There's Water In Them There Rocks!

 

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Plants go to great lengths to obtain the necessities of survival. Nowhere is this more apparent than in the desert regions around the world. Amazingly, myriads of plants have adapted to the harsh conditions that deserts offer up. Needless to say, water is a major limiting resource in these climates and many of the adaptations we see in desert plant species have to do with obtaining and holding on to as much water as possible. Some species get around the issue by going dormant whereas others stick it out using deep taproots that plug into the groundwater. A select few others hit the rocks.

Rocks? Well, gypsum to be precise. This interesting mineral is quite common in arid regions throughout the world. What is more interesting is that 20.8% of a gypsum crystal is water. Because of this, it has been suspected that gypsum in the soil could be a potential source of water for plants growing in these regions and a team of researchers out of Spain may have found just that.

Meet Helianthemum squamatum. This distant relative of hibiscus grows throughout the gypsum hills of the Mediterranean region. Unlike other desert plants, it is shallowly rooted. Unlike other shallowly rooted species, H. squamatum doesn't go dormant during the dry summer months. The physiology of this species in the context of the dry environments that it grows offers up quite a conundrum. How does this plant get the water it needs to grow through the hottest, driest months of the year?

By analyzing the isotopic composition of the water within the plant and comparing it to background sources, the team found that 90% of the plants water intake during the dry summer months comes from the crystallization water in gypsum! How is this possible? How does a plant get water from a mineral?

The actual physiological processes involved are not yet understood but there are some running hypotheses. The first has to do with temperature. When gypsum is exposed to temperatures above 40 degrees C, water can be released from the crystalline matrix. It would then be available to the plants via passive uptake. 40 degrees C is not unheard of in these environments. Any water that isn't taken up by the plants could be reincorporated back into gypsum when things cool down at night. Another possibility is that H. squamatum grows its roots into and around the gypsum. Using root exudates, it is possible that the plant is able to dissolve gypsum to some degree, thus unleashing the water within. This may rely on the microbial community associated with the roots. Until further research can be done on this, the jury is still out.

The most exciting aspect of this research is the doors it has now opened in our search for extraterrestrial life. Life as we know it depends on water. Our search for this molecule has us looking for planets in a sweet spot where water can be found in a liquid state. Knowing now that at least some life on our planet is able to obtain water from gypsum broadens the kinds of places we can look. Mars is chock full of gypsum. Just sayin'.

Photo Credit: José María Escolano (http://bit.ly/ZeSVzB)

Further Reading:

http://www.nature.com/ncomms/2014/140818/ncomms5660/full/ncomms5660.html

Snuffing the Fire

Few childhood memories are more fond to me than catching fireflies on summer evenings. These little beetles are famous the world over for their dazzling light displays. Using chemical means, they are some of the most efficient light producers ever discovered. Their displays are for the purpose of mating and there are as many variations on the theme as there are species. Sadly, like so many natural wonders that we take for granted, fireflies are disappearing from our wild places. Future generations may never know the joys of these natural fireworks. 

Exactly why we are seeing a decline in fireflies is not certain. Researchers are only just beginning to uncover the secret world of the firefly. The answer is undoubtedly complex, however, evidence is beginning to pour in that we should look no farther than ourselves for the cause.

Fireflies require a few things to get by. The first is some sort of standing water. They seem to love ponds, creeks, rivers, and vernal pools. Second is tall grass and a lot of forest litter. Their larvae live and hunt in and amongst fallen logs and plant litter. Though we aren't entirely sure what their larvae eat, they are certainly hunting things like snails, slugs, and small insects, which also require moist areas with a lot of debris. Fireflies also need taller plants like grasses. They will climb up the stems to begin their aerial light displays. Finally, fireflies need darkness. They communicate by light and any surplus light sources are likely to mess them up. 

With increasing human development, former firefly habitat is giving way to paved roads and chemical laden lawns. Mowers run endlessly during the summer, eliminating fireflies and their habitat. People are needlessly clearing land of brush piles and fallen logs, which their larvae as well as their prey need. Light pollution is only getting worse too. As with many other insects, the wanton use of insecticides are undoubtedly taking their toll as well. Areas that once harbored huge populations of fireflies are quickly becoming overrun with human traffic as new housing, commercial and other forms of development garble up what free land remains. 

At this point you may be wondering what you can do to help. If you are a land owner, please consider the following:

- Turn off outside lights at night when they aren't needed
- Let logs and other plant debris accumulate in places around your property
- Consider creating a water feature of some sort
- Avoid the use of pesticides and fertilizers on your lawns
- Plant native plants
- Don't over-mow your lawn and leave some areas un-mowed

The best part about these solutions is that they benefit so much more than just fireflies. Native wildlife will be all the better if you take these steps to making your property more ecologically friendly. We are lucky to be aware of this issue but we must take matters into our own hands. Get out there and enjoy nature and try to be a bit of steward at the same time. 

Photo Credit: Peilun Hsu (http://bit.ly/1rJkufG)

Further Reading:
http://www.firefly.org/why-are-fireflies-disappearing.html