Zooplankton declines by greater than 70% since 1960's

[cedric]

"This is a biodiversity disaster of enormous proportions."

yet the story seems to be ignored.

http://news.bbc.co.uk/1/hi/scotland/highlands_and_islands/7499834.stm

[NickB79]

1. "Soylent Green" comes to mind

kick

[krkaufman]

5. Yep. Same thing I was thinking. n/t

[wurzel]

2. Doesn't Zooplankton have a lot to do with Oxygen generation?

[Muttocracy]

4. Zooplankton are the floating animals; Phytoplankton are the plant-like ones

(algae and cyanobacteria). Phytoplankton, especially cyanobacteria can take credit for the nice oxygen levels the planet has. They release a net of oxygen. Zooplankton, like us, use oxygen and produce CO2.

Chemical and bacterial decomposition of either of them uses oxygen.

Zooplankton can control the amount or type of algae, and they are very important for supporting fish, some whales, other animals up the food chain.

[windoe]

3. A key step in the food chain...

interruption would cause mass extinctions if my understandings are correct.

[kristopher]

6. The sampling problems described here may be relevant

http://www.calcofi.org/newhome/publications/CalCOFI_Reports/v37/pdfs/Vol_37_McGowan_etal.pdf.

The paper is from 96 and describes well the problem with our state of knowledge and ability to sample. If anyone knows of a recent, more comprehensive analysis please post the title.

There has been a dramatic curtailment of NOAA research under Bush; I'm doubt this area is an exception.

One thing to note is that the whale populations seem to be doing OK, so just off the cuff, that would seem to indicate the system isn't crashing down at this moment.

[malakai2]

7. Which whales?

Most extant species' populations are depressed relative to historic levels. Even if they were prey limited before large scale hunting, large declines in global populations decades ago coupled with long doubling times for larger whales would seem to suggest that zooplankton abundance could freefall and whales wouldn't be one of the groups to show early effects.

I'm not even convinced fish with shorter doubling times, even anchovies or sardines, would be good options for study given how intensively they are fished. What about gross biomass? If the total nutrient content and solar irradiance haven't changed, overall biomass shouldn't be much off unless there is some other problem with the system.

[kristopher]

8. The paper I offered speculates warming surface waters.

While you could be correct in your interpretation of the significance of whales, my comment related to the levels of decline pointed to in the OP. If that were generally true, and if the system were crashing in the manner many of the posters have speculated, then I'd expect an impact on the whales, diminished as their populations may be from prewhaing modern times.

[malakai2]

9. Eventually, yes

But problem number one with whale studies is actually collecting good data on whales. Population level studies with whales are difficult given their nature of making themselves unavailable to humans for long stretches of the day. Just getting accurate data for individuals is hard, getting enough accurate information on enough individuals to inform average birth or death rates, or lambda for entire populations, may not be useful to inform a rough sense of trophic cascade because by the time we had that data we'd already know.

Problem number two is the nature of the prey base given the particular species of whale you are studying. What if you are looking at a few species with greatly diminished global populations, but which share a fairly stable prey base? I doubt you'd see much of a trend there. Also, if you were looking at species that are much closer to historic numbers, but which are also very plastic in prey selection, you might not see a trend in those whales until it was very obvious something was wrong in myriad other clades.

Either way, it would be about as difficult to look to whales as canaries as it would be to look to various adult fish, turtle, or seal populations as the same. There is no control, there isn't even a good estimate of populations today relative to historic populations pre-exploitation. That isn't even accounting for changes in oceanic pH, nutrient availability (overall quantity and source), surface temperature, average solar irradiance, etc. They do point that out in the paper...perhaps it would be better to conduct time series collections of phytoplankton and zooplankton, and thoroughly categorize the species captured, to see if overall primary production rates are changing, to see if overall zooplankton biomass tracks such changes in primary production, and to see whether proportions of fish, arthropods, and cnidarians composing the zooplankton are changing.

[kristopher]

10. An overall 70% decline???

Of all species out there I'd be willing to bet that our data on whales is probably the best, as poor as it may be. I'd also be willing to wager that if "Zooplankton declines by greater than 70% since 1960's" had actually ocurred (as the headline in the OP stated) it would have been most visible to us in the whale populations - confounds notwithstanding.