Isotope Fractionation during Primary Production

Fogel, Marilyn L.; Cifuentes, Luis A.

doi:10.1007/978-1-4615-2890-6_3

Cited by 324 publications

(309 citation statements)

References 111 publications

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“…In terms of isotope discrimination, evidence from higher plants shows that there is no fractionation for the transport of NO across cell membranes (Mariotti et al Ϫ 3 1982). However, isotopic fractionation would occur if, under natural conditions, the NO were in sufficient supply to sat-Ϫ 3 urate the nitrate reductase (Fogel and Cifuentes 1993).…”

Section: Model Constraints and Resultsmentioning

confidence: 99%

The fate of nitrogen in the Orbulina universa foraminifera‐symbiont system determined by nitrogen isotope analyses of shell‐bound organic matter

Uhle

Macko

Spero

et al. 1999

Limnology & Oceanography

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To trace the flow of nitrogen through the foraminifera-symbiont system, juvenile specimens of the symbiontbearing planktonic foraminifera, Orbulina universa were collected by SCUBA divers off the coast of Santa Catalina Island, California, and grown in filtered seawater solutions spiked with 15 N-labeled nitrate. Our work isolated each pathway of this symbiotic system to determine the amount of nitrogen translocated to the foraminifera from its endosymbionts and its captured diet. Our model results show that when the nitrate uptake by the symbionts is at a maximum, between 50 and 57% of the foraminiferal nitrogen was translocated from the symbionts and the remainder was derived from the captured diet. In nitrate-deficient environments, when the symbiont nitrate uptake was at a minimum, ϳ90-100% of the nitrogen was transferred to the foraminifer by the symbionts from the recycled nitrogen (NH ) pool. In nitrate-deficient conditions, the primary role of the captured diet may be to provide the system with recycled nitrogen (NH ) is a more important source of nitrogen to the symbionts and the foraminifera than nitrate; ϩ 4 therefore, the ␦ 15 N values of the foraminifera may not reflect the isotopic composition of the surface-water nutrients. Understanding the nitrogen flow within modern foraminifera-symbiont associations is also important to ancient marine systems, because symbiont-bearing foraminifera are ubiquitous in the fossil record. This study shows that analysis of individual, symbiont-bearing foraminifera species is a necessary first step toward the development of more reliable use of nitrogen isotopes for paleoceanographic reconstructions.

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Section: Model Constraints and Resultsmentioning

confidence: 99%

The fate of nitrogen in the Orbulina universa foraminifera‐symbiont system determined by nitrogen isotope analyses of shell‐bound organic matter

Uhle

Macko

Spero

et al. 1999

Limnology & Oceanography

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“…During photosynthesis, phyto-Ž . plankton fix dissolved inorganic C DIC in the surface water into organic biomass C by enzymatic Ž carboxylation reactions Descolas-Gros and Fontugne, 1990;Fogel and Cifuentes, 1993;Goer-. icke et al, 1993 .…”

Section: Comparison Of D 13 C Signatures In Plankton and Sediments Ofmentioning

confidence: 99%

Radiocarbon and stable carbon isotope compositions of organic compound classes in sediments from the NE Pacific and Southern Oceans

Wang

Druffel

2001

Marine Chemistry

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AbstractŽ 14 .Ž 13 . Radiocarbon D C abundance and stable carbon isotope d C compositions were measured for total lipid, total Ž . Ž . hydrolyzable amino acids THAA , total carbohydrates TCHO , and acid-insoluble organic fractions separated from Ž . phytoplankton, zooplankton, and sediment cores collected from two abyssal sites, one in the northeast NE Pacific Ocean and one in the Southern Ocean. These results are compared with those obtained for a separate core from the NE Pacific and w Ž . In contrast, sediment from the Southern Ocean had much lower TOC and D 14 C values, which indicated that organic matter was extremely refractory. Sedimentation rates calculated from 14 C ages of TOC for both sites indicate that the differences in the organic composition and D 14 C signatures of organic matter in the sediments likely resulted from the differences in production and deposition of organic matter to the sediment, and the diagenetic stages of sedimentary organic matter in the two oceans. 14 Ž 13 . Unlike D C, stable carbon isotopic d C compositions of TOC in the sediments of the two oceans had similar values, which reflect not only the organic matter input from marine-derived sources but also the nature of degraded, predominately uncharacterized organic fraction in these sediments. The differences in d 13 C values among the compound classes in sediments at both sites can be attributed to the carbon isotopic signatures in original sources during photosynthesis and associated environmental factors. Preferential degradation of organic matter and heterotrophic effects may also play important roles for the observed d 13 C variations and these effects need to be further investigated. q 2001 Elsevier Science B.V. All rights reserved. -C. Wang, E.R.M. Druffelr Marine Chemistry 73 2001 65-81 66

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“…Therefore, the d 13 C POM from phytoplankton primary production that is exported from the photic zone by sedimentation preferentially removes 12 C. Thereby, the dissolved inorganic carbon (DIC) pool in the photic zone becomes gradually enriched in 13 C. As a consequence, increased primary production should be reflected by an increase in the d 13 C POM of sinking organic matter (Fogel and Cifuentes 1993;Hodell and Schelske 1998). However, factors other than primary production, such as changing pH, temperature, nutrient availability, atmospheric CO 2 concentration and its d 13 C value, varying amounts of allochthonous particulate organic matter (POM), shifts in phytoplankton species composition, plankton growth rate, and microbial processes, can influence lake internal carbon cycling and the stable carbon isotope composition of sinking POM on various timescales.…”

mentioning

confidence: 99%

Controls on the seasonal and interannual dynamics of organic matter stable carbon isotopes in mesotrophic Lake Holzmaar, Germany

et al. 2009

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We investigated the particulate organic matter (POM) flux and its stable carbon isotope composition in response to changes in phytoplankton primary production and abiotic environmental affects in mesotrophic Lake Holzmaar. POM fluxes were determined by sediment traps emptied biweekly from 1995 to 2004. Water chemical measurements and meteorological observations were done concurrently. POM fluxes within and directly below the lake's epilimnion were relatively low during winter (,0.5 g m 22 d 21 ) and increased to 1.0-1.5 g m 22 d 21 during summer months because of enlarged phytoplankton production. In contrast, in the lake's hypolimnion a much higher POM flux was observed during winter as result of resuspension of particulate material from the lake's bottom. C : N (weight, total organic carbon : total nitrogen) ratios of settling organic matter vary around 8 at all three depths, indicating a predominant phytoplankton origin of POM. The annual epilimnic POM flux correlates with the epilimnic phosphate concentration early in the seasonal cycle, indicating that the supply of phosphate is the major control on the amount of algal biomass. A recurrent annual oscillation of the stable carbon isotope composition of POM with low d 13 C values during winter and more positive values during summer is interpreted as the result of phytoplankton primary production. A close d 13 C POM -POM flux relationship was observed, testifying to the primary dependence of d 13 C POM on lacustrine primary production. Contrary to POM flux, the epilimnic d 13 C POM signal is transferred to the lakes bottom notwithstanding sediment resuspension and microbial alteration. Our results demonstrate that sedimentary stable carbon isotopes are a valuable proxy for lacustrine paleo-productivity in Lake Holzmaar.

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Isotope Fractionation during Primary Production

Cited by 324 publications

References 111 publications

The fate of nitrogen in the Orbulina universa foraminifera‐symbiont system determined by nitrogen isotope analyses of shell‐bound organic matter

The fate of nitrogen in the Orbulina universa foraminifera‐symbiont system determined by nitrogen isotope analyses of shell‐bound organic matter

Radiocarbon and stable carbon isotope compositions of organic compound classes in sediments from the NE Pacific and Southern Oceans

Controls on the seasonal and interannual dynamics of organic matter stable carbon isotopes in mesotrophic Lake Holzmaar, Germany

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