Les publications de Columba Martínez-Espinosa

Thirteen personal letters to a wetland

Wed, 27 May 2026 12:03:59

de C Max Finlayson, Columba Martínez-Espinosa, Swapan Paul, R Eugene Turner, Pierre Horwitz, Leonardo Maltchik, Gillian Davies, Andy Herb, John Conallin, Ritesh Kumar, et al.
In Wetland Science & Practice, 44 (April, 2026), 96-110

Thirteen letters to a wetland have been prepared by individuals and combined in a single article. The letters express the personal feelings and views of the writers (or epistolists) to a wetland of their choice, including regret about their condition or the pressures the wetland had experienced, as well as respect and appreciation for their values. The letters are provided as a way of sharing these views with others and in doing so encouraging them to also express their own views in the intimate format of a letter. The letters are writtend to wetlands in seven countries and serve as a model for others in different countries.

Assessing methane emissions and soil carbon stocks in the Camargue coastal wetlands: Management implications for climate change regulation

Wed, 21 Aug 2024 14:29:14

de Maite Martínez-Eixarch, Pere Masqué, Anna Lafratta, Paul Lavery, Samuel Hilaire, Lluís Jornet, Cyrille Thomas, Arnaud Boisnard, Néstor Pérez-Méndez, Carles Alcaraz, et al.
In Science of The Total Environment, 950 (November, 2024), 175224
En ligne : www.sciencedirect.com[...]

Coastal wetlands are crucial in climate change regulation due to their capacity to act as either sinks or sources of carbon, resulting from the balance between greenhouse gas (GHG) emissions, mainly methane (CH4), and soil carbon sequestration. Despite the paramount role of wetlands in climate regulation few studies investigate both aspects. The Camargue is one of the largest wetlands in Europe, yet the ways in which environmental and anthropic factors drive carbon dynamics remain poorly studied. We examined GHG emissions and soil organic carbon (SOC) stocks and accumulation rates in twelve representative wetlands, including two rice fields, to gain insights into the carbon dynamics and how it is influenced by hydrology and salinity. Mean CH4 rates ranged between – 87.0 and 131.0 mg m−2 h−1and the main drivers were water conductivity and redox, water table depth and soil temperature. High emission rates were restricted to freshwater conditions during summer flooding periods whereas they were low in wetlands subjected to summer drought and water conductivity higher than 10 mS cm−1. Nitrous oxide emissions were low, ranging from – 0.5 to 0.9 mg N2O m−2 h−1. The SOC stocks in the upper meter ranged from 17 to 90 Mg OC ha−1. Our research highlights the critical role of low-saline wetlands in carbon budgeting which potentially are large sources of CH4 but also contain the largest SOC stocks in the Camargue. Natural hydroperiods, involving summer drought, can maintain them as carbon sinks, but altered hydrology can transform them into sources. Artificial freshwater supply during summer leads to substantial CH4 emissions, offsetting their SOC accumulation rates. In conclusion, we advocate for readjusting the altered hydrology in marshes and for the search of management compromises to ensure the compatibility of economic and leisure activities with the preservation of the inherent climate-regulating capacity of coastal wetlands.

A dynamic model for assessing soil denitrification in large-scale natural wetlands driven by Earth Observations.

Thu, 20 Oct 2022 11:40:44

de Columba Martínez-Espinosa, Sabine Sauvage, Ahmad Al Bitar, Jose Miguel Sánchez Pérez
In Environmental Modelling and Software, 158 (December, 2022), 12
En ligne : www.sciencedirect.com[...]

The Wetland Soils Denitrification Model (WSDM) developed here for natural wetlands, is a physical based model that proposes: (i) the inclusion of soil moisture and temperature from satellite-based Earth Observations at diurnal temporal resolution and (ii) the distinction of soils under different wetland typologies (i.e., flooded forests, freshwater marshes, brackish wetlands, peatlands, and complex wetlands). Despite uncertainties involved, these two features are key to upscale nitrification/denitrification dynamics in natural wetlands at landscape, regional and global scales. In this study, the performance of WSDM was validated with soils in flooded forests and freshwater marshes in the central Amazonian floodplain. WSDM multiannual time series (2012–2019) show that climate anomalies intensify denitrification events. Flooded forests were identified with the highest annual denitrification rates. Annual denitrification and N2O emissions estimated in this study are in line with previous studies.

Modèle dynamique de dénitrification dans les zones humides naturelles à l'échelle mondiale (2021-10-08)

Tue, 10 May 2022 10:36:14

de Columba Martínez-Espinosa
[S.l.] : Toulouse 3, 2021-10-08, 279
En ligne : www.theses.fr[...]

La biosphère subit une crise environnementale causée par notre modèle économique énergivore. Comprendre les processus de régulation et d'échange des écosystèmes globaux est le défi majeur pour améliorer notre résilience et réduire notre impact sur la Terre. L'objectif de cette thèse est d'évaluer le rôle dynamique des écosystèmes des zones humides dans le cycle global de l'azote. Le modèle de dénitrification du sol (SDM) a été développé en utilisant les observations satellitaires de l'humidité et de la température du sol. Le modèle a été validé à l'échelle locale avec des mesures de laboratoire, puis à l'échelle globale. Identification des moments et des points chauds dans les zones humides naturelles. L'Asie du Sud-Est et l'Océanie ont été identifiées comme le principal point chaud. Les moments chauds varient selon la région et la typologie. Le mois de mai a été le moment chaud pour les marais d'eau douce et les zones humides complexes. Alors que les zones humides saumâtres sont actives toute l'année et les forêts inondées, ont leur pic en décembre et janvier. L'estimation quantitative de la dénitrification a été évaluée à 169.32± 18.31 Tg N (N2O-N +N2-N).an-1 et l'évolution de la dénitrification au cours des 8 dernières années a été analysée et mise en relation avec les anomalies du climat mondial.