Resource utilization and trophic position of nematodes and harpacticoid copepods in and adjacent to &lt;i&gt;Zostera noltii&lt;/i&gt; beds

Abstract. This study examines the resource use and trophic position of nematodes and harpacticoid copepods at the genus/species level in an estuarine food web in Zostera noltii beds and in adjacent bare sediments, using the natural abundance of stable carbon and nitrogen isotopes. Microphytobenthos is among the main resources of most taxa, but seagrass-associated resources (i.e. seagrass detritus and epiphytes) also contribute to meiobenthos nutrition, with seagrass detritus being available also in deeper sediments and in unvegetated patches close to seagrass beds. A predominant dependence on chemoautotrophic bacteria was demonstrated for the nematode genus Terschellingia and the copepod family Cletodidae. A predatory feeding mode is illustrated for Paracomesoma and other Comesomatidae, which were previously considered first-level consumers (deposit feeders) according to their buccal morphology. The considerable variation found in both resource use and trophic level among nematode genera from the same feeding type, and even among congeneric nematode species, shows that interpretation of nematode feeding ecology based purely on mouth morphology should be avoided.

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Resource utilization and trophic position of nematodes and harpacticoid copepods in and adjacent to <i>Zostera noltii</i> beds

Biogeosciences ◽

10.5194/bg-11-4001-2014 ◽

2014 ◽

Vol 11 (14) ◽

pp. 4001-4014 ◽

Cited By ~ 30

Author(s):

A.-M. Vafeiadou ◽

P. Materatski ◽

H. Adão ◽

M. De Troch ◽

T. Moens

Keyword(s):

Resource Use ◽

Nitrogen Isotopes ◽

Trophic Position ◽

Nematode Species ◽

Zostera Noltii ◽

Feeding Mode ◽

Harpacticoid Copepods ◽

Feeding Type ◽

Chemoautotrophic Bacteria ◽

Sediment Layers

Abstract. This study examines the resource use and trophic position of nematodes and harpacticoid copepods at the genus/species level in an estuarine food web in Zostera noltii beds and in adjacent bare sediments using the natural abundance of stable carbon and nitrogen isotopes. Microphytobenthos and/or epiphytes are among the main resources of most taxa, but seagrass detritus and sediment particulate organic matter contribute as well to meiobenthos nutrition, which are also available in deeper sediment layers and in unvegetated patches close to seagrass beds. A predominant dependence on chemoautotrophic bacteria was demonstrated for the nematode genus Terschellingia and the copepod family Cletodidae. A predatory feeding mode is illustrated for Paracomesoma and other Comesomatidae, which were previously considered first-level consumers (deposit feeders) according to their buccal morphology. The considerable variation found in both resource use and trophic level among nematode genera from the same feeding type, and even among congeneric nematode species, shows that the interpretation of nematode feeding ecology based purely on mouth morphology should be avoided.

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Dual stable isotope abundances unravel trophic position of estuarine nematodes

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315405012580 ◽

2005 ◽

Vol 85 (6) ◽

pp. 1401-1407 ◽

Cited By ~ 73

Author(s):

Tom Moens ◽

Steven Bouillon ◽

Fabiane Gallucci

Keyword(s):

Empirical Evidence ◽

Trophic Level ◽

Trophic Position ◽

Feeding Habits ◽

Nematode Species ◽

Trophic Levels ◽

Food Sources ◽

Feeding Mode ◽

Nematode Communities ◽

Carbon And Nitrogen

The role and quantitative importance of free-living nematodes in marine and estuarine soft sediments remain enigmatic for lack of empirical evidence on the feeding habits and trophic position of most nematode species. Here we use natural abundances of carbon and nitrogen stable isotopes of some abundant nematode species/genera from estuarine intertidal sediments to assess their trophic level and major food sources. In all stations, δ15N of different dominant nematode species/genera spanned a range of 3.6 to 6.3 ppt, indicating that at least two trophic levels were represented. The large nematodes Enoplus brevis, Enoploides longispiculosus and Adoncholaimus fuscus consistently had high δ15N, in line with mouth-morphology based predictions and empirical evidence on their predacious feeding modes. Daptonema sp., Metachromadora remanei, Praeacanthonchus punctatus and ‘Chromadoridae’ (dominated by Ptycholaimellus ponticus) had comparatively lower δ15N, and δ13C suggesting that microphytobenthos (MPB) is their major carbon source, although freshly sedimented particulate organic matter may also contribute to their nutrition in silty sediments. The trophic position of Sphaerolaimus sp., a genus with documented predacious feeding mode, was ambiguous. Ascolaimus elongatus had δ15N signatures indicating a predacious ecology, which is at variance with expectations from existing feeding type classifications. Our study shows that—despite limitations imposed by the biomass requirements for EA-IRMS (elemental analyser—isotope ratio mass spectrometry)—natural isotope abundances of carbon and nitrogen are powerful tools to unravel trophic structure within nematode communities. At the same time, the prominence of different trophic levels results in a large span of δ15N, largely invalidating the use of nitrogen isotope abundances to assess food sources and trophic level of whole nematode communities.

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Stable carbon and nitrogen isotopic fractionation between diet and tissue of captive red fox: implications for dietary reconstruction

Canadian Journal of Zoology ◽

10.1139/z00-008 ◽

2000 ◽

Vol 78 (5) ◽

pp. 848-852 ◽

Cited By ~ 186

Author(s):

James D Roth ◽

Keith A Hobson

Keyword(s):

Marine Mammals ◽

Nitrogen Isotopes ◽

Red Fox ◽

Trophic Position ◽

Isotopic Fractionation ◽

Stable Carbon ◽

Red Foxes ◽

Carbon And Nitrogen ◽

Carbon Isotopic ◽

Carbon Isotopic Fractionation

The amount of isotopic fractionation (change in isotope ratios) between diet and animal tissues is generally poorly known and may be affected by trophic position. Diet-tissue fractionation of stable-carbon and -nitrogen isotopes was measured in several tissues of red foxes (Vulpes vulpes) raised on a commercial pellet feed. Stable carbon isotopic fractionation in red fox was positive for all tissues and was greatest in fur (2.6), intermediate in muscle (1.1), and least in liver and blood fractions (0.4-0.6). These carbon isotope fractionation values were greater than those previously measured for mammalian herbivores but were similar to values for marine mammals in most tissues. Little variation in stable nitrogen isotopic fractionation occurred among tissues, except in the blood fractions. Nitrogen isotopic fractionation was much higher in blood serum (4.2) than in liver, muscle, and fur (3.3-3.5). Cellular fractions of blood had the lowest fractionation values (2.6). There was a significant age effect in nitrogen- but not in carbon-isotopic fractionation. Subadult foxes (<1 year) were significantly enriched in 15N compared with adult foxes for fur, muscle, and liver (no blood was collected from adults). The cause of this enrichment is unclear, but it may be related to the higher rate of protein synthesis and catabolism in growing animals. This study is the first to report isotopic fractionation values for a terrestrial mammalian carnivore. Such estimates are necessary to interpret stable-isotope patterns in wild carnivores.

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STABLE CARBON AND NITROGEN ISOTOPES OF HARDWOOD FOREST AND THE PINE BARRENS IN NEW JERSEY

10.1130/abs/2020se-344267 ◽

2020 ◽

Author(s):

Antonio R. Justiniano ◽

◽

Ying Cui

Keyword(s):

New Jersey ◽

Nitrogen Isotopes ◽

Hardwood Forest ◽

Pine Barrens ◽

Stable Carbon ◽

Carbon And Nitrogen Isotopes ◽

Carbon And Nitrogen

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Assessing the utility of sulfur isotope values for understanding mercury concentrations in water and biota from high Arctic lakes

Arctic Science ◽

10.1139/as-2018-0022 ◽

2019 ◽

Vol 5 (2) ◽

pp. 90-106 ◽

Cited By ~ 1

Author(s):

Gretchen L. Lescord ◽

Meredith G. Clayden ◽

Karen A. Kidd ◽

Jane L. Kirk ◽

Xiaowa Wang ◽

...

Keyword(s):

Food Webs ◽

Total Mercury ◽

Nitrogen Isotopes ◽

Sulfur Isotopes ◽

High Arctic ◽

Arctic Lakes ◽

Carbon And Nitrogen ◽

Resolute Bay ◽

Aquatic Food ◽

Globally Stable

Methylmercury (MeHg) biomagnifies through aquatic food webs resulting in elevated concentrations in fish globally. Stable carbon and nitrogen isotopes are frequently used to determine dietary sources of MeHg and to model its biomagnification. However, given the strong links between MeHg and sulfur cycling, we investigated whether sulfur isotopes (δ34S) would improve our understanding of MeHg concentrations ([MeHg]) in Arctic lacustrine food webs. Delta34S values and total mercury (THg) or MeHg were measured in water, sediments, and biota from six lakes near Resolute Bay, NU, Canada. In two lakes impacted by historical eutrophication, aqueous sulfate δ34S was ∼8‰ more positive than sedimentary δ34S, suggestive of bacterial sulfate reduction in the sediment. In addition, aqueous δ34S showed a significant positive relationship with aqueous [MeHg] across lakes. Within taxa across lakes, [THg] in Arctic char muscle and [MeHg] in their main prey, chironomids, were positively related to their δ34S values across lakes, but inconsistent relationships were found across entire food webs among lakes. Across lakes, nitrogen isotopes were better predictors of biotic [THg] and [MeHg] than δ34S within this dataset. Our results suggest some linkages between Hg and S biogeochemistry in high Arctic lakes, which is an important consideration given anticipated climate-mediated changes in nutrient cycling.

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Fifty years of eutrophication and lake restoration reflected in sedimentary carbon and nitrogen isotopes of a small, hardwater lake (south Germany)

Journal of Limnology ◽

10.4081/jlimnol.2013.e21 ◽

2013 ◽

Vol 72 (2) ◽

pp. 21 ◽

Cited By ~ 4

Author(s):

Emanuel Braig ◽

Christoph Mayr ◽

Gerald Kirchner ◽

Andrea Hofmann ◽

Uta Raeder ◽

...

Keyword(s):

Lake Restoration ◽

Nitrogen Isotopes ◽

Carbon And Nitrogen Isotopes ◽

Carbon And Nitrogen ◽

Sedimentary Carbon

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A three year study of seasonal dynamics of a zoobenthos community in a eutrophic lake

Nematology ◽

10.1163/1568541042843568 ◽

2004 ◽

Vol 6 (5) ◽

pp. 655-669 ◽

Cited By ~ 37

Author(s):

Iris Michiels ◽

Walter Traunspurger

Keyword(s):

Seasonal Dynamics ◽

Reproductive Strategies ◽

Seasonal Pattern ◽

Nematode Species ◽

Eutrophic Lake ◽

Nematode Community ◽

Benthic Biomass ◽

The Family ◽

Feeding Type ◽

Meiofauna Community

AbstractThe meiofauna community in the eutrophic Lake Obersee was investigated, with special emphasis on nematodes, from March 2001 to December 2003. Meiobenthos showed a stable annual and seasonal pattern with oligochaetes contributing most to benthic biomass and nematodes to benthic abundance. With 152 nematode species, Lake Obersee is the most nematode species-rich lentic habitat described so far. The nematode community was dominated by the family Monhysteridae. Bacterial feeders were the most abundant feeding type; omnivorous nematodes contributed most to total nematode biomass. Reproduction occurred throughout the year, with most species reproducing parthenogenetically. No seasonal pattern in reproductive strategies was found.

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