Scientists build new atlas of ocean’s oxygen-starved waters(news.mit.edu)
news.mit.edu
Scientists build new atlas of ocean’s oxygen-starved waters
https://news.mit.edu/2021/oxygen-deficient-ocean-map-1227
22 comments
An Olympic swimming pool is 50m x 25m at a depth of 2m, so an area of 1250 square meters. The continental US is 8,080,464,252,719 square meters, so it would take 6,464,371,402 Olympic swimming pools to cover the continental US. Stacking Olympic swimming pools in layers it would take about 37 layers swimming pools to cover the US with 240 billion Olympic-sized swimming pools.
So the volume of water is enough to cover the continental US with water to a depth of 75 meters if I did my math correct. And that second zone, three times larger, could cover the Continental US to a depth of 225 meters.
So the volume of water is enough to cover the continental US with water to a depth of 75 meters if I did my math correct. And that second zone, three times larger, could cover the Continental US to a depth of 225 meters.
I think this principle should apply to any big business or government spending etc: how much is it per person? There's a lot of talk of billions and trillions at the federal level, and millions or billions at more local level. Far more relevant to say how much it costs per person.
Per taxpayer is even more precise.
I want to imagine that lakes might be a good starting point for this comparison. For example, 600,000 km^3 is roughly 50 Lake Superiors. This is still context dependent, but I can at least pull up a map and look at the size of Lake Superior to get a feel for it.
Lakes have a sort of nebulous depth though. They're probably a better measuring stick for area than volume.
The team reasoned that, if sensors showed a constant, unchanging value of oxygen in a continuous, vertical section of the ocean, regardless of the true value, then it would likely be a sign that oxygen had bottomed out, and that the section was part of an oxygen-deficient zone.
Did they bother testing this idea at all? It's a hypothesis absolutely essential to their study. There must be some method of accurately measuring oxygen at various depths, even if it isn't practical to deploy it across the ocean. You could for example spectrographically analyze a set of sample bottles for oxygen content, take a series of measurements of the water column, and then analyze the bottles afterward to determine how much oxygen leached out of them.
Did they bother testing this idea at all? It's a hypothesis absolutely essential to their study. There must be some method of accurately measuring oxygen at various depths, even if it isn't practical to deploy it across the ocean. You could for example spectrographically analyze a set of sample bottles for oxygen content, take a series of measurements of the water column, and then analyze the bottles afterward to determine how much oxygen leached out of them.
If I saw data like that my first thought would be a comms or sensor problem of some kind. Funky sensor readings sometimes mean funky physical values but it's the exception, not the rule.
It is a brilliant insight to reinterpret faulty oxygen measurements to extract a valid signal.
I wonder if anoxic regions could be made useful somehow.
I wonder if anoxic regions could be made useful somehow.
Not useful for humans directly does not mean not useful at all.
I guess the bottom of them is a big carbon sink. Also, some bacteria and archaea like weird environment. Even some animals with very slow metabolism may enjoy a slow peaceful life in them or near the borders.
I guess the bottom of them is a big carbon sink. Also, some bacteria and archaea like weird environment. Even some animals with very slow metabolism may enjoy a slow peaceful life in them or near the borders.
I wouldn’t say the oxygen measurements are faulty, just hard to interpret.
> Life is teeming nearly everywhere in the oceans
Historically, this was true but no longer. There is a fraction of the life that the ocean used to support. A great source is the book Once and Future World, which describes captains' logs before steamship. They reported that ships at sea would be stopped in the middle of the ocean, far from land, by schools of fish that densely packed. Today, people are happy to see a whale if they visit the coast. Not long ago, people could see whales as far as the eye could see all day long some times of year.
Also, to call the waters "oxygen-starved" in response to climate change misses the cause and effect. Specifically, human behavior is causing these things. They aren't just happening. If we change our behavior, we can change the results.
Clarifying the cause and effect helps clarify what to do about it besides passively watch it happen.
Historically, this was true but no longer. There is a fraction of the life that the ocean used to support. A great source is the book Once and Future World, which describes captains' logs before steamship. They reported that ships at sea would be stopped in the middle of the ocean, far from land, by schools of fish that densely packed. Today, people are happy to see a whale if they visit the coast. Not long ago, people could see whales as far as the eye could see all day long some times of year.
Also, to call the waters "oxygen-starved" in response to climate change misses the cause and effect. Specifically, human behavior is causing these things. They aren't just happening. If we change our behavior, we can change the results.
Clarifying the cause and effect helps clarify what to do about it besides passively watch it happen.
Even farther back in history there have been massive anoxic ocean events in the fossil records. Based on what we've discovered they tend to correlate with other mass extinctions.
A citation for the actual paper is given below. Unfortunately, the authors have not paid the extra charges to make it open-access.
Kwiecinski, Jarek V., and Andrew R. Babbin. “A High‐Resolution Atlas of the Eastern Tropical Pacific Oxygen Deficient Zones.” Global Biogeochemical Cycles 35, no. 12 (December 2021). https://doi.org/10.1029/2021GB007001.
Kwiecinski, Jarek V., and Andrew R. Babbin. “A High‐Resolution Atlas of the Eastern Tropical Pacific Oxygen Deficient Zones.” Global Biogeochemical Cycles 35, no. 12 (December 2021). https://doi.org/10.1029/2021GB007001.
If this is the case then the benthic sediments would be of food that hadn’t been eaten far higher up in the water column.
Wouldn’t it be fairly pristine? Ships that sunk, and or whales and fish that expired.
Are whales in the sea referred to as megafauna, or is fauna just for land animals?
Where these waters become more oxygenated they would be a lot more life, oxygen permitting, wouldn’t there?
Wouldn’t it be fairly pristine? Ships that sunk, and or whales and fish that expired.
Are whales in the sea referred to as megafauna, or is fauna just for land animals?
Where these waters become more oxygenated they would be a lot more life, oxygen permitting, wouldn’t there?
Whales are megafauna, yes. Fauna means anything in the Kingdom Animalia.
If it supports very little life then there's very little life to die there and sink.
Generally the oxygen minimum zones aren't extending up into the photic layer near the surface which does support a fair amount of life.
There’s Oxygen near the surface just not further down in the depths.
Whales could swim through an area since the surface to breathe, but could pop their clogs at any time (I assume).
Whales could swim through an area since the surface to breathe, but could pop their clogs at any time (I assume).
Anaerobic microbes will still be able to do a job of it, albeit slower
I assume various organisms have evolved to detect low oxygen content of water, it would be interesting to find out more about this.
The good old GMT, it seems. I remember this color gradient.
You see this a lot with anything involving a description of a volume of liquid. It inevitably ends up using an Olympic-sized swimming pool as a yardstick for the laymen. To me, especially in this case involving hundreds of billions of those pools, this is meaningless to the average reader. It implies that the reader is familiar with or has a good mental image of how much water an Olympic-sized pool will hold. While I do watch the Olympics and have a rough idea of how large they are I find it a bit ridiculous in this case to make this particular comparison.
Most people are not going to have any idea what 240 billion Olympic-sized pools looks like. Maybe it would be better to rephrase in terms of how many pools every one of us could have if this water was all contained in Olympic-sized pools. In that case lets just round the global population to the nearest billion, so ~8 billion people, divide this water equally amongst us so that we can all share in the bounty of oxygen-depleted seawater - so that gives everyone on earth about 30 Olympic-sized pools of water. That is just from the first zone. Including the water in the second zone they describe as being about 3 times larger than the first gives everyone on earth about 90 Olympic-sized pools of oxygen-depleted seawater.
Then you can flip that into terms more recognizable, say acres or hectares or something else.
I think for most of us, that volume is easier to picture than the 240 billion Olympic-sized pools they use in the article.