Protect forests like the Amazon. ...
- Protect the oceans.
Some of the most promising ways to mitigate climate change are what we call “natural climate solutions”: the conservation, restoration, and improved management of land, in order to increase carbon storage or avoid greenhouse-gas emissions in landscapes worldwide.Who stands to benefit from the loss of Arctic sea ice? ›
Winner: Oil, gas, and shipping companies
The Arctic is estimated to be home to 13% of the world's undiscovered oil and 30% of its undiscovered natural gas.
As glaciers melt, they add nutrients to the ocean and fertilize the local ecosystem. In Greenland and Antarctica, the ocean is short on iron, so melting glaciers make up for the lack of iron. Photosynthesizing phytoplankton are the base of the food web in the ocean and require lots of light and nutrients to grow.Why do people want to live in the Arctic? ›
High-paying jobs and life in the wilderness is appealing to many people, and living in the Arctic allows individuals to earn money and go about their lives with minimal interference from the outside world. Many individuals are also attracted by the natural beauty of the region, unspoiled by human habitation.How does the Arctic affect the world? ›
And the Arctic helps to regulate the world's temperature, so as more Arctic ice melts the warmer our world becomes. These are the facts: Melting ice speeds up climate change. Global warming is causing Arctic ice to melt – ice reflects sunlight, while water absorbs it.Why do people want to claim the Arctic? ›
As polar sea ice has melted and opened new potential shipping lanes, the Arctic has become a new frontier where nations are seeking oil and natural gas reserves and preparing to defend them militarily, if necessary.Can you drink melted sea ice? ›
As ice ages, the brine eventually drains through the ice, and by the time it becomes multiyear ice, nearly all the brine is gone. Most multiyear ice is fresh enough that someone could drink its melted water.
There is still some uncertainty about the full volume of glaciers and ice caps on Earth, but if all of them were to melt, global sea level would rise approximately 70 meters (approximately 230 feet), flooding every coastal city on the planet.How long will it take for the doomsday glacier to melt? ›
In 2020, scientists found evidence that warm water was indeed flowing across the base of the glacier, melting it from underneath. And then in 2021, a study showed the Thwaites Ice Shelf, which helps to stabilize the glacier and hold the ice back from flowing freely into the ocean, could shatter within five years.What would happen to Arctic waters if the ocean current stopped? ›
If the currents were to stop completely, the average temperature of Europe would cool 5 to 10 degrees Celsius. There would also be impacts on fisheries and hurricanes in the region. The currents in the North Atlantic are part of a global pattern called thermohaline circulation, or the global ocean conveyor.What is the main problem in the Arctic? ›
Three main interrelated issues are affecting the Arctic environment: climate change, changes in biological diversity and the accumulation of toxic substances. The Arctic appears to be both a harbinger of environmental change and a key determinant of that change, particularly as it relates to climate.How will the loss of Arctic sea ice affect the ocean currents and climate near the western European coast? ›
The cold tide may well slow down the Atlantic currents that bring warmth to Western Europe. Citing the researchers, NASA says in its news release that disruptions to the Gulf Stream would have a negative impact on ocean life and the communities that depend on them.What is one result of the changing conditions in the Arctic? ›
Changes in the Arctic could result in migration of fish stocks to new waters, and could affect protected species. The diminishment of Arctic sea ice has led to increased human activities in the Arctic, and has heightened interest in, and concerns about, the region's future.What are the positive impacts of climate change? ›
The chief benefits of global warming include: fewer winter deaths; lower energy costs; better agricultural yields; probably fewer droughts; maybe richer biodiversity.What happens if all the ice melts? ›
There is still some uncertainty about the full volume of glaciers and ice caps on Earth, but if all of them were to melt, global sea level would rise approximately 70 meters (approximately 230 feet), flooding every coastal city on the planet.When was the last time there was no ice in the Arctic? ›
12,000 years ago, the most recent ice age ended, setting the stage for the beginning of human civilization. 250 years ago, coal was first used to power steam engines in England. 1 year ago, atmospheric carbon dioxide reaches 400 parts per million for the first time in at least 800,000 years, probably longer.What happens if ice glaciers melt? ›
Melting glaciers add to rising sea levels, which in turn increases coastal erosion and elevates storm surge as warming air and ocean temperatures create more frequent and intense coastal storms like hurricanes and typhoons.
The melting of this Arctic sea ice will most likely lead to further climate change. This is a problem because climate change affects almost everything important to humans, like plants, animals, the weather, and commerce. All these things, in turn, affect our food supplies.How long it will be until the next ice age? ›
Predicted changes in orbital forcing suggest that the next glacial period would begin at least 50,000 years from now. Moreover, anthropogenic forcing from increased greenhouse gases is estimated to potentially outweigh the orbital forcing of the Milankovitch cycles for hundreds of thousands of years.Are we still in an ice age? ›
Striking during the time period known as the Pleistocene Epoch, this ice age started about 2.6 million years ago and lasted until roughly 11,000 years ago. Like all the others, the most recent ice age brought a series of glacial advances and retreats. In fact, we are technically still in an ice age.Will the Earth melt a few years from now? ›
Four billion years from now, the increase in Earth's surface temperature will cause a runaway greenhouse effect, creating conditions more extreme than present-day Venus and heating Earth's surface enough to melt it. By that point, all life on Earth will be extinct.How long will it take for all the ice to melt? ›
There are more than five million cubic miles of ice on Earth, and some scientists say it would take more than 5,000 years to melt it all.Is the Arctic getting colder? ›
It finds that the Arctic Circle — the area located above 66.5 degrees latitude — has warmed by more than 5 degrees Fahrenheit since 1979. In all, the study concludes, the Arctic has warmed at about four times the global average rate over the last 43 years.Is the Arctic ice shrinking or growing? ›
Key Takeaway: Summer Arctic sea ice extent is shrinking by 12.6% per decade as a result of global warming. Arctic sea ice reaches its minimum extent (the area in which satellite sensors show individual pixels to be at least 15% covered in ice) each September.How the Earth would look if all the ice melted? ›
The entire Atlantic seaboard would vanish, along with Florida and the Gulf Coast. In California, San Francisco's hills would become a cluster of islands and the Central Valley a giant bay. The Gulf of California would stretch north past the latitude of San Diego—not that there'd be a San Diego.What will the world look like if all the ice melted? ›
If all the ice covering Antarctica , Greenland, and in mountain glaciers around the world were to melt, sea level would rise about 70 meters (230 feet). The ocean would cover all the coastal cities. And land area would shrink significantly. But many cities, such as Denver, would survive.What are the positive effects of Arctic ice melting? ›
As glaciers melt, they add nutrients to the ocean and fertilize the local ecosystem. In Greenland and Antarctica, the ocean is short on iron, so melting glaciers make up for the lack of iron. Photosynthesizing phytoplankton are the base of the food web in the ocean and require lots of light and nutrients to grow.
If the currents were to stop completely, the average temperature of Europe would cool 5 to 10 degrees Celsius. There would also be impacts on fisheries and hurricanes in the region. The currents in the North Atlantic are part of a global pattern called thermohaline circulation, or the global ocean conveyor.