Ecosystem-dependent two-stage SOC changes in CONUS (1970–2014)

Higher Education Press

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The dynamics of soil organic carbon (SOC) play a critical role in the global carbon cycle. In context of global warming, numerous experimental studies have reported temperature-sensitive responses of SOC. However, the limited temporal frequency and spatial density of repeated sampling and whole-profile SOC observations have hindered the understanding of large-scale, long-term spatiotemporal patterns of SOC and their responses to environment changes under global warming, thereby constraining the ability to accurately predict the global carbon cycle.

Motivated by these challenges, Professor Lin Yang, Academician Chenghu Zhou and Dr. Feixue Shen from Nanjing University, in collaboration with Professor A-Xing Zhu from University of Wisconsin-Madison, Academician Shilong Piao from Peking University, and Professor Yiqi Luo from Cornell University, analyzed 10,639 soil profiles from forests and croplands across the contiguous United States to reconstruct the dynamics of soil organic carbon (SOC) over a 45-year period (1970–2014) in both topsoil (0–30 cm) and subsoil (30–100 cm). They further examined the temporal relationships between SOC changes at different depths and key environmental drivers such as climate, vegetation, soil properties, and nitrogen deposition. This study is the first to reveal large‑scale, long-term connections between temperature fluctuations and SOC dynamics across diverse ecosystems, as well as the depth-dependent nature of environmental controls. The findings provide a critical scientific basis for improving Earth system models and refining carbon management strategies in the context of global warming.

Highlights:

Two-stage SOC changes in the CONUS from 1970 to 2014 were strongly associated with changes in warming rates.

Rising temperatures predominantly coincided with reduced topsoil SOC stock.

Soil water content emerged as the strongest negative relationship with subsoil SOC dynamics.

The loss of SOC induced by warming may exhibit a threshold effect controlled by the rate of temperature increase.

 

Core content:

This study integrated SOC measurements, time-series statistical analysis, and machine learning techniques, revealing a two-phase trajectory of SOC change in forest and cropland ecosystems across the contiguous United States. From the 1970s to the 1990s, SOC showed a non-linear loss trend. Since the 1990s, however, SOC loss has stagnated. Furthermore, starting from the late 1990s, while SOC changes in the cropland 0–30 cm layer remained stagnant, both the cropland 30–100 cm layer and the entire soil profile in forest systems began to show an increasing trend.

The study found that the two-phase SOC change patterns in both forest and cropland ecosystems are closely related to the rate of warming. Overall, the rate of temperature change was negatively correlated with the rate of SOC change. Notably, SOC loss commenced only when the rate of temperature increase exceeded a certain threshold.

Partial correlation analysis indicated that air temperature is the primary factor driving SOC loss in surface layers, showing a significant negative correlation in both forests and croplands. In contrast, changes in subsurface SOC were mainly dominated by soil water content, also showing a negative correlation. Other environmental factors—such as increased net primary productivity (NPP) in forest surface layers and nitrogen fertilizer application in croplands—also demonstrated the potential to enhance carbon storage through targeted management.

Using machine learning, this paper mapped SOC stock changes at a ~2 km resolution. Nationwide, SOC stocks in the top 1 meter increased by 1.41% (from 19.05 Pg to 19.32 Pg) in forests and 1.14% (from 13.10 Pg to 13.25 Pg) in croplands.

Outlook: The study highlights a strong connection between the rate of warming and changes in SOC stocks from 1970 to 2014. Given the recorded temperature increases since 2015, the recently accelerated warming may reverse the current trend of increasing SOC stocks in forest and cropland soils. Therefore, extending monitoring beyond 2014 is crucial to validate the observed change patterns. Concurrently, mechanistic research on how warming rates drive SOC changes across different ecosystems and soil depths should be pursued, with particular attention to deep soil moisture dynamics. These insights are essential for improving the parameterization of SOC responses to temperature and precipitation changes in Earth system models.

The change trends of topsoil and subsoil SOC stock in forest and cropland

Regressions between change rate of SOC stock and warming. 

 

Temporal relationships among environmental factors. 

 Spatial pattern of SOC stock change in the top 1 meter of the CONUS. 

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Journal

Geography and Sustainability

DOI

10.1016/j.geosus.2025.100359 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Ecosystem-dependent two-stage changes in soil organic carbon stock across the contiguous United States from 1970 to 2014

Urban–rural interactions promote sustainable rural development

Higher Education Press

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Promoting sustainable development in both urban and rural areas has become a globally shared concern. Urban–rural interactions can contribute to wealth creation, poverty alleviation, employment growth, and improved social equity. It has been widely recognized as a key strategy for addressing sustainability challenges, although it may also bring some negative impacts, such as labor outmigration and imbalanced capital allocation. However, the impacts of urban–rural interactions on rural development and how these impacts contribute to sustainable rural transformation require further in-depth investigation.

Against this backdrop, Professor He Yanhua’s research team at Hunan Normal University took the Changsha–Zhuzhou–Xiangtan urban agglomeration as a case study. Employing a mediating effect model, they analyzed the mediating roles of factors such as capital, technology, labor, and land in the process through which urban–rural interaction promotes sustainable rural development. This research reveals the mechanism by which urban–rural interaction influences sustainable rural development, providing a theoretical foundation and practical guidance for advancing sustainable development in urban–rural regions.

Highlights:

Urban–rural interactions enhance the rural social-economic sustainability.

Urban–rural social and spatial interactions harm rural environmental sustainability.

Capital, technology, and labor mediate urban–rural interactions’ rural sustainability impact.

 

Core content:

Urban–rural interactions have profound impacts on rural development, including population mobility, industrial growth, and public service provision. Currently, they serve as a key driving force in rural transformation in China, especially in densely populated and economically dynamic areas such as urban agglomerations. Based on the case study of an urban agglomeration in central China, this research deeply explores the impact mechanism of urban–rural interaction on sustainable rural development using an urban–rural interaction and rural sustainability assessment framework. Key findings of the study include:

1. Positive urban–rural interactions play a crucial role in addressing rural decline and advancing regional sustainable development.
2. Urban–rural industrial convergence, spatial connectivity, and social integration all contribute positively to rural social and economic sustainability.
3. Urban–rural interactions facilitate the flows of capital, technology, and labor to rural areas, and these flows drive the sustainable development of rural society and the economy.
4. During the process of urban–rural interaction, the expansion of small towns, changes in consumption patterns, and transformations in agricultural production practices have exerted adverse effects on the rural environment.

To effectively leverage the positive effects of urban–rural interaction while mitigating its potential adverse impacts, the study proposes the following recommendations: construct a more compact urban–rural spatial structure to enhance physical connectivity; attract more investment in rural industries to promote industrial transformation, innovation and integration; ensure equitable access to public services; and implement strict environmental protection and land-use management policies.

 

Outlook: Based on empirical analysis, this study confirms the mechanisms through which urban–rural interaction influences sustainable rural development via the flow of factors such as population, capital, and technology. However, urban–rural interactions and rural development pathways vary across countries and regions, which may limit the applicability of the results. For example, in remote villages that do not benefit from urban spillover effects, these measures may be less effective. Consequently, future research could be undertaken in diverse national and regional contexts to further investigate the intrinsic relationships between urban–rural interaction and sustainable rural development.

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Journal

Geography and Sustainability

DOI

10.1016/j.geosus.2025.100338 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

How urban–rural interactions promote sustainable rural development: Evidence from the Chang–Zhu–Tan urban agglomeration, China

 Storms in the Southern Ocean mitigates global warming

University of Gothenburg

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Visible satellite image showing storms sweeping across the Southern Ocean on 4 January 2019.

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Intense storms that sweep over the Southern Ocean enable the ocean to absorb more heat from the atmosphere. New research from the University of Gothenburg shows that today’s climate models underestimate how storms mix the ocean and thereby give less reliable future projections of our climate.

The Southern Ocean is a vast expanse of ocean encircling the Antarctic continent, regulating Earth’s climate by moving heat, carbon, and nutrients out in the world’s oceans.

It provides a critical climate service by absorbing over 75 per cent of the excess heat generated by humans globally. The Southern Ocean’s capacity to reduce climate warming depends on how efficiently it can absorb heat from our atmosphere.

In a new study in Nature Geoscience, researchers from the University of Gothenburg show that storms play a key role in controlling how the Southern Ocean exchanges heat with the atmosphere. The team finds that intense winds churn the ocean, drawing colder deep water upward and pushing warmer surface water downward. The surface stays cooler and can take up more heat from the atmosphere.

Storms lower surface temperature

“Our research shows that summers with stronger storm activity generate lower surface temperatures across the Southern Ocean. Hence, a stormy ocean can absorb more heat from the atmosphere, then in calm weather,” says Marcel du Plessis, Researcher in oceanography at the University of Gothenburg and main author of the study.

How much heat the ocean absorbs from the atmosphere influences everything from how high temperatures will be on land, to the extent of sea ice and the severity of marine heatwaves.

The research team have been studying storm patterns around Antarctica over the last few decades and can now link changes in storm intensity and their windiness to changes in our climate and atmospheric circulation. In general, it is observed that storms are becoming stronger, due to an increase in the atmospheric pressure difference between Antarctica and the Subtropics.

Climate models are inaccurate

Current climate models, which underpin the climate projections used to guide policy, tend to underestimate the strength of Southern Ocean storms and thereby simulate an overly warm ocean.

“That is why our findings are important, because a better representation of storm processes is essential for more accurate future climate projections,” says Marcel du Plessis. 

Conducting research in the Southern Ocean is complicated, challenging, and costly. In the study, the researchers used a combination of advanced autonomous underwater and surface robots that measured the ocean temperature and salinity, and atmospheric conditions above the waves. They combined the results from these robotic observations with multi-year model and satellite data to disentangle these complex storm and ocean heat exchange processes.

Different processes in winter

“This is the first time we can clearly link Southern Ocean storms to changes in ocean warming and our climate variability over the past 20 years. Such results mean we can better understand how the ocean is warming today and thereby predict how our Earth’s climate may change in the future”, says Sebastiaan Swart, Professor of Oceanography, at the University of Gothenburg.

It's in the Antarctic summer that storms have their strongest impact on ocean heat uptake. In winter, completely different processes take place. This will be the next challenge for researchers to observe and understand.

This is the uncrewed surface vehicle, called Wave Glider, that was critical in the study. 

Credit

Sam Fredriksson

Journal

Nature Geoscience

DOI

10.1038/s41561-025-01857-3 

Method of Research

Observational study

Article Title

Southern Ocean summer warming is regulated by storm-driven mixing

Book prepares K-12 leaders for the next public health crisis

University of Illinois at Urbana-Champaign, News Bureau

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The task of keeping children safe and in school was a formidable challenge for educators, parents and community leaders. 

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Credit: Photo by Michelle Hassel

CHAMPAIGN, Ill. — In a new book, a team of experts in educational policy, epidemiology and public health chronicles the challenges faced by educators, public health authorities and school officials during the COVID-19 pandemic and offers a guide to some of the lessons learned as K-12 schools weathered that crisis. One key message: Collaboration between schools, public health authorities and community leaders is essential to success.

The book, “K-12 Schools and Public Health Partnerships: Strategies for Navigating a Crisis with Trust, Equity, and Communication,” describes the enormous challenges schools faced when the World Health Organization declared in March 2020 that COVID-19 was a global pandemic. School district leaders across the U.S. “had to make rapid decisions about school closures, remote learning plans, staff safety, student meal distribution and communication with anxious families — all while working with limited information and unclear guidance,” the authors wrote.

The four co-authors were themselves drawn into the crisis. Each provided their own leadership and expertise to decision-makers in public health and schools and observed the successes and failures of efforts in their communities. During the peak of the crisis, Leah Perkinson, a pandemics manager at The Rockefeller Foundation and a former researcher at the U.S. Centers for Disease Control and Prevention, led national pandemic response efforts, coordinated communities of practice and compiled public health guidance documents. Lisa C. Barrios, currently the director of the Division of Readiness and Response Science at the CDC, led activities to help schools prevent, mitigate and respond to the COVID-19 pandemic. University of Illinois Urbana-Champaign pathobiology professor Rebecca Lee Smith, an epidemiologist, advised those working to track and reduce the spread of infection in schools and businesses across Illinois. Rachel Roegman, a professor of education policy, organization and leadership at the U. of I. whose work focuses on how to make schools more affirming spaces for potentially marginalized students, saw how inequities in school communities could exacerbate the tragic toll of the disease.

The book includes dozens of interviews with school, public health and community leaders who played key roles in responding to the crisis in K-12 schools, harvesting a trove of useful insights and practical guidance. The book focuses on the importance of building trust, prioritizing the needs of those most at risk and building accurate and reliable communication channels. These factors were intertwined and foundational to success, the authors wrote.  

The best way to build trust was to make an effort to reach out to families and students to ask them what they needed — and finding resources to meet those needs, the authors wrote. During the COVID-19 pandemic, this meant offering students the laptops essential for online learning and showing them how to connect, creating Wi-Fi hubs for neighborhoods that lacked them, developing new systems for distributing school lunches and offering in-person learning hubs for students whose parents were essential workers.

Building trust and enhancing communication also meant creating accessible online dashboards that offered up-to-date testing and infection-rate data for the community along with information about how to access testing sites or services. Communication also was enhanced when community organizations, schools and political leaders coordinated their efforts and collaborated on messaging to speak with one voice.

Serving those most at risk of harm from the pandemic meant planning centered on those with disabilities, those speaking languages other than English and low-income or undocumented families. “Planning from the margins” meant that no one was treated as an afterthought or left out of the public health equation, the authors wrote.

The book also describes how leaders dealt with public criticism of their efforts and the spread of misinformation. It helped when community institutions joined forces to put out unified messages, admitted to uncertainty and acknowledged that guidance sometimes changes in the face of new information. It also helped when they showed up and truly listened to community concerns. And, in some circumstances, the best approach was to avoid amplifying misleading claims by debating them. Instead, the most effective teams remained committed to their essential messages.

To keep kids in school, safe and learning during the next public health crisis, the authors urge communities to continue the partnerships that developed during the COVID-19 pandemic. Building and maintaining those relationships and their outreach to the community is foundational to surviving and navigating the next crisis in K-12 schools, they wrote.

 

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Editor’s note:  

The book “K-12 Schools and Public Health Partnerships: Strategies for Navigating a Crisis with Trust, Equity, and Communication” is available for purchase online.