Archive for December, 2009

Omega 3 Fatty Acids

Wednesday, December 30th, 2009

Last summer in a cove on the coast of Maine, a fishing boat trapped a school of Menhaden by extending a net across the cove and then encircling the school with a purse seine. The captured school of fish was a very small one, yet it was the only one trapped there in many years. A few decades ago, menhaden schools were sometimes 40 miles long, supporting a large and thriving fishery, and providing food in turn for the mackeral and tuna that followed their migration north along the coast each summer. Now of course these are just memories. The largest remaining schools are still hunted aggressively in Chesapeake Bay.

Part of a small Menhaden school. The fish accumulate Omega-3 fatty acids from the red-brown algae they eat as part of their diet.

Part of a small Menhaden school. The fish accumulate Omega-3 fatty acids from the red-brown algae they eat as part of their diet.

You probably haven’t eaten menhaden knowingly. It’s a very oily fish, of the clupeid or herring family, and its value is in its oils, rich in Omega-3 fatty acids. Wherever it is still hunted, it is hunted for for Omega-3, to feed to humans in capsules of oil, or to feed to farmed salmon. Even to add to lipsticks and paints.

All ‘oily’ fish are rich in Omega-3 fatty acids – for example salmon, tuna, mackeral, and the smaller herring and menhaden. None of them actually make the Omega-3 themselves, but they store it in their tissues. Omega-3 fatty acids are instead produced in red-brown single-celled marine algae, which are browsed by forage fish such as herring and menhaden, which in turn are eaten by the larger predatory fish.

We know now that Omega-3 fatty acids are essential to our own health. We need them as part of our diet to help us avoid atherosclerosis and heart disease. We can get them from eating salmon and tuna, but then they come with contaminants such as mercury. To avoid the contaminants, one company is marketing Omega-3 extracted from Hoki, a member of the hake family caught from deep cold water near new Zealand. This is a slow growing species that currently supports what appears to be a sustainable fishery, but it will not support a fishery that is focussed on harvesting them for fish oil.

If not salmon, mackeral, tuna or hoki, then where do you get your Omega-3? Probably from menhaden. Yet to supply Omega-3 to humans and farmed salmon, schools of menhaden have shrunk to oblivion in many places, and the remaining populations are small remnants of what they were.

This all sounds quite bleak, once again, but there are solutions. The oils can be extracted from fish discards. More promising, red-brown algae can be cultivated directly, and in fact can be cultivated to be particularly rich in fatty acids. The oil is easily removed, and it uncontaminated by heavy metals and pesticides, and millions of fish are not killed. Check out the company Udo for the details.

You don't need to eat a fish to get your Omega-3. (udoerasmus.com)

You don't need to eat a fish to get your Omega-3. (udoerasmus.com)

My own conclusions are that 1) I probably need more Omega-3 in my diet; 2) it should not come from fish, but from cultivated marine algae; 3) all harvesting of menhaden should cease in hopes of letting the species at least partially recover; 4) if we can’t find an acceptable substitute source of fish oils to feed to farmed salmon, we should again consider abandoning the farming of salmon: and 5) at all costs, we should avoid products from Omega Protein of Houston: it still harvests half a billion menhaden each year.

Past and Future Climate Change

Friday, December 18th, 2009

If we fail to mitigate the extent of climate change, then we will have to adapt to a world that will look very different. How different? We can look into the past to see what may now lie ahead.

Levels of atmospheric carbon dioxide continue to rise at an alarming rate

Levels of atmospheric carbon dioxide continue to rise at an alarming rate

Over the past half billion years, the planet has alternated between two climate modes: cold and dry, or hot and humid. The switch from one stae to the other is correlated with atmospheric carbon dioxide levels approaching 500 ppm. We should at present still be in the middle of a cold, dry glacial period, but we have shaken ourselves out of that by increasing atmospheric carbon dioxide to sufficient levels that the planet is warming – the ice caps are melting, glaciers are receding, permafrost is losing its permanence, winters are shorter, ocean levels are rising, ocean water is starting to acidify. At this extraordinary rate of change, we will relatively soon shift to the hot and humid mode of planet climate.

When did this last happen? 55 million years ago, atmospheric carbon dioxide levels rose to about 1000 parts per million. The polar seas warmed by 8-10 degrees centigrade, and sea levels were high. The pH of oceans dropped, resulting in mass extinctions of plankton dependent on calcium for their skeletons. On land, immense habitat changes forced the migration and dispersal of mammals, and the diversification of deer, horses and primates – including ourt own ancestors. It was a time of ecological upheaval.

The event occurred at the boundary of the Paleocene and Eocene Geological Epochs, so it is known as the Paleocene Eocene Thermal Maximum, or PETM. We dont know what caused the warming, though methane, trapped frozen as clathrates in polar sediments, may have become free as the temperature rose, and accelerated the warming. It took about 20,000 years for the warming to reach its maximum, and then it lasted, in a stable fashion, for 100,000 years. Then gradually the carbon dioxide levels dropped, sea and global temperatures dropped, and the planet shifted to its dryer, colder mode once again.

Clathrate: Methane (green) trapped in cage of frozen water molecules (red)

Clathrate: Methane (green) trapped in cage of frozen water molecules (red)

So what’s different this time? All the same events appear to be occurring. The difference is the rate of change. What took 20,000 years then may now occur in a century or less. Communities and species have a chance to evolve to tolerate new conditions when there is time, but decades or even a century is far too short for evolutionary change. The planet will survive this – it has seen worse – but we will see major habitat and ecosystem changes in the decades ahead, rising seas and major storms will force many millions of humans to become migrants, and life for all of us will become more difficult.

None of this needed to happen. Although we still have the opportunity to mitigate the harshest of the stresses we need action, now. The Copenhagen Conference on Climate Change was a lost opportunity. Without concerted global action by all of us around this little planet, the climate change events of 55 million years ago will soon return, and we’ll have to try to persist on a hot and humid planet.

Colossal Fossil

Friday, December 18th, 2009

The Copenhagen Conference on Climate Change ended today. And today Canada won the Fossil of the Year Award. We are mocked, once again, on the world stage for our extraordinarily weak emission reduction targets. The discredit goes to you, Prime Minister Harper.

Canada receives Fossil of the Year Award, Dec 18, 2009

Canada receives Fossil of the Year Award, Dec 18, 2009

Canada has won this worst of environmental awards three years in a row, celebrating our abysmal record, our inadequate targets, our increasing emissions from the Alberta tar sands, our voiceless leaders, and our apparent intent to do the least possible, compared with all other countries.

This is the worst of times to have no leadership in Canada, for we have little time and now less hope to mitigate the extent of climate change.

Our leader, Prime Minister Stephen Harper at Copenhagen

Our leader, Prime Minister Stephen Harper at Copenhagen

We once had a respected voice in world affairs. Now what do we have? The ridicule of the world.