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  • 1
    In: Global Ecology and Biogeography, Wiley, Vol. 29, No. 6 ( 2020-06), p. 1008-1019
    Abstract: 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.
    Type of Medium: Online Resource
    ISSN: 1466-822X , 1466-8238
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2020
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  • 2
    Online Resource
    Online Resource
    American Geophysical Union (AGU) ; 2022
    In:  Journal of Geophysical Research: Biogeosciences Vol. 127, No. 10 ( 2022-10)
    In: Journal of Geophysical Research: Biogeosciences, American Geophysical Union (AGU), Vol. 127, No. 10 ( 2022-10)
    Abstract: Nutrient recycling by zooplankton stimulates net primary production in the biogeochemical model REcoM‐2 Modeling zooplankton functional types (zPFTs) leads to a switch from a light‐controlled Sverdrup system to a dilution‐controlled Behrenfeld system Implementing multiple zPFTs improves the modeled zooplankton biomass and zooplankton‐mediated biogeochemical fluxes
    Type of Medium: Online Resource
    ISSN: 2169-8953 , 2169-8961
    Language: English
    Publisher: American Geophysical Union (AGU)
    Publication Date: 2022
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    SSG: 16,13
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  • 3
    In: Frontiers in Zoology, Springer Science and Business Media LLC, Vol. 18, No. 1 ( 2021-12)
    Abstract: Trophic interactions are key processes, which determine the ecological function and performance of organisms. Many decapod crustaceans feed on plant material as a source for essential nutrients, e.g. polyunsaturated fatty acids. Strictly herbivorous feeding appears only occasionally in marine decapods but is common in land crabs. To verify food preferences and to establish trophic markers, we studied the lipid and fatty acid composition of the midgut glands of two marine crab species ( Grapsus albolineatus and Percnon affine ), one semi-terrestrial species ( Orisarma intermedium , formerly Sesarmops intermedius ), and one terrestrial species ( Geothelphusa albogilva ) from Taiwan. Results All species showed a wide span of total lipid levels ranging from 4 to 42% of the dry mass (% DM ) in the marine P. affine and from 3 to 25% DM in the terrestrial G. albogilva . Triacylglycerols (TAG) were the major storage lipid compound. The fatty acids 16:0, 18:1(n-9), and 20:4(n-6) prevailed in all species. Essential fatty acids such as 20:4(n-6) originated from the diet. Terrestrial species also showed relatively high amounts of 18:2(n-6), which is a trophic marker for vascular plants. The fatty acid compositions of the four species allow to clearly distinguish between marine and terrestrial herbivorous feeding due to significantly different amounts of 16:0, 18:1(n-9), and 18:2(n-6). Conclusions Based on the fatty acid composition, marine/terrestrial herbivory indices were defined and compared with regard to their resolution and differentiating capacity. These indices can help to reveal trophic preferences of unexplored species, particularly in habitats of border regions like mangrove intertidal flats and estuaries.
    Type of Medium: Online Resource
    ISSN: 1742-9994
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2021
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    SSG: 12
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  • 4
    In: Nature Methods, Springer Science and Business Media LLC, Vol. 17, No. 3 ( 2020-03-02), p. 261-272
    Abstract: SciPy is an open-source scientific computing library for the Python programming language. Since its initial release in 2001, SciPy has become a de facto standard for leveraging scientific algorithms in Python, with over 600 unique code contributors, thousands of dependent packages, over 100,000 dependent repositories and millions of downloads per year. In this work, we provide an overview of the capabilities and development practices of SciPy 1.0 and highlight some recent technical developments.
    Type of Medium: Online Resource
    ISSN: 1548-7091 , 1548-7105
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2020
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    SSG: 12
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  • 5
    Online Resource
    Online Resource
    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
    Abstract: 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.
    Type of Medium: Online Resource
    ISSN: 0045-205X , 1521-415X
    URL: Issue
    RVK:
    Language: German
    Publisher: Wiley
    Publication Date: 2020
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  • 6
    Online Resource
    Online Resource
    Elsevier BV ; 2020
    In:  Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology Vol. 248-249 ( 2020-10), p. 110465-
    In: Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology, Elsevier BV, Vol. 248-249 ( 2020-10), p. 110465-
    Type of Medium: Online Resource
    ISSN: 1096-4959
    RVK:
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2020
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    SSG: 12
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  • 7
    In: Journal of Plankton Research, Oxford University Press (OUP), Vol. 45, No. 1 ( 2023-02-01), p. 110-128
    Abstract: Small copepod genera play an important role in marine food webs and biogeochemical fluxes but have been neglected in many studies. This is the first study determining biomass, carbon consumption and egestion rates of small- ( & lt;1 mm prosome length, PL), medium- (1–1.5 mm PL) and large-sized ( & gt;2 mm PL) copepods along a cross-shelf transect in the southern Benguela upwelling system. Calanoids contributed on average 55 ± 19% to total copepod abundance and 82 ± 13% to total copepod biomass. Small-sized Oithona spp. (114–119 mg C m−2 d−1) and Clausocalanidae/Paracalanidae (87–263 mg C m−2 d−1) as well as large-sized Calanoides natalis (47–193 mg C m−2 d−1) were the dominant consumers at the most inshore stations. Small- and medium-sized copepodite stages of Metridia lucens were also important, especially towards the continental slope. At offshore stations, Clausocalanidae/Paracalanidae, Oithona spp., Pleuromamma spp., Calanus agulhensis, Acartia spp., C. natalis and M. lucens were dominant consumers. Hence, usually small- and medium-sized copepods dominated total copepod ingestion and egestion, emphasizing that inadequate representation of small copepods will lead to significant underestimations and misinterpretations of the functioning of zooplankton communities and finally to inadequate biogeochemical models.
    Type of Medium: Online Resource
    ISSN: 0142-7873 , 1464-3774
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2023
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  • 8
    Online Resource
    Online Resource
    The Royal Society ; 2020
    In:  Philosophical Transactions of the Royal Society B: Biological Sciences Vol. 375, No. 1804 ( 2020-08-03), p. 20190647-
    In: Philosophical Transactions of the Royal Society B: Biological Sciences, The Royal Society, Vol. 375, No. 1804 ( 2020-08-03), p. 20190647-
    Abstract: The study revealed species- and stage-specific differences in lipid accumulation of the dominant Antarctic copepods, the primarily herbivorous Calanoides acutus (copepodite stage V (CV), females) and the more omnivorous Calanus propinquus (females) storing wax esters and triacylglycerols, respectively, which were collected in summer (end of December). Feeding carbon-labelled diatoms to these copepods, 13 C elucidated assimilation and turnover rates of copepod total lipids as well as specific fatty acids and alcohols. The 13 C incorporation was monitored by compound-specific stable isotope analysis (CSIA). CV stages of C. acutus exhibited an intense total lipid turnover and 55% of total lipids were labelled after 9 days of feeding. By contrast, total lipid assimilation of female C. acutus and C. propinquus was lower with 29% and 32%, respectively. The major dietary fatty acids 16:0, 16:1(n − 7) and 20:5(n − 3) had high turnover rates in all specimens. In C. acutus CV, the high rates of the de novo synthesized long-chain monounsaturated fatty acids and alcohols 20:1(n − 9) and 22:1(n − 11) indicate intense lipid deposition, whereas these rates were low in females. The differences in lipid assimilation and turnover clearly show that the copepod species exhibit a high variability and plasticity to adapt their lipid production to their various life phases. This article is part of the theme issue ‘The next horizons for lipids as ‘trophic biomarkers': evidence and significance of consumer modification of dietary fatty acids'.
    Type of Medium: Online Resource
    ISSN: 0962-8436 , 1471-2970
    RVK:
    Language: English
    Publisher: The Royal Society
    Publication Date: 2020
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  • 9
    In: Molecular Ecology Resources, Wiley, Vol. 23, No. 2 ( 2023-02), p. 382-395
    Abstract: 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.
    Type of Medium: Online Resource
    ISSN: 1755-098X , 1755-0998
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2023
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    SSG: 12
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  • 10
    In: Biogeosciences, Copernicus GmbH, Vol. 20, No. 5 ( 2023-03-09), p. 945-969
    Abstract: Abstract. The Humboldt Current Upwelling System (HCS) is the most productive eastern boundary upwelling system (EBUS) in terms of fishery yield on the planet. EBUSs are considered hotspots of climate change with predicted expansion of mesopelagic oxygen minimum zones (OMZs) and related changes in the frequency and intensity of upwelling of nutrient-rich, low-oxygen deep water. To increase our mechanistic understanding of how upwelling impacts plankton communities and trophic links, we investigated mesozooplankton community succession and gut fluorescence, fatty acid and elemental compositions (C, N, O, P), and stable isotope (δ13C, δ15N) ratios of dominant mesozooplankton and microzooplankton representatives in a mesocosm setup off Callao (Peru) after simulated upwelling with OMZ water from two different locations and different N:P signatures (moderate and extreme treatments). An oxycline between 5 and 15 m with hypoxic conditions (〈50 µmol L−1) below ∼10 m persisted in the mesocosms throughout the experiment. No treatment effects were determined for the measured parameters, but differences in nutrient concentrations established through OMZ water additions were only minor. Copepods and polychaete larvae dominated in terms of abundance and biomass. Development and reproduction of the dominant copepod genera Paracalanus sp., Hemicyclops sp., Acartia sp., and Oncaea sp. were hindered as evident from accumulation of adult copepodids but largely missing nauplii. Failed hatching of nauplii in the hypoxic bottom layer of the mesocosms and poor nutritional condition of copepods suggested from very low gut fluorescence and fatty acid compositions most likely explain the retarded copepod development. Correlation analysis revealed no particular trophic relations between dominant copepods and phytoplankton groups. Possibly, particulate organic matter with a relatively high C:N ratio was a major diet of copepods. C:N ratios of copepods and polychaetes ranged 4.8–5.8 and 4.2–4.3, respectively. δ15N was comparatively high (∼13 ‰–17 ‰), potentially because the injected OMZ source water was enriched in δ15N as a result of anoxic conditions. Elemental ratios of dinoflagellates deviated strongly from the Redfield ratio. We conclude that opportunistic feeding of copepods may have played an important role in the pelagic food web. Overall, projected changes in the frequency and intensity of upwelling hypoxic waters may make a huge difference for copepod reproduction and may be further enhanced by varying N:P ratios of upwelled OMZ water masses.
    Type of Medium: Online Resource
    ISSN: 1726-4189
    Language: English
    Publisher: Copernicus GmbH
    Publication Date: 2023
    detail.hit.zdb_id: 2158181-2
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