Playing Russian Roulette with Gaia

The addition of iron to the oceans has been suggested as a mechanism to reduce the amount of carbon dioxide in the atmosphere. In several parts of the ocean, plankton abundance in much lower than expected given the availability of nutrients and sunlight. But, these areas are also low in iron, leading many people to suggest that it's the availability of iron that limits plankton numbers. A while ago I wrote about an experiment in the Southern Ocean that investigated this hypothesis. 

Permission to conduct these experiments was hard to get because the UN has agreed to a moratorium on iron fertilisation until more is known about the effects on other marine life. But, in contravention of the moratorium a rogue businessman has conducted an iron fertilisation 'experiment' in the northeastern Pacific, off the coast of Canada. Russ George has been trying to sell his iron fertilisation scheme to the world as part of the lucrative market for carbon credits.

He convinced the Haida Nation to provide one million dollars funding, apparently by telling them that the dumping of iron would increase salmon numbers in the area. With that money he dumped 100 tons of iron sulfate into the ocean 200 nautical miles west of the islands of Haida Gwaii in July this year. The plankton bloom this created reached 10,000 square kilometers in size. In comparison, the experiment in the Southern Ocean dumped just seven tons of iron sulfate and the bloom peaked at 800 square kilometers.

In conducting this 'experiment' Russ George may have broken international and Canadian laws. It violates the UN moratorium on iron fertilisation and he may have committed fraud in obtaining the funds from the Haida Nation. In any case, there is no evidence that plankton blooms will improve salmon number and only limited evidence that iron fertilisation is an effective mechanism for reducing carbon dioxide. And we know next to nothing about the potential negative impacts of such large blooms.

For more information, including Russ George's history in trying to sell iron fertilisation as a carbon credit scheme, try The Guardian and Deepsea News.

Shark week

Apparently it's the 25th year of the Discovery Channel's shark week. So, you can listen to deep, manly voices leaving dramatic pauses between words as you watch sharks all this week. Well, assuming you have a Discovery Channel subscription...

Perhaps in celebration, but more likely as coincidence, Ed Yong has an interesting piece on discovering the past shark biodiversity of a Central Pacific island by examining cultural artifacts.

It's currently complicated

A few weeks ago I wrote about the problem of plastic in the ocean. In that post I used a simple graphic showing the location and direction of rotation of the five oceanic gyres. On seeing that diagram you may have guessed that things were actually a little more complicated. Well, they are. Something that might have tipped you off was the swirls in the photos of plankton blooms I posted, here and here. If you want to get a sense of just how complex the ocean currents are, here is a great visualisation of a NASA ocean current model. This too, is a simplification.

Tweets in the deep

When the intrepid adventurers in the Lord of the Rings reached Moria they heard drums in the deep. Now James Cameron has reached the oceans deepest point, the Challenger Deep in the Marianna Trench off Guam. I'm not sure if he heard drums, I suspect he didn't, but he's sent a tweet:

Just arrived at the ocean's deepest pt. Hitting bottom never felt so good. Can't wait to share what I'm seeing w/ you.

I'll bet he can't wait because he's going to charge you money to "share" what he's seeing with you. He has plans to release two documentaries with the footage he collects.


It's the first time since 1960 that anyone has been to the Challenger Deep. At 10, 898 meters below the surface, it's an impressive feat. Nice work James. And nice work Australian engineering team who built the submersible he piloted. Now how about lending me the keys?...

Catlin Seaview Survey

The Catlin Seaview Survey will attempt to document the Great Barrier Reef in  a similar way to Google's Street View project. The images of the reef will be available through Google Earth and Google maps and cover a depth range of 0 - 100 meters.

The Catlin Seaview Survey is first and foremost an important scientific expedition. It aims to carry out the first comprehensive study to document the composition and health of coral reefs on the Great Barrier Reef and Coral Sea across an unprecedented depth range (0-100m) – addressing a series of important questions regarding the changes associated with the rapidly warming and acidifying oceans.However this is not just another scientific survey.Usually scientific surveys don’t have the ability to really capture the public’s imagination and engage people in the science. Expeditions and their findings tend only to be fascinating to other scientists. This  project is very different. The images from the expedition, when stitched together, will allow scientists and the public at large to explore the reef remotely through any device connected to the Internet. It will allow them to choose a location, dip underwater, look around and go off on a virtual dive. It has the potential of engaging people with the life and science of our oceans in a way that’s not been possible until now. It is a very exciting time.

An ocean of plastic

There are five major oceans in the world. There's the Arctic Ocean, the Atlantic Ocean, the Pacific Ocean, the Indian Ocean and the Southern Ocean. In the Pacific, the Atlantic and Indian oceans there are huge circular currents called gyres. The Indian Ocean has a single gyre, while the Atlantic and the Pacific have two, one in the northern hemisphere and one in the southern hemisphere.

The five great oceanic gyres showing the direction of rotation

The northern hemisphere gyres rotate in a clockwise direction, while the southern hemisphere gyres rotate in an anti-clockwise direction. The direction of rotation has to do with the Coriolis effect, which is what people joke about when the say that water goes down plug-holes in different directions in Europe compared to Australia. The Coriolis effect doesn't matter too much for water going down plug-holes (other forces are far more important), but operating over long time periods and over large distances it produces gyres.

Because the gyres rotate they are good at accumulating floating items in their centres. Waste material is drawn into the gyres from the countries that surround the gyre. When the waste reaches concentrations that are significantly higher than the rest of the World's oceans that area of ocean is termed a garbage patch. So far surveys have found garbage patches in the North Pacific, North Atlantic and Indian Ocean gyres. Garbage patches also form in other places, but the oceanic gyres form the biggest patches.

Of all the garbage patches the North Pacific gyre is the largest by a considerable margin. Mainland Australia has an area of 7.69 million square kilometres and estimates of the size of the North Pacific Garbage Patch are as high as 15 million square kilometres. So, basically there's a patch of garbage that could cover an area almost twice the size of Australia floating in the North Pacific. It should be noted, however, that other estimates are considerably smaller. Estimates vary largely because different studies use different densities of debris to define what a garbage patch is.

Plastic particles hanging underwater in the North Pacific garbage patch (photo Scripps Oceanography).

The garbage patches collect a huge array of debris and chemical waste. A lot of it, about 80%, comes from land-based sources. Natural disasters, such as a tsunami or a hurricane can lead to large amounts of waste entering the sea. However, the most common route is through storm water and waste water inputs. The other 20% of waste is lost or deliberately dumped from ships at sea. Although it has been illegal to dump waste at sea for the last 20 or so years, the law is almost impossible to enforce.

By far the most common thing found in the garbage patches is plastic. Mostly it's small particles of plastic, but sometimes very large items like fishing nets that are kilometers long can be found. The fact that it is mostly plastic is pretty amazing seeing as plastic has only become common since the Second World War. But the plastic is able to accumulate because, unlike many other type of rubbish that finds its way into the sea, there are very few organisms that can break it down.

A ghost net floating in the North Pacific garbage patch (photo Scripps Oceanography).

Plastic has a number of negative effects on marine animals. Probably the effect that most people would be familiar with is that large items of plastic, like ropes, fishing line and fishing nets can entangle marine animals. This can cause them to drown, if they breath air, it can inhibit their movements making them more vulnerable to predators and it can cause them injuries as they try to struggle free.

A beached whale's tail entangled with ropes (photo Mike Baird).

Another effect is that marine animals can consume the plastic because it looks to them like a tasty piece of food. At its most minor the animal has simply wasted its time and effort catching the plastic. But, if an animal eats enough plastic it can clog their digestive tracts making it hard for them to eat and digest real food. And it is not just the larger animals like whales, turtles and sea birds that are at risk from ingesting plastic. We know that there are some very small, even microscopic animals that are eating plastics.

Plastic bag fragments found in the contents of a turtle's stomach (photo Victoria González Carman).

Plastics have also been reported to accumulate toxic chemicals on their surface in high concentrations. And if marine animals eat the plastics the chemicals can be released during digestion and become incorporated into their tissues. So even if an animal eats plastic rarely, it can acquire a toxic dose of some chemicals that enter its system via the plastic. The research on toxic plastic is controversial and not yet widely accepted.

So plastic waste is a huge problem for life in the ocean. In fact, one researcher looking at plastics in the ocean has argued in a recent book that the biggest effect on the marine environment this century won't be climate change, it'll be plastic waste.