From Rock to Ecosystem
The Critical Role of Biological Weathering in Shaping Nutrient Production at High Altitudes. A Global Exploration Study
Dragos G. Zaharescu (Biosphere 2, University of Arizona) and Adventurers and Scientists for Conservation (ASC)
Short Project Description
Science rationale: Mountain tops are Earth’s Third Pole. Similar to higher latitudes they experience nutrient poor environment, exposure to long range winds, high UV radiation and harsh climatic conditions. The elevated topography, which brings mountains in close contact with the upper atmosphere, adds a strong climatic stratification vertically. These characteristics together imprint a “sky island” effect to high altitude ecosystems, and make them among the most delicate sensors of environmental change globally.
Microbial communities are among the richest ecosystem components that colonize mountain tops. They have developed poorly understood strategies in terms of survival and use of food resources. While most of nutrients available in such places are “locked” within rock structures, an important role of microbes is nevertheless the transformation of minerals (biological-driven weathering) as part of their quest for nutrient sequestration. This is also among the most important mechanisms of nutrient release in the environment, and shapes the productivity and diversity of both, mountain top micro-communities and the more complex ecosystems downstream. In this context first of our objectives for data collection is to unveil the composition of key communities behind the initiation of nutrient production at such elevations and their relationship with the substrate. A second objective, and a pristine topic in science, is to understand whether there are large scale linkages between different mountain tops in terms of microbe communities (genetic islands) and their weathering effect. This will help us appreciate the role of microbial communities in shaping mountain top landscapes from a global perspective, and help predict how environmental/climate change can affect the production of living matter in these sensitive environments. These topics deserve immediate consideration especially in the context of accelerated changes experienced by our cold regions.
This study also provides link to major scientific efforts undertaken at Biosphere-2 and University of Arizona, including Plant-bacteria-rock interactions experiment, Critical Zone Observatory and Landscape Evolution Observatory.
Activities: We aim to conduct sampling of bedrock material and associated biofilm from mountain massifs across the world with the help of trained explorers. To simplify sampling protocol, small-size rock samples, of about 50g each (or 4-5cm), will be collected from exposed geology following elevation gradient (ideally at locations 200 m altitude apart) during either ascent or descent phase of the expedition. A total of 3-5 rock pieces randomly distributed at one location will represent a sampling site.
To allow comparative analysis on elevation gradient, same rock type will be sought. Where possible soil weathered material will be taken from same site as rock. For sampling:
- Look for bare, dry rocks, away from road runoff, other major human influences or animal colonies.
- Samples have to be handled with and taken in sterile plastic bags, and air shipped to our laboratory for freeze storage and further analyses. Small rock pieces broken from bedrock can be cleanly sampled by using unopened sandwich bags turned inside-out to avoid direct contact with the rock (similar to dog poo collection). This is very important to prevent sample contamination with human microorganisms (by air or touch).
- Additionally 3 unopened bags have to be included in the sampling batch for background contamination checks.
- Local landscape and weather condition will be recorded in the field, together with geographical coordinates of sampling sites. Still images or short movies will be recorded at each site to aid in data interpretation and public outreach.
Sampling will be carefully carried out so that no impact on the landscape will be left, including damaging rare plants/animals or their habitats.
Sample processing will be carried out at The University of Arizona, Biosphere-2 and collaborating partners worldwide.
In the laboratory samples will be subjected to biological and geochemical analyses including DNA extraction and sequencing (to screen for biotic community composition), mineral identification, major nutrients and trace element quantifications, together with organic matter analysis. Since this is an exploratory study, the methodology is continuously being refined. Results of this study are to be published in scientific journals as well as presented at relevant meetings or displayed at Biosphere-2. Credit will be given to all significant contribution.
These collaborative expeditions will help answer scientific questions that would otherwise be impossible to answer.
© Copyright 2013 Kurt J. Sanderson unless otherwise noted.