Amazon deforestation alters small stream structure, nitrogen biogeochemistry and connectivity to larger rivers

Deegan, Linda A.; Neill, Christopher; Haupert, Christie L.; Ballester, Maria Victória Ramos; Krusche, Alex V.; Victória, Reynaldo Luiz; Thomas, Stephen; Moor, Emily de

doi:10.1007/s10533-010-9540-4

Cited by 76 publications

(65 citation statements)

References 60 publications

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“…These results agree with meta-data reviews of tropical forests by Downing et al (1999) and measurements by Deegan et al (2011) in forest and pasture tracts in the Amazon basin. In contrast, other studies in wet tropical regions (Amazon basin: , Davidson et al 2007Hawaii: Boehm et al 2010) Our results suggest that first, there are reasonable supplies of available N moving through tropical forested watersheds (e.g.…”

Section: Discussionsupporting

confidence: 90%

“…In terrestrial ecosystems, studies in temperate (Vitousek & Reiners 1975, Lewis et al 1999, Lewis 2002, Perakis & Hedin 2002, and tropical , Hedin et al 2003) latitudes discuss the degree to which soils (Jenny 1950), forests (Vitousek & Howarth 1991, Corre et al 2010, and aquifers process, retain, or release nutrients (Deegan et al 2011). The coupling of watersheds to receiving waters down-gradient might depend on the identity of nutrient-limiting vegetation on the watershed surface, so that nonlimiting or refractory materials dominate exports (Hedin et al 2003).…”

Section: Introductionmentioning

confidence: 99%

“…The widespread conversion of tropical forest to other land covers, mainly pastures, should substantially alter downgradient discharges (Davidson et al 2007, Chaves et al 2009, Deegan et al 2011) from watersheds to streams and estuaries (Downing et al 1999, Borbor-Cordova et al 2006, Boehm et al 2010, Uriarte et al 2011. N uptake and retention in pastures and forests (Downing et al 1999, Deegan et al 2011) differed sufficiently such that N in small tropical streams reflected the mix of surrounding land covers (Saunders et al 2006, Deegan et al 2011.…”

Section: Introductionmentioning

confidence: 99%

“…N uptake and retention in pastures and forests (Downing et al 1999, Deegan et al 2011) differed sufficiently such that N in small tropical streams reflected the mix of surrounding land covers (Saunders et al 2006, Deegan et al 2011.…”

Section: Introductionmentioning

confidence: 99%

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Nutrient gradients in Panamanian estuaries: effects of watershed deforestation, rainfall, upwelling, and within-estuary transformations

Valiela¹,

Giblin²,

Barth-Jensen³

et al. 2013

Mar. Ecol. Prog. Ser.

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To test whether deforestation of tropical forests alters coupling of watersheds, estuaries, and coastal waters, we measured nutrients in 8 watershed-estuarine systems on the Pacific coast of Panama where watershed forest cover ranged from 23 to 92%. Watersheds with greater forest cover discharged larger dissolved inorganic nitrogen concentrations and higher N/P into estuary headwaters. As freshwater mixed with seawater down-estuary, within-estuary biogeochemical processes erased the imprint of watershed deforestation, increased ammonium, lowered nitrate concentrations, and otherwise altered down-estuary water column composition. As estuarine water left mangrove estuaries, ammonium, nitrate, and phosphate, but not dissolved organic nitrogen, were exported to receiving near-shore waters. Mangrove estuaries in this region thus provide important ecological services, by uncoupling coastal waters from changes in terrestrial land covers, as well as by subsidizing adjoined receiving coastal waters by providing nutrients. The pattern of land−sea coupling and exports was disrupted during La Niña-influenced conditions. In one instance when La Niña conditions led to upwelling of deeper layers, high concentrations of marine-derived ammonium were inserted into estuaries. In another instance, La Niña-associated high rainfall diluted nutrient concentrations within estuaries and lowered salinity regionally, and the fresher upper layer impaired coastal upwelling. Regional rainfall has increased during the last decade. If La Niña rainfall continues to increase, disruptions of current land−estuary−sea couplings may become more frequent, with potentially significant changes in nutrient cycles and ecological services in these coupled ecosystems.The impacts of anthropogenic changes in land cover on the export of nutrients to tropical estuaries are attenuated by mangroves (inset).Photos: I. Valiela FREE REE ACCESS CCESS

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Section: Discussionsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Nutrient gradients in Panamanian estuaries: effects of watershed deforestation, rainfall, upwelling, and within-estuary transformations

Valiela¹,

Giblin²,

Barth-Jensen³

et al. 2013

Mar. Ecol. Prog. Ser.

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“…No Brasil, a maioria dos estudos envolvendo a ciclagem de nutrientes em microbacias tem sido realizada na Amazônia (GERMER et al, 2007;CHAVES et al, 2009;NEILL et al, 2001NEILL et al, , 2011DEEGAN et al, 2011); Cerrado (PARRON; BUSTAMANTE; MARKEWITZ, 2011) e na Mata Atlântica no sudeste brasileiro (ANDRADE et al, 2011;SALEMI et al, 2013SALEMI et al, , 2015. Mas, sobre as microbacias na Mata Atlântica no nordeste do país, pouco se sabe a respeito da infl uência dos diferentes usos do solo na ciclagem de nutrientes.…”

Section: Introductionunclassified

Métodos e técnicas de pesquisa em bacias hidrográficas

Moraes¹,

Lorandi²

2016

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Nitrogen Availability Dampens the Positive Impacts of CO₂ Fertilization on Terrestrial Ecosystem Carbon and Water Cycles

Chen

Croft

et al. 2017

Geophysical Research Letters

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The magnitude and variability of the terrestrial CO2 sink remain uncertain, partly due to limited global information on ecosystem nitrogen (N) and its cycle. Without N constraint in ecosystem models, the simulated benefits from CO2 fertilization and CO2‐induced increases in water use efficiency (WUE) may be overestimated. In this study, satellite observations of a relative measure of chlorophyll content are used as a proxy for leaf photosynthetic N content globally for 2003–2011. Global gross primary productivity (GPP) and evapotranspiration are estimated under elevated CO2 and N‐constrained model scenarios. Results suggest that the rate of global GPP increase is overestimated by 85% during 2000–2015 without N limitation. This limitation is found to occur in many tropical and boreal forests, where a negative leaf N trend indicates a reduction in photosynthetic capacity, thereby suppressing the positive vegetation response to enhanced CO2 fertilization. Based on our carbon‐water coupled simulations, enhanced CO2 concentration decreased stomatal conductance and hence increased WUE by 10% globally over the 1982 to 2015 time frame. Due to increased anthropogenic N application, GPP in croplands continues to grow and offset the weak negative trend in forests due to N limitation. Our results also show that the improved WUE is unlikely to ease regional droughts in croplands because of increases in evapotranspiration, which are associated with the enhanced GPP. Although the N limitation on GPP increase is large, its associated confidence interval is still wide, suggesting an urgent need for better understanding and quantification of N limitation from satellite observations.

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Amazon deforestation alters small stream structure, nitrogen biogeochemistry and connectivity to larger rivers

Cited by 76 publications

References 60 publications

Nutrient gradients in Panamanian estuaries: effects of watershed deforestation, rainfall, upwelling, and within-estuary transformations

Nutrient gradients in Panamanian estuaries: effects of watershed deforestation, rainfall, upwelling, and within-estuary transformations

Métodos e técnicas de pesquisa em bacias hidrográficas

Nitrogen Availability Dampens the Positive Impacts of CO₂ Fertilization on Terrestrial Ecosystem Carbon and Water Cycles

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Amazon deforestation alters small stream structure, nitrogen biogeochemistry and connectivity to larger rivers

Cited by 76 publications

References 60 publications

Nutrient gradients in Panamanian estuaries: effects of watershed deforestation, rainfall, upwelling, and within-estuary transformations

Nutrient gradients in Panamanian estuaries: effects of watershed deforestation, rainfall, upwelling, and within-estuary transformations

Métodos e técnicas de pesquisa em bacias hidrográficas

Nitrogen Availability Dampens the Positive Impacts of CO2 Fertilization on Terrestrial Ecosystem Carbon and Water Cycles

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Product

Resources

About

Nitrogen Availability Dampens the Positive Impacts of CO₂ Fertilization on Terrestrial Ecosystem Carbon and Water Cycles