Studying an ecosystem—a community of organisms that houses the interactions needed to maintain life—reveals how organisms generate energy, exchange nutrients, reproduce, and grow within a habitat that has unique physical and chemical influences.

Given all the physical and chemical interconnections in these dynamic biological communities, understanding ecosystems requires a multiscaled and interdisciplinary approach.

With diverse expertise, world-class equipment, and collaborative experience, PNNL researchers are able to analyze ecosystem communities in detail.

A focus on terrestrial processes

PNNL’s ecosystem science research primarily addresses the focus of the Department of Energy’s (DOE's) Office of Biological and Environmental Research. The effort focuses on advancing knowledge of terrestrial ecosystem processes to improve our understanding of Earth system models, and informing policies aimed at securing natural resources and infrastructure.

Researchers at PNNL study the ecosystems of soil, the plant-soil interface, extreme environments, biofilms, surface water, and dynamic subsurface environments where groundwater and river water mix. In every case, complex biogeochemical dynamics are in play.

One such area of enhanced biogeochemical activity, not yet well understood, is the exchange of water between rivers and their surrounding subsurface environments—an area critical for watershed function. PNNL researchers are examining how these exchanges influence water quality, nutrient dynamics, and ecosystem health in river systems, beginning with studies along the local Columbia River corridor.

PNNL’s global effort, the Worldwide Hydrobiogeochemistry Observation Network for Dynamic River Systems (WHONDRS), studies the world’s river corridors.

Increasing knowledge through detailed analysis

Investigating intricate alliances of chemical, physical, hydrologic, and metabolic forces requires an array of genomic, mass spectrometric, computational, and chemical-probe technologies. Researchers make detailed analyses at the Environmental Molecular Sciences Laboratory, a DOE user facility located on the PNNL campus.

As centers of biogeochemical interactivity, ecosystems have profound effects. Their primary living residents, bacteria and archaea, make up 60 percent of Earth’s biomass and account for most of its species diversity. Microbial systems generate 60 percent of respiration from terrestrial habitats, recycle elements and electrons, and prompt much of the planet’s biogeochemical change. PNNL researchers identify, measure, and model these ecosystems as they respond to perturbations, including cycles of wetting, drying, and warming.

One of PNNL’s science focus areas is finding sentinel biomarkers in living soil systems to better understand microbiome responses to changing moisture. These changes have implications for the productivity and fertility of our nation’s lands.

Across models and scales

PNNL’s collaborative PREMIS Initiative—Predicting Ecosystem Resilience through Multiscale and Integrative Science—draws on experts from plant sciences at PNNL and at the Joint Global Change Research Institute. PREMIS looks at feedbacks across scales—from molecular to plant-microbe interactomes to ecosystems. Droughts, storm surges, and sea level rise reduce the availability of fresh water in ecosystems, thereby influencing critical ecosystem processes, including carbon and nutrient cycling.

Some questions can only be answered by computer modeling. Many PNNL scientists, including the PREMIS team, use multiscale modeling informed by findings from the laboratory and the field. Limited understanding of the feedbacks between the biosphere and Earth’s climate system is a large source of uncertainty in global modeling. PNNL’s integrative approach allows for better predictions of how climate change affects ecosystem resilience.

Similar to an ecosystem, PNNL is its own community—one that houses the collaborative researchers providing the foundations for solving today’s most pressing energy and environmental challenges. As new scientific discoveries are achieved, PNNL develops new approaches to further explore our understanding of fundamental Earth science.