top | item 27404512

North Atlantic warming over six decades drives decreases in krill abundance

212 points| aseerdbnarng | 4 years ago |nature.com | reply

63 comments

order
[+] vegetablepotpie|4 years ago|reply
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.

[+] xhkkffbf|4 years ago|reply
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?
[+] pvaldes|4 years ago|reply
> 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.

[+] ajb|4 years ago|reply
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
[+] aseerdbnarng|4 years ago|reply
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
[+] jefurii|4 years ago|reply
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.
[+] lotsofpulp|4 years ago|reply
Do you consider humans to be animals high up in the food chain?
[+] pvaldes|4 years ago|reply
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|4 years ago|reply
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.
[+] MattGaiser|4 years ago|reply
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|4 years ago|reply
All animals depend directly or indirectly on plants. Plants in general can only migrate very slowly (or not at all).
[+] deepzn|4 years ago|reply
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|4 years ago|reply
Could the recovery of whale populations have a role in this?
[+] trainsplanes|4 years ago|reply
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.

[+] morpheos137|4 years ago|reply
I don't know where you live but in the northeast usa this is bullshit. In rural new england wildlife is much more prominent than it was 60 years ago. Deer used to be relatively rare. Beaver were extremely rare as were Turkeys. Forests were less dense and had smaller trees. Black bear were rare. Coyotes were extremely rare. Mt. Lions were unheard of. While we are no where near 1500 AD at most only a few promient species have been lost from the area: chesnut trees, wolves, passenger pigeons, etc. Most of the original northern atlantic forest biome is still intact. Rural new england is teeming with wildlife compared to how it was 100 or even 200 years ago when almost all forests in southern new england were cleared for fuel or agriculture. They came back. You got to get outside your bubble. The world is still full of nature. In many locations the population in rural southern new england towns was half what it was in 1820 in 1920. Nature came back when people moved west or to cities for better land and jobs. Humans are part of nature too. We are a natural phenomenon. I care about biodiversity but I get sick of seeing these uninformed opinions that some how the sky is falling everywhere. Maybe it is some places but not everywhere even in the USA even within a few hundred miles of the largest cities.
[+] eloff|4 years ago|reply
I also remember the windshields covered in insects during long drives as a kid. I haven't experienced that again as an adult.
[+] Amezarak|4 years ago|reply
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!

[+] sk5t|4 years ago|reply
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.
[+] neanderthaler|4 years ago|reply
The world population doubled in those 60 years. People like to eat fish. They also occupy space - many people live in big cities, where wild animals are not commonly expected at the front door.

Insects also need space to breed, which is taken away by farming, roads, buildings and pesticides.

[+] JJMalina|4 years ago|reply
I've noticed the same over the course of my life but recently I drove through the interior of Florida to go on a camping trip and the front of my car was plastered with dead bugs.
[+] f6v|4 years ago|reply
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|4 years ago|reply
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.
[+] gigatexal|4 years ago|reply
I hope the whales and other sea life can adapt.
[+] DFHippie|4 years ago|reply
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.

[+] spodek|4 years ago|reply
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.

[+] DFHippie|4 years ago|reply
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.

[+] blfr|4 years ago|reply
Convenience has been killing fertility for decades. At present rates only Africa is heading for anything like overpopulation and I doubt they'll hold.
[+] ctoth|4 years ago|reply
So, um, how did you post this comment if you are paying $1.40 a month for electricity and presumably need to turn on at least one lightbulb for a couple days? Do you use someone else's electricity to charge your phone or laptop? You did one load of trash in two years. That's great. I suppose that means you received zero packages in the mail, and bought zero things in any store that might have packaging?

Because Bill Gates is rich, you have no excuse not to be rich. Obviously it is possible. Now that you know one person who is rich, you are 20% of the way there!

[+] RosanaAnaDana|4 years ago|reply
So, I'll try and bite in with as much charity as I can muster. The main sentiment I want to push back against is in your final three paragraphs.

To summarize:

-- You, individually, have made significant motions to reduce your impact in the form of reducing emissions, picking up trash, reducing waste, and reducing energy consumption.

-- The 'Resistance'* you identify comes from people with more resources than you. You argue that those pretend they can do very little to change.

My summary of what you are arguing for in terms of how difference can be made is focused on individual action and change. My impression of your argument is that we, either alone or as a set, are or can be responsible for making the differences that will or could result in a significant difference regarding climate change.

I think its disingenuous and irresponsible to put the onus on individuals. Most people on this planet are in a daily struggle to survive and the idea that they have the agency to make the kinds of changes you say that they need to make is presumptuous and frankly, classist. Most families and individuals on this planets are have 80-90% of their waking hours filled with activities that barely sustain them at above struggling conditions. They have 0 additional bandwidth to make the kinds of changes you are describing because even a few mistakes or wasted actions will cause their lives to tumble into collapse where they end up homeless or destitute and begging on the streets. And yes, while living in a hedgerow behind the walmart will result in an overall lower rate of population and over consumption, I don't think global impoverishment is a viable strategy towards reversing climate change.

The second issue with this way of thinking is that as easily as some one changes their actions or behavior for the better, this can just as easily be reversed.

A third issue, is that focusing on individual action only addresses the terminal node in a chain of consumption, the visible obvious bit. What it fails to address is the 'under-the-hood' components of a chain of consumption, when its the 'under-the-components' that represent much/ most of the real environmental impacts of over consumption.

Nibbling around the edges of issues is not going to result in the kinds of change we need. The kinds of change we need have to be baked into the cake of how we engage with society, which means they'll have to be somewhat central to how society is constructed. Fundamentally, I would argue, the unit of organisation or incorporation needs to be addressed. Organisations and corporations need to be attached to the outcome of their behaviors in the same ways that individuals are. A massive overhaul of how we organize institutionally needs to make anything other than a middling difference.

A final point I'll make is that we've put the onus on individuals to make their own difference for the past 60 years and the effects of this strategy are self evident. Individuals simply can not collectively make the kinds of difference required to move the needle with an issue as entire or existential as climate change. Individuals have been engaging in the kind of change implementation strategy you are describing for 60+ years. Consumption and pollution haven't gotten better they've gotten worse.

My proposal to address this: Corporations and institutions need to be able to quantify and address the externalities of their productions before any profits can be made. For changes to be effective we need governments and we need the ability to create regulation which is central to they way our societies operate. Putting the onus on individuals is a short term, ineffective strategy, both in theory and in practice. It puts additional pressure on people who can barely handle it, and is easily reversed. It does nothing to address the vast majority of externalities related to consumption (the ones not visible at the supermarket shelves). It provides a psychological relief valve for people to think that they've 'done enough' and precludes the need for them to invest in institutional change. Addressing change as an individual is nibbling at the edges of something that needs to be addressed systematically at the core of how societies operates. Citing the individual as the unit over which change can or should operate is at best an anesthetic and at worst, prevents the ability to implement change at an institutional level.

*I think you should define what you mean here. I'm not gonna go chase down that definition for some keyboard fencing. Also its your interpretation of that word that matters.