Earth and Environment

What did Earth look like between one billion and two-and-a-half billion years ago? When did our atmosphere and oceans become oxygen-rich? Did oxygenation occur rapidly or during slow oscillations over hundreds of millions of years? These questions have been debated by scientists for decades because of their implications for the evolution of early life, and thus, our very understanding of life on Earth. Through their research, Dr Robert H. Rainbird and his team at the Geological Survey of Canada and Carleton University seek to answer these questions by investigating the ancient sedimentary rocks to the north of Lake Huron in Ontario.

Earthquakes are one of the more destructive phenomena we encounter on Earth. However, the seismic waves that earthquakes send travelling through the Earth are powerful tools to investigate the Earth’s crust and mantle. Through a series of seismic recording stations in Canada and northern USA, Dr Fiona Darbyshire at the Université du Québec à Montréal is doing exactly that. By listening to the seismic waves emitted from earthquakes, she and her team can determine the current composition of the crust and upper mantle, while also revealing tantalising clues about the formation and evolution of tectonic plates over the planet’s long history.

Between 2014 and 2016, the Gulf of Alaska experienced a prolonged and intense heatwave. The hot temperatures disrupted species interactions and stressed the Gulf of Alaska ecosystem past its tipping point. New research led by Dr Robert Suryan at the NOAA Alaska Fisheries Science Center suggests that this event may have left a long-standing mark on the Gulf of Alaska. Dr Suryan and his colleagues quantified the effects of the heatwave on all aspects of marine ecosystems. Their work highlights the importance of long-term ecosystem monitoring in tracking, predicting, and preparing for a changing climate.

Climate models typically use mathematical equations that govern geophysical fluid dynamics to describe the behaviours of the ocean, atmosphere, sea ice and land ice. Computer simulations that use climate models are an essential tool for capturing the complex, interacting motions found throughout Earth’s oceans and atmosphere. Using some of the most advanced simulation techniques available to date, Dr Prajvala Kurtakoti at Los Alamos National Laboratory aims to learn more about how these processes occur within the seas of Earth’s polar regions. Her team’s results are shedding new light on the intricate connections between the oceans and atmosphere, and how these systems are likely to change as the climate warms.

Large-scale circulation patterns can be found throughout Earth’s oceans and atmosphere, and play a crucial role in maintaining the stability of regional climates. As the climate warms, researchers find that these patterns are experiencing a fundamental transformation. Using a combination of satellite observations and computer models, Dr Hu Yang at the Alfred Wegener Institute, identifies and explains the mechanisms of these changes. His study offers crucial insights into how both human populations and natural ecosystems will be affected by these transformations – and how they will need to adapt to cope with them.

In every introductory biology class, students learn the classification system used to catalogue plants, animals, fungi, and other organisms. In order of increasing specificity, the major levels of classification are: domain, kingdom, phylum, class, order, family, genus, and species. Global adoption of this system allows us to create an inventory of the world’s species diversity. For instance, we classify the Redwood tree of the US Pacific coast as the species sempervirens in the genus Sequoia, or Sequoia sempervirens. Until recently, however, there was no comparable standard available in the United States to classify the nation’s diverse types of vegetation – the various combinations of species, growth forms, and ecological factors that occur in certain regions. Instead, many land-management groups created their own classifications, hindering communication and collaboration. To address this issue, stakeholders established the United States National Vegetation Classification (USNVC).

Land-based, or ‘terrestrial’, ecosystems can act as both a sink and a source of greenhouse gases. An active field of research centres on understanding which environmental parameters turn a carbon sink into a carbon source. Dr Ülo Mander from the University of Tartu in Estonia concentrates his work on predicting greenhouse gas fluxes from terrestrial ecosystems and monitoring how environmental conditions, such as soil moisture and temperature, influence emissions. He aims to use his research to help resolve numerous environmental issues, including climate change.

Permafrost is key to maintaining the stability of steep mountain slopes. Yet as the climate warms, this frozen ground is becoming increasingly prone to thawing. In some cases, these events can trigger cascades of loose rock, with potentially devastating consequences for surrounding communities. Using a combination of computer modelling, and daring field experiments, Dr Florence Magnin at the Laboratory of Environments, Dynamics and Mountain Territories (EDYTEM) aims to better predict when and where these rockfalls are likely to occur, and how the state of mountain permafrost will evolve in the future.

As the impacts of climate change become increasingly obvious worldwide, focused efforts to mitigate its worst effects are becoming more urgent. Through his research, Dr Xander Wang at the University of Prince Edward Island aims to innovate the computer models used to predict these future changes on smaller, regional scales. His team’s work is making important strides towards an advanced predictive toolset, which policymakers could use to make the best possible decisions about how to protect local populations from future climate-related disasters.

As they enter the atmosphere, tiny particles emitted by the burning of biomass or fossil fuels can heavily influence the formation of clouds. Yet due to human influence, the roles that these aerosols play in the process are still poorly understood by climate scientists. Using a combination of ground- and space-based measurements, along with advanced computer simulations, Dr Timothy Logan at Texas A&M University has gained important new insights into the atmospheric impacts of aerosols, and how emissions from both wildfires and human activities are having tangible effects on the weather.

The Association for Women Geoscientists (AWG) is an international organisation devoted to increasing the participation of women in geoscience, and inspiring girls and young women to pursue careers in geoscience-related disciplines. In this exclusive interview, we have had the pleasure of speaking with Dr Noelia Beatriz Carmona, AWG’s past president, who describes how the Association supports the professional development of its members, provides education and outreach to young women and girls, and encourages the participation of women in geoscience.

Marine sand is both a vital natural habitat and an essential resource. However, while desert dunes are comparatively easy to observe, their oceanic counterparts are still poorly understood. Dr Xiaochuan Ma and his colleagues at the Chinese Academy of Sciences in Qingdao are mapping the shifting sands of the seafloor and measuring their movement. By investigating how seafloor dunes respond to waves, tides, and typhoons, they can help decision-makers protect and manage this critical resource.