Tag: biology

Salt and CO2 Better for Tomatoes, Now for Lettuce, Too

Wow, will bacon be next?

Last fall we wrote about the improvement in tomato taste that results from growing them in elevated carbon dioxide and seawater (Idso and Michaels, 2015). Now it looks like the same treatment improves lettuce. 

Enhancing crop nutritional value has long been a goal of the agricultural industry. Growing plants under less than optimal conditions for a short period of time generally increases their oxidative stress. To counter such stress, plants will usually increase their antioxidant metabolism which, in turn, elevates the presence of various antioxidant compounds in their tissues, compounds that can be of great nutritional value from a human point of view, such as helping to reduce the effects of ageing.

However, stress-induced nutritional benefits often come at a price, including a reduction in plant growth and yield, making it unproductive and costly to implement these practices in the real world. But what if there was a way achieve such benefits without sacrificing crop biomass, having our cake and eating it, too? An intriguing paper recently published in the journal Scientia Horticulturae explains just how this can happen, involving lettuce, salt stress, and atmospheric CO2.

According to Pérez-López et al. (2015), the authors of this new work, “few studies have utilized salt irrigation combined with CO2-enriched atmospheres to enhance a crop’s nutraceutical value.” Thus, the team of five Spanish researchers set out to conduct just such an experiment involving two lettuce cultivars, Blonde of Paris Badavia (a green-leaf lettuce) and Oak Leaf (a red-leaf lettuce and a common garden variety). In so doing, they grew the lettuce cultivars from seed in controlled environment chambers at either ambient or enriched CO2 for a period of 35 days after which they supplied a subset of the two treatments with either 0 or 200 mM NaCl for 4 days to simulate salt stress. Thereafter they conducted a series of analyses to report growth and nutritional characteristics of the cultivars under these varying growth conditions. And what did those analyses reveal?

The Resilience of an American Pika Metapopulation to Global Warming

The American pika (Ochotona princeps) is an insanely cute critter often found in above-timberline rock fields in the western U.S.  

A Pika

Because they often live near mountain peaks, there’s been concern that global warming could push them over the top, to extinction. Writing in the Journal of Mammalogy, Smith and Nagy (2015) state that American pikas (Ochotona princeps) “have been characterized as an indicator species for the effects of global warming on animal populations,” citing the works of Smith et al. (2004), Beever and Wilkening (2011) and Ray et al. (2012). Indeed, as they continue, “a consideration of the effects of climate, primarily recent warming trends due to climate change, has dominated much of the recent literature on American pikas and their persistence.” Hoping to provide some additional insight on the subject, the two Arizona State University researchers set out to investigate the resilience of a pika metapopulation residing near Bodie, California, USA, that was exposed to several decades of natural warming.

Warming-Assisted Rapid Evolution of a Parasitic Host

In 1980, heated water from a nuclear power plant in Forsmark, Sweden (60.42°N, 18.17°E) began to be discharged into Biotest Lake, an artificial semi-enclosed lake in the Baltic Sea created in 1977 that is adjacent to the power plant and covers an area of 0.9 km2 with a mean depth of 2.5 m. The heated water has raised the temperature of the lake by 6-10°C compared to the surrounding Baltic Sea, but aside from this temperature difference, the physical conditions between the lake and the sea are very similar.

A few years after the power plant began operation, scientists conducted a study to determine the effect of the lake’s increased temperatures on the host-parasite dynamics between a fish parasite, the eyefluke (Diplostomum baeri), and its intermediate host, European perch (Perca fluviatilis). That analysis, performed in 1986 and 1987, revealed that perch in Biotest Lake experienced a higher degree of parasite infection compared to perch living in the cooler confines of the surrounding Baltic Sea (Höglund and Thulin, 1990), which finding is consistent with climate alarmist concerns that rising temperatures may lead to an increase in infectious diseases.

Fast forward to the present, however, and a much different ending to the story is observed.

Nearly three decades later, Mateos-Gonzales et al. (2015) returned to Biotest Lake and reexamined the very same host-parasite dynamic to learn what, if anything, had changed in the intervening time period. According to the team of researchers, Biotest Lake “provides an excellent opportunity to study the effect of a drastically changed environmental factor, water temperature, on the evolution of host-parasite interactions, in a single population recently split into two.” Specifically, it was their aim “to examine if the altered conditions have produced a change in prevalence and/or intensity of infection, and if these potential variations in infection have led to (or might have been caused by) a difference in parasite resistance.”

The Adaptive Response of Salmon to Global Warming

…the extinction horrors of climate change may be a “fish story”

Perhaps the myth-iest chestnut in the scary global warming meme is that our dear earth’s panoply of species is adapted only to the current climatic regime, and changing that regime means certain death, i.e. extinction.

That’s an easy, simplistic sell, but it denies some of the subtleties of organismal biology. Four decades ago, scientists realized that evolution has preserved a variety of responses to environmental change. It turns out that our enzymes, the basic material that catalyze life as we know it, actually change their shape as climate changes. Whether this is because we have so much information stored in our DNA that has survived countless generations and a variety of climates, or whether the response is simply built into the enzymes is unknown, but it is ubiquitous. It even has a catchy name: “Phenotypic Plasticity.”

Before your eyes glaze over, a little explanation is in order.

Each one of us has a genotype, which is our DNA, and each of us has an expression of that, our “phenotype.” Obviously not all genes express themselves—if they did, our physiological destiny would be eminently predictable, but it is not. Instead, we all carry strands of DNA that could theoretically cause major disease that generally do not express (or “penetrate” in the lingo of biology), and we also have DNA that could probably defeat many of the aging processes, that similarly do not express.

Instead, organisms display “plastic” responses when their environment changes. And so, species-related concerns over potential CO2-induced global warming may be dramatically overblown. And, though they don’t get much publicity, scientists are continually documenting our amazing adaptability.