Stories tagged nutrient cycle

Yup, it's Friday.
So let's not beat around the bush.

Science FridayCourtesy Science Friday

This week,

"Malcolm Beck was farming organically in the 1950s, and that's how he got into compost. What started out as a little manure pile on his farm became a 40-acre compost-processing business five decades later. Beck sold his company, Garden Ville, but still works there and is constantly experimenting with different fertilizer formulas--from bat guano to earthworm tea.

When San Antonio’s Malcolm Beck got into the compost business over fifty years ago, many people had never heard of compost, Beck says. Beck began making it for his organic farm and found that his compost more profitable than produce. Science Friday stopped by for a tutorial in the art of composting.

Malcolm Beck's website

Jun
16
2010

A sperm whale: You will never get my precious iron feces! Never!
A sperm whale: You will never get my precious iron feces! Never!Courtesy Pacman
It would be a very special day indeed if a better story than this one popped up. But I wouldn’t ask for that. How could you want any more than this: whale poop fights global warming*.

Sperm whales are the particular focus of this study. The population of sperm whales in the Southern Ocean (the waters around Antarctica) is thought to be about 12,000. (There are more sperm whales in the world, but the study looked at Southern Ocean sperm whales.) Those 12,000 whales are thought to put about 200,000 metric tons of the greenhouse gas carbon dioxide into the atmosphere each year. That’s about the same amount that 40,000 passenger cars contribute each year. Destroy those polluting whales, right?

Wrong! See, it turns out that these sperm whales are also responsible for the removal of 400,000 metric tons of CO2 each year, making up for the amount they produce two times over. Their secret is this: they poop iron.

They don’t only poop iron, but sperm whales poop a lot of iron—each whale is thought to defecate about 50 metric tons of iron each year. That’s over 300 pounds a day! Obviously the whales aren’t pooping out solid iron ingots, though. It’s mixed in with their liquid feces. And that’s important.

The whales themselves don’t remove those 400,000 tons of CO2. They’re removed by phytoplankton. Phytoplankton are microscopic organisms that, like plants, use sunlight and CO2 to build their bodies. And they feed on iron.

The whales have lots of iron in their diets, because of the large amounts of fish and squid they eat. So the iron-rich whale poop is an ideal nutrient for phytoplankton. When the phytoplankton dies, the carbon they contain falls to the bottom of the ocean instead of being released back into the atmosphere. Where more carbon is trapped than is released back into the atmosphere, it’s called a “carbon sink,” and that’s what whale poop and phytoplankton create in the Southern Ocean.

Other parts of the ocean may naturally contain more iron for phytoplankton, but the Southern Ocean is poor in the nutrient, and the microorganisms rely on an iron cycle that the whales apparently play a large part in. More whales, greater carbon sink. Fewer whales, less whale poop, more atmospheric carbon.

Coincidentally, the International Whaling Commission will be meeting next week, to discuss regulations on how many whales can be harvested from the oceans each year. It’s a complicated world, isn’t it?

*I thought about making the headline “Whale poop is ‘green’” but… yuck.

Apr
09
2010

By Our Hands: Cities are perhaps the most impressive mark humankind has left upon the face of planet Earth.
By Our Hands: Cities are perhaps the most impressive mark humankind has left upon the face of planet Earth.Courtesy anaxila

Throughout the ongoing debate about exactly how, to what extent, and the ethical implications, the indisputable fact remains that humankind has altered the planet. Back when the human population was only a few thousand strong and agriculture and cooked food were the latest inventions, it was easy for the Joneses to pick up and move camp when the water ran dry, the soil stopped producing tasty wheat, or the garbage piled too high in the backyard. The same can’t be said for the populations of world cities today.

Advances in public health, industry, and agriculture have blown the human population out of the brush. There will soon be 9 billion people on the face of planet Earth! Coupled with rising affluence, our ballooning population’s resource consumption and waste outputs are wrecking havoc on natural systems. New research (see several links below for more info) suggests that within a fixed amount of space, humankind is in danger of causing our own extinction and the only way out is to discard traditional ideas of industrialization and embrace sustainability.

No, silly...: Not THAT kind of tipping point!
No, silly...: Not THAT kind of tipping point!Courtesy Go Gratitude

The first step to bailing out humankind is to investigate how close to failure the world actually is. This was the point of a recent international collaboration: to calculate safe limits for pivotal environmental processes. The key idea here is that of “tipping points,” which can be thought of as thresholds or breaking points. Think about being pestered by your brother or sister: aren’t you able to put up with the annoyance for even a little while before you get so upset you retaliate? That’s your tipping point – the last straw that put you over the edge.

Led by Stockholm Resilience Center’s Johan Rockstrom, a group of European, Australian, and American scientists – including the University of Minnesota’s Institute on the Environment’s director, Jonathan Foley – identified nine processes reaching their tipping points. Three (climate change, nutrient cycles, and biodiversity loss) have already been pushed past their tipping points, four (ocean acidification, ozone depletion, freshwater use, and land use) are approaching their tipping points, and two (aerosol loading and chemical pollution) do not yet have identified tipping points because they require more research. The Institute on the Environment recently released a YouTube video addressing the conclusion of this new research:

Blissfully, there are things we can do to stop hurting the planet and begin patching its wounds. According to Foley’s article, we can’t let ourselves get any closer to the tipping points and piecemeal solutions won’t cut it because of the interconnectedness of the issues. Instead, we should focus on switching to low- or no-carbon fuel sources, stopping deforestation, and rethinking our approaches to agriculture.

There's No Place Like Home: It's worth keeping healthy.
There's No Place Like Home: It's worth keeping healthy.Courtesy NASA

The conclusions of this research have been well-accepted, but there has been some criticisms for 1) attempting to establish tipping points at all, and 2) for the appropriateness of the establish tipping points. If you would like more information, including commentaries, please check out the following sources:

Article in Nature: A safe operating space for humanity

Commentaries: Planetary Boundaries

Article in Scientific American: Boundaries for a Health Planet

Article in Ecology and Society: Planetary Boundaries: Exploring the Safe Operating Space for Humanity

Two questions to consider as you watch the YouTube video and take a look through the links and articles referenced above are:

1) What are the consequences of being past our tipping points?

2) How do the solutions discussed prevent us from reaching tipping points?

You are encouraged to post your thoughtful answers below!