4 ms·

There isn't much fish in the deep sea. There's a lot of fish (and other animals) in the top four meters, a lot of others in the forty meters below that, and so

by Arnt 8y ago

There isn't much fish in the deep sea. There's a lot of fish (and other animals) in the top four meters, a lot of others in the forty meters below that, and somewhat less in the layer below that, but once you get to kilometers of depth things change. There are many species still, but fewer individuals of each species. Life also slows down — animals down there grow slowly and reproduce late. I personally don't like to mine down there. We should make our mess where we can get to it, and can clean up any problems. But conflicts with fish aren't likely to be a big problem. Driving some rare species into extinction, perhaps releasing a bunch of contaminants where we can't clean up and don't know where they will flow, yes, both of those, but not conflicts with the rich fisheries near the surface.

moh_maya 8y ago
Not really. Deep sea mining on the floor will kick up sediments, that will probably affect growth of plankton, which form one of the foundations of the ocean ecosystem. Also related to what I've quoted below, you'll probably end up releasing a lot of minerals into the ocean water that drive algal blooms. "Bottom trawling also stirs up the sediment at the bottom of the sea. The resulting undersea plumes of “suspended solids” can drift with the current for tens of miles from the source of the trawling, introducing turbidity throughout the water that inhibits the transfer of light down to the depths where it is needed for photosynthesis in plankton, sea kelp and other undersea plants that serve as the basis for the marine food chain. Also, ocean sediments serve as natural safe resting places for many persistent organic pollutants (such as DDT and PCBs). Dredging these sediments up effectively reintroduces such toxins into the water where they are unwittingly absorbed and consumed by the fish we eat and other marine life already trying to cope with otherwise compromised undersea habitats. The sediment plumes also reintroduce nutrient solids from agricultural and other practices, increasing demand for oxygen in the water (causing algae blooms) and contributing to the outbreak of ocean “dead zones” devoid of marine life." [1] [1] https://www.scientificamerican.com/article/saving-deep-ocean-species/ https://www.scientificamerican.com/article/saving-deep-ocean...
- jessaustin 8y ago
  The link is talking about damaging coral. Coral requires sunlight. I'm not sure what they mean by "deep sea", but if it's got sunlight it's not what's under discussion here. They're not pulling valuable fish species like tuna out of the hadal zone. It's confusing, to countenance the current abuses like those described in that link but use them to criticize a completely unrelated activity.
  - pvaldes 8y ago
    Not all coral species need light. There are "coral forests" adapted to cold waters. Lophelia builds "deep-water briars" there. They are super-mega-slow growing. And of course there are comercial species of very expensive yummy crustaceans living there. A couple of trawls and all is lost for the next thousands of years.
    - jessaustin 8y ago
      1000 m < 5500 m What we do on the surface has far more effect on these species than does the researchers' mud-digging at far greater depths.
      - pvaldes 8y ago
        Hem, nope, because you are messing with the deep water layers. You are messing with the marine snow, temperature, salinity and oxygen at a local scale. Research activity is one thing. Mining the sea bottom for rare matherials is a totally different situation, even if wouldn't be so hugely expensive.
        jessaustin 8y ago
        You're assuming that, but that isn't how energy works in the ocean. Stuff in the water falls down. Disturbances at 5500 m and deeper do not affect distant (hundreds of nautical miles) seafloor life at far shallower depths. If a mud-collection operation transported lots of abyssal mud to the surface and then dispersed it into the water column, it would affect pelagic life in that location, but not coral. Coral do not grow at these depths. Anyway, any feasible rare earth operation would need to "refine" the mud before hauling it to the surface, as described in TFA, so the mud wouldn't be dispersed into the water column anyway. Actually even Lophelia should be considered in the category "too deep to worry about", because as you pointed out they don't photosynthesize. They don't interact with us, and they don't interact with anything we interact with.
specialp 8y ago
https://en.wikipedia.org/wiki/Gonostomatidae https://en.wikipedia.org/wiki/Gonostomatidae Bristlemouth fish are the most numerous vertebrates in the world by far. They live exclusively in water between 800M and 4500M. There are 100s of billions to quadrillions of them.
jessaustin 8y ago
You're right, of course. Sometimes it seems that online "environmentalists" have feelings deeper than their knowledge or common sense... a momentary consideration of how energy is transferred in a food chain would disprove most of the speculations in this thread.

by Arnt 8y ago

moh_maya 8y ago

Not really. Deep sea mining on the floor will kick up sediments, that will probably affect growth of plankton, which form one of the foundations of the ocean ecosystem. Also related to what I've quoted below, you'll probably end up releasing a lot of minerals into the ocean water that drive algal blooms. "Bottom trawling also stirs up the sediment at the bottom of the sea. The resulting undersea plumes of “suspended solids” can drift with the current for tens of miles from the source of the trawling, introducing turbidity throughout the water that inhibits the transfer of light down to the depths where it is needed for photosynthesis in plankton, sea kelp and other undersea plants that serve as the basis for the marine food chain. Also, ocean sediments serve as natural safe resting places for many persistent organic pollutants (such as DDT and PCBs). Dredging these sediments up effectively reintroduces such toxins into the water where they are unwittingly absorbed and consumed by the fish we eat and other marine life already trying to cope with otherwise compromised undersea habitats. The sediment plumes also reintroduce nutrient solids from agricultural and other practices, increasing demand for oxygen in the water (causing algae blooms) and contributing to the outbreak of ocean “dead zones” devoid of marine life." [1] [1] https://www.scientificamerican.com/article/saving-deep-ocean-species/ https://www.scientificamerican.com/article/saving-deep-ocean...

jessaustin 8y ago
The link is talking about damaging coral. Coral requires sunlight. I'm not sure what they mean by "deep sea", but if it's got sunlight it's not what's under discussion here. They're not pulling valuable fish species like tuna out of the hadal zone. It's confusing, to countenance the current abuses like those described in that link but use them to criticize a completely unrelated activity.
- pvaldes 8y ago
  Not all coral species need light. There are "coral forests" adapted to cold waters. Lophelia builds "deep-water briars" there. They are super-mega-slow growing. And of course there are comercial species of very expensive yummy crustaceans living there. A couple of trawls and all is lost for the next thousands of years.
  - jessaustin 8y ago
    1000 m < 5500 m What we do on the surface has far more effect on these species than does the researchers' mud-digging at far greater depths.
    - pvaldes 8y ago
      Hem, nope, because you are messing with the deep water layers. You are messing with the marine snow, temperature, salinity and oxygen at a local scale. Research activity is one thing. Mining the sea bottom for rare matherials is a totally different situation, even if wouldn't be so hugely expensive.
      - jessaustin 8y ago
        You're assuming that, but that isn't how energy works in the ocean. Stuff in the water falls down. Disturbances at 5500 m and deeper do not affect distant (hundreds of nautical miles) seafloor life at far shallower depths. If a mud-collection operation transported lots of abyssal mud to the surface and then dispersed it into the water column, it would affect pelagic life in that location, but not coral. Coral do not grow at these depths. Anyway, any feasible rare earth operation would need to "refine" the mud before hauling it to the surface, as described in TFA, so the mud wouldn't be dispersed into the water column anyway. Actually even Lophelia should be considered in the category "too deep to worry about", because as you pointed out they don't photosynthesize. They don't interact with us, and they don't interact with anything we interact with.

specialp 8y ago

https://en.wikipedia.org/wiki/Gonostomatidae https://en.wikipedia.org/wiki/Gonostomatidae Bristlemouth fish are the most numerous vertebrates in the world by far. They live exclusively in water between 800M and 4500M. There are 100s of billions to quadrillions of them.

jessaustin 8y ago

You're right, of course. Sometimes it seems that online "environmentalists" have feelings deeper than their knowledge or common sense... a momentary consideration of how energy is transferred in a food chain would disprove most of the speculations in this thread.