Research in Thailand

Control of vector-borne diseases is a public health priority in Thailand, especially the control of malaria, dengue fever and Japanese Encephalitis (JE). These diseases have one thing in common, the transmission of their pathogens (parasites or viruses) necessarily passes through a mosquito vector. These mosquitoes belong to different genera, Anopheles, Aedes and Culex, respectively responsible for the transmission of the diseases cited above. Since there is either no vaccine available for these diseases or the vaccine has low efficacy (JE), vector control is the most effective approach for their control. However, before implementing appropriate vector control strategies, a good understanding of the entomo-epidemiological context is necessary.

Thus, the collaboration over the past 15 years with the Medical Entomology Team of Kasetsart University (KU) has allowed us to work on 6 lines of research ranging from molecular species identification to vector control, along with the study of their vectorial capacity, behaviour and geographic distribution (see diagram). This work is being developed more widely within an Asian network (Cambodia, China, Indonesia), whose epicentre is Thailand, which has provided relevant and useful data to local and national decision-makers for better management of vector-borne diseases.

IRD research unit involved: UMR HSM - HydroSciences Montpellier (IRD/CNRS/University of Montpellier/Mines-Télécom School/The Carnot Network)

Partners: Faculty of Agriculture, Kasetsart University (KU) & Faculty of Science, Mahidol University (MU)

Funding: 

• European & French: MALVECASIA European Project (2002-06), PHC Siam (2009-10 et 2015-16), Programme Bio-Asie (2013-15), JEAI BioVecThai (2012-15), Erasmus Mundus Scholarships (2012-14) et Panacea (2013-14), ARTS Biomérieux/IRD (2014-2017)
• Thai: Thai Research Fund (TRF), Golden Royal Jubilee scholarships, International Research Network (IRN)

To find out more: Detailed project description

Contacts: Sylvie Manguin, 

Published articles

• Tainchum K, Dupont C, Chareonviriyaphap T, Jumas-Bilak E, Bangs MJ, Manguin S. 2020. Bacterial Microbiome in Wild-Caught Anopheles Mosquitoes in Western Thailand. Front Microbiol. 2020;11:965. DOI: 10.3389/fmicb.2020.00965
• Nararak J, Giorgio CD, Sukkanon C, Mahiou-Leddet V, Ollivier E, Manguin S, Chareonviriyaphap T. 2020. Excito-repellency and biological safety of β-caryophyllene oxide against Aedes albopictus and Anopheles dirus (Diptera: Culicidae). Acta Trop. 2020;210:105556.   DOI: 10.1016/j.actatropica.2020.105556
• Sumarnrote A, Overgaard H J,Vincent Corbel V, Thanispong K, Chareonviriyaphap T,  Manguin S. 2020. Species diversity and insecticide resistance within the Anopheles hyrcanus group in Ubon Ratchathani Province, Thailand. Parasites Vectors. (2020) 13:525.   DOI: 10.1186/s13071-020-04389-4
• Udom C, Thanispong K, Manguin S, Chareonviriyaphap T, Fungfuang W. 2021. Trophic Behavior and Species Diversity of the Anopheles barbirostris Complex (Diptera: Culicidae) in Thailand. Journal of Medical Entomology. 58(6), 2021, 2376–2384.    DOI: 10.1093/jme/tjab067

Preliminary investigations on available samples collected in 2013 gave a mean nucleotide identity of 96% with the genome of a Sarbecovirus (genus Betacoronavirus) of a Rhinolophidae bat specimen. Despite these announcements, the most recent and direct ancestor of the virus responsible for the Covid-19 pandemic is yet to be discovered and the natural history of its emergence remains to be elucidated. This brings both the WHO and the French National Agency for Research (ANR) to list the quest for the reservoir and the natural history of the emergence as a top priority.

DisCoVER aims at answering the question of the origin of SARS-CoV by bringing together an interdisciplinary team of experts in the field from the Caen University, IRD, CNRS, Kasetsart University, Mahidol University and Center of Infectiology Lao Christophe Mérieux. The main objective of the project is to track the origin of SARS-CoV2 in natural settings sharing biogeographical and socio-ecological features with South-Western China (northern regions of Thailand and Lao PDR). The aim is to characterize the SARS-CoV2 natural cycle and the modalities of its emergence in humans. The zoonotic/emergence risk of SARS-CoV2-related Sarbecovirus members infecting wild animals in northern Southeast Asia will be estimated using a model that will integrate phylodynamic data/analyses with socio-ecological factors to develop real strategies for anticipation and prevention of future emergence.

IRD research unit involved: UMR MIVEGEC (IRD/CNRS/University of Montpellier)

Partners : Caen Normandie University-Caen University Hospital Center, Faculty of Veterinary Technology, Kasertsart University & Mahidol University

Thai researcher partners: Kasetsart university: Sathaporn Jittapalapong PhD and Dean of the Faculty of Veterinary Technology, Anamika Kritiyakan PhD, Chuanphot Thinphovong PhD

IRD researchers involved in the project: Éric Deharo (IRD Representative in Laos), Sabrina Locatelli, Rodolphe Hamel, Emmanuel Paradis

Funding: ANR Flash funding call COVID-19

To find out more: Detailed project description

Contact: 

• Éric Leroy (IRD)
• Meriadeg Le Gouil (University of Caen)
• Serge Morand (CNRS)
   

Located in the heart of South-East Asia, Thailand is largely covered with forests and rural areas interspersed with urbanized areas and thus offers a suitable study site to assess factors involved in mosquito-borne virus emergence and circulation. Dengue virus (DENV) and Japanese Encephalitis virus (JEV) are actively circulating in the country as well as less known mosquito-borne flaviviruses, such as the Tembusu virus (TMUV) which was recently described as a potential zoonotic emerging virus.

This research project aims to investigate the presence of potential emerging MBVs associated with birds, in and nearby domestic poultry farms in rural and urban areas, with a specific focus on TMUV. Paired with screenings of animal samples, we will use an innovative strategy, called molecular xenomonitorring, based on virus detection on trapped mosquito excreta using molecular techniques. 3D-printing will be used to modify commercial mosquito trap in order to screen the presence of MBVs at low cost on a large scale. All investigation will be conducted in close collaboration with Thai researcher partners located in different places in Thailand.

This project can bring a new perspective on bird-associated MBV ecology in Asia and identify factors responsible for the spillover of these viruses in the human population. We expect that results obtained in this exploratory project will provide new information on the bio-diversities and human activities impact on mosquito-borne viruses in Thailand and will also supplement ecological data obtained through the program ANR “FutureHealthSEA” led by Dr Morand.

IRD research units involved: UMR MIVEGEC (IRD/CNRS/University of Montpellier), UMR ISEM (IRD/CNRS/CIRAD/University of Montpellier/PSL University/INRAP)

Partners : 

• Dr. Jiraporn Jaroenpool, Medical Technology Department, Walaïlak University
• Dr. Ronald Vargas, Medical Entomology Department, Faculty of Tropical Medicine, Mahidol University
• Dr. Albin Fontaine, Parasitology & Entomology Unit, Armed Forces Biomedical Research Institute (IRBA)

Funding: Labex CEMEB (University of Montpellier)

To find out more: Detailed project description

Contact: Rodolphe Hamel

Hepatitis B virus infects the liver and causes liver damage with a risk of fibrosis, cirrhosis and liver cancer in adulthood. Perinatal transmission is the number one source of new infections worldwide. Stopping this transmission is needed to eliminate hepatitis B infections, and this is therefore a priority for the CMU-IRD collaboration. 

In a first clinical trial, iTAP-1, women with HBV infection took tenofovir disoproxil fumarate (TDF) once a day from 28 weeks’ pregnancy until 2 months postpartum. None of their infants were infected. The tolerance of TDF was excellent for the mothers and for the infants. In this clinical trial, all infants received both hepatitis B vaccine and immune globulin. However, the price of immunoglobulin is high and it is very difficult to maintain stocks outside of important health centers.

A second trial, iTAP-2, ongoing, aims at determining whether immune globulin is needed when mothers receive TDF as in iTAP-1. The results of this study are expected in Q2-2022.

More details:

• iTAP-1 results: https://www.nejm.org/doi/full/10.1056/NEJMoa1708131
• iTAP-2 study: https://clinicaltrials.gov/ct2/show/NCT03343431

IRD research unit involved: UMR MIVEGEC (IRD/CNRS/University of Montpellier)

Partners: Chiang Mai University

Funding: US National Institute of Child Health and Human Development - NIH 5R01HD092527

To find out more: Detailed project description

Contact: Gonzague Jourdain

The number of HIV-infected people who know their HIV status and of those uninfected but at high risk of infection using appropriate prevention methods is still far too low to defeat the epidemic. The number of HIV-infected people who know their HIV status and of those uninfected but at high risk of infection using appropriate prevention methods is still far too low to defeat the epidemic. Effective interventions do exist and are affordable. Insufficient use of testing and prevention services is, therefore, a major problem. Napneung is an interventional research programme developed by the CMU-IRD collaboration and aimed at evaluating strategies to optimise the use of these services.

During Napneung's first phase, awareness-raising methods targeting people at risk were developed (social media, field interventions). More than 7,000 screening sessions were carried out. In addition, retention strategies in screening and prevention services for people at high risk of HIV infection were evaluated using clinical research methods such as randomised controlled trials. During Napneung's first phase, awareness-raising methods targeting people at risk were developed (social media, field interventions). More than 7,000 screening sessions were carried out. In addition, retention strategies in screening and prevention services for people at high risk of HIV infection were evaluated using clinical research methods such as randomised controlled trials. This showed that computer-assisted counselling is well received and reduces the time spent on counselling without reducing the proportion of users who subsequently come for re-testing, the educational value of the counselling, or the likelihood of risky sexual behaviour. Furthermore, interventions as simple, easy to implement and affordable as booking an appointment and sending a reminder one week in advance can significantly increase follow-up for people at high risk of infection.

The second phase - currently ongoing - aims at studying the requirements for implementing and integrating widespread access to quality HIV prevention and testing services into the existing health system in medium-sized cities in Thailand. The project is evaluating the use of supervised self-tests, a computer-based counselling programme and an online appointment system. All users are also tested for syphilis and viral hepatitis B and C, and for those at risk for other STIs. Sub-studies are dedicated to these three infections.

IRD research unit involved: UMR MIVEGEC (IRD/CNRS/University of Montpellier)

Partners: Chiang Mai University, Phayao University, Ministry of Public Health in Thailand, public hospitals in the provinces of Chiang Mai, Chiang Rai, Phayao and Lampang, support associations for people affected by HIV or viral hepatitis.

Funding:

• First phase: Initiative 5%, Expertise France (14SANIN204). Amount: 632,705.09 €.
• Second phase: Initiative 5%, Expertise France (18SANIN210). Amount : 1,384,938.03 €.

To find out more: Detailed project description

Contacts: Gonzague Jourdain, Nicolas Salvadori

Links: 
Website Napneung
Facebook Napneung
ClinicalTrials.gov : First phase, Second phase

Last published articles:

• Salvadori et al, AIDS Behav. 2020
• Salvadori et al, J Int AIDS Soc. 2020

Overuse of caesarean section (C-section) has adverse consequences on maternal and child health. It also deviates essential resources worldwide and hinders universal access to healthcare services. QUALI-DEC project aims at developing and evaluating a strategy to implement non-clinical interventions and reduce unnecessary C-sections in Argentina, Burkina Faso, Thailand and Vietnam.

This strategy combines four active ingredients:

• Opinion leaders to implement evidence-based clinical guidelines
• Caesarean audits and feedback to help providersidentify potentially avoidable C-sections
• A decision-analysis tool to empower women for better decision-making on mode of delivery
• The implementation of WHO recommendations on companionship during labour to support women during vaginal birth

The project promotes the engagement of stakeholders at all levels (policymakers, health providers and end-users i.e. women) from the very start of the project to implement intervention components, which take into account the local context and to ensure a maximisation of the expected impacts. To improve the quality of implementation and use of evidence, knowledge transfer activities will be implemented.The evaluation will examine physical and psycho-social effects of the strategy and will highlight the interdependent relationship between maternal and child outcomes related to overuse of C-section. Particular attention will be given to equity issues and gender considerations in the interpretation of results.

Overall, our project will improve appropriate use of C-sections and will address several SDG targets including
improving maternal and neonatal health and reducing inequalities within and between countries.

IRD research unit involved: UMR CEPED (IRD/University of Paris)

Partners: 

• Centro Rosarino De Estudios Perinatales (Argentina)
• Fundacio Blanquerna (Spain)
• Institut de Recherche en Sciences de la Santé - CNRST (Burkina Faso)
• Karolinska Institutet (Sweden)
• Khon Kaen University (Thailand)
• Pham Ngoc Thach University of Medicine (Vietnam)
• University College Dublin (Ireland)
• World Health Organization (Switzerland)

Funding: European Commission (H2020 program), WHO : 3 997 295 €

To find out more: Detailed project description

Website QualiDec

Contacts: Alexandre Dumont, Myriam De Loenzien

Zika virus (ZIKV) is a mosquito-borne Flavivirus that causes Zika disease characterized by fever, rash, arthralgia and conjunctivitis which, given the rapid worldwide spread of the virus, is now considered an emerging infectious disease. Of particular concern are recent reports of neurological complications, such as Guillain-Barré Syndrome and congenital microcephaly associated with Zika disease. To date no strategies for ZIKV control are available, hence the urgency to initiate the development of antiviral strategies.The partners of the ZIKAHOST proposal consortium were the first to explore and to report on the biology of ZIKV.

ZIKAHOST first findings show that ZIKV modulates gene expression in hNPC involved in neurogenesis dependent on the nature of the viral strain. At present, the precise molecular mechanisms permitting ZIKV to escape the host antiviral response in human brain cells remain to be determined. In addition, many questions remain unanswered regarding the complications caused by different primary isolates of ZIKV. The specific aims
of the ZIKAHOST consortium are:

• To identify key entry factors involved in ZIKV infection and to determine their involvement in ZIKV neurotropism
• To determine the cellular responses of the human brain cells to ZIKV infection
• To characterize the different steps of ZIKV-induced brain injury in the developing human brain cells and tissue

This project will be crucial for a better understanding of how ZIKV hijacks cellular functions and is able to avoid antiviral mechanisms in human brain cells and tissue. Future findings should provide significant insights into ZIKV pathogenesis and will uncover host factors that might serve as therapeutic targets to block ZIKV infection.

IRD research unit involved: UMR MIVEGEC (IRD/CNRS/University of Montpellier)

Partners: 

• Dr. Sineewanlaya Wichit, Department of Clinical Microbiology and Applied Technology, Faculty of Medical Technology, Mahidol University
• Dr Ali Amara, UMR NEURODIDEROT (INSERM/Université de Paris)
• Dr Pierre Gressens, UMR 944 - 7212 Pathologie et virologie moléculaire (INSERM/Université de Paris)

Funding:

• ANR Générique
• Thailand Research Fund (TRF) (grant no. MRG6280009) PI: Dr. Wichit Sineewanlaya
• PHC-SIAM: 2021-2022 The Host factors of Zika virus neuro-pathogenesis (PI France: Dorothée Missé, PI Thailand: Sineewanlaya Wichit)

To find out more: Detailed project description

Contacts: Dorothée Missé, Sineewanlaya Wichit, Ali Amara, Pierre Gressens

Latest published articles:

• Wichit S, Hamel R, Zanzoni A, Diop F, Cribier A, Talignani L, Diack A, Ferraris P, Liegeois F, Urbach S, Ekchariyawat P, Merits A, Yssel H, Benkirane M, Missé D. SAMHD1 Enhances Chikungunya and Zika Virus Replication in Human Skin Fibroblasts. Int J Mol Sci. 2019 Apr 5;20(7):1695. DOI: 10.3390/ijms20071695.
• Wichit, S., Hamel, R., Yainoy, S., Gumpangseth, N., Panich, S., Phuadraksa, T., Saetear, P., Monteil, A., Morales Vargas, R., & Missé, D. (2019). Interferon-inducible protein (IFI) 16 regulates Chikungunya and Zika virus infection in human skin fibroblasts. EXCLI journal, 18, 467–476. DOI: 10.17179/excli2019-1271

The BufFarm OneHealth Sea project seeks to explore the relationships between farm animals, local knowledge, and wider systems of agriculture and environment. On a global scale evidence has been made on the role of expanding livestock farming both as a threat to biodiversity and as increasingly putting human and animal health at risk. However, little distinction is generally made between the different production systems ranging from smallholders to industrial farms, and between the diversity and species distribution on the planet. This last aspect being particularly complex as it depends both on variations of specific socio-economic contexts and on the cultural values associated with animals in different cultures. In to better understand the complex links between farm production system, biodiversity, animal and human health, the project focuses on extensive buffalos farming in Thailand, Laos and Vietnam.

Grounded in Anthropology the project has a strong participatory dimension. The herders knowledge will be the starting point of investigation. Once documented the local knowledge will be putted into dialogue with various scientific perspectives (anthropology, botany and ecology). This will help to encourage and promote virtuous practices for livestock farming guaranteeing the good health of humans, animals and the environment.

The seasonality of extensive buffalo farming implies a multiscale perspective at the village and the forest level:

At the village level, the objective is to take an interest on the daily animal care practices and local medicine, by carrying out in situ plant collection with identification and taxonomic survey of fauna and flora. The associated uses and techniques, as well as the interpretation of animal behavior will also be documented. The medical pluralism including ethnoveterinary medicine and contemporary veterinary biomedicine will be fully considered, notably the use of antibiotics. At the village level, the ecological impact of the presence of buffalo will also be studied.

At the forest level, the project will first aim at completing the buffalo plant database and seek to explore self-medication practices. The idea is to follow the animal along with their owner to observe the plants specimen, roots, flowers, etc. consumed in situ and seek for potential self-medication practices. In order to assess the environmental and sanitarian risks an innovative methodology of tracing will be developed. Some individual buffalos will be equipped with collar GPS to track their presence and satellite images will be used to counting interaction with wild animals and define specific area that buffalos spread on the grazing area. Camera traps will also be positioned in strategical point of contacts and interactions with wild animals.

IRD research unit involved: UMR PALOC (IRD/MNHN)

Partners:

• Thailand:  University of Kasetsart, Bangkok Herbarium (Department of Agriculture), International Buffalo Information Center (IBIC)
• Laos:  Centre EFEO de Vientiane
• Vietnam:  University of Hué

Funding: IRD, TICA ‘Innovative Animal Health’, FSPI One Health SEA 

Contact: Nicolas Lainé

During the dry season, between February and April, a thick cloud of pollution covers Chiang Mai (as well as much of South and Southeast Asia but with variations in timing and intensity), causing many health (respiratory diseases) and economic problems (reduced tourist numbers, disruption of air traffic). Contrary to the physicochemical and biophysical aspects (absence of rainfall in the dry season, temperature inversion, biomass combustion in particular), the social and economic factors at the origin of this phenomenon have not (or little) been studied for the moment.

Within the framework of a collaborative project, we show that this cloud of pollution is also a social production: customary uses of fire for the management of forests and fields, rapid transitions to market agriculture, rural exodus, second homes in the countryside and development of the tourist economy etc. All these elements contribute to the constitution of “narratives” (knowledge, stories and representations) about the environment which are an integral part of the problem of air pollution: they question its antiquity, reality and extent; they frequently point the finger at those responsible, with the consequence of reinforcing divisions, real or imagined, between ethnic groups, social classes or between urban and rural areas; finally, they are taken up, in whole or in part, by local decision-makers and directly influence environmental policies.

IRD research unit involved: UMR PALOC (IRD/MNHN)

Partners: University of Hawai’i at Manoa, Chiang Mai University

Funding: NSF Fund

To find out more: Detailed project description

Contacts: Olivier Évrard, Mary Mostafanezhad

Published articles:

• Mostafanezhad M, Evrard, O. 2020. Chronopolitics of crisis: A historical political ecology of seasonal air pollution in northern Thailand. Geoforum. ISSN 0016-7185.   DOI: 10.1016/j.geoforum.2020.05.011.
• Olivier Evrard et Mary Mostafanezhad, « La pollution de l’air en Thaïlande du Nord : d’un phénomène saisonnier à une crise écologique », Moussons, 34 | 2019, 49-69.   DOI: 10.4000/moussons.5310

Project countries: Thailand, India, Vietnam, Benin, Egypt, Ghana, Kenya, Senegal

Air pollution is a global environmental and health problem. Although it has become a major concern in large cities of the South, few of them are able to effectively combat this pollution. The Global Smog research project proposes to better understand what causes such an impediment by analyzing the perceptions of this public health problem, the orientations of public action and the obstacles to its implementation in five African and five Asian cities.

This interdisciplinary project is an international project involving Dr. Olivier Évrard, an anthropologist at IRD in Thailand. The project aims to identify and explain the technical, social and political processes that influence the management of air pollution in cities in the South. The objective of this study is to improve theoretical and practical knowledge of urban public policy processes at different scales in developing countries.

Working with the tools of sociology of science, urban geography, political anthropology and sociology of policy making, the project explores the social construction of ambient air pollution as both a global and local problem, and how it is embedded in socio-technical representations of health, environment and economy.

Research unit involve in Thailand: UMR PALOC (IRD, MNHN)

Partner:

Learn more about the project: https://en.ird.fr/project-globalsmog-researching-air-pollution-cities-global-south

Global Smog website: https://www.globalsmog.org/

Funding: Agence Nationale de la Recherche (ANR)

Contact: Olivier Évrard

Understanding variations in the diversity and composition of tropical tree species on a large scale is extremely difficult from ground level. New remote sensing technologies are promising tools for mapping this diversity on a large scale, especially over large areas inaccessible in dense tropical forests.

This project aims at assessing the capacity of airborne data acquired over Khao Yai National Park to map tree diversity at the landscape scale. This mapping will then be used to extrapolate large-scale diversity estimates using satellite data. More specifically, the objective is to acquire LiDAR (laser) and hyperspectral (using hundreds of wavelengths) data by combining them with fine field measurements.

The project will lead to a better understanding of the spatial distribution of forest diversity in tropical forests and will enable the implementation of a methodology to monitor the biodiversity of these hyper-diverse ecosystems on a large scale.

IRD research unit involved: UMR AMAP (IRD/Cirad/CNRS/INRAE/University of Montpellier)

Partners: National Biobank of Thailand (NBT), University of Kasetsart

Funding: National Biobank of Thailand (NBT)

Contact: Maxime Réjou-Méchain

The LMI PRESTO (PRotect-dEtect-STOp) is a joint research and training program at the regional level, supported by the IRD, universities and research institutes in the Southeast Asian region.

This LMI is a multidisciplinary collaboration bringing together experts and researchers from France, Laos and Thailand sharing the common objective of preventing and combating emerging infectious diseases in the Greater Mekong Region. It is based on the existence of several long-standing partnerships and the pooling of complementary knowledge, experience and expertise in biodiversity, bioinformatics, disease ecology, epidemiology, molecular biology, public health, social sciences and virology. This will facilitate the development of an intervention platform for the early recognition and control of infectious diseases of zoonotic origin in this region, a recognized hot-spot for disease emergence risks.

The objectives of the PRESTO LMI are to

• Establish a sustainable research platform on emerging diseases at the human/animal/environment interface that will help regional partners to develop and thrive, while decreasing dependence on international financial support
• Establish a local alert system with a bottom-up/mixed approach to better prepare for future outbreaks
• Develop a sustainable surveillance toolkit with good practice guidance, to improve knowledge sharing and assist in the design and implementation of biodiversity conservation and public health strategies and policies in the Greater Mekong Subregion

IRD research unit involved: UMR MIVEGEC (IRD/CNRS/Université de Montpellier)

Academic institutions in the South involved in the project:

Laos

University of Health Sciences

National University of Laos (NUoL)

Thailand

Faculty of Associated Medical Sciences, Chiang Mai University

Faculty of Sciences et Faculty of Veterinary Medicine, Chiang Mai University

Faculty of Veterinary Technology, Kasertsart University

Faculty of Tropical Medicine, Mahidol University

Other institutions involved in the project:

Laos

National Animal Health Laboratory (NAHL)

ANOULAK (French NGO based in Laos)

NAM THEUN 2 POWER COMPANY LIMITED (NTPC) - Laotian, Thai and French shareholders

Lao-Christophe Mérieux Infectiology Centre (CILM)

Contact:

LOCATELLI Sabrina

NGO-GIANG-HUONG Nicole

KHAMDUANG Woottichai

Soil is an ecosystem that is essential to terrestrial and human life, as it directly or indirectly allows the production of 98% of our food. Soils not only contain the minerals that are essential for plant life, but they also store 80% of the water from rainfall, thanks to an infinite number of millimetre and micrometre pores. This water storage allows plants (cultivated and natural) to be fed and also limits the risk of flooding (by slowing down the flow of water towards rivers).

However, over the last few decades, modern agricultural development techniques (mechanised cultivation, chemical inputs) have led to widespread soil degradation. A recent FAO report on the state of soils was subtitled: "systems on the verge of collapse". Soil compaction has important consequences for agricultural production, but it is almost invisible. It is, in fact, a reduction in pore volume that takes place in the millimetre to micrometre range, which requires laboratory equipment to be demonstrated, but which considerably reduces the soil's capacity to store water (even in the case of irrigation) and which results in a reduction in agricultural production.

In this context, IRD and its partners in the region have launched the GDRI COMPACSOL in 2022 to organise a network of laboratories and research teams working on soil compaction. The first objective will be to set up standardised procedures in order to obtain quality and reliable analytical results that will enable an inventory to be made of the situation at the Mekong Basin level and to measure the evolution (geographical extension and intensity) of soil compaction over the next four years. The second objective will be to involve farmers in the development of cultivation techniques for soil prevention and rehabilitation through a participatory approach that will make the most of local knowledge and at the same time disseminate validated scientific knowledge on soils and water management.

Partners:

Institute of Ecology and Environmental Sciences of Paris (IRD - UMR IEES), France

Institute of Technology of Cambodia (ITC), Cambodia

Department of Agricultural Land Management (DALaM), Laos

Faculty of Agriculture, Khon Kaen University (KKU), Thailand

Soil and Fertilizers Research Institute (SFRI), Vietnam

Water/Soil/Plant Exchange team - University of Liège, Gembloux Agro-Bio Tech, Belgium

NGO ECLOSIO – University of Liège, Belgium & Cambodia

Black Carbon (BC), or soot, is the product of incomplete combustion of fossil fuels, biofuels and biomass, and is co-emitted with other aerosols. BC and co-emitted aerosols make up the majority of fine particle air pollution, and is the leading environmental cause of poor health and premature death. BC also impacts climate by :

• Exerting a direct net positive radiative forcing at the top-of-the atmosphere equivalent to ~40% of the current radiative forcing due to the CO2 greenhouse effect
• Influencing cloud formation/properties and rainfall patterns
• Reducing the albedo of the cryosphere when deposited on ice and snow, hence increasing melting rate

Owing to its impacts on health and climate, BC is receiving growing attention. Another impact of BC, much less known than its direct impacts on health and climate, is related to its introduction in the ocean. The atmospheric lifetime of BC ranges from a few days to one month, and BC eventually deposits on the surface of lands and oceans. In addition to the direct deposition on the surface of the ocean, large amounts of BC deposited on land are washed out by rainfall and transported by rivers, hence ultimately ending up in the ocean. The estimated total flux of BC to the ocean via atmospheric deposition and fluvial transport is equivalent to the estimated emission rate.

Considering that most BC ends up in the ocean, it is important to understand how this material impacts marine systems. Because BC particles are highly porous and surface-active, with a high density, they can sorb dissolved compounds, increase aggregation processes and ballast sinking particulate organic matter. Because they bring nutrients and contaminants to the surface ocean, and modify the structuring of the environment at the microscale, BC may alter phyto- and bacterio-plankton composition and activity. As a result, BC may alter the efficiency of the biological carbon pump, and lead to either a positive or a negative feedback on the atmospheric concentration of CO2. In addition, BC can sorb contaminants in seawater and either introduce them into the food chain, hence alter food security, or export them to the seafloor, hence cleanse the water column. In order to determine the actual impacts of BC, it is necessary to obtain accurate emission and deposition rates.

At present, there are still large uncertainties related to the magnitude of the impact of atmospheric BC due to difficulties in obtaining accurate emission inventories, and in particular in South East Asia (SEA). For example, current climate models systematically underrate aerosol absorption by 3-fold when compared to observations, which is attributed to the underestimation of BC emissions. Since estimates of the atmospheric flux of BC to the ocean are derived from emission estimates, they may be underestimated as well. In order to determine the effects of BC on marine resources and biogeochemistry, it is also necessary to understand how BC interacts with biological/chemical/physical marine processes. Owing to its short residence time in the atmosphere, atmospheric BC is currently considered a short-lived climate/health forcer. In contrast, because BC in the ocean will last for millennia, and its impacts on carbon cycling in the ocean can have long-lasting feedbacks on climate and marine biogeochemistry, marine BC may act as a long-lived climate/ecosystem forcer.

SOOT-SEA seeks to stimulate research, innovation, observation and capacity-building activities related to the impacts of BC on climate, health and ecosystem, taking into account for the first time its marine dimension, by increasing interactions between scientists from the South and the North.

The objectives of this multidisciplinary GDRI-Sud, which addresses a major societal, health and environmental issue, are :

• to promote and structure the development of research on BC, considering both atmospheric and marine dimensions in SEA (Figure below)
• to create the conditions for the establishment of a monitoring network of the concentrations and characteristics of atmospheric, fluvial and marine BC at the regional scale
• to inform the general public and assist decision makers with regard to the intricate health, climate and ecosystem BC-issues

SOOT-SEA is organized around a targeted theme (following a common thread), calling for interdisciplinarity between atmospheric and marine sciences, and bridging intertwined climate, ecosystems and health issues.

Partners:

AirParif, France

Asian Institute of Technology, Thailand

Centre national de la recherche scientifique, France

Consiglio nazionale delle ricerche, Italy

Environment Quality Management, Myanmar

Institute of Marine Environment and Ressources, Vietnam

International Atomic Energy Agency, Monaco

Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Germany

Ministry of Natural Resources and Environment, Laos

Royal University of Phnom Penh, Cambodia

Sorbonne Université, France

Swansea University, United Kingdom

Technical University of Denmark

Universität Oldenburg, Germany

Universität Wien, Austria

Université de La Réunion, France

Université de Liège, Belgium

Université de Pau et des pays de l'Adour, France

Université Toulouse 3 Paul Sabatier, France

University of Science and Technology of Hanoï, Vietnam

Vietnam Academy of Science and Technology