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  • 1
    Keywords: Cytoplasm ; Biomembran ; Protoplasma ; Histologie ; Zoologie
    Type of Medium: Book
    Pages: gr. 8
    Language: German , English , French
    Note: Ab 1960 herausgegeben von M. Alfert, H. Bauer,
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  • 2
    Keywords: Asien ; Fische ; Wirbeltiere ; Zoologie
    Type of Medium: Book
    Language: English
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  • 3
  • 4
    Publication Date: 2022-04-01
    Description: The mean trophic position (TP) of mesozooplankton largely determines how much mass and energy is available for higher trophic levels like fish. Unfortunately, the ratio of herbivores to carnivores in mesozooplankton is difficult to identify in field samples. Here, we investigated changes in the mean TP of mesozooplankton in a highly dynamic environment encompassing four distinct habitats in the southern South China Sea: the Mekong River plume, coastal upwelling region, shelf waters, and offshore oceanic waters. We used a set of variables derived from bulk and amino acid nitrogen stable isotopes from particulate organic matter and four mesozooplankton size fractions to identify changes in the nitrogen source and TP of mesozooplankton across these habitats. We found clear indications of a shift in N sources for biological production from nitrate in near‐coastal waters with shallow mixed layer depths toward an increase in diazotroph‐N inputs in oceanic waters with deep mixed layer depths where diazotrophs shaped the phytoplankton community. The N source shift was accompanied by a lengthening of the food chain (increase in the TP). This may provide further support for the connection between diazotrophy and the indirect routing of N through the marine food web. Our combined bulk and amino acid δ15N approach also allowed us to estimate the trophic enrichment (TE) of mesozooplankton across the entire regional ecosystem. When put in the context of literature values, a high TE of 5.1‰ suggested a link between ecosystem heterogeneity and the less efficient transfer of mass and energy across trophic levels.
    Description: Plain Language Summary: Zooplankton are one of the central pillars of the marine food web and form an important link between the production of organic matter by phytoplankton and biomass at higher trophic levels (e.g., fish). Of particular interest are mesozooplankton (0.2–20 mm in size), which encompass a diverse assemblage of animals utilizing a range of feeding strategies, including herbivory, omnivory, and carnivory. Since mass and energy are lost with each trophic step, their prevailing feeding strategy determines the availability of mass and energy to the upper food web. The exact relationship between carnivores and herbivores in mesozooplankton has so far only been studied with complex experiments or in homogenous environments. We have now resolved zooplankton feeding relationships in a highly dynamic marine environment. Specifically, we used stable nitrogen isotopes in amino acids and bulk organic matter in combination with a habitat‐delineating method for phytoplankton to directly determine the ratio of carnivores to herbivores in zooplankton from dynamic habitats in the South China Sea. The mass and energy transfer across trophic levels is less efficient in such variable marine environments compared to stable open ocean systems. These findings represent a big step toward understanding the dynamics of planktonic food webs in general.
    Description: Key Points: Trophic structure of mesozooplankton is regulated by similar environmental factors such as phytoplankton assemblages. Diazotrophy and nutrient availability correlated with enhanced mesozooplankton carnivory in a complex tropical marine ecosystem. Mass and energy transfer across trophic levels of planktonic food webs are less efficient in spatially and temporally variable ecosystems.
    Description: Deutsche Forschungsgemeinschaft (DFG) http://dx.doi.org/10.13039/501100001659
    Description: National Foundation for Science and Technology Development (NAFOSTED) http://dx.doi.org/10.13039/100007224
    Description: National Aeronautics and Space Administration (NASA) http://dx.doi.org/10.13039/100000104
    Description: Schmidt Ocean Institute
    Description: National Science Foundation (NSF) http://dx.doi.org/10.13039/100000001
    Description: https://doi.org/10.5061/dryad.bk3j9kdbv
    Keywords: ddc:577.7
    Language: English
    Type: doc-type:article
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  • 5
    Publication Date: 2022-03-22
    Description: We investigated mid‐infrared reflectance spectra of anorthosite samples from Mt. Briand near the Manicouagan impact structure. Microprobe analyses of the plagioclase minerals reveal that they have a similar chemical composition (labradoritic), which is corroborated by the location of the Christiansen Feature at around 7.96 μm (1256 cm−1). However, their respective spectral shapes differ from each other in the region of the reststrahlen bands. This is linked to the degree of Al,Si order within the plagioclase minerals, which also correlates with the previously assumed distance of the sample site to the impact melt. Powdering and sieving led to remarkable changes in the spectra resulting from different mechanical stability of minerals contained in the sample. Our data show that even very weakly shocked (6–10 GPa, shockstage S2) anorthosites could show spectra of Al,Si disordered plagioclase which we attribute to post shock heating after the impact shock. Consequently, the degree of Al,Si order has to be taken into account in the interpretation of remote sensing data. A comparison of synthetic linear mixture with an average Mercury spectrum reveals the possible presence of more or less anorthositic material with reduced degree of Al,Si order of the plagioclase component on Mercury's surface. The results of our study are helpful for the interpretation of data returned by space missions, especially for MERTIS ‐ an infrared spectrometer on its way to Mercury.
    Description: Plain Language Summary: The studied rocks, which contain predominantly the feldspar mineral plagioclase, are very common in our Solar System, for example, on the Moon and probably also on Mercury. The surface of planets without atmosphere, like Moon and Mercury are constantly the target of asteroid impacts. These impacts cause changes in the constituents of the rocks. The studied samples are from the area near a meteorite crater and show weak effects of the former meteorite impact. The infrared spectra of the samples have different shapes. This shape does not correlate with the chemical composition, but with the distribution of aluminum and silicon ions in the plagioclase components of the investigated samples. This distribution is often underestimated in remote sensing. Our study shows that this distribution of these ions is related to a previously assumed distance of the sample location from the impact. The results are useful for interpreting remote sensing data coming back from space missions. In our case, in particular, from an infrared spectrometer on its way to the planet Mercury called MERTIS. The study also presents a spectrum calculated from various mineral spectra comparable to the samples analyzed. This spectrum shows similarities to an average Mercury surface spectrum and suggests that the feldspars on the Mercury surface have a very disordered ion distribution.
    Description: Key Points: Low impact shock with proposed impact melt influences Al,Si order of plagioclases. Grinding of rocks leads to modal changes of the minerals. Potential plagioclases with reduced degree of Al,Si order on the surface of Mercury.
    Description: Deutsches Zentrum für Luft‐ und Raumfahrt (DLR) http://dx.doi.org/10.13039/501100002946
    Language: English
    Type: doc-type:article
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  • 6
    Publication Date: 2022-05-26
    Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Babbin, A. R., Tamasi, T., Dumit, D., Weber, L., Rodríguez, M. V. I., Schwartz, S. L., Armenteros, M., Wankel, S. D., & Apprill, A. Discovery and quantification of anaerobic nitrogen metabolisms among oxygenated tropical Cuban stony corals. ISME Journal, (2020), doi:10.1038/s41396-020-00845-2.
    Description: Coral reef health depends on an intricate relationship among the coral animal, photosynthetic algae, and a complex microbial community. The holobiont can impact the nutrient balance of their hosts amid an otherwise oligotrophic environment, including by cycling physiologically important nitrogen compounds. Here we use 15N-tracer experiments to produce the first simultaneous measurements of ammonium oxidation, nitrate reduction, and nitrous oxide (N2O) production among five iconic species of reef-building corals (Acropora palmata, Diploria labyrinthiformis, Orbicella faveolata, Porites astreoides, and Porites porites) in the highly protected Jardines de la Reina reefs of Cuba. Nitrate reduction is present in most species, but ammonium oxidation is low potentially due to photoinhibition and assimilatory competition. Coral-associated rates of N2O production indicate a widespread potential for denitrification, especially among D. labyrinthiformis, at rates of ~1 nmol cm−2 d−1. In contrast, A. palmata displays minimal active nitrogen metabolism. Enhanced rates of nitrate reduction and N2O production are observed coincident with dark net respiration periods. Genomes of bacterial cultures isolated from multiple coral species confirm that microorganisms with the ability to respire nitrate anaerobically to either dinitrogen gas or ammonium exist within the holobiont. This confirmation of anaerobic nitrogen metabolisms by coral-associated microorganisms sheds new light on coral and reef productivity.
    Description: Research was conducted in the Gardens of the Queen, Cuba in accordance with the requirements of the Republic of Cuba, conducted under permit NV2370 and NV2568 issued by the Ministerio de Relaciones Exteriores. We gratefully acknowledge funding for this research by MIT Sea Grant award #2018-DOH-49-LEV, Simons Foundation award #622065, and MIT ESI seed funding to ARB, the MIT Montrym, Ferry, and mTerra Seed Grant Funds, and the generous contributions by Dr Bruce L. Heflinger.
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 7
    Publication Date: 2022-10-27
    Description: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Muenzer, P., Negro, R., Fukui, S., di Meglio, L., Aymonnier, K., Chu, L., Cherpokova, D., Gutch, S., Sorvillo, N., Shi, L., Magupalli, V. G., Weber, A. N. R., Scharf, R. E., Waterman, C. M., Wu, H., & Wagner, D. D. NLRP3 inflammasome assembly in neutrophils is supported by PAD4 and promotes NETosis under sterile conditions. Frontiers in Immunology, 12, (2021): 683803, https://doi.org/10.3389/fimmu.2021.683803.
    Description: Neutrophil extracellular trap formation (NETosis) and the NLR family pyrin domain containing 3 (NLRP3) inflammasome assembly are associated with a similar spectrum of human disorders. While NETosis is known to be regulated by peptidylarginine deiminase 4 (PAD4), the role of the NLRP3 inflammasome in NETosis was not addressed. Here, we establish that under sterile conditions the cannonical NLRP3 inflammasome participates in NETosis. We show apoptosis-associated speck-like protein containing a CARD (ASC) speck assembly and caspase-1 cleavage in stimulated mouse neutrophils without LPS priming. PAD4 was needed for optimal NLRP3 inflammasome assembly by regulating NLRP3 and ASC protein levels post-transcriptionally. Genetic ablation of NLRP3 signaling resulted in impaired NET formation, because NLRP3 supported both nuclear envelope and plasma membrane rupture. Pharmacological inhibition of NLRP3 in either mouse or human neutrophils also diminished NETosis. Finally, NLRP3 deficiency resulted in a lower density of NETs in thrombi produced by a stenosis-induced mouse model of deep vein thrombosis. Altogether, our results indicate a PAD4-dependent formation of the NLRP3 inflammasome in neutrophils and implicate NLRP3 in NETosis under noninfectious conditions in vitro and in vivo.
    Description: This work was supported by a grant from National Heart, Lung, and Blood Institute of the National Institutes of Health (grant R35 HL135765) and a Steven Berzin family support to DDW, an Individual Erwin Deutsch fellowship by the German, Austrian and Swiss Society of Thrombosis and Hemostasis Research to RES, a Whitman fellowship (MBL) to DDW, and an Individual Marie Skłodowska-Curie Actions fellowship by the European Commission (796365 - COAGULANT) to PM. ANRW was funded by the Deutsche Forschungsgemeinschaft (TRR156/2 –246807620) and a research grant (We-4195/15-19). CMW was supported by the Division of Intramural Research, NHLBI, NIH.
    Keywords: Neutrophils ; NETs ; NLRP3 inflammasome ; MCC950 ; Deep vein thrombosis ; PAD4
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 8
    Publication Date: 2022-10-20
    Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Loranger, S., & Weber, T. C. . Shipboard acoustic observations of flow rate from a seafloor-sourced oil spill. Journal of Geophysical Research: Oceans, 125(10), (2020): e2020JC016274, https://doi.org/10.1029/2020JC016274.
    Description: In 2004 a debris flow generated by Hurricane Ivan toppled an oil production platform in Mississippi Canyon lease block 20 (MC20). Between 2004 and the installation of a containment system in 2019 MC20 became an in situ laboratory for a wide range of hydrocarbon in the sea‐related research, including different methods of assessing the volumetric flow rate of hydrocarbons spanning different temporal scales. In 2017 a shipboard acoustic Doppler current profiler (ADCP) and high‐frequency (90 to 154 kHz) broadband echosounder were deployed to assess the flow rate of liquid and gas phase hydrocarbons. Measurements of horizontal currents were combined with acoustic mapping to determine the rise velocity of the seep as it moved downstream. Models of the rise velocity for fluid particles were used to predict the size of oil droplets and gas bubbles in the seep. The amplitude and shape of the broadband acoustic backscatter were then used to differentiate between, and determine the flow rate of, hydrocarbons. Oil flow rate in the seep was estimated to be 56 to 86 barrels/day (mean urn:x-wiley:jgrc:media:jgrc24228:jgrc24228-math-0001 barrels/day) while the flow rate of gaseous hydrocarbons was estimated to be 98 to 359 m3/day (mean urn:x-wiley:jgrc:media:jgrc24228:jgrc24228-math-0002 m3/day).
    Description: The work was supported by the National Oceanic and Atmospheric Administration (Grant NA15NOS4000200).
    Keywords: Oil spill ; Acoustics ; Flow rate ; MC20
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 9
    Publication Date: 2022-05-26
    Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Becker, C. C., Weber, L., Suca, J. J., Llopiz, J. K., Mooney, T. A., & Apprill, A. Microbial and nutrient dynamics in mangrove, reef, and seagrass waters over tidal and diurnal time scales. Aquatic Microbial Ecology, 85, (2020): 101-119, https://doi.org/10.3354/ame01944.
    Description: In coral reefs and adjacent seagrass meadow and mangrove environments, short temporal scales (i.e. tidal, diurnal) may have important influences on ecosystem processes and community structure, but these scales are rarely investigated. This study examines how tidal and diurnal forcings influence pelagic microorganisms and nutrient dynamics in 3 important and adjacent coastal biomes: mangroves, coral reefs, and seagrass meadows. We sampled for microbial (Bacteria and Archaea) community composition, cell abundances and environmental parameters at 9 coastal sites on St. John, US Virgin Islands that spanned 4 km in distance (4 coral reefs, 2 seagrass meadows and 3 mangrove locations within 2 larger bays). Eight samplings occurred over a 48 h period, capturing day and night microbial dynamics over 2 tidal cycles. The seagrass and reef biomes exhibited relatively consistent environmental conditions and microbial community structure but were dominated by shifts in picocyanobacterial abundances that were most likely attributed to diel dynamics. In contrast, mangrove ecosystems exhibited substantial daily shifts in environmental parameters, heterotrophic cell abundances and microbial community structure that were consistent with the tidal cycle. Differential abundance analysis of mangrove-associated microorganisms revealed enrichment of pelagic oligotrophic taxa during high tide and enrichment of putative sediment-associated microbes during low tide. Our study underpins the importance of tidal and diurnal time scales in structuring coastal microbial and nutrient dynamics, with diel and tidal cycles contributing to a highly dynamic microbial environment in mangroves, and time of day likely contributing to microbial dynamics in seagrass and reef biomes.
    Description: This research was supported by NSF awards OCE-1536782 to T.A.M., J.K.L., and A.A. and OCE-1736288 to A.A., NOAA Cooperative Institutes award NA19O AR 4320074 to A.A. and E. Kujawinski and the Andrew W. Mellon Foundation Endowed Fund for Innovative Research to A.A.
    Keywords: Tide ; Picoplankton ; Mangrove ; Coral reef ; Seagrass ; Time series ; 16S rRNA gene
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 10
    Publication Date: 2022-05-26
    Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Wilson, S. T., Al-Haj, A. N., Bourbonnais, A., Frey, C., Fulweiler, R. W., Kessler, J. D., Marchant, H. K., Milucka, J., Ray, N. E., Suntharalingam, P., Thornton, B. F., Upstill-Goddard, R. C., Weber, T. S., Arevalo-Martinez, D. L., Bange, H. W., Benway, H. M., Bianchi, D., Borges, A., V., Chang, B. X., Crill, P. M., del Valle, D. A., Farias, L., Joye, S. B., Kock, A., Labidi, J., Manning, C. C., Pohlman, J. W., Rehder, G., Sparrow, K. J., Tortell, P. D., Treude, T., Valentine, D. L., Ward, B. B., Yang, S., & Yurganov, L. N. Ideas and perspectives: a strategic assessment of methane and nitrous oxide measurements in the marine environment. Biogeosciences, 17(22), (2020): 5809-5828, https://doi.org/10.5194/bg-17-5809-2020.
    Description: In the current era of rapid climate change, accurate characterization of climate-relevant gas dynamics – namely production, consumption, and net emissions – is required for all biomes, especially those ecosystems most susceptible to the impact of change. Marine environments include regions that act as net sources or sinks for numerous climate-active trace gases including methane (CH4) and nitrous oxide (N2O). The temporal and spatial distributions of CH4 and N2O are controlled by the interaction of complex biogeochemical and physical processes. To evaluate and quantify how these mechanisms affect marine CH4 and N2O cycling requires a combination of traditional scientific disciplines including oceanography, microbiology, and numerical modeling. Fundamental to these efforts is ensuring that the datasets produced by independent scientists are comparable and interoperable. Equally critical is transparent communication within the research community about the technical improvements required to increase our collective understanding of marine CH4 and N2O. A workshop sponsored by Ocean Carbon and Biogeochemistry (OCB) was organized to enhance dialogue and collaborations pertaining to marine CH4 and N2O. Here, we summarize the outcomes from the workshop to describe the challenges and opportunities for near-future CH4 and N2O research in the marine environment.
    Description: This article was an outcome of a workshop organized by the Ocean Carbon and Biogeochemistry (OCB) project office, which is supported by the US National Science Foundation (grant no. 1558412) and the National Aeronautics and Space Administration (grant no. NNX17AB17G). The workshop received additional funding from the Scientific Committee on Ocean Research (SCOR) which receives funding from the US National Science Foundation (grant no. 1840868) and contributions by additional national SCOR committees. The Chilean COPAS N2O time-series measurements were supported by Agencia Nacional de Investigación y Desarrollo (grant no. 1200861).
    Repository Name: Woods Hole Open Access Server
    Type: Article
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