Assessing the fate and transformation of plant residues in the terrestrial environment using HR-MAS NMR spectroscopy

Kelleher, Brian P.; Simpson, Myrna J.; Simpson, André J.

doi:10.1016/j.gca.2006.06.012

Cited by 102 publications

(76 citation statements)

References 62 publications

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“…Dissolved proteins could have sources throughout the watershed. For example, N-rich compounds can originate in soils due to selective preservation of refractory proteins 42,43 and/or production of labile proteins in situ 41,42 and then be transported via runoff and stream flow. Terrestrial DON can sometimes account for up to 90% of the N that enters highelevation lakes 44,45 .…”

Section: Discussionmentioning

confidence: 99%

Refractory dissolved organic nitrogen accumulation in high-elevation lakes

et al. 2015

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The role of dissolved organic matter (DOM) as either a sink for inorganic nutrients or an additional nutrient source is an often-neglected component of nutrient budgets in aquatic environments. Here, we examined the role of DOM in reactive nitrogen (N) storage in Sierra Nevada (California, USA) lakes where atmospheric deposition of N has shifted the lakes toward seasonal phosphorus (P)-limitation. Nuclear magnetic resonance (NMR) spectroscopy and isotope analyses performed on DOM isolated from Lake Tahoe reveal the accumulation of refractory proteinaceous material with a 100-200-year residence time. In contrast, smaller lakes in the same watershed contain DOM with typical terrestrial characteristics, indicating that proteins in Lake Tahoe are autochthonously produced. These data support the role of DOM as a possible sink for reactive N in these lake ecosystems and identify a potential role for DOM in affecting the inorganic nutrient stoichiometry of these environments.

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Section: Discussionmentioning

confidence: 99%

Refractory dissolved organic nitrogen accumulation in high-elevation lakes

et al. 2015

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“…3), often the most intense signal in soil OM. [9,22,34] Methoxy cross-peaks are clearly present in all the lake samples (overlapped with carbohydrate cross-peaks), especially Hare Island and Dromineer. Lignin is a strong indicator of terrestrial plant inputs and may be an indication of the age of DOM and the influence of the surrounding environment.…”

Section: General Characterisationmentioning

confidence: 99%

“…The degradation experiment was conducted according to a modified version of the protocol described by Kelleher et al [22] The experimental design attempted to mimic in situ conditions and enable collection of transformed and leached organic matter (OM) for further analysis. Glass funnels with borosilicate sintered discs, with porosity grade 4 were submerged until flush with soil in a clay pot.…”

Section: Growth and Degradation Of Soil Microbial Biomassmentioning

confidence: 99%

“…2a displays sharp peaks, especially in the carbohydrate region (3). Sharper lines observed in NMR spectra are often characteristic of smaller structures, [22] and this may indicate the breakdown of the carbohydrates from large polymeric structures into smaller fragments. To test this, diffusion edited (DE) NMR spectroscopy was performed on the Ballina sample.…”

Section: General Characterisationmentioning

confidence: 99%

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Composition of dissolved organic matter within a lacustrine environment

McCaul¹,

Sutton²,

Simpson³

et al. 2011

Environ. Chem.

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Environmental context. Freshwater dissolved organic matter is a complex chemical mixture central to many environmental processes, including carbon and nitrogen cycling. Questions remain, however, as to its chemical characteristics, sources and transformation mechanisms. We studied the nature of dissolved organic matter in a lake system and found that it is influenced by anthropogenic activities. Human activities can therefore influence the huge amounts of carbon sequestered in lakes as dissolved organic matter.Abstract. Freshwater dissolved organic matter (DOM) is a complex mixture of chemical components that are central to many environmental processes, including carbon and nitrogen cycling. However, questions remain as to its chemical characteristics, sources and transformation mechanisms. Here, we employ 1-and 2-D nuclear magnetic resonance (NMR) spectroscopy to investigate the structural components of lacustrine DOM from Ireland, and how it varies within a lake system, as well as to assess potential sources. Major components found, such as carboxyl-rich alicyclic molecules (CRAM) are consistent with those recently identified in marine and freshwater DOM. Lignin-type markers and protein/peptides were identified and vary spatially. Phenylalanine was detected in lake areas influenced by agriculture, whereas it is not detectable where zebra mussels are prominent. The presence of peptidoglycan, lipoproteins, large polymeric carbohydrates and proteinaceous material supports the substantial contribution of material derived from microorganisms. Evidence is provided that peptidoglycan and silicate species may in part originate from soil microbes.

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“…Por serem os derivados da lignina mais pobres em 13 C (Benner et al, 1987) e ela e seus derivados contribuírem substancialmente para a formação da MOS (Stevenson, 1994;Simpson et al, 2003;Kelleher et al, 2006), torna-se necessário alto nível (intensidade) de marcação com 13 C em plantas lenhosas, em particular, para possibilitar o estudo da dinâmica da formação e degradação da MOS derivada de seus resíduos. Poucos estudos estão disponíveis sobre o método necessário para obter esse alto nível de marcação; particularmente no caso do eucalipto, não foram encontrados estudos com esse propósito.…”

Section: Introductionunclassified

Enriquecimento e alocação de 13C em plantas de eucalipto

Machado

Novais²,

Silva³

et al. 2011

Rev. Bras. Ciênc. Solo

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RESUMONas últimas décadas, a utilização de isótopos estáveis em várias áreas de pesquisa vem se destacando, como na análise de fluxos e rotas metabólicas, análise de efeitos de estresses em plantas e, em grande escala, no estudo da matéria orgânica do solo (MOS). Estudos de alterações e dinâmica da MOS usando a variação da abundância natural do 13 C requerem mudanças na razão isotópica do C. Quando não existe essa possibilidade, uma das alternativas é enriquecer o material vegetal (planta) com 13 C, via fixação de 13 CO 2 , de modo que a razão isotópica seja distinta daquela da MOS original. O objetivo deste trabalho foi investigar a magnitude e a homogeneidade do enriquecimento em 13 C em diferentes componentes da planta de eucalipto. No processo de marcação, três plantas de eucalipto, com 4 meses de idade, cultivadas em solução nutritiva foram expostas a uma atmosfera enriquecida com 13 CO 2 , em uma câmara de vidro (448 dm 3 ), com temperatura em torno de 24 ºC. A concentração de CO 2 e a razão 13 C/ 12 C foram monitoradas por um espectrômetro de massa de razão isotópica (IRMS) em amostras de ar retiradas ao longo do processo (126 dias com três pulsos de 13 CO 2 semanais). Após o período de marcação, as plantas foram separadas em folha (folha-fonte e folha-dreno), galho, casca, lenho e raiz e analisadas em IRMS. O resultado foi expresso em partes por mil (‰) em relação ao padrão internacional de C denominado Pee-Dee Belemnite (PDB), obtendo-se a δ δ δ δ δ 13 C PDB delas: folha-fonte (828,07 ‰), folha-dreno (645,72 ‰), galho (672,49 ‰), casca (691,86 ‰), lenho (632,02 ‰) e raiz (536,55 ‰). O padrão de alocação e enriquecimento de 13 C entre os componentes das plantas foi homogêneo, embora com diferenças numéricas da ordem de 291 ‰ na δ δ δ δ δ 13 C PDB . As plantas de eucalipto mantiveram alta taxa de absorção de CO 2 e, consequentemente, alta taxa fotossintética em concentrações de CO 2 muito acima (180,4 mmol L -1 -7.934 ppmv) da encontrada na atmosfera (8,64 mmol L -1 -380 ppmv). O 13 C fixado durante o dia foi liberado em menor escala na respiração noturna, em comparação com o 12 C.(1) Recebido para publicação em maio de 2009 e aprovado em março de 2011.

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Assessing the fate and transformation of plant residues in the terrestrial environment using HR-MAS NMR spectroscopy

Cited by 102 publications

References 62 publications

Refractory dissolved organic nitrogen accumulation in high-elevation lakes

Refractory dissolved organic nitrogen accumulation in high-elevation lakes

Composition of dissolved organic matter within a lacustrine environment

Enriquecimento e alocação de 13C em plantas de eucalipto

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