Search for: All records

In the cold deserts of the McMurdo Dry Valleys (MDV) the suitability of soil for microbial life is determined by both contemporary processes and legacy effects. Climatic changes and accompanying glacial activity have caused local extinctions and lasting geochemical changes to parts of these soil ecosystems over several million years, while areas of refugia may have escaped these disturbances and existed under relatively stable conditions. This study describes the impact of historical glacial and lacustrine disturbance events on microbial communities across the MDV to investigate how this divergent disturbance history influenced the structuring of microbial communities across this otherwise very stable ecosystem. Soil bacterial communities from 17 sites representing either putative refugia or sites disturbed during the Last Glacial Maximum (LGM) (22-17 kya) were characterized using 16 S metabarcoding. Regardless of geographic distance, several putative refugia sites at elevations above 600 m displayed highly similar microbial communities. At a regional scale, community composition was found to be influenced by elevation and geographic proximity more so than soil geochemical properties. These results suggest that despite the extreme conditions, diverse microbial communities exist in these putative refugia that have presumably remained undisturbed at least through the LGM. We suggest that similarities in microbial communities can be interpreted as evidence for historical climate legacies on an ecosystem-wide scale. 

Like many social behaviors, aggression can be rewarding, leading to behavioral plasticity. One outcome of reward-induced aggression is the long-term increase in the speed in which future aggression-based encounters is initiated. This form of aggression impacts dendritic structure and excitatory synaptic neurotransmission in the nucleus accumbens, a brain region well known to regulate motivated behaviors. Yet, little is known about the intracellular signaling mechanisms that drive these structural/functional changes and long-term changes in aggressive behavior. This study set out to further elucidate the intracellular signaling mechanisms regulating the plasticity in neurophysiology and behavior that underlie the rewarding consequences of aggressive interactions. Female Syrian hamsters experienced zero, two or five aggressive interactions and the phosphorylation of proteins in reward-associated regions was analyzed. We report that aggressive interactions result in a transient increase in the phosphorylation of extracellular-signal related kinase 1/2 (ERK1/2) in the nucleus accumbens. We also report that aggressive interactions result in a transient decrease in the phosphorylation of mammalian target of rapamycin (mTOR) in the medial prefrontal cortex, a major input structure to the nucleus accumbens. Thus, this study identifies ERK1/2 and mTOR as potential signaling pathways for regulating the long-term rewarding consequences of aggressive interactions. Furthermore, the recruitment profile of the ERK1/2 and the mTOR pathways are distinct in different brain regions. 

The Toolik Field Station (TFS) plant phenology program monitors the timing of specific phenological developmental stages of plant species commonly found in the dry heath tundra plant community. The TFS phenology program began in response to TFS research community requests to collect baseline environmental data that would be broadly applicable and provide context to research projects conducted near TFS. The TFS plant phenology data collection protocol is based on the International Tundra Experiment (ITEX) (www.geog.ubc.ca/itex) protocol for the Toolik Snowfence Experiment. This dry heath tundra dataset began in 2011 and continues through 2023. 

The Toolik Field Station (TFS) plant phenology program monitors the timing of specific phenological developmental stages of plant species commonly found in the moist acidic tundra plant community. The TFS phenology program began in response to TFS research community requests to collect baseline environmental data that would be broadly applicable and provide context to research projects conducted near TFS. The TFS plant phenology data collection protocol is based on the International Tundra Experiment (ITEX, www.geog.ubc.ca/itex) protocol for the Toolik Snowfence Experiment. This moist acidic tundra dataset began in 2007 and continues through 2023.