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Jonathan Grey

Lancaster University, Lancaster Environment Centre, Faculty Member

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My research focuses primarily on using stable isotope analyses to answer questions in aquatic ecology. I am particularly interested in methane-derived carbon and its role in food webs and the impacts of invasive species, but I also work on ecosystem subsidies, dietary specialisation, and the role of parasites in ecology

My research is funded by the Natural Environment Research Council, the Environment Agency, and the British Ecological Society.

I am always keen to hear from highly motivated Post Docs and potential PhD students to discuss research and funding opportunities. Visit:

http://webspace.qmul.ac.uk/jgrey/index.html

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Papers by Jonathan Grey

Isotopic variation complicates analysis of trophic relations within the fish community of Plußsee: a small, deep, stratifying lake

Archiv für Hydrobiologie, 2006

Terrestrial support of lake food webs: Synthesis reveals controls over cross-ecosystem resource use

Science advances, 2017

Widespread evidence that organic matter exported from terrestrial into aquatic ecosystems support... more Widespread evidence that organic matter exported from terrestrial into aquatic ecosystems supports recipient food webs remains controversial. A pressing question is not only whether high terrestrial support is possible but also what the general conditions are under which it arises. We assemble the largest data set, to date, of the isotopic composition (δ(2)H, δ(13)C, and δ(15)N) of lake zooplankton and the resources at the base of their associated food webs. In total, our data set spans 559 observations across 147 lakes from the boreal to subtropics. By predicting terrestrial resource support from within-lake and catchment-level characteristics, we found that half of all consumer observations that is, the median were composed of at least 42% terrestrially derived material. In general, terrestrial support of zooplankton was greatest in lakes with large physical and hydrological connections to catchments that were rich in aboveground and belowground organic matter. However, some consu...

Fossil chironomid d 13 C as a proxy for past methanogenic contribution to benthic food webs in lakes?

J Paleolimnol, 2010

ABSTRACT

Selectivity and competition between two benthic invertebrate grazers (Asellus aquaticus and Potamopyrgus antipodarum): an experimental study using 13C- and 15N-labelled diatoms

Epic3freshwater Biology 50 Pp 369 379, 2005

Feeding selectivity in brown trout (Salmo trutta) in Loch Ness

Stable isotope analysis of the origins of zooplankton carbon in lakes of differing trophic state

Oecologia, Apr 30, 2000

Abstract Carbon stable isotope analysis was carried out on zooplankton from 24 United Kingdom lak... more Abstract Carbon stable isotope analysis was carried out on zooplankton from 24 United Kingdom lakes to examine the hypothesis that zooplankton dependence on allochthonous sources of organic carbon declines with increasing lake trophy. Stable isotope analysis was also carried out on particulate and dissolved organic matter (POM and DOM) and, in 11 of the lakes, of phytoplankton isolates. In 21 of the 24 lakes, the zooplankton were depleted in 13 C relative to bulk POM, consistent with previous reports. δ 13 C for POM showed ...

Experimental delta C-13 evidence for a contribution of methane to pelagic food webs in lakes

Methane cycling in lake sediments and its influence on chironomid larval d 13C

Fems Microbiol Ecol, 2005

Stable carbon isotope analysis of chironomid larvae gave rise to the hypothesis that methane-oxid... more Stable carbon isotope analysis of chironomid larvae gave rise to the hypothesis that methane-oxidizing bacteria can provide an important food source for higher trophic levels in lakes. To investigate the importance of the methane cycle for the larval stable carbon signatures, isotope analysis and microbiological and biogeochemical investigations were combined. The study was based on comparison of a dimictic lake (Holzsee) and a polymictic, shallow lake (Grosser Binnensee), both located in northern Germany. Both lakes are inhabited by Chironomus plumosus larvae, which exhibited a stronger (13)C-depletion in Holzsee than in Grosser Binnensee, indicating a greater contribution of methane-carbon in the former. Indeed, the processes involved in the microbial methane cycle were found to be more active in Holzsee, showing higher potential methane production and methane oxidation rates. Consistently, cell numbers of methane-oxidizing bacteria were with 0.5 - 1.7 x 10(6) cells g(dw)(-1) about one order of magnitude higher in Holzsee than in Grosser Binnensee. Molecular analysis of the microbial community structure revealed no differences in the methanotrophic community between the two lakes, with a clear dominance of type I methanotrophs. The methanogenic population seemed to be adapted to the prevailing substrate in the respective lake (H(2)/CO(2) in Holzsee and acetate in Grosser Binnensee), even though differences were minor. In conclusion, the stronger larval (13)C-depletion in Holzsee was not reflected in differences in the microbial community structure, but in the activity and size of the methanogenic and methanotrophic populations in the lake sediment.

The use of stable isotopes to trace small-scale movements by small fish species

Hydrobiologia, 2010

Abstract Valuable biological information can be obtained by monitoring the movement of organisms.... more Abstract Valuable biological information can be obtained by monitoring the movement of organisms. However, the choice of monitoring method becomes highly restricted when following small organisms (&amp;amp;lt; 100 mm), especially in aquatic ecosystems. Stable isotopes are being increasingly used in this respect but rarely at the local spatial scale, ie 10–1000 s of metres. We sought to identify movement of small fishes between a main river channel and its tributary. Little overlap in isotope baseline was detected between the two channels ...

Stable isotope analysis of chironomid larvae from some Finnish forest lakes indicates dietary contribution from biogenic methane

Boreal Environment Research, 2004

Feeding selectivity of brown trout (Salmo trutta) in Loch Ness, Scotland

Linking larval chironomids to methane: seasonal variation of the microbial methane cycle and chironomid delta C-13

Aquatic Microbial Ecology, 2007

Dietary niche constriction when invaders meet natives: evidence from freshwater decapods

Journal of Animal Ecology, 2016

Selectivity and competitive interactions between two benthic invertebrate grazers (Asellus aquaticus and Potamogpyrgus antipodarum): an experimental study using 13 C- and 15 N-labelled diatoms

Freshwater Biology Pp 369 379, 2005

$Research paper thumbnail of Trophic fractionation and the effects of diet switch on the carbon stable isotopic "signatures" of pelagic consumers$

Trophic fractionation and the effects of diet switch on the carbon stable isotopic "signatures" of pelagic consumers

Publikationsansicht. 20098686. Trophic fractionation and the effects of diet switch on the carbon... more

Site-specific methane production and subsequent midge mediation within Esthwaite Water, UK

Archiv Fur Hydrobiologie, Sep 1, 2006

Abstract: Previous analyses of larval chironomid δ 13 C have suggested that methanotrophic contri... more Abstract: Previous analyses of larval chironomid δ 13 C have suggested that methanotrophic contribution to biomass is site-specific within lakes. We determined larval biomass, larval and methane gas stable carbon isotopes, and potential methane production from the sediments underlying different water column depths in Esthwaite Water, UK. Methane production increased whereas larval δ 13 C values typically became lighter with increasing lake depth. Reduced methane production at 15 m depth and correspondingly less 13 C- ...

The Use of Stable Isotope Analyses in Freshwater Ecology: Current Awareness

Polish Journal of Ecology, 2006

Selective removal of 13C/15N-labelled algal cells by two benthic grazers (

Helgoland Marine Research

D 3.14. Review on processes and effects of nutrients and organic material in lakes and threats due to climate change on current adaptive management and restoration efforts

A revised model for lipid-normalising d13C values from aquatic organisms, with implications for isotope mixing models

Stable isotope analyses coupled with mixing models are being used increasingly to evaluate ecolog... more Stable isotope analyses coupled with mixing models are being used increasingly to evaluate ecological management issues and questions. Such applications of stable isotope analyses often require simultaneous carbon and nitrogen analyses from the same sample. Correction of the carbon isotope values to take account of the varying content of 13C-depleted lipids is then frequently achieved by a lipid-normalization procedure using

Isotopic variation complicates analysis of trophic relations within the fish community of Plußsee: a small, deep, stratifying lake

Archiv für Hydrobiologie, 2006

Terrestrial support of lake food webs: Synthesis reveals controls over cross-ecosystem resource use

Science advances, 2017

Widespread evidence that organic matter exported from terrestrial into aquatic ecosystems support... more Widespread evidence that organic matter exported from terrestrial into aquatic ecosystems supports recipient food webs remains controversial. A pressing question is not only whether high terrestrial support is possible but also what the general conditions are under which it arises. We assemble the largest data set, to date, of the isotopic composition (δ(2)H, δ(13)C, and δ(15)N) of lake zooplankton and the resources at the base of their associated food webs. In total, our data set spans 559 observations across 147 lakes from the boreal to subtropics. By predicting terrestrial resource support from within-lake and catchment-level characteristics, we found that half of all consumer observations that is, the median were composed of at least 42% terrestrially derived material. In general, terrestrial support of zooplankton was greatest in lakes with large physical and hydrological connections to catchments that were rich in aboveground and belowground organic matter. However, some consu...

Fossil chironomid d 13 C as a proxy for past methanogenic contribution to benthic food webs in lakes?

J Paleolimnol, 2010

ABSTRACT

Selectivity and competition between two benthic invertebrate grazers (Asellus aquaticus and Potamopyrgus antipodarum): an experimental study using 13C- and 15N-labelled diatoms

Epic3freshwater Biology 50 Pp 369 379, 2005

Feeding selectivity in brown trout (Salmo trutta) in Loch Ness

Stable isotope analysis of the origins of zooplankton carbon in lakes of differing trophic state

Oecologia, Apr 30, 2000

Abstract Carbon stable isotope analysis was carried out on zooplankton from 24 United Kingdom lak... more Abstract Carbon stable isotope analysis was carried out on zooplankton from 24 United Kingdom lakes to examine the hypothesis that zooplankton dependence on allochthonous sources of organic carbon declines with increasing lake trophy. Stable isotope analysis was also carried out on particulate and dissolved organic matter (POM and DOM) and, in 11 of the lakes, of phytoplankton isolates. In 21 of the 24 lakes, the zooplankton were depleted in 13 C relative to bulk POM, consistent with previous reports. δ 13 C for POM showed ...

Experimental delta C-13 evidence for a contribution of methane to pelagic food webs in lakes

Methane cycling in lake sediments and its influence on chironomid larval d 13C

Fems Microbiol Ecol, 2005

Stable carbon isotope analysis of chironomid larvae gave rise to the hypothesis that methane-oxid... more Stable carbon isotope analysis of chironomid larvae gave rise to the hypothesis that methane-oxidizing bacteria can provide an important food source for higher trophic levels in lakes. To investigate the importance of the methane cycle for the larval stable carbon signatures, isotope analysis and microbiological and biogeochemical investigations were combined. The study was based on comparison of a dimictic lake (Holzsee) and a polymictic, shallow lake (Grosser Binnensee), both located in northern Germany. Both lakes are inhabited by Chironomus plumosus larvae, which exhibited a stronger (13)C-depletion in Holzsee than in Grosser Binnensee, indicating a greater contribution of methane-carbon in the former. Indeed, the processes involved in the microbial methane cycle were found to be more active in Holzsee, showing higher potential methane production and methane oxidation rates. Consistently, cell numbers of methane-oxidizing bacteria were with 0.5 - 1.7 x 10(6) cells g(dw)(-1) about one order of magnitude higher in Holzsee than in Grosser Binnensee. Molecular analysis of the microbial community structure revealed no differences in the methanotrophic community between the two lakes, with a clear dominance of type I methanotrophs. The methanogenic population seemed to be adapted to the prevailing substrate in the respective lake (H(2)/CO(2) in Holzsee and acetate in Grosser Binnensee), even though differences were minor. In conclusion, the stronger larval (13)C-depletion in Holzsee was not reflected in differences in the microbial community structure, but in the activity and size of the methanogenic and methanotrophic populations in the lake sediment.

The use of stable isotopes to trace small-scale movements by small fish species

Hydrobiologia, 2010

Abstract Valuable biological information can be obtained by monitoring the movement of organisms.... more Abstract Valuable biological information can be obtained by monitoring the movement of organisms. However, the choice of monitoring method becomes highly restricted when following small organisms (&amp;amp;lt; 100 mm), especially in aquatic ecosystems. Stable isotopes are being increasingly used in this respect but rarely at the local spatial scale, ie 10–1000 s of metres. We sought to identify movement of small fishes between a main river channel and its tributary. Little overlap in isotope baseline was detected between the two channels ...

Stable isotope analysis of chironomid larvae from some Finnish forest lakes indicates dietary contribution from biogenic methane

Boreal Environment Research, 2004

Feeding selectivity of brown trout (Salmo trutta) in Loch Ness, Scotland

Linking larval chironomids to methane: seasonal variation of the microbial methane cycle and chironomid delta C-13

Aquatic Microbial Ecology, 2007

Dietary niche constriction when invaders meet natives: evidence from freshwater decapods

Journal of Animal Ecology, 2016

Selectivity and competitive interactions between two benthic invertebrate grazers (Asellus aquaticus and Potamogpyrgus antipodarum): an experimental study using 13 C- and 15 N-labelled diatoms

Freshwater Biology Pp 369 379, 2005

$Research paper thumbnail of Trophic fractionation and the effects of diet switch on the carbon stable isotopic "signatures" of pelagic consumers$

Trophic fractionation and the effects of diet switch on the carbon stable isotopic "signatures" of pelagic consumers

Publikationsansicht. 20098686. Trophic fractionation and the effects of diet switch on the carbon... more

Site-specific methane production and subsequent midge mediation within Esthwaite Water, UK

Archiv Fur Hydrobiologie, Sep 1, 2006

Abstract: Previous analyses of larval chironomid δ 13 C have suggested that methanotrophic contri... more Abstract: Previous analyses of larval chironomid δ 13 C have suggested that methanotrophic contribution to biomass is site-specific within lakes. We determined larval biomass, larval and methane gas stable carbon isotopes, and potential methane production from the sediments underlying different water column depths in Esthwaite Water, UK. Methane production increased whereas larval δ 13 C values typically became lighter with increasing lake depth. Reduced methane production at 15 m depth and correspondingly less 13 C- ...

The Use of Stable Isotope Analyses in Freshwater Ecology: Current Awareness

Polish Journal of Ecology, 2006

Selective removal of 13C/15N-labelled algal cells by two benthic grazers (

Helgoland Marine Research

D 3.14. Review on processes and effects of nutrients and organic material in lakes and threats due to climate change on current adaptive management and restoration efforts

A revised model for lipid-normalising d13C values from aquatic organisms, with implications for isotope mixing models

Stable isotope analyses coupled with mixing models are being used increasingly to evaluate ecolog... more Stable isotope analyses coupled with mixing models are being used increasingly to evaluate ecological management issues and questions. Such applications of stable isotope analyses often require simultaneous carbon and nitrogen analyses from the same sample. Correction of the carbon isotope values to take account of the varying content of 13C-depleted lipids is then frequently achieved by a lipid-normalization procedure using