Where is the best place to put your ocean cleanup device? Not where currently proposed.

Dr. Martini — Wed, 20 Jan 2016 17:55:06 +0000

You might think that to clean up the problem of plastic in the ocean, you should place your cleanup device where there is the most plastic. And this isn’t a horrible initial assumption, which has been made by “The Ocean Cleanup”. But a slick new modeling study by Peter Sherman and Erik van Sebille show that’s not the case. If you want to extract plastic from the ocean, you had better cast your nets right off the coasts of the world’s largest polluters, not in the center of the North Pacific Garbage Patch as proposed by the Ocean Cleanup.

Them dots? Put your newfangled contraptions there. [Source: https://iopscience.iop.org/article/10.1088/1748-9326/11/1/014006 ]

To do this, a bunch of plastic was dumped into a model ocean. They simulated litter bugs: countries that mismanaged waste and had higher population densities input more plastic; and chronic human addiction to plastic use: exponentially increasing plastic input from 1965-2025. Stir in some tracers, sprinkle in a bunch of hypothetical sinks to capture plastic, add in a dash of ecosystem modeling (moar plastic = moar problems for phytoplankton), prepare 500 different scenarios and simmer for a week*.

The results? You had better put most of your 29 giant plastic scooping machines close to where the biggest litter bugs reside, near coastal Asia. Where you shouldn’t put them? In the center of the North Pacific Gyre.

Depressing graph shows removing plastic isn’t that effective [Source: https://iopscience.iop.org/article/10.1088/1748-9326/11/1/014006]

Even sadder, if you place the sinks at the most optimal locations, only 31% of the total plastic in the ocean will be removed by 2025. That means there will STILL BE A 4% increase in plastic. If the sinks are placed in the locations proposed by the Ocean Cleanup, only 17% of plastic will be removed. Bummer on both accounts.

But it’s not all doom and gloom people, this study lends support for reducing plastic use and just stopping it from getting into the ocean. That’s why I think projects like the Baltimore’s Mr. Trash Wheel and Seabin are so awesome, they are stopping trash and plastic from getting into the ocean right now. And while it’s known that I am not an ardent fan of the Ocean Cleanup, and this is certainly not an endorsement, this study does lend some support for relocating the proposed array closer to the coasts in shallower water which would be easier to design, build and service**. Here’s to hoping the Ocean Cleanup takes the conclusions of this research to heart, but I’m not holding my breath since they are only oceanographers.

*This paper judiciously doesn’t address engineering or even feasibility, but rightfully so. It just assumes that no matter where a plastic sink was put it operates at 45% efficiency (the number put forth by the Ocean Cleanup people), which is all you need to figure out the best place for your ocean cleanup booms.

** This is totally ignoring that when the array is moved inshore, you might not be in international waters anymore, subject to maritime laws of different countries and will now have to contend with much more ship traffic and larger sea life.

REFERENCES:

P. Sherman and E. van Sebille. Modeling marine surface microplastic transport to assess optimal removal locations. Environmental Research Letters, 11(1):014006, 2016.

The post Where is the best place to put your ocean cleanup device? Not where currently proposed. first appeared on Deep Sea News.

Easy Big Fella

Dr. M — Mon, 29 Jun 2009 01:16:45 +0000

Dunkleosteus skull at the Cincinnati Museum of Natural History

Way before even your great-great-grandpappy was born and Ohio was ocean instead of cornfields, it was the “Age of the Fishes”. During this Devonian (400-360 million years ago), the placoderms, giant, shark-like, armored fishes, ruled the oceans. Among the largest and most fearsome of these were the arthrodires, the joint necks. The lovely pet above is Dunkleosteus at 25 feet in length. I think we are going to need more butter! Given all the weight of the armor, Dunkleosteus was probably a slow swimmer. But hey when you are that big and armored how fast do you need to be?

Illustration by Steveoc 86 and licensed under the Creative Commons Attribution 3.0 Unported

Instead of teeth, those bony plates you see above would shear past one another forming vicious cutting edges. In 2007 Anderson and Westneat, built a computer model based on this big boy’s bones and muscle attachements. The two authors determined that a large individual could rip apart its prey with a force of 8000lbs at the tip of the jaws and with more than 11000lbs at the back of the dental plates. The authors conclude that “This bite force capability is the greatest of all living or fossil fishes and is among the most powerful bites in animals.”

Illustration by Arthur Weasley and licensed under the Creative Commons Attribution 3.0 Unported

Anderson, P., & Westneat, M. (2007). Feeding mechanics and bite force modelling of the skull of Dunkleosteus terrelli, an ancient apex predator Biology Letters, 3 (1), 76-79 DOI: 10.1098/rsbl.2006.0569

The post Easy Big Fella first appeared on Deep Sea News.

computer model | Deep Sea News

Where is the best place to put your ocean cleanup device? Not where currently proposed.

REFERENCES:

Easy Big Fella