Trophic interactions of the pelagic ecosystem over the Reykjanes Ridge as evaluated by fatty acid and stable isotope analyses

Pétursdóttir, Hildur; Gíslason, Ástþór; Falk‐Petersen, Stig; Hop, Haakon; Svavarsson, Jörundur

doi:10.1016/j.dsr2.2007.09.003

Cited by 80 publications

(65 citation statements)

References 46 publications

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“…In one, Calanus spp. are important in the diet of Maurolicus muelleri , B. glaciale , and Sergestes arcticus , whereas in the other pathway Meganyctiphanes norvegica is the dominant food for the redfi sh Sebastes mentella and Calanus are of less importance (Petursdottir et al 2008 ). For S. arcticus , Calanus hyperboreus is an important part of the food.…”

Section: Food Webs and C Arbon F Luxesmentioning

confidence: 99%

“…), but lacking for most other species. The general trophic positions of some common zooplankton species, primarily copepods, amphipods, and euphausiids, inhabiting the epi -and upper mesopelagic layers above the Reykjanes Ridge have been described (Magnusson & Magnusson 1995 ;Petursdottir et al 2008 ). Also, the spawning aggregations of redfish confined to the western slopes of the Reykjanes Ridge suggest that this is a productive area (Pedchenko & Dolgov 2005 ).…”

Section: Introductionmentioning

confidence: 99%

“…For S. arcticus , Calanus hyperboreus is an important part of the food. Additionally, S. arcticus probably has a benthic component in the diet (Petursdottir et al 2008 ).…”

Section: Food Webs and C Arbon F Luxesmentioning

confidence: 99%

See 2 more Smart Citations

Biodiversity Patterns and Processes on the Mid‐Atlantic Ridge

Vecchione

Bergstad

Byrkjedal

et al. 2010

Life in the World's Oceans

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Section: Food Webs and C Arbon F Luxesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Biodiversity Patterns and Processes on the Mid‐Atlantic Ridge

Vecchione

Bergstad

Byrkjedal

et al. 2010

Life in the World's Oceans

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“…This method gives a time-integrated average trophic position of a given species, since the heavier isotopes accumulate from prey to predator over time (Fry & Sherr 1984, Fry 1988 C) values can be used as a proxy for the source of primary production, and the inshore and benthic versus offshore and pela gic feeding preferences of a consumer (Hobson et al 1994, France 1995. Previous studies have investigated stable isotopes in krill around Svalbard (Søreide et al 2006, Søreide et al 2013, Iceland (Petursdottir et al 2008(Petursdottir et al , 2012 and Greenland (Holst Hansen et al 2012). However, these studies only investigate a specific area and do not look at spatial differences in stable isotopes among species present.…”

Section: Torkel Gissel Nielsenmentioning

confidence: 99%

“…and C. finmarchicus of 2, which is similar to the values we found in our study. Petursdottir et al (2008) also measured fatty acids in M. norvegica and found low levels of Calanus fatty acid trophic markers, but high amounts of 18:1(n-9) fatty acid, the latter indicating carnivorous feeding (Falk-Petersen et al 2000, Dalsgaard et al 2003. This suggests that C. finmarchicus is not the primary food item for M. norvegica, and other non-Calanus species might be a preferable prey item for M. norvegica in this area.…”

mentioning

confidence: 99%

Trophic position of coexisting krill species: a stable isotope approach

Agersted¹,

Bode

Nielsen³

2014

Mar. Ecol. Prog. Ser.

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Four krill species with overlapping functional biology coexist in Greenland waters. Here, we used stable isotopes to investigate and discuss their trophic role and mode of coexistence. Bulk carbon (δ Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 516: 139-151, 2014 140 Krill have a broader prey-size spectrum than copepods, and are capable of exploiting several trophic levels (Boyd et al. 1984, McClatchie 1985, Barange et al. 1991, Agersted et al. 2011. The fact that krill are generalists could be a key trait that resolves 'the paradox' for this group as this means that interspecific food competition is reduced. A prerequisite for interspecific competition to occur between sympatric congeners such as krill is food scarcity; therefore, if food is in excess, competition for resources will be irrelevant.A standard approach for investigating the preysize spectrum and trophic position of zooplankton is bottle grazing experiments, where the experimental results also can be extrapolated to grazing impacts in situ. However, the limitation of these experiments is that they only represent a snapshot in time: They do not reflect the in situ prey variability in time and space because the experimental animals are unable to display migratory behaviour within the confines of a bottle.Analysis of gut content or faecal pellet composition is another approach to investigate krill feeding (e.g. González 1992, Karlson & Båmstedt 1994, Schmidt et al. 2003. However, this method only provides snapshot information of recently ingested prey and is biased towards prey with an exoskeleton, such as larger zooplankton, and thus underestimates or ignores soft-bodied prey (Båmstedt et al. 2000).Stable isotope analysis provides an alternative and complimentary method for determining trophic position (Peterson & Fry 1987, Fry 1988, Hobson & Welch 1992. This method gives a time-integrated average trophic position of a given species, since the heavier isotopes accumulate from prey to predator over time (Fry & Sherr 1984, Fry 1988. Stable nitrogen isotope (δ 15 N) values provide an estimate of the trophic position of a consumer (Vander Zanden & Rasmussen 2001), whereas carbon isotope (δ 13 C) values can be used as a proxy for the source of primary production, and the inshore and benthic versus offshore and pela gic feeding preferences of a consumer (Hobson et al. 1994, France 1995. Previous studies have investigated stable isotopes in krill around Svalbard (Søreide et al. 2006, Søreide et al. 2013, Iceland (Petursdottir et al. 2008 and Greenland (Holst Hansen et al. 2012). However, these studies only investigate a specific area and do not look at spatial differences in stable isotopes among species present. Because isotope signals at the base of the food web vary at spatial scales (e.g. Holst Hansen et al. 2012), studies considering spatial differences in stable isotopes provide insights into the origin of nutrients as well as into the local variability of feeding preferences.Go...

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Contemporary ocean warming and freshwater conditions are related to later sea age at maturity in Atlantic salmon spawning in Norwegian rivers

Otero

Jensen

L’Abée-Lund

et al. 2012

Ecology and Evolution

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Atlantic salmon populations are reported to be declining throughout its range, raising major management concerns. Variation in adult fish abundance may be due to variation in survival, growth, and timing of life history decisions. Given the complex life history, utilizing highly divergent habitats, the reasons for declines may be multiple and difficult to disentangle. Using recreational angling data of two sea age groups, one-sea-winter (1SW) and two-sea-winter (2SW) fish originated from the same smolt year class, we show that sea age at maturity of the returns has increased in 59 Norwegian rivers over the cohorts 1991–2005. By means of linear mixed-effects models we found that the proportion of 1SW fish spawning in Norway has decreased concomitant with the increasing sea surface temperature experienced by the fish in autumn during their first year at sea. Furthermore, the decrease in the proportion of 1SW fish was influenced by freshwater conditions as measured by water discharge during summer months 1 year ahead of seaward migration. These results suggest that part of the variability in age at maturity can be explained by the large-scale changes occurring in the north-eastern Atlantic pelagic food web affecting postsmolt growth, and by differences in river conditions influencing presmolt growth rate and later upstream migration.

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Trophic interactions of the pelagic ecosystem over the Reykjanes Ridge as evaluated by fatty acid and stable isotope analyses

Cited by 80 publications

References 46 publications

Biodiversity Patterns and Processes on the Mid‐Atlantic Ridge

Biodiversity Patterns and Processes on the Mid‐Atlantic Ridge

Trophic position of coexisting krill species: a stable isotope approach

Contemporary ocean warming and freshwater conditions are related to later sea age at maturity in Atlantic salmon spawning in Norwegian rivers

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