Tucking into beef could be good for your health – but not the planet’s

As the barbeque season gets into full swing, New Zealand researchers are investigating whether certain kinds of red meat could actually protect against heart disease.

Researchers have recruited men aged 35-55 willing to eat free meat three times a week for eight weeks in the name of science, according to a press statement from the Liggins Institute.

Participants are supplied with either grass-fed Wagyu beef, grain-finished beef or soy-based meat alternative (they can’t choose which).

The study is looking at how the complex lipids (fats) in high quality, unprocessed red meat affect heart health, using the vegetarian protein group as a control. It follows earlier evidence that eating Wagyu beef in moderation may help protect against heart disease. Continue reading

Canterbury University scientists involved in intermittent rivers study

University of Canterbury scientists are part of a global research collaboration into the environmental impacts of dry riverbeds, with their findings published today in a new paper in one of the world’s top scientific journals (see AgScience report HERE).

New Zealand researchers, Professor of Freshwater Ecology Angus McIntosh and Dr Catherine Febria, of the School of Biological Sciences, UC College of Science, have been part of a global team from 22 countries evaluating what happens to plant litter that falls into in river beds when they are dry (i.e. not flowing).

They co-authored the paper titled ‘A global analysis of terrestrial plant litter dynamics in non-perennial waterways’ which was published today in Nature Geoscience.

“People might feel that a pile of plant litter accumulating in a dry river bed couldn’t possibly contribute to global climate warming, but the surprising reality is it very likely is,” Professor McIntosh says.

The contributions of drying rivers haven’t been included in global carbon accounting previously and their CO2 effects  could be significant.

“This is especially important because, surprisingly, intermittent streams and drying rivers are thought to include more than 50% of the river length world-wide,” he says.

Dr Febria says it is known that when rivers dry up fish and insects die, and the whole food web of the river collapses.

“However, we haven’t previously appreciated the significance of all the decomposition that happens when the water comes back. The amount of carbon dioxide released in many cases is huge,” she says.

“We should all care about this because carbon dioxide in our atmosphere is the driver of global climate warming.

“Our research indicates that increasingly drying rivers, along with other land use changes, are contributing to global climate warming. Moreover, climate warming in many places like Canterbury is predicted to increase the frequency and magnitude of drought which could also cause more river drying.

“That is a really worry because that could form a positive feedback cycle by releasing even more carbon dioxide.”

This is the first piece of research published from this collaborative study involving 94 international partners from 22 countries studying the dry beds of 212 rivers from round the world, including Canterbury.

Until recently, drying and intermittent rivers had been largely ignored. This global study is beginning to reveal they really are very important and should not be ignored.

Such extensive global research efforts have traditionally been rare. That a very large group of researchers from around the world, led by a group in France, have come together to contribute is really quite significant, Professor McIntosh says.

He didn’t expect the magnitude of emissions to be so high. Therefore the findings should force a rethink of how the global carbon models are made so that they include CO2 emissions from intermittent rivers.

Source: University of Canterbury

Plants show an unexpected response to more carbon dioxide 

Plants are split into broad categories based on how they process carbon. The two main groups are C3 (eg rice, wheat, trees) and C4 (most grasses including corn and sugarcane).

It was thought C3 grasses are more sensitive to carbon dioxide levels and will grow more vigorously under higher CO2 levels. But a new, 20-year study suggests this is only in the short-term:  after 12 years the patterns reversed with C4 ramping up their growth.

A scimex post (HERE) reports that Australian and New Zealand experts say this long-term information is essential to understanding future distribution of plants with increased CO2 in the atmosphere.

A media statement from The American Association for the Advancement
of Science
 tells us more:

Past research has clearly established that two groups of plants respond differently to elevated carbon dioxide levels, with one group gaining substantially more biomass when carbon dioxide is more abundant; however, a new study monitoring plots over a 20-year period reveals that this well-established pattern is in fact reversed over long time scales.

Scientists categorise plants based on the way in which they process carbon, the two most common classes being C3 (eg, rice, wheat, trees) and C4 (eg, corn, sugarcane, most other grasses). Theory and experimental evidence have suggested that C3 grasses are more sensitive to carbon dioxide levels than C4 species and thus will grow and gain more biomass in response to rising carbon dioxide levels – a pattern that is critical to understand to accurately model future climate.

But, past experiments have only looked at C3 and C4 responses over relatively short periods.

Peter B. Reich et al. now report results from a 20-year study monitoring 88 plots in Minnesota, U.S., which are part of the BioCON project.

They found that, during the first 12 years of the study, C3 plots averaged a 20% increase in total biomass in response to elevated carbon dioxide levels, compared to ambient conditions, while C4 plots averaged a 1% increase, changes that were in line with expectations.

However, during the subsequent eight years, the pattern reversed: C3 plots averaged 2% less than their ambient counterparts, and C4 plots averaged 24% more biomass. The researchers found that variables such as rainfall and net photosynthesis of the plants had little correlation with this reversal, while, mysteriously, the mineralisation of nitrogen did.

Mark Hovenden and Paul Newton provide more context in a related Perspective, illustrating the value of longer-term research in revealing the complexities of ecological patterns. They note that because C4 plant species contribute 25% of land biomass globally, provide an important forage source for grazing animals, and are over-represented among weeds, it is especially important to correctly estimate the future distribution of these plants.

  • The research can be found HERE on the AAAS web page.
  • Editorial/opinion from the AAAS is HERE.