Amino acid nitrogen isotopic fractionation patterns as indicators of heterotrophy in plankton, particulate, and dissolved organic matter

McCarthy, Matthew D.; Benner, Ronald; Lee, Cindy; Fogel, Marilyn L.

doi:10.1016/j.gca.2007.06.061

Cited by 211 publications

(308 citation statements)

References 71 publications

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“…The overall patterns in P. resedaeformis are very similar to those observed in pure plankton samples (4, 7), indicating that the basic photoautotrophic patterns are well preserved during POM transit and trophic incorporation into coral gorgonin. This qualitative observation is confirmed by the ΣV, a parameter tied to microbial resynthesis and alteration of δ 15 N-AA patterns (7). The ΣV values in P. resedaeformis all fall in the range expected for fresh biomass (i.e., live phytoplankton and zooplankton; 0.53 to 1.35), and further there is no significant trend in ΣV in our samples (Table 1 and Fig.…”

Section: Resultssupporting

confidence: 76%

“…4). The Tr-AA are substantially enriched in δ 15 N versus the Src-AA, reflecting both autotrophic base metabolic patterns, as well as subsequent trophic transfers (4)(5)(6)(7)(8)23). We note that within the Src-AA, Thr appears to constitute an outlier, with very negative values.…”

Section: Resultsmentioning

confidence: 81%

“…One group of "trophic" amino acids (Tr-AA) becomes strongly enriched in 15 N with each trophic transfer, while a second group of "source" amino acids (Src-AA) have δ 15 N values that undergo little or no change (4,5). The use of compound-specific δ 15 N analysis of AA (δ 15 N-AA) to deconvolute the effects of trophic transfer on bulk δ 15 N signals has been demonstrated in a number of environments (5)(6)(7)(8). Here, for the first time, we apply δ 15 N-AA measurements to a paleo-archive (coral) in order to resolve a major issue in the interpretation of bulk δ 15 N records from a marine ecosystem.…”

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confidence: 99%

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Nutrient regime shift in the western North Atlantic indicated by compound-specific δ ¹⁵ N of deep-sea gorgonian corals

Sherwood

Lehmann

Schubert

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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Despite the importance of the nitrogen (N) cycle on marine productivity, little is known about variability in N sources and cycling in the ocean in relation to natural and anthropogenic climate change. Beyond the last few decades of scientific observation, knowledge depends largely on proxy records derived from nitrogen stable isotopes ( δ 15 N) preserved in sediments and other bioarchives. Traditional bulk δ 15 N measurements, however, represent the combined influence of N source and subsequent trophic transfers, often confounding environmental interpretation. Recently, compound-specific analysis of individual amino acids ( δ 15 N-AA) has been shown as a means to deconvolve trophic level versus N source effects on the δ 15 N variability of bulk organic matter. Here, we demonstrate the first use of δ 15 N-AA in a paleoceanographic study, through analysis of annually secreted growth rings preserved in the organic endoskeletons of deep-sea gorgonian corals. In the Northwest Atlantic off Nova Scotia, coral δ 15 N is correlated with increasing presence of subtropical versus subpolar slope waters over the twentieth century. By using the new δ 15 N-AA approach to control for variable trophic processing, we are able to interpret coral bulk δ 15 N values as a proxy for nitrate source and, hence, slope water source partitioning. We conclude that the persistence of the warm, nutrient-rich regime since the early 1970s is largely unique in the context of the last approximately 1,800 yr. This evidence suggests that nutrient variability in this region is coordinated with recent changes in global climate and underscores the broad potential of δ 15 N-AA for paleoceanographic studies of the marine N cycle.

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Section: Resultssupporting

confidence: 76%

Section: Resultsmentioning

confidence: 81%

mentioning

confidence: 99%

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Nutrient regime shift in the western North Atlantic indicated by compound-specific δ ¹⁵ N of deep-sea gorgonian corals

Sherwood

Lehmann

Schubert

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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155

172

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“…We used a lower value of 16 atm% 13 C based on the whole cell measurement and an upper value of 95 atm% 13 C based on the calculated atm% 13 C for the number of cell doublings that occurred assuming uptake of fully labeled medium. The starting ambient DCAA pool was assumed to have a δ 13 C of − 20‰ (McCarthy et al, 2004) and δ 15 N of 8‰ (McCarthy et al, 2007). Limitations to this method include an incomplete characterization of both the isotopically labeled protein preparation and the ambient DCAA pool, and considerable uncertainties in the starting concentrations of both (Lipschultz, 2008).…”

Section: Protein Remineralization Ratesmentioning

confidence: 99%

Diverse, uncultivated bacteria and archaea underlying the cycling of dissolved protein in the ocean

et al. 2016

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Dissolved organic nitrogen (DON) supports a significant amount of heterotrophic production in the ocean. Yet, to date, the identity and diversity of microbial groups that transform DON are not well understood. To better understand the organisms responsible for transforming high molecular weight (HMW)-DON in the upper ocean, isotopically labeled protein extract from Micromonas pusilla, a eukaryotic member of the resident phytoplankton community, was added as substrate to euphotic zone water from the central California Current system. Carbon and nitrogen remineralization rates from the added proteins ranged from 0.002 to 0.35 μmol C l − 1 per day and 0.03 to 0.27 nmol N l − 1 per day. DNA stable-isotope probing (DNA-SIP) coupled with high-throughput sequencing of 16S rRNA genes linked the activity of 77 uncultivated freeliving and particle-associated bacterial and archaeal taxa to the utilization of Micromonas protein extract. The high-throughput DNA-SIP method was sensitive in detecting isotopic assimilation by individual operational taxonomic units (OTUs), as substrate assimilation was observed after only 24 h. Many uncultivated free-living microbial taxa are newly implicated in the cycling of dissolved proteins affiliated with the Verrucomicrobia, Planctomycetes, Actinobacteria and Marine Group II (MGII) Euryarchaeota. In addition, a particle-associated community actively cycling DON was discovered, dominated by uncultivated organisms affiliated with MGII, Flavobacteria, Planctomycetes, Verrucomicrobia and Bdellovibrionaceae. The number of taxa assimilating protein correlated with genomic representation of TonB-dependent receptor (TBDR)-encoding genes, suggesting a possible role of TBDR in utilization of dissolved proteins by marine microbes. Our results significantly expand the known microbial diversity mediating the cycling of dissolved proteins in the ocean.

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“…As a result, CSIA of amino acids overcomes several of the challenges associated with bulk isotopic methods (e.g., O'Reilly et al 2002;Post 2002). Consequently, the CSIA of amino acids has been used to elucidate the trophic position of organisms in recent ecological studies of shrimp in the sub-Antarctic archipelago (Pakhomov et al 2004), krill in the Antarctic (Schmidt et al 2004(Schmidt et al , 2006, plankton in the central Pacific (McCarthy et al 2007), yellow-fin tuna in the eastern tropical Pacific (Popp et al 2007), zooplankton near Hawaii (Hannides et al 2009), and penguin in the Southern Ocean (Lorrain et al 2009). Recent evidence suggests that CSIA of amino acids is also useful in the evaluation of terrestrial food webs (Chikaraishi et al 2010a;Naito et al 2010;Styring et al 2010).…”

Section: Introductionmentioning

confidence: 99%

¹⁵N/¹⁴N ratios of amino acids as a tool for studying terrestrial food webs: a case study of terrestrial insects (bees, wasps, and hornets)

Chikaraishi

Ogawa

Doi

et al. 2011

Ecological Research

113

161

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Compound-specific stable isotope analysis (CSIA) of amino acids is a new method that enables estimates of trophic position for consumers in food webs. We examined the nitrogen isotopic composition (d 15 N) of amino acids of Japanese social insects (three bee, three wasp, and four hornet species) to evaluate the potential of CSIA of amino acids in studies of terrestrial food webs. For wasps, we also examined samples at different growth stages (ranging from egg to adult) to assess the effect of metamorphosis on CSIA estimates of trophic position. The d 15 N values of bulk tissues for Japanese social insects are only weakly correlated with the biologically expected trophic positions. In contrast, the trophic positions estimated from the d 15 N values of amino acids (yielding values of between 2.0 and 2.3 for bees, between 2.8 and 3.3 for wasps, and between 3.5 and 4.1 for hornets) are consistent with the biologically expected trophic positions for these insects (i.e., 2.0 for bees, 3.0 for wasps, and 3.0-4.0 for hornets). Although large variability is observed among the d 15 N values of individual amino acids (e.g., ranging from 3.0 to 14.9& for phenylalanine), no significant change is observed in the trophic position during wasp metamorphosis. Thus, the CSIA of amino acids is a powerful tool for investigating not only aquatic food webs but also terrestrial food webs with predatory insects.

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Amino acid nitrogen isotopic fractionation patterns as indicators of heterotrophy in plankton, particulate, and dissolved organic matter

Cited by 211 publications

References 71 publications

Nutrient regime shift in the western North Atlantic indicated by compound-specific δ ¹⁵ N of deep-sea gorgonian corals

Nutrient regime shift in the western North Atlantic indicated by compound-specific δ ¹⁵ N of deep-sea gorgonian corals

Diverse, uncultivated bacteria and archaea underlying the cycling of dissolved protein in the ocean

¹⁵N/¹⁴N ratios of amino acids as a tool for studying terrestrial food webs: a case study of terrestrial insects (bees, wasps, and hornets)

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Amino acid nitrogen isotopic fractionation patterns as indicators of heterotrophy in plankton, particulate, and dissolved organic matter

Cited by 211 publications

References 71 publications

Nutrient regime shift in the western North Atlantic indicated by compound-specific δ 15 N of deep-sea gorgonian corals

Nutrient regime shift in the western North Atlantic indicated by compound-specific δ 15 N of deep-sea gorgonian corals

Diverse, uncultivated bacteria and archaea underlying the cycling of dissolved protein in the ocean

15N/14N ratios of amino acids as a tool for studying terrestrial food webs: a case study of terrestrial insects (bees, wasps, and hornets)

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Nutrient regime shift in the western North Atlantic indicated by compound-specific δ ¹⁵ N of deep-sea gorgonian corals

Nutrient regime shift in the western North Atlantic indicated by compound-specific δ ¹⁵ N of deep-sea gorgonian corals

¹⁵N/¹⁴N ratios of amino acids as a tool for studying terrestrial food webs: a case study of terrestrial insects (bees, wasps, and hornets)