Home » INTERNATIONAL MARINE LITTER DATABASE » Year of publication » 2013 » Numerical estimation of inflow flux of floating natural macro-debris into Tokyo Bay

T. Kataoka, H. Hinata, Y. Nihei, Numerical estimation of inflow flux of 
floating natural macro-debris into Tokyo Bay, Estuarine, Coastal and 
Shelf Science, Volume 134, 1 December 2013, Pages 69-79, ISSN 0272-7714, 
Abstract: We numerically estimated the inflow flux of terrestrial grass, 
which is the main floating macro-debris, into Tokyo Bay from April 2008 
to March 2009 based on a two-way particle-tracking model and an inverse 
method applying a Lagrange multiplier. In the estimation, we used 
surface current velocities derived by high-frequency ocean radar and the 
quantity of grass collected by clean-up vessels which are operated daily 
in the bay. At least 2115 m3 yr−1 of the grass flowed into the bay 
annually, and the contribution of a flood event to the inflow flux of 
grass was larger than that of the inflow flux of freshwater. We show 
that 39% of the annual inflow flux of grass into the bay was collected, 
and 61% flowed out of the bay or sank to the seabed. The numerical 
estimation in this study will be useful to establish a system for 
predicting patches of floating macro-debris in the bay, and to evaluate 
the effects of river development or clean-up along river banks and flood 
plains in the upper reaches.


November 21, 2013
Artists Join Scientists on an Expedition to Collect Marine Debris

Washed up on the remote beaches of southern Alaska are plastics of every 
shape, size and color. There are detergent bottles, cigarette lighters, 
fishing nets and buoys, oil drums, fly swatters and Styrofoam balls in 
various states of decay. They come from around the world, adrift in 
rotating sea currents called gyres, and get snagged in the nooks and 
crannies of Alaska’s shoreline. Set against a backdrop of trees, grizzly 
bears and volcanic mountains, these plastics are eye-catching, almost 
pretty—and yet they are polluting the world’s oceans.

The garbage, dubbed “marine debris” by the National Oceanic and 
Atmospheric Administration, wreaks havoc on marine ecosystems. It 
destroys habitats, transports nonnative species, entangles and 
suffocates wildlife. Animals mistake the garbage for food and, feeling 
full, starve to death with bellies full of junk. For humans, the problem 
is more than cosmetic; marine debris endangers our food supply.

In June 2013, a team of artists and scientists set out to see the blight 
firsthand. Expedition GYRE, a project of the Anchorage Museum and the 
Alaska SeaLife Center, traveled 450 nautical miles along the coast of 
the Gulf of Alaska to observe, collect and study marine debris. A 
companion exhibition, opening in February 2014 at the Anchorage Museum, 
will showcase artworks made using ocean debris.

For the artists on the GYRE expedition, each day in Alaska was filled 
with scientific briefings, trash reconnaissance and individual pursuits. 
All four artists—Mark Dion, Pam Longobardi, Andy Hughes and Karen 
Larsen—are known for work that explores environmental themes and, more 
or less explicitly, the pleasures and perils of plastic.

Numerical estimation of inflow flux of floating natural macro-debris into Tokyo Bay

22. Dezember 2013