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Solar Cell Greenhouses | Earth Wise

April 21, 2021 By EarthWise Leave a Comment

A recent study at North Carolina State University has shown that it can be feasible to use see-through solar panels in greenhouses to generate electricity. The idea is to use semi-transparent solar panels on greenhouses that allow some of the light to get in for the plants to grow while making the greenhouses energy neutral or even allowing them to generate more power than they use.

The question is how the semi-transparent solar panels might affect greenhouse crops. To investigate this issue, researchers grew crops of red leaf lettuce from seed to full maturity under a standard set of growing conditions – temperature, water, fertilizer, and CO2 concentration – but varied the light they get.

A control group was exposed to the full spectrum of white light while three experimental groups were exposed to light through different types of filters that absorbed the particular wavelengths of light that would be absorbed by different types of semitransparent solar cells.

The researchers paid close attention to characteristics of the lettuce that are important to growers, grocers, and consumers: general appearance, leaf number, leaf size, and weight. The results were that the lettuce produced using all three kinds of filtered light was essentially identical to that produced in the control group. Further research is underway looking at how harvesting various wavelengths of light affects biological processes for lettuces, tomatoes, and other crops.

Getting growers to use solar-powered greenhouses would be very difficult if doing so would result in a loss of productivity. But given these experimental results, it appears as though the decision will boil down to a simple economic argument about whether the investment in new greenhouse technology would be offset by energy production and its resultant savings.

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Study Finds Plants Would Grow Well in Solar Cell Greenhouses

Photo, posted April 8, 2008, courtesy of Brian Boucheron via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Why Have Crocodiles Changed So Little Over Time? | Earth Wise

February 9, 2021 By EarthWise Leave a Comment

Crocodiles today look very similar to ones from the Jurassic period some 200 million years ago. In fact, there are very few species of crocodilians alive today – approximately two dozen to be exact. Many other species have achieved a diversity of many thousands of species in the same amount of time.

During prehistoric times, many more types of crocodiles roamed the earth, including some as big as dinosaurs and other serpentine forms that lived in the sea.

According to findings by scientists at the University of Bristol in the U.K., a stop-start pattern of evolution could explain why crocodiles have changed so little over time. In the study, which was recently published in the journal Nature Communications Biology, researchers describe how crocodiles follow a pattern of evolution known as “punctuated equilibrium.” In other words, crocodiles’ rate of evolution is generally slow, but occasionally picks up because the environment has changed.

According to the research team, this slow rate of evolution is how crocodile diversity became so limited. It appears crocodiles arrived at a body that was efficient and versatile. They didn’t need to continue to change in order to survive.

This efficiency and versatility could be an explanation for why crocodiles survived the meteor impact that wiped out the dinosaurs. Since crocodiles can’t control their body temperature and rely on the environment for warmth, they generally fare better in warm conditions. During the age of dinosaurs, the climate was warmer than it is today, which could explain why crocodile diversity was higher.

The scientists next step is to try to figure out why some prehistoric crocodiles died out while others did not.

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Why crocodiles have changed so little since the age of the dinosaurs

Photo, posted December 26, 2012, courtesy of Nicholas Smith via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Restoring The Taste Of Tomatoes

March 1, 2017 By EarthWise

Over the years, tomatoes have been selectively bred for qualities such as size and firmness for shipping purposes and appearance, but selection for flavor has generally been overlooked. Many of us find that the tomatoes we buy in the grocery store just don’t taste like they used to. In fact, often they don’t taste like much of anything. Comparing them to the delicious local-grown varieties we can find during the summer provides evidence for this conclusion.

Why Do Animals Eat Ocean Plastic?

November 21, 2016 By WAMC WEB

It’s no secret that there is a lot of plastic debris in our oceans. In fact, scientists estimate that there is more than 165 million tons of plastic trash swirling about in our oceans today, with an additional 8.8 million tons flowing in every year. And as the oceans swell with plastic litter, hundreds of marine species are ingesting the stuff – often with dire consequences.

Food Waste And Behavior

May 27, 2016 By WAMC WEB

In a recent article in Science entitled “Waste not, want not, emit less,” Danish researchers looked at the problem of food waste in both developed and developing countries. Overall, about a third of the world’s food is lost or wasted, but the reasons for this vary in different parts of the world.