Tag: ecology

More Fun with Not-so-Dumb Organisms and the U.S. National Assessment of Climate Change

Last time around, we brought forth evidence against organismal “dumbness”—the notion that species found only in defined climatic environments will go extinct if the climate changes beyond their range. We picked on cute little Nemo, and “found,” much like in the animation, that his kind (Amphiprion ocellaris) could actually survive far beyond their somewhat circumscribed tropical reef climate.

The key was the notion of plasticity—the concept that, despite being linked to a fixed genetic compliment, or genotype, the products of those genes (the “phenotype”) changed along with the environment, allowing organisms some degree of insurance against climate change. How this comes about through evolution remains a mystery, though we may occasionally indulge in a bit of high speculation.

“Science,” according to the late, great philosopher Karl Popper, is comprised of theories that are capable of making what he called “difficult predictions.” The notion that gravity bends light would be one of those made by relativity, and it was shown to be true by Sir Arthur Eddington in the 1919 total solar eclipse. It just happened to be in totality in the Pleiades star cluster (also the corporate logo of Subaru), and, sure enough, the stars closest to the eclipsed sun’s limb apparently moved towards it when compared to their “normal” positions.

So we have been interested in a truly difficult test of phenotypic plasticity, and we think we found one.

How about a clam that lives in the bottom of the great Southern Ocean surrounding Antarctica? Specifically, the burrowing clam Laternula elliptica. According to a recent (2017) paper by Catherine Waller of the University of Hull (in the, perhaps temporarily, United Kingdom) “75 percent of the recorded specimens [of L. elliptica] are from localities shallower than 100 m,” where the populations are exposed to “low and stable water temperatures in the range of -1.9 to +1.8 °C” (the remaining 25 percent inhabit cooler waters of the continental slope down to ~700m).

Laternula elliptica

Laternula elliptica

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.