Michael J. Lathuillière

Water use by terrestrial ecosystems: temporal variability in rainforest and agricultural contributions to evapotranspiration in Mato Grosso, Brazil

The state of Mato Grosso, Brazil, has experienced rapid land use changes from the expansion of rain-fed agriculture (primarily soybean and pasture). This study presents changes to evapotranspiration contributions from terrestrial ecosystems in Mato Grosso over the 2000?9 period. Instead of focusing on land use change to infer hydrologic change, in this paper we assess hydrologic changes using remote sensing, meteorological and agricultural production data to determine the rainforest, crop and pasture components of total evapotranspiration. Humid tropical rainforest evapotranspiration represented half of the state?s total evapotranspiration in 2000 despite occupying only 40% of the total land area. Annual evapotranspiration fluxes from rainforest declined at a rate of 16.2?km3?y?1 (R2?=?0.82, p-value ?<?0.01) as a result of deforestation between 2000 and 2009, representing a 25% decline in rainforest evapotranspiration since 2000. By 2009, rainforest cover accounted for only 40% of total evapotranspiration. Over the same period, crop evapotranspiration doubled, but this increase was offset by a decline in pasture evapotranspiration. Pasture fluxes were at least five times larger than crop evapotranspiration fluxes in 2000?9, with increases spatially focused at the agricultural frontier. The results highlight the expanding appropriation of soil moisture stocks for use in Mato Grosso?s rain-fed agroecosystems.

Environmental footprints show China and Europe’s evolving resource appropriation for soybean production in Mato Grosso, Brazil

Mato Grosso has become the center of Brazil’s soybean industry, with production located across an agricultural frontier expanding into savanna and rainforest biomes. We present environmental footprints of soybean production in Mato Grosso and resource flows accompanying exports to China and Europe for the 2000s using five indicators: deforestation, land footprint (LF), carbon footprint (CF), water footprint (WF), and nutrient footprints. Soybean production was associated with 65% of the state’s deforestation, and 14–17% of total Brazilian land use change carbon emissions. The decade showed two distinct production systems illustrated by resources used in the first and second half of the decade. Deforestation and carbon footprint declined 70% while land, water, and nutrient footprints increased almost 30% between the two periods. These differences coincided with a shift in Mato Grosso’s export destination. Between 2006 and 2010, China surpassed Europe in soybean imports when production was associated with 97 m 2 deforestation yr �1 ton �1 of soybean, a LF of 0.34 ha yr �1 ton �1 , a carbon footprint of 4.6 ton CO2eq yr �1 ton �1 , a WF of 1908 m 3 yr �1 ton �1 , and virtual phosphorous and potassium of 5.0 kg P yr �1 ton �1 and 0.0042 g K yr �1 ton �1 . Mato Grosso constructs soil fertility via

Soil CO2 concentrations and efflux dynamics of a tree island in the Pantanal wetland

The Pantanal is the largest tropical wetland on the planet and yet little information is available on the biomes carbon cycle. We used an automatic station to measure soil CO2 concentrations and oxidation-reduction potential over the 2014 and 2015 flood cycles of a tree island in the Pantanal that is immune to inundation during the wetlands annual flooding. The soil CO2 concentration profile was then used to estimate soil CO2 efflux over the two periods. In 2014, subsurface soil saturation at 0.30 m depth created conditions in that layer that led to CO2 buildup close to 200,000 ppm and soil oxidation-reduction potential below –300 mV, conditions that were not repeated in 2015 due to annual variability in soil saturation at the site. Mean CO2 efflux over the 2015 flood cycle was 0.023 ± 0.103 mg CO2-C m-2 s-1 representing a total annual efflux of 593 ± 2690 mg CO2-C m-2 y-1. Unlike a nearby tree island site that experiences full inundation during the wet season, here the soil dried quickly following repeated rain events throughout the year which led to the release of soil CO2 pulses from the soil. This study not only highlights the complexity and heterogeneity in the Pantanals carbon balance based on differences in topography, flood cycles and vegetation, but also the challenges of applying the gradient-method in the Pantanal due to deviations from steady-state conditions.

Spatial patterns of DOC concentration and DOM optical properties in a Brazilian tropical river‐wetland system

The Cerrado (savanna) and Pantanal (wetland) biomes of central-western Brazil have experienced significant development activity in recent decades, including extensive land cover conversion from natural ecosystems to agriculture and urban expansion. The Cuiaba River transects the Cerrado biome prior to inundating large areas of the Pantanal, creating one of the largest biodiversity hotspots in the world. We measured dissolved organic carbon (DOC) and the optical absorbance and fluorescence properties of dissolved organic matter (DOM) from 40 sampling locations spanning Cerrado and Pantanal biomes during wet and dry seasons. In the upper, more agricultural region of the basin, DOC concentrations were highest in the rainy season with more aromatic and humified DOM. In contrast, DOC concentrations and DOM optical properties were more uniform for the more urbanized middle region of the basin between wet and dry seasons, as well as across sample locations. In the lower region of the basin, wet season connectivity between the river and the Pantanal floodplain led to high DOC concentrations, a four-fold increase in HIX (an indicator of DOM humification) and a 50% reduction in the spectral slope (SR). Basin-wide, wet season values for SR, HIX and FI (fluorescence index) indicated an increasing representation of terrestrially derived DOM that was more humified. Parallel factor analysis (PARAFAC) identified two terrestrially derived components (C1 and C2) representing 77% of total fluorescing DOM (fDOM). A third, protein-like fDOM component increased markedly during the wet season within the more urban-impacted region.

Harmonizing water footprint assessments for agricultural production in Southern Amazonia

Since its inception in 2002, the water footprint (WF) has brought new insight into the direct and indirect (or supply chain) uses of water in the production and consumption of goods and services. Today, this emerging field is mainly represented by two distinct communities following distinct WF approaches: the water resources management community which follows guidelines from the WF Network, and the life cycle assessment (LCA) community which focuses on assessing impacts from water use. This thesis seeks to harmonize WF assessments by combining and contrasting methods and objectives from both communities with the overarching goal of informing water decision-making by (1) considering limits to water resources within a river basin (the “Nature” domain), and (2) considering water use in production systems (the “Production” domain). Following this proposed framework to combine WF assessments (Chapter 2), I assess how each approach may address water management for agricultural production in Southern Amazonia (Mato Grosso, Brazil), a region that has dramatically increased its soybean and cattle production through deforestation. In Chapters 3 and 4, I respectively measure andmodel theWF of cropland and cattle to highlight on-farm water use strategies for agricultural production (the volumetric WF assessment phase). Chapter 5 focuses on the Xingu Basin of Mato Grosso for which I assess water scarcity of current and future agricultural production (the volumetric WF sustainability assessment phase). Finally, in Chapter 6, I integrate existing water use in LCA methods to highlight water use efficiencies through impact assessment (the WF impact assessment phase). Results show different land and water management options for crops and cattle in Southern Amazonia, but also demonstrate that water use for future production could reach sustainable limits, should cropland irrigation and cattle confinement become more widespread. Moreover, the role of water vapour supply to the atmosphere through evapotranspiration is stressed as an important process that could affect future water availability due to the importance of moisture recycling on regional precipitation. This research provides context on the role of land management on water resources, while combining water decisions affecting both production systems and resource limits imposed by the water cycle.

A Multimedia Hydrological Fate Modeling Framework To Assess Water Consumption Impacts in Life Cycle Assessment

Many new methods have recently been developed to address environmental consequences of water consumption in life cycle assessment (LCA). However, such methods can only partially be compared and combined, because their modeling structure and metrics are inconsistent. Moreover, they focus on specific water sources (e.g., river) and miss description of transport flows between water compartments (e.g., from river to atmosphere via evaporation) and regions (e.g., atmospheric advection). Consequently, they provide a partial regard of the local and global hydrological cycle and derived impacts on the environment. This paper proposes consensus-based guidelines for a harmonized development of the next generation of water consumption LCA indicators, with a focus on consequences of water consumption on ecosystem quality. To include the consideration of the multimedia water fate between compartments of the water cycle, we provide spatial regionalization and temporal specification guidance. The principles and recommendations of the paper are applied to an illustrative case study. The guidelines set the basis of a more accurate, novel way of modeling water consumption impacts in LCA. The environmental relevance of this LCA impact category will improve, yet much research is needed to make the guidelines operational.

Water use LCA—Methodology

Freshwater is a unique resource essential to both human life and terrestrial and aquatic ecosystems. Water resource management plays a critical role in sustainability. While life cycle assessment (LCA) has been applied to model direct water pollution impacts such as freshwater eutrophication, acidification or human and aquatic (eco)toxicity; potential impacts from water deprivation are at an earlier stage of modeling. In 2007, the Water Use in LCA (WULCA) Working Group was formed to bring together experts in academia, public, and private sectors in the fields of water resources and LCA as part of the United Nations Environment Programme and Society of Environmental Toxicology and Chemistry Life Cycle Initiative to address water use in LCA and to make methodological recommendations consistent with the principles, requirements, and guidelines of the ISO standard, 14046:2014 (Water Footprint: Principles, Requirements and Guidelines). This article outlines the framework recommended by the WULCA Working Group to quantify potential impacts of water use on human health and ecosystem quality, and from consumptive and degradative water use in LCA.