Temperature Response of Metabolic Activity of an Antarctic Nematode

Abstract

Because of climate change, the McMurdo Dry Valleys of Antarctica (MCM) have experienced an increase in the frequency and magnitude of summer pulse warming and surface ice and snow melting events. In response to these environmental changes, some nematode species in the MCM have experienced steady population declines over the last three decades, but Plectus murrayi, a mesophilic nematode species, has responded with a steady increase in range and abundance. To determine how P. murrayi responds to increasing temperatures, we measured metabolic heat and CO2 production rates and calculated O2 consumption rates as a function of temperature at 5 °C intervals from 5 to 50 °C. Heat, CO2 production, and O2 consumption rates increase approximately exponentially up to 40 °C, a temperature never experienced in their polar habitat. Metabolic rates decline rapidly above 40 °C and are irreversibly lost at 50 °C due to thermal stress and mortality. Caenorhabditis elegans, a much more widespread nematode that is found in more temperate environments reaches peak metabolic heat rate at just 27 °C, above which it experiences high mortality due to thermal stress. At temperatures from 10 to 40 °C, P. murrayi produces about 6 times more CO2 than the O2 it consumes, a respiratory quotient indicative of either acetogenesis or de novo lipogenesis. No potential acetogenic microbes were identified in the P. murrayi microbiome, suggesting that P. murrayi is producing increased CO2 as a byproduct of de novo lipogenesis. This phenomenon, in conjunction with increased summer temperatures in their polar habitat, will likely lead to increased demand for carbon and subsequent increases in CO2 production, population abundance, and range expansion. If such changes are not concomitant with increased carbon inputs, we predict the MCM soil ecosystems will experience dramatic declines in functional and taxonomic diversity.

Nematicidal and Toxicity Effects of Eupatorium adenophorum Spreng against the Root-Knot Nematode Meloidogyne incognita in Soil Producing Cucumber

“…However, as the temperature approached the upper limits, nematode sensitivity to plant compounds of E. adenophorum. The increase in metabolic temperature, on the one hand, and the increase in the release rate of compounds to the soil at higher temperatures can reason for the increase in mortality in the nematode [44].…”

The pervasive impact of global climate change on plant-nematode interaction continuum

“…On the other hand, high temperature has been found to cause sex reversal from female to male (which are non-parasitic in nature) in the parthenogenetic root-knot nematodes ( Papadopoulou and Triantaphyllou, 1982 ). A recent study with Antarctic population of free-living nematode Plectus murrayi showed that rise in temperature increases the metabolic activities and O 2 consumption thereby disrupting the ecosystem structure and function ( Robinson et al., 2023 ). The authors, in context of carbon-limited soil ecosystem of polar habitat, speculated higher nematode abundance in deeper soil due to vertical range expansion.…”