Friday, September 26, 2025

 

Inequality in agri-food chains: the Global South produces the food, but the Global North keeps the wealth


Increasing inequality in agri-food value chains: global trends from 1995-2020




Universitat Autonoma de Barcelona






In the global agri-food system, most agricultural goods are produced in the Global South but value is captured by countries of the Global North through growth and control of the post farmgate sectors.

This is shown by a study from the Institute of Environmental Science and Technology at the Universitat Autònoma de Barcelona (ICTA-UAB), which reveals that between 1995 and 2020, non-agricultural sectors absorbed much of the value added in global agri-food systems. These sectors are disproportionately dominated by countries of the Global North.

The research, published in the journal Global Food Security and led by ICTA-UAB researcher Meghna Goyal together with Jason Hickel, also from ICTA-UAB, and Praveen Jha from Jawaharlal Nehru University, India, analyses for the first time on a global scale the distribution of economic value in agri-food chains over a 25-year period. The results show that, although the Global South has increased its share of agricultural production, countries of the North continue to capture a disproportionate share of income from higher-value sectors such as processing, logistics, finance, and services.

The study also notes that a substantial portion of revenue is recorded in low-tax jurisdictions with little agricultural production, suggesting that value-addition is recorded according to profit-maximizing strategies, rather than according to actual production or employment. This demonstrates that value chains in agri-food systems reinforce structural inequalities through the international division of labor. Countries such as Singapore and Hong Kong capture up to 60 and 27 times more from the global agri-food system than the value of their agricultural production.

Researchers warn of the urgent need for economic sovereignty for the Global South to address structural unequal exchange in the global agri-food system.

"Value capture strategies reshape supply chains. Our findings alert us to its potentially negative consequences for development and equity for farming, and the Global South economies”, says Meghna Goyal, main author of the study.

ICTA-UAB researcher and coauthor Jason Hickel states that "this is the first study to measure the global distribution of value in the agri-food system, and the results are damning. The people who do most of the agricultural production, which sustains global civilization, do not get a fair share of food-system incomes."

 

 

Baltic diatoms remained genetically stable for millennia – then humans came into play



After humans started using the Baltic Sea, its diatom populations started to experience accelerated – and, so far, irreversible – changes in genetic composition and diversity. These are the results of a recent study led by researchers in Konstanz




University of Konstanz





Our seas contain countless algae and other microscopic single-cell organisms that photosynthesize. Not only do these phytoplankton form the basis for marine food webs, but, because they produce oxygen and sequester carbon, they also have a major impact on the global climate. Yet, how resilient are phytoplankton to climate events and human influence?

To answer this question, a team of interdisciplinary researchers in the project PHYTOARK examined the genetic makeup and diversity of the Baltic diatom species Skeletonema marinoi across the last 8,000 years. The latest results from a study led by the Environmental Genomics group at the University of Konstanz (Germany), were just published in the journal Global Change Biology. They indicate that human activity has a profound impact on the genetic stability of diatom populations.

"Over many thousands of years, the genetic patterns of the diatom populations we studied remained surprisingly stable. It was only after humans began using the Baltic Sea more intensively in the last millennium that we observed more rapid changes in the diatoms' genetic composition", explains Alexandra Schmidt, first author of the study and a postdoctoral researcher in the research team of Laura Epp in the Department of Biology at the University of Konstanz. This shift is not necessarily negative, but the fact that it has been much faster and more massive shows the impact of human activities. It is unclear whether the populations will ever return to their original genetic state.

Detective work on the sea floor
In order to collect the genetic material of diatoms from the past few thousand years, the research team took sediment cores from the bottom of the Baltic Sea. These cores taken from the Eastern Gotland Basin and the Gulf of Finland are like genetic time capsules. "In the mud and sand deposits on the sea floor, we find so-called 'ancient DNA', preserved for thousands of years in the sediment, after the death of the organisms", Laura Epp says. Studying the DNA extracted from individual layers of the core sample makes it possible to follow genetic patterns of the diatom populations over time – the deeper the layer of sediment, the older the genetic material.

From their sediment cores, the research team extracted DNA-remains of diatoms from the present up to about 8,000 years ago. To reliably assess the genetic resilience of the studied species, the team enriched and sequenced diatom DNA of two cell organelles – chloroplasts and mitochondria. These organelles contain particular genomic information, and by comparing this from different layers of the sediment core, researchers can analyze genetic changes in the diatom populations over the entire sample period – the past 8,000 years.

Stable despite climate fluctuations
The results of the study show that the genetic makeup of the diatom populations remained mostly stable over long periods of time. Although there were temporary changes during climate phases such as the Holocene Thermal Maximum (about 6,000-10,000 years ago) or the Late Antique Little Ice Age (about 1,300-1,400 years ago), the genetic composition continually returned to its original state. It was only in past centuries that remarkably faster and, so far, irreversible changes have taken place in the genetic composition of the diatom populations. "The changes do not directly coincide with phases of temperature change, but rather with phases of increased human activity in the Baltic Sea – for example, the Viking Age, the Hanseatic period or industrialization", Schmidt explains.

The Baltic Sea populations of diatoms thus showed high genetic resilience over thousands of years, despite natural fluctuations in climate. In historical times, however, changes in the genetic makeup of the populations have accelerated significantly, pointing to human influence. Potential causes could be increased use of the Baltic Sea and its coastline – as a result of maritime travel, coastline construction or nutrient input from agriculture in the region. "Human activities can apparently lead to changes in the genetic composition of species that we do not exploit directly in any form. We can now study and discover such effects across thousands of years and use this information to better understand ecological and evolutionary dynamics and develop suitable conservation strategies", Epp concludes.

 

Key facts:

  • Original publication: A. Schmidt, S. Bolius, A. Chagas, J. Romahn, J. Kaiser, H.W. Arz, M. Bálint, A. Kremp & L.S. Epp (2025) Multi‐Millennial Genetic Resilience of Baltic Diatom Populations Disturbed in the Past Centuries. Global Change Biology; doi: https://doi.org/10.1111/gcb.70467 
  • An interdisciplinary team led by researchers in Konstanz studies the genetic stability of Baltic diatoms from 8,000 years ago until the present.
  • Except for temporary variations during extreme climate phases, the genetic makeup of diatom populations remained stable for thousands of years. However, in the last centuries, as the Baltic Sea has been used by humans, faster changes have taken place that, so far, have been irreversible.
  • Participating institutions:
    • University of Konstanz (Alexandra Schmidt, Anna Chagas and Laura S. Epp)
    • Leibniz Institute for Baltic Sea Research Warnemünde (Sarah Bolius, Jérôme Kaiser, Helge W. Arz and Anke Kremp)
    • Senckenberg Biodiversity and Climate Research Centre Frankfurt/Main (Juliane Romahn and Miklós Bálint)
  • Funding: Leibniz Association, German Research Foundation (DFG), LOEWE Research Initiatives Network, International Max Planck Research School for Quantitative Behaviour, Ecology and Evolution

 

Note to editors:

Images can be downloaded here:

Link: https://www.uni-konstanz.de/fileadmin/pi/fileserver/2025/ostseealgen_jahrtausende_stabil_1.jpg
Caption: Stain of a culture of the diatom Skeletonema marinoi using Lugol's solution
Copyright: Sarah Bolius

Link: https://www.uni-konstanz.de/fileadmin/pi/fileserver/2025/ostseealgen_jahrtausende_stabil_2.jpg  
Caption: Individual sections of a long sediment core sample before analysis
Copyright: Laura Epp

Link: https://www.uni-konstanz.de/fileadmin/pi/fileserver/2025/ostseealgen_jahrtausende_stabil_3.jpg  
Caption: Analysis of a core sample on board the research vessel Elisabeth Mann Borgese In the photo: Dr Anke Kremp, IOW Warnemünde
Copyright: Laura Epp

Link: https://www.uni-konstanz.de/fileadmin/pi/fileserver/2025/ostseealgen_jahrtausende_stabil_4.jpg  
Caption: Extraction of the DNA from the sediment core sample. In the photo: Dr Alexandra Schmidt, University of Konstanz
Copyright: Miklós Bálint

Link: https://www.uni-konstanz.de/fileadmin/pi/fileserver/2025/ostseealgen_jahrtausende_stabil_5.jpg  
Caption: Elisabeth Mann Borgese research vessel
Copyright: Laura Epp

 

Ancient fishing nets resurrected from pottery using X-ray CT: a world-first achievement by Kumamoto University researchers



Reconstruction of 6,000-year-old Jomon fishing nets sheds light on prehistoric sustainability practices




Peer-Reviewed Publication

Kumamoto University

Shizunai-Nakano style pottery (top) showing net impressions, with reconstructed knot structures and reproductions (bottom) 

image: 

X-ray computed tomography (CT) was used to examine and digitally reconstruct net impressions preserved in pottery from the Hidaka region of Hokkaido, Japan, dating to the Early Jomon period (referred to as ‘Shizunai-Nakano style pottery’). This study revealed that fishing nets were (re)used in various ways during pottery production. Differences in thread twist direction, knotting methods, and mesh size provide insights into the nets’ functions and the cultural practices of the time—shedding light on the importance of net-making in prehistoric Japan.

Figure reproduced from Obata & Lee, 2025, Journal of Archaeological Science, under a Creative Commons Attribution 4.0 International License (CC BY 4.0).

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Credit: Hiroki Obata, Kumamoto University






In a groundbreaking archaeological achievement, researchers from Kumamoto University have successfully reconstructed the structure of prehistoric fishing nets from the Jomon period (ca. 14,000–900 BCE) by analyzing impressions preserved in ancient pottery using advanced X-ray computed tomography (CT). This marks the first time in the world that nets from over 6,000 years ago have been digitally and physically resurrected in such detail.

Led by Professor Emeritus Hiroki Obata from Faculty of Humanities And Social Sciences, Kumamoto University, the team examined pottery unearthed from sites in Hokkaido and Kyushu—regions in northern and southern Japan respectively—where ancient net impressions remained hidden inside and on the surfaces of ceramic fragments. By using high-resolution X-ray CT imaging alongside silicone cast replication techniques, the researchers visualized and reconstructed the nets’ intricate structures, including thread twists, knot types, and mesh sizes.

The study revealed a rich diversity in net-making techniques between regions. In northern Japan’s Hokkaido region, large-mesh nets with tightly tied "reef knots" were found embedded in the clay coils of so-called Shizunai-Nakano style pottery. These nets, believed to have been used for ocean fishing, were then repurposed as structural core materials in pottery making—a practice suggesting the early reuse and recycling of tools.

In contrast, pottery from the southern Kyushu region, dating to the Final Jomon and early Yayoi periods (ca. 3,200–2,800 years ago), contained fine-mesh nets tied with simpler overhand knots or using “knotted wrapping” methods. These nets likely served as molds or release agents during pottery production and may have originally been used as bags.

Remarkably, the study also estimated the labor involved in net production, suggesting that crafting a single fishing net could take more than 85 hours—highlighting the value of these tools and the cultural importance of their reuse. “This reuse of materials reflects an early form of sustainability, akin to today’s SDGs,” said Prof. Obata.

The findings challenge previous assumptions that all net impressions represented fishing gear and demonstrate that not all preserved impressions can be interpreted as functional nets. Instead, the nets appear to have had multiple lives—first as tools for fishing or carrying, and later as integral elements in the creation of pottery.

This world-first study, published in the Journal of Archaeological Science, not only reconstructs ancient technology but also opens new doors for identifying and preserving other vanished organic materials in archaeological contexts.

Four twisted threads converge at a single knot, forming a continuous structure indicative of a 'net product.' Since the net is embedded in the clay cord, it is stretched horizontally. Gaps without netting appear every 2–3 cm, revealing that the net was used as a core material for the clay cord.

Figure reproduced from Obata & Lee, 2025, Journal of Archaeological Science, under a Creative Commons Attribution 4.0 International License (CC BY 4.0).

X-ray Cross-Section, 3D Scan, and SEM Images of Threads Found in Shizunai-Nakano Style Pottery 

This image shows X-ray cross-sections, 3D scans, and SEM images of threads preserved in Shizunai-Nakano style pottery. Sample (a), from the Tobinodai site, and samples (b) and (d), from the Shiomidai site, include 3D renderings based on the voids left by threads inside the pottery fragments. Sample (c), also from the Shiomidai site, along with (d), features replicas of thread impressions found on the pottery surfaces. These advanced imaging techniques reveal how threads were embedded or left impressions during the pottery-making process.


Figure reproduced from Obata & Lee, 2025, Journal of Archaeological Science, under a Creative Commons Attribution 4.0 International License (CC BY 4.0).

Credit

Hiroki Obata, Kumamoto University


Researchers discover an active role played by the asthenosphere in shaping seafloor structures





Science China Press





The global mid-ocean ridge, with a total length over 65,000 km, is the longest volcanic chain on Earth. Hot magmas are extracted from the upwelling asthenosphere beneath the ridge axis to produce ocean crust, which covers two-thirds of Earth’s surface. According to the plate motion rate at each side of ocean ridges, seafloor spreading can be classified in two different modes, i.e., symmetrical or asymmetrical, which show much difference in ocean crustal thickness and seafloor morphology. The fast- and intermediate-spreading ridges (with a full spreading rate of >80 mm/yr and 55-80 mm/yr, respectively) are dominated by symmetric spreading. Nevertheless, both symmetric and asymmetric spreading occur along the slow- to ultrslow-spreading ridges (with a full spreading rate of 55-20 mm/yr and <20 mm/yr, respectively).

Change in spreading mode reflects the variation in magma flux at ocean ridges, which have commonly related to mantle temperature or spreading rate. An implicit assumption in these interpretations is that the asthenosphere with homogeneous compositions passively uprises beneath ocean ridges and gives rise to magma. Nevertheless, numerous studies have demonstrated that the asthenosphere is not compositionally homogeneous at all, in which refractory mantle domains with experience of ancient melt depletion are preserved. A plausibility is that the volumetric content of the ancient refractory mantle domains within the asthenosphere could control the magma flux and thus play an active role in modulate the spreading mode.

The slow-spreading Mid-Atlantic Ridge (MAR) at 23°N is an ideal place to test such a hypothesis. The 23°N MAR has experienced a shift from asymmetric to symmetric spreading in the past 3.3 million years (Ma), during which neither mantle temperature nor spreading rate shows remarkable variations. More importantly, abyssal peridotites, residues of the asthenosphere after partial melting, are quasi-continuously outcropped along the strike of spreading, which could provide well constraints on the temporal change in compositions of the asthenosphere.

An international team led by Prof. Chuan-Zhou Liu of the Laoshan Laboratory has conducted a multi-disciplinary study using geophysical data, geochemical analyses of mantle peridotites and basalts, and numerical modeling. They found that the asthenosphere contained higher volumes of ancient refractory mantle domains during the asymmetric spreading phase (3.3-0.4 Ma) than the asthenosphere during the symmetrical spreading phase (<0.4 Ma). Such a simultaneity in the change of mantle composition and spreading mode provides a robust support for the hypothesis that the asthenosphere’s composition can modulate magma flux and thus the spreading mode.

Moreover, the discovery in this study corroborates that the asthenosphere plays an active role in constructing the ocean lithosphere rather than being a passive actor as commonly assumed. The reason lies in the mantle heterogeneity of the asthenosphere, which has been widely demonstrated but underestimated by the community. “Earth’s upper mantle is like a mixed stew shaped by plate tectonics,” said Prof. Chuan-Zhou Liu. “Over billions of years in Earth’s history, old mantle from different tectonic settings can be recycled into the asthenospehere. They are not completely homogeneized by mantle convection at all.”

This study exemplifies that effects of the mantle heterogeneity on magma genesis and seafloor spreading can be enlarged at slow- to ultraslow-spreading ridges. More attentions should be paid to mantle heterogeneity of the asthenosphere in the future studies. We thus call upon a paradiam shift from a homogeneous asthenosphere to a heterogeneous asthenosphere.

Container-based sanitation improves quality of life in urban slums



The study, co-authored by Bangor University and Cranfield University, has been published in Nature Water and could pave the way for CBS to be used more widely




Cranfield University

Container based sanitation systems 

image: 

container based sanitation systems 1

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Credit: Cranfield University





  • In 2024, 3.4 billion people lacked safely managed sanitation

  • Sustainable Development Goal 6 has a target to achieve access to adequate and equitable sanitation and hygiene for all by 2030

  • Portable toilet service of container-based sanitation is having a positive impact

An international study on container-based sanitation (CBS) systems has found that this portable toilet option significantly improves the quality of life for people living in urban slums in Kenya, Peru and South Africa.

CBS systems use sealed, portable toilet containers that are collected, emptied, and cleaned regularly as part of a subscription-based service. Unlike traditional sanitation solutions that require heavy infrastructure, CBS offers a flexible and practical alternative for densely populated urban areas.

The study, co-authored by Bangor University and Cranfield University, has been published in Nature Water and could pave the way for CBS to be used more widely. While container-based sanitation is not a permanent replacement for sewered systems, it represents a transformative interim solution for improving health, dignity, and quality of life in the world’s most vulnerable urban communities.

Dr Alison Parker, Reader in International Water and Sanitation at Cranfield University, who led the project, said: “It has been a huge privilege to work with such dedicated researchers from around the world to reveal the potential that CBS has to provide a safe toilet for the billions of people that don’t have one. Access to safe sanitation and hygiene is one of the most basic human needs for health and wellbeing, so the importance of services like this can’t be overstated.”

Quality of life improved by CBS

Researchers used smartphone-based surveys to regularly collect data on sanitation and health from users of CBS systems. They closely tracked the experiences of residents over time, providing one of the most detailed looks yet at CBS services in urban slums.

The key findings include:

  • CBS users reported significantly fewer problems with their toilets compared to non-CBS users.
  • Satisfaction with CBS services was high across multiple components, including collection and cleaning.
  • Improved servicing of CBS systems was directly linked to higher sanitation quality of life for residents.

Lead author Dr Ben Exton, Research Assistant at Bangor University, explained: “Working with such a rich dataset of hundreds of participants, surveyed regularly over a year across three countries, we demonstrate that container-based sanitation – especially when well serviced – can meaningfully improve sanitation-related quality of life for people living in informal settlements.”

Co-author Simon Willcock, Principle Research Scientist at Rothamsted Research, and Professor of Sustainability at Bangor University said: “The study also revealed important differences between countries. In Kenya and Peru, where CBS toilets are provided through social enterprises supported by grants, users reported fewer problems and higher satisfaction compared to South Africa, where CBS toilets are provided free at scale by local authorities.”

Rémi Kaupp, Executive Director, Container Based Sanitation Alliance, commented: "I am delighted to see the results of this long-term, rigorous and multi-country study, with has shown an excellent way to understand how sanitation users really perceive their service. 

"Besides highlighting the crucial role that container based sanitation plays in ensuring continuous access in informal settlements, the study also shows the importance of professional sanitation operators to ensure residents enjoy uninterrupted and safe essential services.”

Caption

container based sanitation systems 2

Caption

container based sanitation systems 3

Credit

Cranfield University