8 ms·

North Atlantic warming over six decades drives decreases in krill abundance

212 points by aseerdbnarng 5y ago

MattGaiser 5y ago
I was assuming that outside of niche animals, upward/downward migration by animals would buy us time in dealing with climate change. Apparently not.
- aliasEli 5y ago
  All animals depend directly or indirectly on plants. Plants in general can only migrate very slowly (or not at all).
vegetablepotpie 5y ago
The cause is further down in the abstract > Consequently the two temperatures defining the core of krill distribution (7–13 °C) were 8° of latitude apart 60 years ago but are presently only 4° apart. Krill lost 50% of their habitat in the last 60 years. This article has been added to my favorites because this is one piece of evidence that shows that climate change won’t just shift organisms north, but will result in reductions of species that will impact our ecosystems.
- ajb 5y ago
  Reduction from 8 degrees of latitude to 4 doesn't tell us the area reduction, because the area depends on the absolute distance from the pole. It's also not linear because if the outer radius changes, the change should be proportional to the square of the radius, so potentially more than 50%, or potentially no change or even growth, if the ideal thermal area moved outwards
  - h0l0cube 5y ago
    Or you could click on the article and see for yourself, under the safe presumption that the researchers would do a more thorough job than the lay person. From the article, figure 2: > Mean spatial abundance of euphausiids per decade in the North Atlantic from 1958–2017 split into six time-periods 1958–1967; 1968–1977; 1978–1987; 1988–1997; 1998–2007; 2008–2017. https://www.nature.com/articles/s42003-021-02159-1/figures/2 https://www.nature.com/articles/s42003-021-02159-1/figures/2
- xhkkffbf 5y ago
  I realize that habitat loss is a big thing, but I also know that some krill-eating species like the big whales have rebounded over the last 60 years. Could this decline in krill be the result of the return of the whales?
  - jheitzeb 5y ago
    Krill is a keystone species. Lose krill and the food chain collapses — at least krill is thought to hold such a role in the Southern Hemisphere. There, it is harvesting for omega 3 supplements that’s causing the decline. https://www.theguardian.com/environment/2008/mar/23/fishing.food https://www.theguardian.com/environment/2008/mar/23/fishing....
    - eloff 5y ago
      I think mostly the krill is used as fish and animal feed as a source of protein. Supplements are probably a small part of the consumption. It seems like a bad idea to overfish the base food chain species. But then pretty much everything we do with the ocean is a bad idea. The only thing that has been positive where the oceans are concerned is creating marine reserves where commercial fishing is prohibited, and enforcing that.
  - aliasEli 5y ago
    It seems pretty unlikely. For all whale specious the numbers are far lower than historical numbers. There is a huge amount of krill and there are a lot of other species that have been doing this for a very long time.
- pvaldes 5y ago
  > Krill lost 50% of their habitat in the last 60 years. Not necessarily. Krill species live from surface to fairly deep waters. Surface is an important, but small part on its entire habitat. We need to take in mind that all in this study is about the situation found when sampling an area between 0-10m deep. For Thysanoessa for example this means that if you don't find them at the surface there is still a 390m deep layer where they could still be located. Meganyctiphanes, Nematobranchion and Thysanopoda concentrate normally in waters below 400m by day (Saunders et al, 2013). They can migrate to surface [1] at night, but can also choose to remain close to the sea bottom in much deeper areas. It depends a lot on the species, location and time of the year. [1] More or less, surface does not mean 0m necessarily, can mean -15m or -20m also.
spodek 5y ago
We can dance around our environmental issues all we want, we'll always reach overpopulation and overconsumption driven by cultural beliefs. Until we act on values other than growth, efficiency, comfort, convenience, extraction, and externalizing costs, we will continue this trend. Plenty of cultures have thrived with other values. We can too. People insist that individual actions don't matter and that only governments and corporations can make a difference. We accept this hogwash proven wrong by history over and over to mollify our indulgence. Acting in stewardship doesn't bring deprivation or sacrifice. It brings joy, fun, freedom, community, connection, meaning, and purpose. The greatest change we make is leading others, because it multiplies our effect, which requires leading ourselves. Still, logic, facts, and figures don't change behavior. We change when five people around us do, loosely speaking. In that spirit, I'll share that I've dropped my emissions over 90 percent with only improvements to my life. I take two years to fill a load of trash and haven't flown since March 2016, picking up litter daily since 2017, my last electrical bill $1.40 so nearly off-grid living in Manhattan, plus plenty more. All sources of joy, more time with family and friends, more control over my career, saving money, more gratitude from people with less resources who tell me their changes improve their lives and save them time, money, and the other resources they lack. The main Resistance (capitalized to refer to Steven Pressfield's relevant book The War of Art) comes from people with more resources than me, who say what I did before changing. Strangely, those with the most act like they can change the least. Resources that were supposed to improve our lives make us spoiled, entitled, needy, and dependent, the opposite of free and fun. To those who insist there's no point, you can argue against me, but now that you know someone who's done it, you're 20 percent there. Find another few who have changed and you'll change too.
- blfr 5y ago
  Convenience has been killing fertility for decades. At present rates only Africa is heading for anything like overpopulation and I doubt they'll hold.
- DFHippie 5y ago
  Change through government regulation is really only compelled individual change. If everyone changed their behavior of their own free will -- well, we wouldn't need laws at all; this would be a solution for everything! So, on the one hand I agree with you, justifying one's own failure to change by claiming only federal action will work is mostly just laziness and selfishness papered over with a thin excuse. On the other, mass personal enlightenment will not occur nearly fast enough to solve the problem if it's even possible at all. And in the meantime you'll have unrepentant selfish people freeloading, some of them rolling coal to spite you because they take your virtue as a personal slight or because they're sadists. By all means, everyone should take this seriously and do what they can without compulsion. I've been striving to do this since the eighties. But honestly if we want to fix the problem the only thing that can come up to scale with sufficient speed is decisions by people who control large segments of the economy, i.e. governments and corporations.
aseerdbnarng 5y ago
I had casually assumed climate change would only really impact animals high up the food chain. But to see this amount of species loss in animals at the very bottom of the food chain frightens me
- lotsofpulp 5y ago
  Do you consider humans to be animals high up in the food chain?
  - menzoic 5y ago
    We can hunt and eat any animal that we "want" and systematically control and produce supply. That's the highest you can get in the food chain.
    - lotsofpulp 5y ago
      I was just making a tongue in cheek comment about being frightened by loss at the bottom of the chain, but (presumably) not about the top, where we are.
      - chrisseaton 5y ago
        They didn't say they weren't afraid of loss at the top, but that they were also afraid of loss at the bottom.
  - ben_w 5y ago
    Food chain vs. food web aside, not many of us die from being eaten.
  - slver 5y ago
    You can get meta and demonstrate the food chain is closed in a circle, which it is, but in a conventional sense, yes we are.
- jefurii 5y ago
  If I've understood the science stories I've been reading the organisms closer to the bottom of the food chain (plankton, krill, insects, etc) outnumber us in terms of biomass, and we are incredibly dependent on the part they play in our ecosystem. The decline in these species is something to take very seriously.
gigatexal 5y ago
I hope the whales and other sea life can adapt.
- DFHippie 5y ago
  With less food the only avenues for adaptation I can see are becoming fewer or smaller. ETA At mass extinctions the things that survive and repopulate the Earth are the small generalists with a fast reproductive cycle. Whales are the opposite of this.
  - gigatexal 5y ago
    :( Let’s hope we get climate change handled so at least the animals that didn’t add to it don’t have to needlessly suffer.
    - ajmurmann 5y ago
      Really hard to be optimistic about this given anything we do will take a while to take effect and we aren't doing anything of any substance.
deepzn 5y ago
What's interesting too is they could not find other instances of this happening in others, could perhaps be unique to Krill > Another important group of zooplankton, the appendicularians, have shown a dramatic increase, nearly quadrupling their abundance since the 1960s, suggesting that, while there has been an overall increase in phytoplankton biomass in this region, there could also be a trend towards a smaller size-fraction of phytoplankton. It is unclear why the euphausiids alone among the most dominant zooplankton taxa in this region have shown a particular decline since the 1990s.
thedogeye 5y ago
Could the recovery of whale populations have a role in this?
trainsplanes 5y ago
Talk to a person who spent a lot of time in nature 60 years ago and they'll tell you about water was overflowing with fish. Insects basically clouded the skies in summer. Forests and fields were full of animals and they'd regularly wake up to wild animals at their front door every morning. It sounds like tall tales to a large number of people today, but even in my short life of only 30 years, the change is huge. I remember being a kid and windshields being covered in insects after a 30 minute drive. I remember turning a light on outside at night and the sides of the house being swarmed luna moths, hordes of bats swooping by and grabbing everything they could, and possums scattering away from the porch. I'd walk around the lake and see snapping turtles lazing about in the sun. Fish splashing in the water. Walking in streams, there'd be so many crayfish that they'd slip inside my sandals and I'd accidentally crush them. Now I see nothing.
- Amezarak 5y ago
  Same here. I think a lot of this is due to the massive increase in plastic pollution, endocrine disruptors, and insecticides wrecking the bottom part of the food chain. Even the swarms of lovebugs are noticeably thinner these days. Correlation isn't causation, but it wasn't that long ago plastic was much, much rarer - talk to people over 60!
  - lotsofpulp 5y ago
    People were rarer too. 3B in 1960 to 7.7B today. Not to mention resource consumed per capita exploded.
- sk5t 5y ago
  Or else tadpoles and tiny shrimp in a cup dipped into a pond. Grasshoppers thick in an autumn meadow. And now it feels as if the plants are okay but the animals are all gone.
- f6v 5y ago
  I don’t know, I still see bats every night in a ~250k city. And don’t get me started on all the bugs that get into the apartment. I hate when I have to kill that helicopter-sized moth.
skinkestek 5y ago
I recently learned that another problem is that whales used to bring minerals up from the deep ocean and poop it out which provided food for plankton on the surface.
pvaldes 5y ago
Dear Nature peer reviewers, maybe could I introduce you to the 112,000 jumpback whales or the 40,000 fin whales returning to the area after its chase was forbidden just 6 decades ago? It seems a fact that would merit to be discussed in the article at least. Several big populations of whales where at the brink of extinction then. Maybe the euphausiacean population was abnormally high before, and more normal now?. Finding preys to quit gradually the surface and search for deeper areas when its main predators gradually increase is not a strange outcome, or one that would need necessarily a climate change explanation as the main factor. The study toke samples of the first 10 meters of water only.
- hallarempt 5y ago
  a) s/yourself/you to/ b) a laughably small number of whales -- even though it's more than it was -- doesn't invalidate the premise of the article. The only reason there are a few more whales than there were is the ban on hunting. The reason there aren't lot more of them is that there isn't enough food, because you, and me, and everyone else is fucking up the climate.
  - pvaldes 5y ago
    Fixed, many thanks. If the main predator of one species is increased by, lets say x500 (nobody knows the real value really) and we observe a significant reduction in the number of preys, this is the first thing that we must assure to mention in our discussion. As research is a so slow process I'm having a hard time thinking that everybody just forgot to see the 'big whale in the room'. A logical explanation is that they put their bet in the winner horse (those that would sell better and had more options to end the publishing race). The logical, but boring explanation would be put under the rug. I could be wrong, of course, but this is not how science should work (in my arrogant opinion). > The reason there aren't lot more of them is that there isn't enough food, because everyone is fucking up the climate. We need to choose between the truth or the ideology. A simpler alternative explanation is that the ecosystem changed and do not have room for allowing more whales. Other that we just see the population in the middle of a recovery, not the final phase and our grandsons will see much more whales and even much less krill. Whales mature and breed slowly so they recover slowly. Ship traffic, fish nets, fish hooks, diseases or whale fishing quotes don't help. The lack of food can be related with climate warming, but also with over-fishing and plastic pollution.

212 points by aseerdbnarng 5y ago

I was assuming that outside of niche animals, upward/downward migration by animals would buy us time in dealing with climate change. Apparently not.

aliasEli 5y ago
All animals depend directly or indirectly on plants. Plants in general can only migrate very slowly (or not at all).

vegetablepotpie 5y ago

The cause is further down in the abstract > Consequently the two temperatures defining the core of krill distribution (7–13 °C) were 8° of latitude apart 60 years ago but are presently only 4° apart. Krill lost 50% of their habitat in the last 60 years. This article has been added to my favorites because this is one piece of evidence that shows that climate change won’t just shift organisms north, but will result in reductions of species that will impact our ecosystems.

ajb 5y ago
Reduction from 8 degrees of latitude to 4 doesn't tell us the area reduction, because the area depends on the absolute distance from the pole. It's also not linear because if the outer radius changes, the change should be proportional to the square of the radius, so potentially more than 50%, or potentially no change or even growth, if the ideal thermal area moved outwards
- h0l0cube 5y ago
  Or you could click on the article and see for yourself, under the safe presumption that the researchers would do a more thorough job than the lay person. From the article, figure 2: > Mean spatial abundance of euphausiids per decade in the North Atlantic from 1958–2017 split into six time-periods 1958–1967; 1968–1977; 1978–1987; 1988–1997; 1998–2007; 2008–2017. https://www.nature.com/articles/s42003-021-02159-1/figures/2 https://www.nature.com/articles/s42003-021-02159-1/figures/2
xhkkffbf 5y ago
I realize that habitat loss is a big thing, but I also know that some krill-eating species like the big whales have rebounded over the last 60 years. Could this decline in krill be the result of the return of the whales?
- jheitzeb 5y ago
  Krill is a keystone species. Lose krill and the food chain collapses — at least krill is thought to hold such a role in the Southern Hemisphere. There, it is harvesting for omega 3 supplements that’s causing the decline. https://www.theguardian.com/environment/2008/mar/23/fishing.food https://www.theguardian.com/environment/2008/mar/23/fishing....
  - eloff 5y ago
    I think mostly the krill is used as fish and animal feed as a source of protein. Supplements are probably a small part of the consumption. It seems like a bad idea to overfish the base food chain species. But then pretty much everything we do with the ocean is a bad idea. The only thing that has been positive where the oceans are concerned is creating marine reserves where commercial fishing is prohibited, and enforcing that.
- aliasEli 5y ago
  It seems pretty unlikely. For all whale specious the numbers are far lower than historical numbers. There is a huge amount of krill and there are a lot of other species that have been doing this for a very long time.
pvaldes 5y ago
> Krill lost 50% of their habitat in the last 60 years. Not necessarily. Krill species live from surface to fairly deep waters. Surface is an important, but small part on its entire habitat. We need to take in mind that all in this study is about the situation found when sampling an area between 0-10m deep. For Thysanoessa for example this means that if you don't find them at the surface there is still a 390m deep layer where they could still be located. Meganyctiphanes, Nematobranchion and Thysanopoda concentrate normally in waters below 400m by day (Saunders et al, 2013). They can migrate to surface [1] at night, but can also choose to remain close to the sea bottom in much deeper areas. It depends a lot on the species, location and time of the year. [1] More or less, surface does not mean 0m necessarily, can mean -15m or -20m also.

spodek 5y ago

We can dance around our environmental issues all we want, we'll always reach overpopulation and overconsumption driven by cultural beliefs. Until we act on values other than growth, efficiency, comfort, convenience, extraction, and externalizing costs, we will continue this trend. Plenty of cultures have thrived with other values. We can too. People insist that individual actions don't matter and that only governments and corporations can make a difference. We accept this hogwash proven wrong by history over and over to mollify our indulgence. Acting in stewardship doesn't bring deprivation or sacrifice. It brings joy, fun, freedom, community, connection, meaning, and purpose. The greatest change we make is leading others, because it multiplies our effect, which requires leading ourselves. Still, logic, facts, and figures don't change behavior. We change when five people around us do, loosely speaking. In that spirit, I'll share that I've dropped my emissions over 90 percent with only improvements to my life. I take two years to fill a load of trash and haven't flown since March 2016, picking up litter daily since 2017, my last electrical bill $1.40 so nearly off-grid living in Manhattan, plus plenty more. All sources of joy, more time with family and friends, more control over my career, saving money, more gratitude from people with less resources who tell me their changes improve their lives and save them time, money, and the other resources they lack. The main Resistance (capitalized to refer to Steven Pressfield's relevant book The War of Art) comes from people with more resources than me, who say what I did before changing. Strangely, those with the most act like they can change the least. Resources that were supposed to improve our lives make us spoiled, entitled, needy, and dependent, the opposite of free and fun. To those who insist there's no point, you can argue against me, but now that you know someone who's done it, you're 20 percent there. Find another few who have changed and you'll change too.

blfr 5y ago
Convenience has been killing fertility for decades. At present rates only Africa is heading for anything like overpopulation and I doubt they'll hold.
DFHippie 5y ago
Change through government regulation is really only compelled individual change. If everyone changed their behavior of their own free will -- well, we wouldn't need laws at all; this would be a solution for everything! So, on the one hand I agree with you, justifying one's own failure to change by claiming only federal action will work is mostly just laziness and selfishness papered over with a thin excuse. On the other, mass personal enlightenment will not occur nearly fast enough to solve the problem if it's even possible at all. And in the meantime you'll have unrepentant selfish people freeloading, some of them rolling coal to spite you because they take your virtue as a personal slight or because they're sadists. By all means, everyone should take this seriously and do what they can without compulsion. I've been striving to do this since the eighties. But honestly if we want to fix the problem the only thing that can come up to scale with sufficient speed is decisions by people who control large segments of the economy, i.e. governments and corporations.

aseerdbnarng 5y ago

I had casually assumed climate change would only really impact animals high up the food chain. But to see this amount of species loss in animals at the very bottom of the food chain frightens me

lotsofpulp 5y ago
Do you consider humans to be animals high up in the food chain?
- menzoic 5y ago
  We can hunt and eat any animal that we "want" and systematically control and produce supply. That's the highest you can get in the food chain.
  - lotsofpulp 5y ago
    I was just making a tongue in cheek comment about being frightened by loss at the bottom of the chain, but (presumably) not about the top, where we are.
    - chrisseaton 5y ago
      They didn't say they weren't afraid of loss at the top, but that they were also afraid of loss at the bottom.
- ben_w 5y ago
  Food chain vs. food web aside, not many of us die from being eaten.
- slver 5y ago
  You can get meta and demonstrate the food chain is closed in a circle, which it is, but in a conventional sense, yes we are.
jefurii 5y ago
If I've understood the science stories I've been reading the organisms closer to the bottom of the food chain (plankton, krill, insects, etc) outnumber us in terms of biomass, and we are incredibly dependent on the part they play in our ecosystem. The decline in these species is something to take very seriously.

gigatexal 5y ago

I hope the whales and other sea life can adapt.

DFHippie 5y ago
With less food the only avenues for adaptation I can see are becoming fewer or smaller. ETA At mass extinctions the things that survive and repopulate the Earth are the small generalists with a fast reproductive cycle. Whales are the opposite of this.
- gigatexal 5y ago
  :( Let’s hope we get climate change handled so at least the animals that didn’t add to it don’t have to needlessly suffer.
  - ajmurmann 5y ago
    Really hard to be optimistic about this given anything we do will take a while to take effect and we aren't doing anything of any substance.

deepzn 5y ago

What's interesting too is they could not find other instances of this happening in others, could perhaps be unique to Krill > Another important group of zooplankton, the appendicularians, have shown a dramatic increase, nearly quadrupling their abundance since the 1960s, suggesting that, while there has been an overall increase in phytoplankton biomass in this region, there could also be a trend towards a smaller size-fraction of phytoplankton. It is unclear why the euphausiids alone among the most dominant zooplankton taxa in this region have shown a particular decline since the 1990s.

thedogeye 5y ago

Could the recovery of whale populations have a role in this?

trainsplanes 5y ago

Talk to a person who spent a lot of time in nature 60 years ago and they'll tell you about water was overflowing with fish. Insects basically clouded the skies in summer. Forests and fields were full of animals and they'd regularly wake up to wild animals at their front door every morning. It sounds like tall tales to a large number of people today, but even in my short life of only 30 years, the change is huge. I remember being a kid and windshields being covered in insects after a 30 minute drive. I remember turning a light on outside at night and the sides of the house being swarmed luna moths, hordes of bats swooping by and grabbing everything they could, and possums scattering away from the porch. I'd walk around the lake and see snapping turtles lazing about in the sun. Fish splashing in the water. Walking in streams, there'd be so many crayfish that they'd slip inside my sandals and I'd accidentally crush them. Now I see nothing.

Amezarak 5y ago
Same here. I think a lot of this is due to the massive increase in plastic pollution, endocrine disruptors, and insecticides wrecking the bottom part of the food chain. Even the swarms of lovebugs are noticeably thinner these days. Correlation isn't causation, but it wasn't that long ago plastic was much, much rarer - talk to people over 60!
- lotsofpulp 5y ago
  People were rarer too. 3B in 1960 to 7.7B today. Not to mention resource consumed per capita exploded.
sk5t 5y ago
Or else tadpoles and tiny shrimp in a cup dipped into a pond. Grasshoppers thick in an autumn meadow. And now it feels as if the plants are okay but the animals are all gone.
f6v 5y ago
I don’t know, I still see bats every night in a ~250k city. And don’t get me started on all the bugs that get into the apartment. I hate when I have to kill that helicopter-sized moth.

skinkestek 5y ago

I recently learned that another problem is that whales used to bring minerals up from the deep ocean and poop it out which provided food for plankton on the surface.

pvaldes 5y ago

Dear Nature peer reviewers, maybe could I introduce you to the 112,000 jumpback whales or the 40,000 fin whales returning to the area after its chase was forbidden just 6 decades ago? It seems a fact that would merit to be discussed in the article at least. Several big populations of whales where at the brink of extinction then. Maybe the euphausiacean population was abnormally high before, and more normal now?. Finding preys to quit gradually the surface and search for deeper areas when its main predators gradually increase is not a strange outcome, or one that would need necessarily a climate change explanation as the main factor. The study toke samples of the first 10 meters of water only.

hallarempt 5y ago
a) s/yourself/you to/ b) a laughably small number of whales -- even though it's more than it was -- doesn't invalidate the premise of the article. The only reason there are a few more whales than there were is the ban on hunting. The reason there aren't lot more of them is that there isn't enough food, because you, and me, and everyone else is fucking up the climate.
- pvaldes 5y ago
  Fixed, many thanks. If the main predator of one species is increased by, lets say x500 (nobody knows the real value really) and we observe a significant reduction in the number of preys, this is the first thing that we must assure to mention in our discussion. As research is a so slow process I'm having a hard time thinking that everybody just forgot to see the 'big whale in the room'. A logical explanation is that they put their bet in the winner horse (those that would sell better and had more options to end the publishing race). The logical, but boring explanation would be put under the rug. I could be wrong, of course, but this is not how science should work (in my arrogant opinion). > The reason there aren't lot more of them is that there isn't enough food, because everyone is fucking up the climate. We need to choose between the truth or the ideology. A simpler alternative explanation is that the ecosystem changed and do not have room for allowing more whales. Other that we just see the population in the middle of a recovery, not the final phase and our grandsons will see much more whales and even much less krill. Whales mature and breed slowly so they recover slowly. Ship traffic, fish nets, fish hooks, diseases or whale fishing quotes don't help. The lack of food can be related with climate warming, but also with over-fishing and plastic pollution.