Hydrogen and oxygen in brine shrimp chitin reflect environmental water and dietary isotopic composition

Nielson, K. E.; Bowen, Gabriel J.

doi:10.1016/j.gca.2009.12.025

Cited by 47 publications

(62 citation statements)

References 38 publications

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“…30 km from sampling location) may be a more significant source given that lake water temperatures are warmer than those of the atmosphere throughout the winter, and this vapor is also expected to have a distinctive isotopic composition due to the high degree of evapoconcentration characterizing the lake water. We use observed GSL water isotope ratios (33) and a model for isotope fractionation during evaporation (32), modified to account for the high lake water salinity (24,34), to estimate the range of δ 2 H and δ 18 O values expected for lakederived vapor (see SI Materials and Methods). Although the estimates include d values < 10‰, the distribution of δ 2 H and δ 18 O values for this source cannot account for the observed boundary layer vapor values through mixing with background atmospheric vapor (Fig.…”

Section: Water Of Combustionmentioning

confidence: 99%

Vapor hydrogen and oxygen isotopes reflect water of combustion in the urban atmosphere

Gorski¹,

Strong²,

Good³

et al. 2015

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

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Anthropogenic modification of the water cycle involves a diversity of processes, many of which have been studied intensively using models and observations. Effective tools for measuring the contribution and fate of combustion-derived water vapor in the atmosphere are lacking, however, and this flux has received relatively little attention. We provide theoretical estimates and a first set of measurements demonstrating that water of combustion is characterized by a distinctive combination of H and O isotope ratios. We show that during periods of relatively low humidity and/or atmospheric stagnation, this isotopic signature can be used to quantify the concentration of water of combustion in the atmospheric boundary layer over Salt Lake City. Combustion-derived vapor concentrations vary between periods of atmospheric stratification and mixing, both on multiday and diurnal timescales, and respond over periods of hours to variations in surface emissions. Our estimates suggest that up to 13% of the boundary layer vapor during the period of study was derived from combustion sources, and both the temporal pattern and magnitude of this contribution were closely reproduced by an independent atmospheric model forced with a fossil fuel emissions data product. Our findings suggest potential for water vapor isotope ratio measurements to be used in conjunction with other tracers to refine the apportionment of urban emissions, and imply that water vapor emissions associated with combustion may be a significant component of the water budget of the urban boundary layer, with potential implications for urban climate, ecohydrology, and photochemistry. A nthropogenic perturbation of the atmospheric water cycle is expressed over a wide range of spatial and temporal scales. Recent global changes resulting from warming-associated increases in saturation vapor pressure have been observed in satellite and reanalysis data (1, 2). Regional impacts related to large-scale land use change are detectible in precipitation data and models (3-5). Humidity anomalies (both positive and negative) have been observed in many urban centers and associated with changes in land cover, direct anthropogenic sources, and interaction of evapotranspiration and condensation processes with the urban heat island effect (6-10).Fossil fuel combustion releases water vapor to the atmosphere. Assuming an average molar ratio of H 2 O to CO 2 emission of 1.5 (see Water of Combustion) and current anthropogenic carbon emission rates of 9.5 Pg C/y (11), global combustion vapor emissions total ∼21 Pg/y. At the global scale, these numbers are four orders of magnitude smaller than the gross global exchange of water vapor between the Earth surface and the atmosphere, which totals more than 480,000 Pg/y (12). However, anthropogenic emissions are highly concentrated in space and time and, locally, may be a significant source of vapor and impact atmospheric water cycling, ambient humidity, and photochemistry. Water of combustion has been hypothesized to be an important contributor...

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Section: Water Of Combustionmentioning

confidence: 99%

Vapor hydrogen and oxygen isotopes reflect water of combustion in the urban atmosphere

Gorski¹,

Strong²,

Good³

et al. 2015

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

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“…However, detailed studies dealing with strictly limnic invertebrate groups, and especially Chironomidae, are still relatively rare. Nielson and Bowen (2010) have shown that the δ 18 O of brine shrimp (Artemia franciscana) chitin is mainly influenced by the isotopic composition of the ambient water, whereas δ 18 O of the food ingested by these invertebrates played only a relatively minor role. In contrast, δD of brine shrimp chitin seemed strongly influenced by both food and water.…”

Section: The Challengementioning

confidence: 99%

Stable isotopic analysis of fossil chironomids as an approach to environmental reconstruction: state of development and future challenges

2012

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. 2012. Stable isotopic analysis of fossil chironomids as an approach to environmental reconstruction: state of development and future challenges. Fauna norvegica 31: 7-18.Remains of chironomid larvae, especially their strongly sclerotized head capsules, can be found abundantly and well preserved in most lake sediment records. These remains mainly consist of chitin and proteins and, since their chemical composition does not seem to be strongly affected by decompositional processes, they can be used to develop palaeoenvironmental reconstructions based on their stable isotopic composition. Here we review available stable isotope studies based on fossil chironomids and indicate future research necessary to further develop this still relatively new research approach. Efforts to produce stable isotope records based on fossil chironomids have mainly examined the elements H, N, C, and O. They have focussed on (1) developing the methodology for preparing samples for isotopic analysis, (2) laboratory studies cultivating chironomid larvae under controlled conditions to determine the factors affecting their stable isotopic composition, (3) ecosystem-scale studies relating stable isotopic measurements of fossil chironomid assemblages to environmental conditions, and (4) developing first down-core records describing past changes in the stable isotopic composition of chironomid assemblages. These studies have shown that chemical sample pretreatment may affect the isotopic composition for some elements. Laboratory runs suggest that the diet of the larvae influences their stable isotopic composition for H, N, C and O, whereas stable isotopes in the ambient water also strongly influence their oxygen and to a lesser extent hydrogen isotopic composition. These experiments also indicate only minor offsets between the nitrogen and carbon isotopic composition of chironomid soft tissue and the fossilizing head capsules, whereas for hydrogen and oxygen this offset remains to be explored. Though few datasets have been published, the available ecosystem studies and developed down-core sediment records indicate that stable isotopes in chironomid remains have the potential to provide reconstructions of past climatic change (H, O) and insights into past food web structure, methane production and pollution of lake ecosystems (N, C). Future efforts will be necessary to develop these approaches including more detailed analyses of the effects of sample pretreatment on stable isotope measurements on chitinous fossils, more extensive laboratory studies constraining the effects of external factors (e.g., isotopic composition of food and ambient water, temperature) on stable isotopes in chironomid larvae, and surveys exploring seasonal changes in the isotopic composition of chironomid larvae and assessing how this seasonality influences fossil assemblages. Finally, multi-site field studies relating chironomid δD, δ 15 N, δ 13 C and δ 18 O to parameters such as δ 18 O of precipitation, air and water temperatures, and nutrient and greenhouse gas conc...

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“…These were separated chromatographically in a helium carrier gas stream and introduced sequentially into the ion source of an isotope ratio mass spectrometer (IRMS, Thermo Fisher Scientific) (Delta V Plus, TheremoFinnigan) for isotope ratio determination (Gehre et al, 2004). Six sequential injections were made for each sample and the reported values represent the average of three final injections (Nielson and Bowen, 2010). All lake water stable isotope data were calibrated using repeated analysis of three internal standards (PT, UT and PZ) relative to Vienna-Standard Mean Ocean…”

Section: Stable Isotope Analysesmentioning

confidence: 99%

“…Three commercial keratin laboratory reference materials (powdered KHS, FH and UH) were used to normalize the results. Oxygen isotope δ 18 O data and δ 2 H values were calibrated against primary reference materials (Nielson and Bowen, 2010) and all data were reported as per mil (‰) relative to the VSMOW standard (Coplen, 1995). Average precisions of ± 0.8‰ and ± 4.0‰ for δ 18 O and δ 2 H of Chironomus spp.…”

Section: Stable Isotope Analysesmentioning

confidence: 99%

“…Here, hydrogen isotope ratios were not corrected for the contribution of exchangeable hydrogen. This was because at the time of analysis, a set of exchangecalibrated chitin standards was not yet established at PSI (Nielson and Bowen, 2010). The amount of exchangeable hydrogen is usually expressed as percentage of the total amount of hydrogen and is 15.3 ± 2.9% in chitin (Schimmelmann et al, 1993).…”

Section: Regression Analyses Of δ 2 H Of Chironomus Spp Values Againmentioning

confidence: 99%

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Development and application of subfossil chironomid-based methods for late Quaternary climate reconstructions in eastern Australia

Chang¹

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The lack of tools to quantify past climate has hindered the development of our knowledge of climate change in the late Quaternary in eastern Australia. This thesis developed two methods using subfossil remains of non-biting midge larvae (Chironomid, Diptera: Chironomidae) preserved in lake sediments to reconstruct past changes in the Australian climate system during and since the Last Glacial Maximum (LGM). Firstly a transfer function model for reconstructing past summer temperatures based on the temperature tolerance of modern Australian chironomid taxa was created. Secondly the stable oxygen and hydrogen isotope composition (δ 18 O, δ 2 H) of the chitinous head capsules was used to determine temperature changes from chironomids from the same lakes.Both techniques were tested and the complexities of applying these methods as independent temperature proxies in Australia were explored.In order to develop the transfer function, forty-five lakes were examined in eastern Australia for eighteen physical and chemical parameters. The physical and chemical analysis of the lakes suggests that sub-humid and semi-arid sites are naturally eutrophic, whereas high altitude and actively managed sites were mostly mesotrophic. Thirty-four lakes were subsequently used in the transfer function. The transfer function first axis was Mean February Temperature which explains 9.5% of the variance and the secondary axis is pH which also explains 9.5% of the variance. iii | P a g e

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Hydrogen and oxygen in brine shrimp chitin reflect environmental water and dietary isotopic composition

Cited by 47 publications

References 38 publications

Vapor hydrogen and oxygen isotopes reflect water of combustion in the urban atmosphere

Vapor hydrogen and oxygen isotopes reflect water of combustion in the urban atmosphere

Stable isotopic analysis of fossil chironomids as an approach to environmental reconstruction: state of development and future challenges

Development and application of subfossil chironomid-based methods for late Quaternary climate reconstructions in eastern Australia

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