2020
Ishikawa, Naoto F.; Finlay, Jacques C.; Uno, Hiromi; Ogawa, Nanako O.; Ohkouchi, Naohiko; Tayasu, Ichiro; Power, Mary E.
Combined use of radiocarbon and stable carbon isotopes for the source mixing model in a stream food web Journal Article
In: Limnology and Oceanography, vol. 65, no. 11, pp. 2688-2696, 2020.
Abstract | Links | BibTeX | Tags: ERCZO, food web, freshwater ecosystem, stable isotopes, stream invertebrates
@article{Ishikawa2020,
title = {Combined use of radiocarbon and stable carbon isotopes for the source mixing model in a stream food web},
author = {Naoto F. Ishikawa and Jacques C. Finlay and Hiromi Uno and Nanako O. Ogawa and Naohiko Ohkouchi and Ichiro Tayasu and Mary E. Power},
doi = {10.1002/lno.11541},
year = {2020},
date = {2020-07-06},
journal = {Limnology and Oceanography},
volume = {65},
number = {11},
pages = {2688-2696},
abstract = {Radiocarbon natural abundance (Δ14C) has emerged as a useful dietary tracer in freshwater ecology for the past decade, yet its applicability for separating aquatic and terrestrial resources has not been examined quantitatively. Here, we report Δ14C values of stream invertebrates in different functional feeding groups collected from the upper South Fork Eel River watershed, northern California. We found that algae‐grazing insect larvae show low Δ14C values (−43.1 ± 21.8‰, mean ± standard deviation},
keywords = {ERCZO, food web, freshwater ecosystem, stable isotopes, stream invertebrates},
pubstate = {published},
tppubtype = {article}
}
Radiocarbon natural abundance (Δ14C) has emerged as a useful dietary tracer in freshwater ecology for the past decade, yet its applicability for separating aquatic and terrestrial resources has not been examined quantitatively. Here, we report Δ14C values of stream invertebrates in different functional feeding groups collected from the upper South Fork Eel River watershed, northern California. We found that algae‐grazing insect larvae show low Δ14C values (−43.1 ± 21.8‰, mean ± standard deviation
2010
Finlay, Jacques C.; Doucett, Richard R.; McNeely, Camille
Tracing energy flow in stream food webs using stable isotopes of hydrogen Journal Article
In: Freshwater Biology, vol. 55, no. 5, pp. 941–951, 2010.
Abstract | Links | BibTeX | Tags: energy flow, food webs, stable isotopes, subsidies, trophic interactions
@article{Finlay2010,
title = {Tracing energy flow in stream food webs using stable isotopes of hydrogen},
author = {Jacques C. Finlay and Richard R. Doucett and Camille McNeely},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Finlay_2010_FreshBio.pdf},
doi = {10.1111/j.1365-2427.2009.02327.x},
year = {2010},
date = {2010-05-01},
journal = {Freshwater Biology},
volume = {55},
number = {5},
pages = {941–951},
abstract = {1. Use of the natural ratios of carbon and nitrogen stable isotopes as tracers of trophic interactions has some clear advantages over alternative methods for food web analyses, yet is limited to situations where organic materials of interest have adequate isotopic separation between potential sources. This constrains the use of natural abundance stable isotope approaches to a subset of ecosystems with biogeochemical conditions favourable to source separation.
2. Recent studies suggest that stable hydrogen isotopes (δD) could provide a robust tracer to distinguish contributions of aquatic and terrestrial production in food webs, but variation in δD of consumers and their organic food sources are poorly known. To explore the utility of the stable hydrogen isotope approach, we examined variation in δD in stream food webs in a forested catchment where variation in δ13C has been described previously.
3. Although algal δD varied by taxa and, to a small degree, between sites, we found consistent and clear separation (by an average of 67‰) from terrestrial carbon sources. Environmental conditions known to affect algal δ13C, such as water velocity and stream productivity did not greatly influence algal δD, and there was no evidence of seasonal variation. In contrast, algal δ13C was strongly affected by environmental factors both within and across sites, was seasonally variable at all sites, and partially overlapped with terrestrial δ13C in all streams with catchment areas larger than 10 km2.
4. While knowledge of isotopic exchange with water and trophic fractionation of δD for aquatic consumers is limited, consistent source separation in streams suggests that δD may provide a complementary food web tracer to δ13C in aquatic food webs. Lack of significant seasonal or spatial variation in δD is a distinct advantage over δ13C for applications in many aquatic ecosystems.},
keywords = {energy flow, food webs, stable isotopes, subsidies, trophic interactions},
pubstate = {published},
tppubtype = {article}
}
1. Use of the natural ratios of carbon and nitrogen stable isotopes as tracers of trophic interactions has some clear advantages over alternative methods for food web analyses, yet is limited to situations where organic materials of interest have adequate isotopic separation between potential sources. This constrains the use of natural abundance stable isotope approaches to a subset of ecosystems with biogeochemical conditions favourable to source separation.
2. Recent studies suggest that stable hydrogen isotopes (δD) could provide a robust tracer to distinguish contributions of aquatic and terrestrial production in food webs, but variation in δD of consumers and their organic food sources are poorly known. To explore the utility of the stable hydrogen isotope approach, we examined variation in δD in stream food webs in a forested catchment where variation in δ13C has been described previously.
3. Although algal δD varied by taxa and, to a small degree, between sites, we found consistent and clear separation (by an average of 67‰) from terrestrial carbon sources. Environmental conditions known to affect algal δ13C, such as water velocity and stream productivity did not greatly influence algal δD, and there was no evidence of seasonal variation. In contrast, algal δ13C was strongly affected by environmental factors both within and across sites, was seasonally variable at all sites, and partially overlapped with terrestrial δ13C in all streams with catchment areas larger than 10 km2.
4. While knowledge of isotopic exchange with water and trophic fractionation of δD for aquatic consumers is limited, consistent source separation in streams suggests that δD may provide a complementary food web tracer to δ13C in aquatic food webs. Lack of significant seasonal or spatial variation in δD is a distinct advantage over δ13C for applications in many aquatic ecosystems.
2. Recent studies suggest that stable hydrogen isotopes (δD) could provide a robust tracer to distinguish contributions of aquatic and terrestrial production in food webs, but variation in δD of consumers and their organic food sources are poorly known. To explore the utility of the stable hydrogen isotope approach, we examined variation in δD in stream food webs in a forested catchment where variation in δ13C has been described previously.
3. Although algal δD varied by taxa and, to a small degree, between sites, we found consistent and clear separation (by an average of 67‰) from terrestrial carbon sources. Environmental conditions known to affect algal δ13C, such as water velocity and stream productivity did not greatly influence algal δD, and there was no evidence of seasonal variation. In contrast, algal δ13C was strongly affected by environmental factors both within and across sites, was seasonally variable at all sites, and partially overlapped with terrestrial δ13C in all streams with catchment areas larger than 10 km2.
4. While knowledge of isotopic exchange with water and trophic fractionation of δD for aquatic consumers is limited, consistent source separation in streams suggests that δD may provide a complementary food web tracer to δ13C in aquatic food webs. Lack of significant seasonal or spatial variation in δD is a distinct advantage over δ13C for applications in many aquatic ecosystems.