Every day we see more complexity in the vast, intricate tapestry that makes up this spinning sphere we call Earth. It’s really quite humbling. There are connections between things that we’d never suspect. Once we see them, though, it’s so obvious we wonder how we could have missed them.
Take, for instance, findings from this report just released from the National Science Foundation.
Researchers John Dabiri, a Caltech bioengineer and Caltech graduate student Kakani Katija, have discovered that the tiniest creatures in the ocean (plankton, krill, copepods and jellyfish) mix enormous quantities of water as they migrate and move up and down through the layers of the sea.
“Results from this study will change some of our long-held conceptions about mixing processes in the oceans," says David Garrison, director of NSF's biological oceanography program, which funded the research.
The assumption has always been that the massive tidal force of the Earth’s oceans affected the movements and patterns of the creatures within it. Our scientific models, and our view of the roles different elements play, have been skewed by this mindset. We figured that currents, temperatures, winds, chemical and seismic activity were the driving forces behind sea-water mixing.
Dabiri's and Katija's findings show the inverse is also true, and are published in the July 30 issue of the journal Nature. It seems the daily actions of animals play a dramatic role in the movements of the ocean.
Critically endangered amphipod. Photo: Uwe Kils
Looking at it now, in the face of new evidence, doesn’t it seem obvious that the swimming motions of billions of tiny animals migrating in one direction might, in turn, influence the movements of the water?
The way it works is based on a phenomenon called Darwinian (because it was first observed and described by Darwin’s grandson) or biogenic mixing. In the same way that a car gets pulled along as it ‘drafts’ a semi on the expressway, huge swarms of tiny swimmers drag water with them as they travel.
"There are enough of these animals in the ocean," Dabiri says, "that the global power input from this process is as much as a trillion watts of energy, comparable to that of wind forcing and tidal forcing."
Implications are not yet fully understood, but may have an affect temperature layers, nutrient and egg dispersal, and the sinking and sequestering of carbon to the ocean floor. Even fecal pellets and ‘marine snow’ (falling organic debris) pull surface water down as it falls.
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Copepod species. Photo: Uwe Kils
Without the billions of plankton, krill, copepods and jellies regulating the structure of the water column, we now realize that the ocean would be a very different place. Our own lives as well as the fates of countless other species would suffer if they disappeared, as their absence impacted the lives and breeding cycles of food fish, shellfish, whales (like the critically endangered Bowhead whale that feeds on plankton), dolphins, birds . . . we have no way of knowing how far the ripples might extend if this single piece of the puzzle were pulled out.
Jellies. Photo: Michael Dawson, University of California at Merced
Unfortunately, we can’t take any single element of our natural world – including plankton, for granted.
This study was, of course, about the sea, but the same theory of mutual influence holds true for fresh water animal interactions as well as those of the land.
The concept of interconnectedness actually goes way back, but has been repeatedly swept under the rug by business interests more concerned with profits than environmental concerns. As far back as Rachael Carson’s landmark book, Silent Spring , money, as much as ignorance, has driven people to ignore or discredit evidence – in this case that the pesticide DDT had wide-spread and lingering effects on species far removed from the target ‘pests’ it was designed to control.
It was a book that made many realize, for the first time, that cause-and-effect in nature wasn’t simply linear. It’s not even a ‘domino effect’. Think, instead, of ripples on a pond. Drop a single pebble into the middle, and the result is ever- widening rings that eventually touch the shore.
More graphic, however, is the concept of ‘cascade failure’.
A quote from author Andrew Taylor: “For example, if a network of power generators [is] all running at full blast and one cuts out, the demand is distributed to the others. Since they are all running at 100 percent already, the increased load sends them over the top. The weak ones go first, distributing an even greater load to the others until one by one they are all overwhelmed. Hence the name 'cascade failure.' I use the example of electrical networks, but the same can be true for natural ecosystems, computer networks, biological systems, and on and on. “
Cascade failure means ‘Many systems are so reliant upon each other, it is often unknown the full extent of how one system's breakdown will affect another. The interdependency of many of our systems allows failures in one system to affect others down the line. Such breakdowns have threatened to affect some of our largest interconnected systems over the years. Failures in one system or line have shut down entire power grids. Single corrupt bits of data have caused the collapse of programs and systems around the world . . .”
I would like the reader take from this article the idea that, if humans pull enough pieces out of the puzzle, the Earth may not be able bounce back in a way that will support us. Those living in big cities may have a harder time seeing this cause and effect, because people there are so seemingly removed from the natural world.
If however, a natural disaster or war suddenly prevented the transport of food and goods into cities and developed areas, if the water treatment plants and pipelines were incapacitated and electricity was down, it would be a matter of days before everyone would be trying to evacuate the cities in order to survive.
Where would they head? To ‘the country’, in search of wild foods to collect or hunt, wood to burn, fertile land on which to grow crops and livestock.
We can’t evacuate the Earth if it begins to break down.
Many might argue that the Earth has self-regulating and self-healing mechanisms. So do computers and power grids. As we know all too well, that does not make them immune from failure.
Unlike computers and power grids, however, re-building a healthy Earth after a systems-crash is far beyond our expertise.
The research on ocean mixing plankton was also supported by the Office of Naval Research, the Department of Defense's National Science and Engineering Graduate Fellowship, and the Charles Lee Powell Foundation.
Other articles you might find of interest:
Plants that ‘tell time’ help climate researchers
We may not be able to count on zoos to save species
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