The BBC's environment correspondent David Shukman has been reporting from the Pacific island of Midway on the threat of plastic waste drifting in the ocean.
A Laysan albatross on the Midway Atol Wildlife Refuge feeds its chick
The Midway islands are home for some of the world's most valuable and endangered species and they are all at risk from the effects of the plastic debris.
Nearly two million Laysan albatrosses live on the islands. Researchers have concluded that every single one contains some quantity of plastic.
About one-third of all albatross chicks die on Midway, many as the result of being mistakenly fed plastic by their parents.
Below, David Shukman and Matt Brown, deputy manager of the wildlife refuge on Midway, answer your questions about the environmental threat facing the islands.
How is the plastic getting into the oceans? Do ships with passengers dump plastic trash while on a voyage? Are there such a thing as ocean-going trash hawlers and are they dumping their wastes in the oceans? Are airplanes dumping waste over the oceans?
Kerry Painter, Schwarzenborn, Germany
MATT BROWN: A relatively small percentage of the plastic found in the oceans is coming from marine sources (ships at sea for example). Most of the debris is coming from the major urban areas of the world. In some parts of the developing world, streams and rivers serve as garbage dumps, and debris flows down these waterways and into the oceans. In the developed world, storm-water runoff and improper disposal of household waste combine to add tons of plastic to the oceans every year.
Apart from reducing my own use of plastic and plastic bags (a challenge in itself), I would be interested to know if there is something more hands-on and practical. Are there volunteer/action groups, are people needed to help collect litter on Midway - even if it is only two weeks at a time?
Lesley Dickinson, Longframlington, Northumberland, England
MATT BROWN: Thinking globally and acting locally is the best way for an individual to combat the issue of marine debris. While very few people can get to Midway Atoll National Wildlife Refuge to clean up debris, almost everyone can get to a local beach, park, school-ground or even vacant lot and clean up that area. Picking up the rubbish locally will prevent it from reaching the marine ecosystem and eventually impacting a place like Midway.
It was distressing to see the Albatross chicks with various pieces of discarded plastic in their beaks and swallowed. As plastic is a by-product of oil, surely the oil companies should be forced to safely dispose it?
David Cook, Inverness Scotland
DAVID SHUKMAN: Good question. Who is ultimately responsible for this waste? The oil producers or the manufacturers or the retailers or the consumers or the waste disposal authorities? Maybe awareness of this issue will trigger a serious debate. Meanwhile the team on Midway is involved in a study supported by Dow Chemicals to try to trace the chemical signatures of the waste to identify its source.
I assume that someone is collecting the plastic garbage on the islands. What is done with the collected garbage?
Jack Ware, North Palm Beach Florida USA
MATT BROWN: Unfortunately there is not a great solution to the problem of what to do with the plastic that finds its way to Midway. We currently collect the garbage and periodically send it back to the main Hawaiian Islands on large boats. In Hawaii the waste is either incinerated or buried in landfills, each which has negative consequences.
Presumably the plastic travels from many parts of the world, including our own. What's our best action as consumers and voters, apart from trying to cut down on individual plastic use (a drop in the ocean, no pun intended)?
Catherine Liddle, Keighley, England
MATT BROWN: The less plastic we use, the less plastic will inadvertently make its way into the environment. If you have plastic bags Ė reuse them. Instead of buying a new bottle of water every day, buy a reusable container and fill it with tap water each morning. Take canvas bags shopping with you. Finally, no matter what your level of plastic usage is, make sure you recycle or properly dispose of your rubbish instead of littering.
How many tons of CO2 did you and your film crew put into the atmosphere for that little jolly? You could have picked any island off the coast of the UK. How do you justify it?
Peter Dunn, Falkirk, Scotland
DAVID SHUKMAN: I hope our visitís carbon cost is justified by the enormous interest shown in our reports by people all over the world. And, as always, I will offset my flights by investing in renewable energy schemes.
Do the authorities on Midway have to pay for the rubbish to be removed, or is it under the jurisdiction of the government?
Chris Watson, Boston, UK
MATT BROWN: Midway Atoll is managed by the US Government as a National Wildlife Refuge. The refuge has to work within a set budget, so any money used on marine debris clean-up is money not being used to monitor endangered species, educate the public, etc.
You allude to the cold water at the reef where you were gathering plastic. Are the corals cold-adapted, then? What, if you know, is the water-temperature range through the year. Does much in the way of mollusk shells or other biological remains wash up on the beaches?
Wallace Ward, Houston, Texas, USA
MATT BROWN: Midway Atoll is home to some of the northernmost coral formations in the world (Kure Atoll, approximately 40 miles away is the most northern location). Water temperatures ranger from the upper 60ís to upper 70ís depending on the season.
I am a retired Navy Officer- Civil Engineer Corp. I was on Midway in the early '80's to supervise minor construction. Have you been surprised at the amount of different bird types on Midway? Have you seen the yellow song canaries? Story being that years ago a school teacher let a pair loose. When I was on Midway, I also saw the amount of floating junk that "hit " the beach.
John McKenna, Lone Rock, Wisconsin, United States
DAVID SHUKMAN: I have seen the yellow canaries and they are adorable, dwarfed by the albatrosses but very pretty. The story I heard was that they were brought by an employee of the company working on Midway laying the first trans-Pacific cable. But Midway is full of wonderful stories....