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So whales poop krill which feeds algae which feeds krill. Add in sunlight and saltwater microorganisms and I guess it’s possible that whales eating then shittin

So whales poop krill which feeds algae which feeds krill. Add in sunlight and saltwater microorganisms and I guess it’s possible that whales eating then shitting krill = even more krill. But like so many complex systems it’s hard to draw any conclusions. Whales are beautiful creatures and it would be great if the oceans were so full of them again!

thaumasiotes 5y ago
In general, it's difficult for a process that takes krill as the only input to have more krill in the output than there were in the input. If whales cause a net increase in krill, it has to be through some other means than eating krill.
- jazzyjackson 5y ago
  maybe krill reproduce faster when they’re under threat, like how WWII preceded the baby boom (i am not a krill expert)
  - pvaldes 5y ago
    Oh, I have it! I have it! What if somebody would be fishing all this krill and sending it to floating factories to feed pets?
- danielheath 5y ago
  For example, wolves eating deer meant more deer (because losses to illness decrease when sick deer are caught and eaten before they can infect others).
  - thaumasiotes 5y ago
    OK, but that would seem to fall under "through some other means than eating the deer". If instead of eating sick deer the wolves exiled them, or vaccinated healthy deer, presumably you'd see the same increase in deer population.
    - choeger 5y ago
      That's too simplistic. The moment wolves start vaccinating healthy deer, there'll be a 20-30% anti-vax deer population.
    - EdwardDiego 5y ago
      Yeah, but then there's the impact of too many deer on the forests that they browse (assuming it's a species that's a browser rather than a grazer) - when there's overpopulation, they'll eat everything they can as they grow desperate through hunger. A forest with all the seedlings eaten out struggles to recover from the death of mature trees, which is normally an opportunity for an explosion of growth - the decaying trunk restores nutrients to the soil, the sunlight streaming through gives the seedlings an opportunity to grow as fast as they can. So continual overpopulation ultimately leads to the head of deer a given area of forest can support dropping significantly. Predation, whether by wolves or humans, can reduce the deer population to the extent that allows the forest to recover, which in turns leads to the forest being able to sustain larger populations of deer.
  - deleted 5y ago
    [deleted]
- foerbert 5y ago
  Not necessarily. It's not immediately intuitive is all. For example, maybe krill do a poor job recovering nutrients from dead krill, while they do great job of it with whale waste. In this case, whales would keep the overall amount of nutrients available to krill high while also consuming them. Who knows what's actually going on here, but it's really not difficult for these sorts of highly interrelated systems to end up with counterintuitive dynamics.
  - choeger 5y ago
    Logically, it cannot work via pre-existing nutrients alone. Even if wales poop out 100% of the relevant chemicals they ingest from krill again, because they do not need it, krill won't be able to eat it completely as it is diluted in the sea. There's always losses. So someone has to produce something. For instance: Krill need chemical X when young but create it when older in large quantities. Wales poop out X then. Or wales create X, while krill do not.
    - EdwardDiego 5y ago
      You're missing the phytoplankton bit - they need iron for photosynthesis, krill eat phytoplankton, whales eat krill, whales poop bioavailable iron.
    - Retric 5y ago
      The limitation is on biomass not numbers of krill. Replacing a X million with average weight 2g with a population that weighs 1.8g and numbers could increase even if biomass decreased. But even that’s assuming a uniform static population. Suppose in area X there is an abundance of Krill and iron, but in area Y they are heavily limited. Whales migrating through Y might cause a net migration of iron from X to Y even if they aren’t 100% efficient. Another possibility is recycling. Suppose the rate of iron addition via dust seeding is A tons per day, the rate of iron lost when a krill dies of old age is 60% and the rate of iron lost when a krill is eaten by a whale is only 30%. If the average age of krill dropped by say 20% then the biomass of krill should significantly increase.
  - EdwardDiego 5y ago
- crazydoggers 5y ago
  Your forgetting one more input… the sunlight. The intermediate step is the phytoplankton. The whale poop (the iron specifically) is a limiting factor that limits how much phytoplankton can photosynthesize. It’s like fertilizing soil with the dead… it could in theory support ever growing populations.
  - thaumasiotes 5y ago
    Sunlight is a source of power; by assuming unlimited sunlight input we can rearrange as much material as we want, but we can't add or subtract any. If we arrange more material into phytoplankton, that would seem to leave less material available to be krill. > It’s like fertilizing soil with the dead… it could in theory support ever growing populations. But this cannot work in theory. A population cannot grow if its only nutrient input comes from dead members.
    - crazydoggers 5y ago
      > But this cannot work in theory. A population cannot grow if its only nutrient input comes from dead members. That’s the point your missing. The nutrient input is coming first from the sunlight. The phytoplankton nutrient for the krill is limited by the available iron. > Sunlight is a source of power; by assuming unlimited sunlight input we can rearrange as much material as we want, but we can't add or subtract any. Photosynthesis creates nutrients at the base of all food webs (except deep sea geothermal vents) It’s able to allow plants to take carbon dioxide out of the air and fix it as a source of chemical energy. The sunlights radiative energy then is converted to chemical energy which then acts as a nutrient for other living things. The nutrient addition is literally arriving out of thin air. (C02 into sugars) However, organisms and in this case the phytoplankton doing that photosynthesis, are limited by specific nutrients, otherwise known as regulating factors. [1] In this case sunlight, carbon dioxide, etc would allow for massive growth of phytoplankton in the ocean. However, even given unlimited amounts of those, the phytoplankton will hit a growth wall when it runs out of iron. That iron, in this case, was locked up in vast amounts of krill. Krill from my knowledge can live up to 10 years. So that means that a balance will be reached between the krill and phytoplankton in terms of population densities and where that limiting nutrient of iron is stored. Whales change that limiting nutrient balance. By eating the krill and releasing the iron, the phytoplankton is able to increase its growth rate. Krill then, feeding on the phytoplankton blooms will reproduce quicker. Iron that was once locked up in krill for 10 years allows faster reproduction rates of new krill. The energy input that allows both populations to grow in this scenario is the sunlight. Again, the iron is only a limiting factor. The limiting factor is not 100% of the energy input. The iron is not “used up” meaning it’s availability to allow increased photosynthesis remains. The end result is that a significantly larger proportion of sunlight is captured and converted to living matter which allows a net positive gain in both populations. This is possible because the regulating factor for increased photosynthesis is maintained in the ocean at higher levels with whales. 1. https://en.wikipedia.org/wiki/Limiting_factor#Ecology https://en.wikipedia.org/wiki/Limiting_factor#Ecology https://sciencing.com/effect-limiting-nutrient-ecosystem-5170836.html https://sciencing.com/effect-limiting-nutrient-ecosystem-517...
- EdwardDiego 5y ago
  The process's starting inputs are sunlight and dissolved carbon dioxide that phytoplankton convert to biomass. But a limiting factor is the trace minerals they need to do so - iron is key to photosynthesis. In fact, people have proposed deliberately seeding the ocean with iron to stimulate phytoplankton blooms to fix carbon dioxide... not sure I agree with that, given the risks of harmful algal blooms. The krill eat the plankton, the whales eat the krill, the whale poop contains iron that the phytoplankton need, it's the great circle of life.
  - thaumasiotes 5y ago
    Are the krill sequestering more iron than they need? Assuming they aren't, then in this model processing by whales can lead to fatter krill (more biomass per unit of iron), but not more krill.
    - deleted 5y ago
      [deleted]
    - noselasd 5y ago
      In most of biology, abundance of food would lead to more individuals as well.
      - thaumasiotes 5y ago
        You're talking about a fixed amount of iron. It can be in algae or it can be in krill. But it can only be in one thing at a time. More algae can't lead to more krill if the existence of the larger krill population precludes the existence of the larger algae population. Suppose I told you that by draining the iron from a bunch of humans we could promote the growth of iron-bearing plants that would feed a bunch of new humans. How much surplus iron could we drain from a living human? How many new humans could sustain themselves on that amount of iron?
        SuoDuanDao 5y ago
        But it's not necessarily true that both populations are limited by iron availability. These iron-hungry plants could be producing more, say, zinc than they themselves need, which could allow the human population to expand even with less iron available. Give it a long time for coevolution to take place, then have something suddenly happen to the mosquito population that was extracting the iron from the people, and we could see the same dynamic.
- WithinReason 5y ago
  A theory I read is that when whales dive to the deep ocean they induce currents that bring iron to the upper layers. A sibling comment points out that iron is the bottleneck food for algae, so even a small amount of iron can create a huge mass of algae and krill as a consequence. Just some quick Googling found this: "Other types of whales, such as sperm whales, migrate to waters much deeper than the euphotic zone and they can scavenge iron from below and then return to the surface layer to defecate."¹ ¹: https://theconversation.com/bottoms-up-how-whale-poop-helps-feed-the-ocean-27913 https://theconversation.com/bottoms-up-how-whale-poop-helps-...
  - Nasrudith 5y ago
    Wouldn't that mean we could also blame whales for occasionally causing red tides? Not the main causes of course, I believe it is mine and fertilizer runoff which are the current leaders.
- adrian_b 5y ago
  The likely reason is that when krill die by being eaten by whales, their remains are spread at the surface of the ocean, and algae can use the scarce elements that were sequestered in the krill bodies, allowing the cycle to continue. When krill die due to old age, they might sink to the bottom and be buried in sediments, so the elements stored in their bodies will exit the cycle, causing reduced biomass in the cycle, and this loss will not be completely compensated by what river water brings from the erosion of the continents.
  - Robotbeat 5y ago
    That makes some sense. Thank you.
- snowwrestler 5y ago
  Sunlight and iron are also inputs. Sunlight from the sky, obviously, and iron from transported sediment. A system that uses either more efficiently could result in a net increase in biomass, even if the system is “processing” more krill per unit time while doing so.
zeristor 5y ago
I understand the limiting factor is iron, which the plankton require. This can be blown in from the Sahara occasionally. The whale faeces float, whales eat at depth but due to the high pressure of the deep ocean they can only defaecate at the surface. If they’re in an eddy and grouped as a pod the nutrients are concentrated in an area the plankton can then use the iron, and the krill which live for six years or so feed on it. The idea being to seed the oceans with simulated whale faeces this should jump start the plankton and ideally the krill giving the whales an opportunity to feed should their numbers expand, a trial in the Arabian ocean is planned to start. Currently iron levels are only sufficient near the coasts, the hope being that all far more of the oceans could start to support life instead of being deserts. This Inside Science podcast has a good bit about it all: https://www.bbc.co.uk/programmes/m00114n7 https://www.bbc.co.uk/programmes/m00114n7 Just thinking about it, this sounds slightly like Dune. The whales being the sand worm of the oceans, reprocessing krill into plankton food which is thought to have a huge effect in sequestering carbon.
- naravara 5y ago
  It sounds like what's happening is the whales are working as a sort of churn, cycling material from deeper in the water up to the surface where plankton can metabolize it.
- denton-scratch 5y ago
  Isn't whale poop also known as "ambergris", a very valuable commodity used in perfume manufacture? I wonder how much of this recycled krill nutrient is removed by humans in the form of ambergris, to meet the requirements of wealthy women. [Edit] Apparently it is excreted, perhaps by pooping; but it isn't quite poop. https://en.wikipedia.org/wiki/Ambergris https://en.wikipedia.org/wiki/Ambergris
  - opwieurposiu 5y ago
    Ambergris comes from sperm whales, a toothed whale that mainly eats squid, not krill.
pvaldes 5y ago
I would suggest an alternative possibility. Whales eat squids. And ships are made of iron. Humans are probably putting more iron in the sea than whales do.
- Alan_Dillman 5y ago
  A different type of whale eat squid. The baleen combs of baleen whales is unsuited for chewing squidy bits. Rusty ships are avoided, some of the iron is molecularly bonded to other metals and minerals, and rust from ships will sink immediately, and isn't really very bio available anyway. Rust flakes and particles are kinda difficult (and large) for crustaceans to rend and digest. Irony whale poop has buoyancy, and the iron is bio available.
  - naravara 5y ago
    What about fortified breakfast cereals? Could we just scatter a boatload of Captain Crunch instead?
  - pvaldes 5y ago
    100% correct. May I introduce squid floating larvae in this equation? And squid eat...
- denton-scratch 5y ago
  <pedantry> The plural of "squid" is "squid", as the plural of "sheep" is "sheep". Perhaps "squids" refers to multiple superconducting quantum interference devices. </pedantry>
kulikalov 5y ago
While I’m sure you are not eating whales, you may be consuming some resources that consecutively affect whales population, so it’s might not be as easy as it sounds.

thaumasiotes 5y ago

In general, it's difficult for a process that takes krill as the only input to have more krill in the output than there were in the input. If whales cause a net increase in krill, it has to be through some other means than eating krill.

jazzyjackson 5y ago
maybe krill reproduce faster when they’re under threat, like how WWII preceded the baby boom (i am not a krill expert)
- pvaldes 5y ago
  Oh, I have it! I have it! What if somebody would be fishing all this krill and sending it to floating factories to feed pets?
danielheath 5y ago
For example, wolves eating deer meant more deer (because losses to illness decrease when sick deer are caught and eaten before they can infect others).
- thaumasiotes 5y ago
  OK, but that would seem to fall under "through some other means than eating the deer". If instead of eating sick deer the wolves exiled them, or vaccinated healthy deer, presumably you'd see the same increase in deer population.
  - choeger 5y ago
    That's too simplistic. The moment wolves start vaccinating healthy deer, there'll be a 20-30% anti-vax deer population.
  - EdwardDiego 5y ago
    Yeah, but then there's the impact of too many deer on the forests that they browse (assuming it's a species that's a browser rather than a grazer) - when there's overpopulation, they'll eat everything they can as they grow desperate through hunger. A forest with all the seedlings eaten out struggles to recover from the death of mature trees, which is normally an opportunity for an explosion of growth - the decaying trunk restores nutrients to the soil, the sunlight streaming through gives the seedlings an opportunity to grow as fast as they can. So continual overpopulation ultimately leads to the head of deer a given area of forest can support dropping significantly. Predation, whether by wolves or humans, can reduce the deer population to the extent that allows the forest to recover, which in turns leads to the forest being able to sustain larger populations of deer.
- deleted 5y ago
  [deleted]
foerbert 5y ago
Not necessarily. It's not immediately intuitive is all. For example, maybe krill do a poor job recovering nutrients from dead krill, while they do great job of it with whale waste. In this case, whales would keep the overall amount of nutrients available to krill high while also consuming them. Who knows what's actually going on here, but it's really not difficult for these sorts of highly interrelated systems to end up with counterintuitive dynamics.
- choeger 5y ago
  Logically, it cannot work via pre-existing nutrients alone. Even if wales poop out 100% of the relevant chemicals they ingest from krill again, because they do not need it, krill won't be able to eat it completely as it is diluted in the sea. There's always losses. So someone has to produce something. For instance: Krill need chemical X when young but create it when older in large quantities. Wales poop out X then. Or wales create X, while krill do not.
  - EdwardDiego 5y ago
    You're missing the phytoplankton bit - they need iron for photosynthesis, krill eat phytoplankton, whales eat krill, whales poop bioavailable iron.
  - Retric 5y ago
    The limitation is on biomass not numbers of krill. Replacing a X million with average weight 2g with a population that weighs 1.8g and numbers could increase even if biomass decreased. But even that’s assuming a uniform static population. Suppose in area X there is an abundance of Krill and iron, but in area Y they are heavily limited. Whales migrating through Y might cause a net migration of iron from X to Y even if they aren’t 100% efficient. Another possibility is recycling. Suppose the rate of iron addition via dust seeding is A tons per day, the rate of iron lost when a krill dies of old age is 60% and the rate of iron lost when a krill is eaten by a whale is only 30%. If the average age of krill dropped by say 20% then the biomass of krill should significantly increase.
- EdwardDiego 5y ago
crazydoggers 5y ago
Your forgetting one more input… the sunlight. The intermediate step is the phytoplankton. The whale poop (the iron specifically) is a limiting factor that limits how much phytoplankton can photosynthesize. It’s like fertilizing soil with the dead… it could in theory support ever growing populations.
- thaumasiotes 5y ago
  Sunlight is a source of power; by assuming unlimited sunlight input we can rearrange as much material as we want, but we can't add or subtract any. If we arrange more material into phytoplankton, that would seem to leave less material available to be krill. > It’s like fertilizing soil with the dead… it could in theory support ever growing populations. But this cannot work in theory. A population cannot grow if its only nutrient input comes from dead members.
  - crazydoggers 5y ago
    > But this cannot work in theory. A population cannot grow if its only nutrient input comes from dead members. That’s the point your missing. The nutrient input is coming first from the sunlight. The phytoplankton nutrient for the krill is limited by the available iron. > Sunlight is a source of power; by assuming unlimited sunlight input we can rearrange as much material as we want, but we can't add or subtract any. Photosynthesis creates nutrients at the base of all food webs (except deep sea geothermal vents) It’s able to allow plants to take carbon dioxide out of the air and fix it as a source of chemical energy. The sunlights radiative energy then is converted to chemical energy which then acts as a nutrient for other living things. The nutrient addition is literally arriving out of thin air. (C02 into sugars) However, organisms and in this case the phytoplankton doing that photosynthesis, are limited by specific nutrients, otherwise known as regulating factors. [1] In this case sunlight, carbon dioxide, etc would allow for massive growth of phytoplankton in the ocean. However, even given unlimited amounts of those, the phytoplankton will hit a growth wall when it runs out of iron. That iron, in this case, was locked up in vast amounts of krill. Krill from my knowledge can live up to 10 years. So that means that a balance will be reached between the krill and phytoplankton in terms of population densities and where that limiting nutrient of iron is stored. Whales change that limiting nutrient balance. By eating the krill and releasing the iron, the phytoplankton is able to increase its growth rate. Krill then, feeding on the phytoplankton blooms will reproduce quicker. Iron that was once locked up in krill for 10 years allows faster reproduction rates of new krill. The energy input that allows both populations to grow in this scenario is the sunlight. Again, the iron is only a limiting factor. The limiting factor is not 100% of the energy input. The iron is not “used up” meaning it’s availability to allow increased photosynthesis remains. The end result is that a significantly larger proportion of sunlight is captured and converted to living matter which allows a net positive gain in both populations. This is possible because the regulating factor for increased photosynthesis is maintained in the ocean at higher levels with whales. 1. https://en.wikipedia.org/wiki/Limiting_factor#Ecology https://en.wikipedia.org/wiki/Limiting_factor#Ecology https://sciencing.com/effect-limiting-nutrient-ecosystem-5170836.html https://sciencing.com/effect-limiting-nutrient-ecosystem-517...
EdwardDiego 5y ago
The process's starting inputs are sunlight and dissolved carbon dioxide that phytoplankton convert to biomass. But a limiting factor is the trace minerals they need to do so - iron is key to photosynthesis. In fact, people have proposed deliberately seeding the ocean with iron to stimulate phytoplankton blooms to fix carbon dioxide... not sure I agree with that, given the risks of harmful algal blooms. The krill eat the plankton, the whales eat the krill, the whale poop contains iron that the phytoplankton need, it's the great circle of life.
- thaumasiotes 5y ago
  Are the krill sequestering more iron than they need? Assuming they aren't, then in this model processing by whales can lead to fatter krill (more biomass per unit of iron), but not more krill.
  - deleted 5y ago
    [deleted]
  - noselasd 5y ago
    In most of biology, abundance of food would lead to more individuals as well.
    - thaumasiotes 5y ago
      You're talking about a fixed amount of iron. It can be in algae or it can be in krill. But it can only be in one thing at a time. More algae can't lead to more krill if the existence of the larger krill population precludes the existence of the larger algae population. Suppose I told you that by draining the iron from a bunch of humans we could promote the growth of iron-bearing plants that would feed a bunch of new humans. How much surplus iron could we drain from a living human? How many new humans could sustain themselves on that amount of iron?
      - SuoDuanDao 5y ago
        But it's not necessarily true that both populations are limited by iron availability. These iron-hungry plants could be producing more, say, zinc than they themselves need, which could allow the human population to expand even with less iron available. Give it a long time for coevolution to take place, then have something suddenly happen to the mosquito population that was extracting the iron from the people, and we could see the same dynamic.
WithinReason 5y ago
A theory I read is that when whales dive to the deep ocean they induce currents that bring iron to the upper layers. A sibling comment points out that iron is the bottleneck food for algae, so even a small amount of iron can create a huge mass of algae and krill as a consequence. Just some quick Googling found this: "Other types of whales, such as sperm whales, migrate to waters much deeper than the euphotic zone and they can scavenge iron from below and then return to the surface layer to defecate."¹ ¹: https://theconversation.com/bottoms-up-how-whale-poop-helps-feed-the-ocean-27913 https://theconversation.com/bottoms-up-how-whale-poop-helps-...
- Nasrudith 5y ago
  Wouldn't that mean we could also blame whales for occasionally causing red tides? Not the main causes of course, I believe it is mine and fertilizer runoff which are the current leaders.
adrian_b 5y ago
The likely reason is that when krill die by being eaten by whales, their remains are spread at the surface of the ocean, and algae can use the scarce elements that were sequestered in the krill bodies, allowing the cycle to continue. When krill die due to old age, they might sink to the bottom and be buried in sediments, so the elements stored in their bodies will exit the cycle, causing reduced biomass in the cycle, and this loss will not be completely compensated by what river water brings from the erosion of the continents.
- Robotbeat 5y ago
  That makes some sense. Thank you.
snowwrestler 5y ago
Sunlight and iron are also inputs. Sunlight from the sky, obviously, and iron from transported sediment. A system that uses either more efficiently could result in a net increase in biomass, even if the system is “processing” more krill per unit time while doing so.

zeristor 5y ago

I understand the limiting factor is iron, which the plankton require. This can be blown in from the Sahara occasionally. The whale faeces float, whales eat at depth but due to the high pressure of the deep ocean they can only defaecate at the surface. If they’re in an eddy and grouped as a pod the nutrients are concentrated in an area the plankton can then use the iron, and the krill which live for six years or so feed on it. The idea being to seed the oceans with simulated whale faeces this should jump start the plankton and ideally the krill giving the whales an opportunity to feed should their numbers expand, a trial in the Arabian ocean is planned to start. Currently iron levels are only sufficient near the coasts, the hope being that all far more of the oceans could start to support life instead of being deserts. This Inside Science podcast has a good bit about it all: https://www.bbc.co.uk/programmes/m00114n7 https://www.bbc.co.uk/programmes/m00114n7 Just thinking about it, this sounds slightly like Dune. The whales being the sand worm of the oceans, reprocessing krill into plankton food which is thought to have a huge effect in sequestering carbon.

naravara 5y ago
It sounds like what's happening is the whales are working as a sort of churn, cycling material from deeper in the water up to the surface where plankton can metabolize it.
denton-scratch 5y ago
Isn't whale poop also known as "ambergris", a very valuable commodity used in perfume manufacture? I wonder how much of this recycled krill nutrient is removed by humans in the form of ambergris, to meet the requirements of wealthy women. [Edit] Apparently it is excreted, perhaps by pooping; but it isn't quite poop. https://en.wikipedia.org/wiki/Ambergris https://en.wikipedia.org/wiki/Ambergris
- opwieurposiu 5y ago
  Ambergris comes from sperm whales, a toothed whale that mainly eats squid, not krill.

pvaldes 5y ago

I would suggest an alternative possibility. Whales eat squids. And ships are made of iron. Humans are probably putting more iron in the sea than whales do.

Alan_Dillman 5y ago
A different type of whale eat squid. The baleen combs of baleen whales is unsuited for chewing squidy bits. Rusty ships are avoided, some of the iron is molecularly bonded to other metals and minerals, and rust from ships will sink immediately, and isn't really very bio available anyway. Rust flakes and particles are kinda difficult (and large) for crustaceans to rend and digest. Irony whale poop has buoyancy, and the iron is bio available.
- naravara 5y ago
  What about fortified breakfast cereals? Could we just scatter a boatload of Captain Crunch instead?
- pvaldes 5y ago
  100% correct. May I introduce squid floating larvae in this equation? And squid eat...
denton-scratch 5y ago
<pedantry> The plural of "squid" is "squid", as the plural of "sheep" is "sheep". Perhaps "squids" refers to multiple superconducting quantum interference devices. </pedantry>

kulikalov 5y ago

While I’m sure you are not eating whales, you may be consuming some resources that consecutively affect whales population, so it’s might not be as easy as it sounds.