Climate response of the soil nitrogen cycle in three forest types of a headwater Mediterranean catchment

Lupon, Anna; Gerber, Stefan; Sabater, Francesc; Bernal, Susana

doi:10.1002/2014jg002791

Cited by 17 publications

(18 citation statements)

References 60 publications

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“…Based on existing published data, we forecast that denitrification is not significant in riparian zones along low stream order streams under Mediterranean, arid or arctic climate due to low water availability and/or short residence time of water and solutes (Jones et al, 2005;Bernal et al, 2007;Mu et al, 2017;Poblador et al, 2017). Therefore, we forecast that in Mediterranean and arid regions, denitrification rates are consistently low compared to more humid catchments (Holmes et al, 1996;Bernal et al, 2007;Harms and Grimm, 2010;Lupon et al, 2015;Poblador et al, 2017). Yet, the capacity for denitrification can rapidly increase once waterlogged conditions develop in riparian zones (Harms et al, 2009).…”

Section: Riparian Corridors Function As Kidneys Of River Systemsmentioning

confidence: 80%

Riparian Corridors: A New Conceptual Framework for Assessing Nitrogen Buffering Across Biomes

Pinay

Bernal

Abbott

et al. 2018

Front. Environ. Sci.

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Anthropogenic activities have more than doubled the amount of reactive nitrogen circulating on Earth, creating excess nutrients across the terrestrial-aquatic gradient. These excess nutrients have caused worldwide eutrophication, fundamentally altering the functioning of freshwater and marine ecosystems. Riparian zones have been recognized to buffer diffuse nitrate pollution, reducing delivery to aquatic ecosystems, but nutrient removal is not their only function in river systems. In this paper, we propose a new conceptual framework to test the capacity of riparian corridors to retain, remove, and transfer nitrogen along the continuum from land to sea under different climatic conditions. Because longitudinal, lateral, and vertical connectivity in riparian corridors influences their functional role in landscapes, we highlight differences in these parameters across biomes. More specifically, we explore how the structure of riparian corridors shapes stream morphology (the river's spine), their multiple functions at the interface between the stream and its catchment (the skin), and their biogeochemical capacity to retain and remove nitrogen (the kidneys). We use the nitrogen cycle as an example because nitrogen pollution is one of the most pressing global environmental issues, influencing directly and indirectly virtually all ecosystems on Earth. As an initial test of the applicability of our interbiome approach, we present synthesis results of gross ammonification and net nitrification from diverse ecosystems.

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Section: Riparian Corridors Function As Kidneys Of River Systemsmentioning

confidence: 80%

Riparian Corridors: A New Conceptual Framework for Assessing Nitrogen Buffering Across Biomes

Pinay

Bernal

Abbott

et al. 2018

Front. Environ. Sci.

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“…No pulses of soil N cycling were detected in summer in the upland soils, which can be explained by their dryness (WFPS < 20%) (Lupon et al , ). Conversely, we recorded summer pulses of NNM and NN at the riparian site, probably because the riparian groundwater kept the soil relatively wet (WFPS > 30%) throughout the year, which was supported by the lack of correlation between ΣP4d and WFPS at this site.…”

Section: Discussionmentioning

confidence: 99%

Contribution of pulses of soil nitrogen mineralization and nitrification to soil nitrogen availability in three Mediterranean forests

Lupon

Sabater

Miñarro

et al. 2016

European J Soil Science

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Pulses of microbial nitrogen (N) supply often occur during storms in Mediterranean regions, but their contribution to soil N availability and catchment N exports is still unknown. We investigated patterns and controls of pulses of net N mineralization (NNM) and nitrification (NN) at three forest sites (riparian, evergreen oak and beech) that coexist within a Mediterranean headwater catchment. In addition, we examined the effect of these pulses on soil N availability and stream N loads. For a year, we measured NNM, NN, precipitation, moisture and temperature within each forest site. Mean NNM and NN rates varied widely among forest sites (NNM = 1.35, 0.62 and 0.50 µg N g soil−1 day−1; NN = 1.18, 0.24 and 0.07 µg N g soil−1 day−1 for riparian, oak and beech, respectively). In general, pulses of NNM and NN occurred in spring, immediately after large rain events (> 20 mm). High soil temperatures (> 16°C) promoted microbial pulses in summer at the riparian site, but there were no pulses of NN at the beech site. Although pulses of microbial activity were infrequent, they could account for account for 21–35% of the annual rates of the annual rates of NNM and NN. However, NN pulses only at the riparian site led to disproportional increases in soil N availability and stream N loads. These results suggest that upland Mediterranean forests are sinks of N even after storms, whereas riparian soil can be a critical source of nitrate for the stream. Our study emphasizes the relevance of intensive monitoring in to evaluate the effect of microbial pulses on soil N biogeochemistry in Mediterranean catchments. Highlights We investigated the contribution of microbial pulses to soil N availability at three forest sites Microbial pulses occurred after rewetting in spring and also in summer at the riparian site Microbial pulses contributed > 20% of annual rates of mineralization and nitrification Riparian soil can be a source of N for Mediterranean streams, especially after nitrification pulses

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“…Allison and Treseder (2008) reported that simultaneous temperature increase (0.5°C) and decline in water content (22%) of soil had negative effects on microbial respiration and bacterial and fungal abundances in boreal forest soils. The impacts of changed climate on soil nitrogen transformation processes (N-mineralisation, nitrification and denitrification) and nitrogen availability in various ecosystems (including forests) have been shown in many studies (Landesman and Dighton, 2010; Lupon et al, 2015). The characteristics of the climate change and concordant effect on N-cycling can be different according to the region (Lupon et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

“…The impacts of changed climate on soil nitrogen transformation processes (N-mineralisation, nitrification and denitrification) and nitrogen availability in various ecosystems (including forests) have been shown in many studies (Landesman and Dighton, 2010; Lupon et al, 2015). The characteristics of the climate change and concordant effect on N-cycling can be different according to the region (Lupon et al, 2015). Gerten et al (2008) showed that the magnitude of changes in carbon and water dynamics in response to changes in precipitation is determined by the degree of the ecosystem water limitation (ratio between atmospheric transitional demand and soil water supply) and seasonal timing of precipitation change (doubling or halving rather than altered frequency and intensity at constant annual amounts).…”

Section: Introductionmentioning

confidence: 99%

Elevated Air Humidity Changes Soil Bacterial Community Structure in the Silver Birch Stand

et al. 2017

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Soil microbes play a fundamental role in forest ecosystems and respond rapidly to changes in the environment. Simultaneously with the temperature increase the climate change scenarios also predict an intensified hydrological cycle for the Baltic Sea runoff region. The aim of this study was to assess the effect of elevated air humidity on the top soil microbial community structure of a silver birch (Betula pendula Roth.) stand by using a free air humidity manipulation facility (FAHM). The bacterial community structures of bulk soil and birch rhizosphere were analyzed using high-throughput sequencing of bacteria-specific16S rRNA gene fragments and quantification of denitrification related genes. The increased air humidity altered both bulk soil and rhizosphere bacterial community structures, and changes in the bacterial communities initiated by elevated air humidity were related to modified soil abiotic and biotic variables. Network analysis revealed that variation in soil bacterial community structural units is explained by altered abiotic conditions such as increased pH value in bulk soil, while in rhizosphere the change in absorptive root morphology had a higher effect. Among root morphological traits, the absorptive root diameter was strongest related to the bacterial community structure. The changes in bacterial community structures under elevated air humidity are associated with shifts in C, N, and P turnover as well as mineral weathering processes in soil. Increased air humidity decreased the nir and nosZ gene abundance in the rhizosphere bacterial community. The potential contribution of the denitrification to the N2O emission was not affected by the elevated air humidity in birch stand soil. In addition, the study revealed a strong link between the bacterial community structure, abundance of denitrification related genes, and birch absorptive root morphology in the ecosystem system adaptation to elevated air humidity.

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Climate response of the soil nitrogen cycle in three forest types of a headwater Mediterranean catchment

Cited by 17 publications

References 60 publications

Riparian Corridors: A New Conceptual Framework for Assessing Nitrogen Buffering Across Biomes

Riparian Corridors: A New Conceptual Framework for Assessing Nitrogen Buffering Across Biomes

Contribution of pulses of soil nitrogen mineralization and nitrification to soil nitrogen availability in three Mediterranean forests

Elevated Air Humidity Changes Soil Bacterial Community Structure in the Silver Birch Stand

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