Science News
R. Ramanujam, The Institute of Mathematical Sciences, Chennai
Headlines
. Using smell to detect malaria
. How birds adjust to mountain climbers
. From tiny bacteria to the global carbon cycle
. A giant gas wave right next to us!
Read more about these articles below.
Using smell to detect malaria
Scientists have known for some time that malaria parasites alter the odours of infected people (and other animal hosts). We know that the anopheles mosquito carries the malaria parasite. The theory is that the change in smell helps to attract mosquitoes that will carry them to new hosts. Recently scientists have tried to see whether this can be used as a tool to detect the presence of malaria parasites even among people who do NOT show symptoms of malaria. The answer is YES, they can!
This was a clinical study conducted in Kenya, with nearly 400 children under the age of 12. Medical researchers collected two kinds of samples from each of them: blood samples and odour---chemical samples (one from a foot and one from a forearm). How did they get the latter? They sealed the children's feet and arms in plastic bags, ran air through the bags and collected the chemicals from their odour on a filter.
They tested the blood samples for malaria using rapid diagnostic tests, microscopy and parasite DNA analysis. They used special techniques called mass spectrometry and gas chromatography to that separates the different odour chemicals by their mass or structure. They constructed patterns and used the created patterns of one-third of the children's samples to see if they could predict the malaria status of the other two thirds – only based on the odour chemicals.
They divided the children into three groups: uninfected (134), those that showed malaria symptoms (134) and those that did not show symptoms (62). The "gas chromatogram" technique clearly showed that each of these three groups showed a different chemical pattern in the odour samples.
It turned out that the chemical patterns are very reliable as a diagnostic tool – using this model they were able to identify 95% of the children with malaria. In addition they also found that foot odour was a better indicator of malaria than arm odour.
This is an important line of research in dealing with a deadly disease like malaria. Many infected people who do not show symptoms do not seek treatment. Searching for parasite DNA is the best, but that is too expensive. So any sensitive method that does not involve the taking of blood samples is welcome.

How birds adjust to mountain climbers
Exploring the great outdoors is a wonderful way to connect with nature. However, as visitor numbers increase, they can harm the environment. In the western world, rock climbing is a recreational activity in which athletes climb up, down, and across natural rock formations. Despite the heights, climbers enjoy this peaceful experience in nature. Lately, more and more people are visiting climbing destinations around the world.
The question is: does all this climbing affect the cliff environment adversely? Of course, human climbing cannot harm the rock. But cliffs provide habitat for many life forms. Cliff habitats are special, and some life forms can survive only there. Scientists have known for some time that climbing activity disturbs the nesting of birds of prey.
Recently some scientists decided to study how climbing impacts all the different birds living together on a cliff (known as a community). Studying the Flatiron Cliffs of Colorado in the USA, they selected 16 areas in with lots of climbing (more than 500 climbers per year), and 16 areas with not much climbing (less than 100 climbers per year). They looked at climbing sites facing different directions: north, south, east, and west (called "cliff aspect"). They sat 20 metres away from the cliff base, and watched a 30 metre wide section of the cliff, and the air space above. They noted how many birds they saw, what species and where the birds were. They also recorded whether there were climbers at the site (and how many). Each observation was 1-hour long and they conducted 5-6 observations at each of their 32 study sites. This took a lot of patience!
They used a mathematical model to calculate which things had the biggest influence on "avian diversity" (the number of different bird species on a cliff). They also calculated which things affected "avian abundance" (the number of birds on a cliff). They considered things like whether climbers were present, cliff height, cliff aspect, and how close the cliff was to roads.
They found that both bird diversity (that means the variety and type of birds) and abundance (their number) differed between east and west facing cliffs. Their results show that rock climbing does not much impact the number of birds, but it does reduce the diversity of birds on each cliff. It seems likely that some bird species put up with human activity well, and some do not; but this needs to be researched further.
However, this research does suggest opening up new routes for climbers where there is less diversity. Science based information for decision making is the best way to conserve our environment.

From tiny bacteria to the global carbon cycle
Do you know that the oceans teem with not only fish but also tiny photosynthetic microbes and bacteria? Scientists have wondered for long about how these microscopic life forms contribute to the oceanic carbon cycle (which explains how carbon is gained and lost from Earth and our environment). Recent research that combines insights and techniques from chemistry, biology and computer science offers hope for solving this mystery.
Carbon is the elemental building block for all living things. Over time, carbon moves through the land, air, and oceans in a process called the carbon cycle. For example, part of the carbon cycle happens when we breathe: animals exhale carbon dioxide into the air, and plants take in carbon dioxide from the air during photsynthesis.
Carbon moves into the ocean when microscopic underwater cells, called phytoplanktons take carbon dioxide from water for photosynthesis, just as plants on land do from the air. Even though phytoplanktons are tiny, they are vast in number, and therefore affect the carbon cycle. They also release carbon-based materials that dissolve into the ocean, just like sugar dissolves into hot tea. These materials, known as dissolved organic carbon are food for bacteria in the sea. These bacteria are part of the carbon cycle, because they use some types and then ooze out other types of dissolved organic carbon into the water (the bacterial equivalent of poop!) and release carbon dioxide back into the atmosphere.
While this is a nice story, scientists do not know many details. For instance, how quickly does dissolved organic carbon move from the ocean back out into the atmosphere? Scientists want to know these things in terms of actual numbers and rates, which is not easy at all. This is where collaboration between chemists, marine biologists and data scientists, combined with the immense power of today's computers, have proved to be very useful. Recent research, reported in the journal Proceedings of the National Academy of Sciences (USA) offers many technical answers. They show that much of the dissolved organic carbon is produced at the surface of the water, where bacteria gobble it up quickly, in seconds, whereas in deeper water this process can take months or even years. Apparently, in the deepest parts of the ocean, dissolved organic carbon can hang around for a very long time: on average for 6000 years!
As scientists map more and more bacterial genes, we understand just a little more about the mystery of the oceans. One big question interesting the scientists now is how climate change affects the oceanic carbon cycle. Does hotter water make bacteria eat faster, cycle carbon more quickly back into the atmosphere?

A giant gas wave right next to us!
The new year began with a bang for science: on January 7, speaking at the American Astronomical Society conference, Dr Alyssia Goodman, a physicist from Harvard University, announced that a giant gas rope has been found, right next to our solar system! The Earth and sun are right next to a wavy rope of star-forming gas, but astronomers only just noticed it.
Many of the well-known "stellar nurseries" nearby (where stars are being formed, for example in the Orion nebula) are actually strung along a thread of gas that stretches roughly 9000 light years, according to the report. The thread resembles a sine wave, soaring above and below the disk of the galaxy by about 500 light years, and at one point, coming within a 1000 light years of our solar system. (The picture shows the Radcliffe wave data superimposed on an image of our Milky Way Galaxy.) Though it is "so close", scientists have noticed it only recently, because apparently until now we have not had the ability to pinpoint distances to star-forming clouds. Scientists looked at stars behind these clouds and deduced how dust within those clouds altered the colours of the stars. Now they can do 3-dimensional mapping of these, and have "seen" this rope-like structure.
The wave has been named "Radcliffe Wave" honouring Radcliffe College in which many early 20th century female astronomers studied.
Much is unknown: we do not know how the wave formed, or what it means for understanding our Milky Way galaxy. But they can tell, tracing the motion of the sun backward in time, that our solar system passed right through the Radcliffe Wave roughly 13 million years ago. Life forms on earth at that time must have had a spectacular nighttime show!
Sources: Nature, Health for kids, Environmental science journal