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  • Wiley  (7)
  • Hagen, Wilhelm  (7)
  • 1
    In: Global Ecology and Biogeography, Wiley, Vol. 29, No. 6 ( 2020-06), p. 1008-1019
    Kurzfassung: Biodiversity dynamics comprise evolutionary and ecological changes on multiple temporal scales from millions of years to decades, but they are often interpreted within a single time frame. Planktonic foraminifera communities offer a unique opportunity for analysing the dynamics of marine biodiversity over different temporal scales. Our study aims to provide a baseline for assessments of biodiversity patterns over multiple time‐scales, which is urgently needed to interpret biodiversity responses to increasing anthropogenic pressure. Location Global (26 sites). Time period Five time‐scales: multi‐million‐year (0–7 Myr), million‐year (0–0.5 Myr), multi‐millennial (0–15 thousand years), millennial (0–1,100 years) and decadal (0–32 years). Major taxa studied Planktonic foraminifera. Methods We analysed community composition of planktonic foraminifera at five time‐scales, combining measures of standing diversity (richness and effective number of species, ENS) with measures of temporal community turnover (presence–absence‐based, dominance‐based). Observed biodiversity patterns were compared with the outcome of a neutral model to separate the effects of sampling resolution (the highest in the shortest time series) from biological responses. Results Richness and ENS decreased from multi‐million‐year to millennial time‐scales, but higher standing diversity was observed on the decadal scale. As predicted by the neutral model, turnover in species identity and dominance was strongest at the multi‐million‐year time‐scale and decreased towards the millennial scale. However, contrary to the model predictions, modern time series show rapid decadal variation in the dominance structure of foraminifera communities, which is of comparable magnitude as over much longer time periods. Community turnover was significantly correlated with global temperature change, but not on the shortest time‐scale. Main conclusions Biodiversity patterns can be to some degree predicted from the scaling effects related to different durations of time series, but changes in the dominance structure observed over the last few decades reach higher magnitude, probably forced by anthropogenic effects, than those observed over much longer durations.
    Materialart: Online-Ressource
    ISSN: 1466-822X , 1466-8238
    URL: Issue
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2020
    ZDB Id: 1479787-2
    ZDB Id: 2021283-5
    SSG: 12
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 2
    Online-Ressource
    Online-Ressource
    Wiley ; 1998
    In:  Limnology and Oceanography Vol. 43, No. 8 ( 1998-12), p. 1894-1901
    In: Limnology and Oceanography, Wiley, Vol. 43, No. 8 ( 1998-12), p. 1894-1901
    Materialart: Online-Ressource
    ISSN: 0024-3590
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 1998
    ZDB Id: 2033191-5
    ZDB Id: 412737-7
    SSG: 12
    SSG: 14
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 3
    In: Molecular Ecology Resources, Wiley, Vol. 23, No. 2 ( 2023-02), p. 382-395
    Kurzfassung: Species identification is pivotal in biodiversity assessments and proteomic fingerprinting by MALDI‐TOF mass spectrometry has already been shown to reliably identify calanoid copepods to species level. However, MALDI‐TOF data may contain more information beyond mere species identification. In this study, we investigated different ontogenetic stages (copepodids C1–C6 females) of three co‐occurring Calanus species from the Arctic Fram Strait, which cannot be identified to species level based on morphological characters alone. Differentiation of the three species based on mass spectrometry data was without any error. In addition, a clear stage‐specific signal was detected in all species, supported by clustering approaches as well as machine learning using Random Forest. More complex mass spectra in later ontogenetic stages as well as relative intensities of certain mass peaks were found as the main drivers of stage distinction in these species. Through a dilution series, we were able to show that this did not result from the higher amount of biomass that was used in tissue processing of the larger stages. Finally, the data were tested in a simulation for application in a real biodiversity assessment by using Random Forest for stage classification of specimens absent from the training data. This resulted in a successful stage‐identification rate of almost 90%, making proteomic fingerprinting a promising tool to investigate polewards shifts of Atlantic Calanus species and, in general, to assess stage compositions in biodiversity assessments of Calanoida, which can be notoriously difficult using conventional identification methods.
    Materialart: Online-Ressource
    ISSN: 1755-098X , 1755-0998
    URL: Issue
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2023
    ZDB Id: 2406833-0
    SSG: 12
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 4
    In: Journal of Phycology, Wiley, Vol. 52, No. 2 ( 2016-04), p. 260-273
    Kurzfassung: The giant kelp, Macrocystis pyrifera , is exposed to highly variable irradiance and temperature regimes across its geographic and vertical depth gradients. The objective of this study was to extend our understanding of algal acclimation strategies on different temporal scales to those varying abiotic conditions at various water depths. Different acclimation strategies to various water depths (0.2 and 4 m) between different sampling times (Jan/Feb and Aug/Sept 2012; long‐term acclimation) and more rapid adjustments to different depths (0.2, 2 and 4 m; short‐term acclimation) during 14 d of transplantation were found. Adjustments of variable Chl a fluorescence, pigment composition (Chl c , fucoxanthin), and the de‐epoxidation state of the xanthophyll cycle pigments were responsible for the development of different physiological states with respect to various solar radiation and temperature climates. Interestingly, the results indicated that phlorotannins are important during long‐term acclimation while antioxidants have a crucial role during short‐term acclimation. Furthermore, the results suggested that modifications in total lipids and fatty acid compositions apparently also might play a role in depth acclimation. In Aug/Sept (austral winter), M. pyrifera responded to the transplantation from 4 m to 0.2 m depth with a rise in the degree of saturation and a switch from shorter‐ to longer‐chain fatty acids. These changes seem to be essential for the readjustment of thylakoid membranes and might, thus, facilitate efficient photosynthesis under changing irradiances and temperatures. Further experiments are needed to disentangle the relative contribution of solar radiation, temperature and also other abiotic parameters in the observed physiological changes.
    Materialart: Online-Ressource
    ISSN: 0022-3646 , 1529-8817
    URL: Issue
    RVK:
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2016
    ZDB Id: 281226-5
    ZDB Id: 1478748-9
    SSG: 12
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 5
    Online-Ressource
    Online-Ressource
    Wiley ; 2003
    In:  Limnology and Oceanography Vol. 48, No. 4 ( 2003-07), p. 1685-1700
    In: Limnology and Oceanography, Wiley, Vol. 48, No. 4 ( 2003-07), p. 1685-1700
    Kurzfassung: The application of marker fatty acids to trace the feeding habits of Euphausia superba (krill) has produced contradictory results. We examined the effects of various diets on the fatty acid composition of larval, juvenile, and adult E. superba collected in April 1999 in the southwest Lazarev Sea and in April 2001 in the Bellingshausen Sea. Specimens were fed four different diets (mixed phytoplankton, mixed ice algae, the ice diatom Fragilariopsis cylindrus , and mixed copepod assemblages) or starved for up to 44 d. Total lipid content, lipid classes, and fatty acid composition showed very little variation in juvenile and adult krill with the different feeding regimes. Furcilia lipids were much more strongly influenced by the fatty acid signatures of their food. No stage‐specific food preferences were detected in the larvae, and spatial patterns were mirrored by all furcilia stages. Comparison of the fatty acid profiles of the offered food with those of the subsequently excreted feces indicated preferential assimilation of polyunsaturated fatty acids by E. superba .
    Materialart: Online-Ressource
    ISSN: 0024-3590 , 1939-5590
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2003
    ZDB Id: 2033191-5
    ZDB Id: 412737-7
    SSG: 12
    SSG: 14
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 6
    Online-Ressource
    Online-Ressource
    Wiley ; 2022
    In:  Aquaculture, Fish and Fisheries Vol. 2, No. 5 ( 2022-10), p. 334-342
    In: Aquaculture, Fish and Fisheries, Wiley, Vol. 2, No. 5 ( 2022-10), p. 334-342
    Kurzfassung: Brown shrimp, Crangon crangon (L.), is the most valuable target of coastal fisheries in the southern North Sea. Annual landings exceeded 30,000 tons in the last decade, yielding up to 100 Mio Euro. The shrimp are boiled immediately after capture onboard the fishing vessel for preservation and easy peeling. After landing, the shrimp are collected by traders and exported for manual peeling. Only the muscle of the pleon is returned and sold as regional delicacy. The remains, comprising the cephalothorax, the shell of the pleon, and, in case, adhering eggs, account for up to 70% of the total body mass. This potential resource, for example as aquaculture feed, has not yet been considered for exploitation. In this respect, the fatty acid (FA) profile and the share of essential FAs are crucial quality factors. Since boiling alters the quality of shrimp, this study evaluates changes in the FA composition of shrimp muscle and remains by comparing frozen and boiled samples. Major FAs in C. crangon were the saturated palmitic acid (PA, 16:0), accounting for 16.6%–19.1% of total fatty acids (TFAs), and the long‐chain polyunsaturated FAs (LC‐PUFAs) eicosapentaenoic acid (EPA, 20:5(n‐3), 16.1–21.6% TFA ) and docosahexaenoic acid (DHA, 22:6(n‐3), 11.5–13.6% TFA ). Frozen muscle and frozen remains showed similar FA profiles. Boiling changed the FA profile. PA, EPA, and DHA decreased by up to 25%, whereas palmitoleic acid 16:1(n‐7) and oleic acid 18:1(n‐9) increased by 2% to 3% each. Boiled muscle and boiled remains showed similar FA profiles. Despite the loss of FAs, the boiled shrimp remains are suggested to be a suitable PUFA supplement for aquaculture feeds, deserving further investigation.
    Materialart: Online-Ressource
    ISSN: 2693-8847 , 2693-8847
    URL: Issue
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2022
    ZDB Id: 3119348-1
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 7
    Online-Ressource
    Online-Ressource
    Wiley ; 2020
    In:  Biologie in unserer Zeit Vol. 50, No. 1 ( 2020-02), p. 28-35
    In: Biologie in unserer Zeit, Wiley, Vol. 50, No. 1 ( 2020-02), p. 28-35
    Kurzfassung: Polar plankton Climatic changes such as the rise in temperature and ocean acidification have already severely impacted the planktonic life of the Southern Ocean. Our studies demonstrate that Antarctic plankton is changing. Large diatoms contribute most to primary production in the current Southern Ocean, whereas in the future small flagellates could become more abundant. Also zooplankton is impacted. Recent studies reveal a shift from a krill‐ to a salp‐dominated food web in the Southern Ocean and the replacement of polar cold‐water species by warm‐tolerant species of adjacent regions.
    Materialart: Online-Ressource
    ISSN: 0045-205X , 1521-415X
    URL: Issue
    RVK:
    Sprache: Deutsch
    Verlag: Wiley
    Publikationsdatum: 2020
    ZDB Id: 120079-3
    ZDB Id: 2006653-3
    SSG: 12
    Standort Signatur Einschränkungen Verfügbarkeit
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