Isotopic turnover in aquatic predators: quantifying the exploitation of migratory prey

2001 ◽  
Vol 58 (5) ◽  
pp. 923-932 ◽  
Author(s):  
Stephen E MacAvoy ◽  
Stephen A Macko ◽  
Greg C Garman
Keyword(s):  
Ictalurus Punctatus ◽  
Isotope Composition ◽  
Significant Proportion ◽  
Ictalurus Furcatus ◽  
Turnover Rates ◽  
Tissue Replacement ◽  
Spawning Run ◽  
Tidal Freshwaters ◽  
Slow Turnover ◽  
Isotopic Turnover

In the tidal freshwaters of Virginia, U.S.A., the blue catfish (Ictalurus furcatus), an introduced piscivore, derives a significant proportion of its nutrition from spawning anadromous fish (genus Alosa, including blueback herring (A. aestivalis), American shad (A. sapidissima), and alewife (A. pseudoharengus)). Because the Alosa are not continually available to I. furcatus, there is an isotopic turnover, defined as change in isotope composition due to growth and metabolic tissue replacement, in I. furcatus tissues associated with the diet switch from freshwater to anadromous fishes. However, isotopic turnover rates for ictalurid fish are unknown. This study determined the maximum isotopic turnover rate of channel catfish (Ictalurus punctatus) tissues and compared this maximum rate with that of I. furcatus captured in the field over the 3-month Alosa spawning run. Maximum turnover rates for δ13C were 0.014 and 0.017‰ per day in muscle and blood. For δ34S, rates were 0.017 and 0.020‰ per day in muscle and blood, respectively. Isotopic turnover of muscle carbon reflected growth rate, but sulfur did not match growth as well. Ictalurus furcatus captured in the field showed no enrichment during the Alosa spawning run owing to slow turnover and variable diet. In aquatic ecosystems that have migrating prey, exploitation by predators may be underestimated using isotopes because of slow tissue turnover.

scholarly journals Pond-raised Hybrid Catfish, ♀ Ictalurus punctatus × ♂ Ictalurus furcatus , Do Not Respond to Microbial Phytase Superdosing

2018 ◽  
Vol 50 (1) ◽  
pp. 78-86 ◽  
Author(s):  
Menghe H. Li ◽  
David J. Wise ◽  
Charles C. Mischke ◽  
Suja Aarattuthodiyil ◽  
Ambika Tiwari ◽  
...  
Keyword(s):  
Ictalurus Punctatus ◽  
Ictalurus Furcatus ◽  
Hybrid Catfish ◽  
Microbial Phytase

CO2 Output of Mice Measured by D2O18 Under Conditions of Isotope Re-entry Into the Body

1958 ◽  
Vol 195 (3) ◽  
pp. 721-725 ◽  
Author(s):  
Ruth McClintock ◽  
Nathan Lifson
Keyword(s):  
Material Balance ◽  
Body Water ◽  
The Body ◽  
Turnover Rates ◽  
Weight Changes ◽  
Body Weight Changes ◽  
Co2 Output ◽  
The Difference ◽  
Isotopic Turnover ◽  
Fractional Turnover

The fractional turnover rates of the hydrogen and oxygen of the body water of mice were measured in three ways: a) by material intake, b) by material output and c) isotopically. Discrepancies occurred between the intake and output turnover rates which could be explained at least in large part by body weight changes. The isotopic turnover rates were lower than those calculated from material output. This finding is discussed in relationship to the diarrhea which the animals developed on the milk diet employed and to the circumstance that opportunity was present for isotope re-entry from excreta. The difference between the turnover rates of the oxygen and hydrogen of the body water was practically the same whether obtained isotopically or calculated from the material balance data. This probably explains the observation that the D2O18 method for calculating the total CO2 output of the mice from the difference between the isotope turnover rates gave valid results in animals in which the absolute values for the isotopic turnover rates were presumably in error.

scholarly journals Technical note: Lithium isotopes in dolostone as a palaeo-environmental proxy – an experimental approach

2019 ◽  
Vol 15 (2) ◽  
pp. 635-646 ◽  
Author(s):  
Holly L. Taylor ◽  
Isaac J. Kell Duivestein ◽  
Juraj Farkas ◽  
Martin Dietzel ◽  
Anthony Dosseto
Keyword(s):  
Isotope Fractionation ◽  
Isotope Composition ◽  
Relative Proportion ◽  
Significant Proportion ◽  
Technical Note ◽  
Fractionation Factor ◽  
Calcium Carbonates ◽  
Marine Carbonates ◽  
Li Isotope ◽  
Environmental Proxy

Abstract. Lithium (Li) isotopes in marine carbonates have considerable potential as a proxy to constrain past changes in silicate weathering fluxes and improve our understanding of Earth's climate. To date the majority of Li isotope studies on marine carbonates have focussed on calcium carbonates. The determination of the Li isotope fractionation between dolomite and a dolomitizing fluid would allow us to extend investigations to deep times (i.e. Precambrian) when dolostones were the most abundant marine carbonate archives. Dolostones often contain a significant proportion of detrital silicate material, which dominates the Li budget; thus, pretreatment needs to be designed so that only the isotope composition of the carbonate-associated Li is measured. This study aims to serve two main goals: (1) to determine the Li isotope fractionation between Ca–Mg carbonates and solution, and (2) to develop a method for leaching the carbonate-associated Li out of dolostone while not affecting the Li contained within the detrital portion of the rock. We synthesized Ca–Mg carbonates at high temperatures (150 to 220 ∘C) and measured the Li isotope composition (δ7Li) of the precipitated solids and their respective reactive solutions. The relationship of the Li isotope fractionation factor with temperature was obtained: 103ln⁡αprec-sol=-(2.56±0.27)106(1)/T2+(5.8±1.3) Competitive nucleation and growth between dolomite and magnesite were observed during the experiments; however, there was no notable effect of their relative proportion on the apparent Li isotope fractionation. We found that Li isotope fractionation between the precipitated solid and solution is higher for Ca–Mg carbonates than for Ca carbonates. If the temperature of a precipitating solution is known or can be estimated independently, the above equation could be used in conjunction with the Li isotope composition of dolostones to derive the composition of the solution and hence make inferences about the past Li cycle. In addition, we also conducted leaching experiments on a Neoproterozoic dolostone and a Holocene coral. Results show that leaching with 0.05 M hydrochloric acid (HCl) or 0.5 % acetic acid (HAc) at room temperature for 60 min releases Li from the carbonate fraction without a significant contribution of Li from the siliciclastic detrital component. These experimental and analytical developments provide a basis for the use of Li isotopes in dolostones as a palaeo-environmental proxy, which will contribute to further advance our understanding of the evolution of Earth's surface environments.

Response of Pond-raised Fingerling Hybrid Catfish, ♀ Ictalurus punctatus × ♂ Ictalurus furcatus , to Dietary Protein Concentrations and Sources

2017 ◽  
Vol 49 (5) ◽  
pp. 912-918 ◽  
Author(s):  
Menghe H. Li ◽  
David J. Wise ◽  
Charles C. Mischke ◽  
Ganesh Kumar ◽  
Penelope M. Lucas
Keyword(s):  
Ictalurus Punctatus ◽  
Dietary Protein ◽  
Ictalurus Furcatus ◽  
Hybrid Catfish

scholarly journals Complete Genome Sequence of an Ictalurid Herpesvirus 1 Strain Isolated from Blue Catfish (Ictalurus furcatus)

2019 ◽  
Vol 8 (15) ◽  
Author(s):  
Kuttichantran Subramaniam ◽  
Arun Venugopalan ◽  
Andrew J. Davison ◽  
Matt J. Griffin ◽  
Lorelei Ford ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Ictalurus Punctatus ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Ictalurus Furcatus ◽  
Blue Catfish ◽  
Content Type ◽  
Genomic Analyses ◽  
Distinct Strain ◽  
Herpesvirus 1

The complete genome sequence of an alloherpesvirus isolated from blue catfish (Ictalurus furcatus) is reported. Genomic analyses revealed that this virus is a distinct strain of ictalurid herpesvirus 1, the first strain of which was isolated previously from a channel catfish (Ictalurus punctatus).

scholarly journals Methane mapping, emission quantification, and attribution in two European cities: Utrecht (NL) and Hamburg (DE)

2020 ◽  
Vol 20 (23) ◽  
pp. 14717-14740
Author(s):  
Hossein Maazallahi ◽  
Julianne M. Fernandez ◽  
Malika Menoud ◽  
Daniel Zavala-Araiza ◽  
Zachary D. Weller ◽  
...  
Keyword(s):  
Urban Areas ◽  
Fossil Fuel ◽  
Isotope Composition ◽  
Significant Proportion ◽  
Ambient Air ◽  
Mitigation Strategies ◽  
Emission Rates ◽  
Gas Distribution ◽  
Ch4 Emissions ◽  
Street Level

Abstract. Characterizing and attributing methane (CH4) emissions across varying scales are important from environmental, safety, and economic perspectives and are essential for designing and evaluating effective mitigation strategies. Mobile real-time measurements of CH4 in ambient air offer a fast and effective method to identify and quantify local CH4 emissions in urban areas. We carried out extensive campaigns to measure CH4 mole fractions at the street level in Utrecht, the Netherlands (2018 and 2019), and Hamburg, Germany (2018). We detected 145 leak indications (LIs; i.e., CH4 enhancements of more than 10 % above background levels) in Hamburg and 81 LIs in Utrecht. Measurements of the ethane-to-methane ratio (C2:C1), methane-to-carbon dioxide ratio (CH4:CO2), and CH4 isotope composition (δ13C and δD) show that in Hamburg about 1∕3 of the LIs, and in Utrecht 2∕3 of the LIs (based on a limited set of C2:C1 measurements), were of fossil fuel origin. We find that in both cities the largest emission rates in the identified LI distribution are from fossil fuel sources. In Hamburg, the lower emission rates in the identified LI distribution are often associated with biogenic characteristics or (partly) combustion. Extrapolation of detected LI rates along the roads driven to the gas distribution pipes in the entire road network yields total emissions from sources that can be quantified in the street-level surveys of 440±70 t yr−1 from all sources in Hamburg and 150±50 t yr−1 for Utrecht. In Hamburg, C2:C1, CH4:CO2, and isotope-based source attributions show that 50 %–80 % of all emissions originate from the natural gas distribution network; in Utrecht more limited attribution indicates that 70 %–90 % of the emissions are of fossil origin. Our results confirm previous observations that a few large LIs, creating a heavy tail, are responsible for a significant proportion of fossil CH4 emissions. In Utrecht, 1∕3 of total emissions originated from one LI and in Hamburg >1/4 from two LIs. The largest leaks were located and fixed quickly by GasNetz Hamburg once the LIs were shared, but 80 % of the (smaller) LIs attributed to the fossil category could not be detected and/or confirmed as pipeline leaks. This issue requires further investigation.

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