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  • 1
    Online Resource
    Online Resource
    Cambridge :Cambridge University Press,
    Keywords: Ultraviolet radiation--Environmental aspects. ; Electronic books.
    Description / Table of Contents: This book, first published in 2000, provides a comprehensive, multidisciplinary review of UV radiation effects in the marine environment. It is aimed at researchers and graduate students in photobiology, photochemistry and environmental science. It will also be useful as a supplementary text for courses in oceanography, climatology and ecology.
    Type of Medium: Online Resource
    Pages: 1 online resource (336 pages)
    Edition: 1st ed.
    ISBN: 9780511155109
    Series Statement: Cambridge Environmental Chemistry Series ; v.Series Number 10
    DDC: 577.7
    Language: English
    Note: Cover -- Half-title -- Series-title -- Title -- Copyright -- Contents -- Contributors -- Preface -- 1 Enhanced UV radiation - a new problem for the marine environment -- 1.1 Introduction -- 1.2 The solar spectrum and the nature of light -- 1.3 Attenuation of solar energy -- 1.3.1 Attenuation in the atmosphere -- 1.3.1.1 Absorbance of UV and the ozone cycle -- 1.3.1.2 Effects on UV intensity and UV/PAR ratios -- 1.3.1.3 Effects of clouds and particles -- 1.3.1.4 Season and latitude -- 1.3.2 Attenuation in the water column -- 1.3.2.1 Surface reflection -- 1.3.2.2 Scattering and absorption -- 1.4 Effect of light on biomolecules and processes -- 1.4.1 Bond energies -- 1.4.2 Production of radicals -- 1.4.3 UV in photosynthesis -- 1.4.4 UV in biogeochemical cycles -- 1.5 Summary -- References -- 2 UV physics and optics -- 2.1 Atmospheric UV radiation -- 2.1.1 Direct and diffuse UV radiation -- 2.1.2 Natural variability -- 2.1.3 Atmospheric UV instrumentation -- 2.1.4 Ozone -- 2.1.4.1 Natural variability -- 2.1.4.2 Ozone depletion -- 2.1.4.3 Impact of ozone depletion in surface irradiances -- 2.1.5 Artificial sources of UV -- 2.2 Hydrologic optics -- 2.2.1 Underwater light and UV penetration -- 2.2.2 Models -- 2.2.3 Underwater UV instrumentation -- 2.2.4 Measurements -- Acknowledgements -- References -- 3 Spectral weighting functions for quantifying effects of UV radiation in marine ecosystems -- 3.1 Introduction -- 3.2 Action spectra -- 3.3 Biological weighting functions -- 3.4 Relating response to exposure -- 3.4.1 Kinetics of UV damage -- 3.4.2 Kinetics of UV damage and recovery -- 3.5 Marine biological weighting functions -- 3.6 Biological weighting function methodology -- 3.6.1 Experimental considerations -- 3.6.2 Analytical considerations -- 3.7 Comprehensive models of UV effects -- 3.8 Predicting the effects of ozone depletion -- 3.9 Summary. , Acknowledgements -- References -- 4 Marine photochemistry and its impact on carbon cycling -- 4.1 Introduction -- 4.2 Photochemistry of dissolved organic matter -- 4.3 Impact of photochemical reactions on marine processes -- 4.4 Impact of photochemistry on oceanic carbon cycling -- 4.5 Summary -- Acknowledgements -- References -- 5 Photochemical production of biological substrates -- 5.1 Introduction -- 5.2 Photochemical sources of biological substrates -- 5.3 Summary -- Acknowledgements -- References -- 6 Mechanisms of UV damage to aquatic organisms -- 6.1 Introduction -- 6.2 Direct effects -- 6.2.1 Genetic damage -- 6.2.2 Protein damage -- 6.2.3 Photosynthesis -- 6.2.4 Carbon allocation -- 6.2.5 Pigment damage -- 6.2.6 Respiration -- 6.2.7 Nutrient uptake -- 6.2.8 Nitrogen fixation -- 6.2.9 Cell motility -- 6.2.10 Other effects -- 6.3 Indirect effects -- 6.3.1 Hydrogen peroxide and hydroxyl radicals -- 6.3.2 Superoxide radicals -- 6.3.3 Membrane lipid peroxidation -- 6.3.4 Singlet oxygen and other photochemical reactions -- 6.4 General issues -- 6.4.1 Variability in response -- 6.4.2 Evaluating the literature -- Acknowledgements -- References -- 7 Strategies for the minimisation of UV-induced damage -- 7.1 Introduction -- 7.2 UV avoidance mechanisms -- 7.3 Reduction of effective UV radiation -- 7.3.1 Extracellular screening agents -- 7.3.2 Intracellular screening agents -- 7.3.2.1 Mycosporine-like amino acids -- 7.3.2.2 Other intracellular screening agents -- 7.3.3 Behaviourally mediated UV screening -- 7.4 Repair of UV-induced damages -- 7.4.1 DNA repair -- 7.4.1.1 Photoreactivation -- 7.4.1.2 Nucleotide excision repair -- 7.4.1.3 Other mechanisms of DNA repair -- 7.4.2 Protein repair -- 7.4.3 Defences against forms of reactive oxygen -- 7.4.3.1 Antioxidant enzymes -- 7.4.3.2 Carotenoids -- 7.4.3.3 Other antioxidants. , 7.5 Acclimation to changes in the UV light field -- 7.5.1 Physiological acclimation -- 7.5.2 Community changes -- 7.6 Summary and perspectives -- Acknowledgements -- References -- 8 UV radiation effects on heterotrophic bacterioplankton and viruses in marine ecosystems -- 8.1 Introduction -- 8.2 Early studies -- 8.3 Solar UVR effects on bacterioplankton production -- 8.4 UVR effects on microbial biogeochemical cycles -- 8.5 Effects of UVR on nucleic acids -- 8.6 DNA damage repair -- 8.7 Influence of UV radiation on viruses - destruction rates of particles and infectivity -- 8.8 Virus repair processes -- 8.9 DNA damage in the natural viral community -- 8.10 Induction of lysogens by UV radiation in marine systems -- 8.11 Summary -- Acknowledgements -- References -- 9 Effects of UV radiation on the physiology and ecology of marine phytoplankton -- 9.1 Introduction -- 9.2 Effects of UV radiation on phytoplankton processes -- 9.2.1 Primary production -- 9.2.1.1 Carbon uptake -- 9.2.1.2 Pigmentation -- 9.2.1.3 Modelling -- 9.2.2 Nutrient metabolism -- 9.2.3 Respiration -- 9.2.4 Organic matter excretion -- 9.2.5 Swimming and vertical migration -- 9.2.6 Specific growth rate -- 9.2.7 Cell size -- 9.2.8 Community composition -- 9.3 Ecological considerations -- 9.3.1 Photosynthetically active and UV radiation -- 9.3.2 Mixing in the upper water column -- 9.3.3 Spatial and temporal scales -- 9.4 Summary -- Acknowledgements -- References -- Note added in proof -- 10 Impact of solar UV radiation on zooplankton and fish -- 10.1 Introduction -- 10.2 Effects and responses to UV radiation in zooplankton and fish -- 10.2.1 Damaging effects -- 10.2.2 Recovery from UV radiation damage -- 10.2.3 Wavelength dependence of damage and repair -- 10.2.4 Reciprocity with and without repair mechanisms -- 10.2.5 Indirect effects -- 10.2.6 Photoprotective compounds. , 10.2.7 UV radiation vulnerability in relation to habitat -- 10.2.8 UV detection -- 10.3 The pelagic environment -- 10.3.1 The structure of pelagic habitats -- 10.3.2 UV radiation attenuation and water mixing -- 10.4 Diel patterns of vertical distribution -- 10.5 Statistical issues -- 10.6 Concluding remarks -- Acknowledgements -- References -- 11 Implications of UV radiation for the food web structure and consequences on the carbon flow -- 11.1 Introduction -- 11.2 UV radiation and biological systems -- 11.3 Herbivorous versus microbial food web: implication of the UV-B radiation -- 11.4 UV-B and the carbon flux -- Acknowledgements -- References -- Index.
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  • 2
    Keywords: Ultraviolet radiation Environmental aspects ; Marine ecology ; Aufsatzsammlung ; Ultraviolett ; Meeresökosystem ; Meeresökologie
    Type of Medium: Book
    Pages: X, 324 S , Ill., graph.Darst , 26 cm
    ISBN: 9780521632188 , 0521632188
    Series Statement: Cambridge environmental chemistry series 10
    DDC: 577.7
    RVK:
    RVK:
    RVK:
    Language: English
    Note: Includes bibliographical references and index
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Polar research 10 (1991), S. 0 
    ISSN: 1751-8369
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geography , Geosciences
    Notes: Pigment budgets use chlorophyll a and phaeopigment standing stock in combination with their photo-oxidation and sedimentation rates in the euphotic zone to estimate phytoplankton growth and grazing by micro- and macrozooplankton. Using this approach, average phytoplankton growth in the euphotic zone of the Barents Sea was estimated at 0.17 and 0.14 d−1 during spring of 1987 and 0.018 and 0.036 d−1 during late- and postbloom conditions in summer of 1988. Spring growth was 65% lower than the estimates from radiocarbon incorporation, supporting a 33% pigment loss during grazing. Macrozooplankton grazing and cell sinking were the main loss terms for phytoplankton during spring while microzooplankton grazing was dominant in summer.In contrast to tropical and temperate waters, Arctic waters are characterized by a high phaeopigment: chlorophyll a ratio in the seston. Photooxidation rates of phaeopigments at in situ temperatures (0 ± 1°C) are lower than in temperate waters and vary by a factor of 2 for individual forms (0.009 to 0.018 m−2mol−1). The phaeopigment fraction in both the suspended and sedimenting material was composed of seven main compounds that were isolated using high-performance liquid chromatography and characterized by spectral analysis. The most abundant phaeopigment in the sediment traps, a phaeo-phorbide-like molecule of intermediate polarity (phaeophorbide a3), peaked in abundance in the water column below the 1% isolume for PAR (60-80 m) and showed the highest rate of photooxidation. This phaeopigment was least abundant in the seston when phytoplankton was dominated by prymnesiophytcs but increased its abundance in plankton dominated by diatoms. This distribution suggests that larger grazers feeding on diatoms are the main producers of this phaeopigment.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1365-2486
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Geography
    Notes: In the nearshore coastal waters along the Antarctic Peninsula, a recurrent shift in phytoplankton community structure, from diatoms to cryptophytes, has been documented. The shift was observed in consecutive years (1991–1996) during the austral summer and was correlated in time and space with glacial melt-water runoff and reduced surface water salinities. Elevated temperatures along the Peninsula will increase the extent of coastal melt-water zones and the seasonal prevalence of cryptophytes. This is significant because a change from diatoms to cryptophytes represents a marked shift in the size distribution of the phytoplankton community, which will, in turn, impact the zooplankton assemblage. Cryptophytes, because of their small size, are not grazed efficiently by Antarctic krill, a keystone species in the food web. An increase in the abundance and relative proportion of cryptophytes in coastal waters along the Peninsula will likely cause a shift in the spatial distribution of krill and may allow also for the rapid asexual proliferation of carbon poor gelatinous zooplankton, salps in particular. This scenario may account for the reported increase in the frequency of occurrence and abundance of large swarms of salps within the region. Salps are not a preferred food source for organisms that occupy higher trophic levels in the food web, specifically penguins and seals, and thus negative feedbacks to the ecology of these consumers can be anticipated as a consequence of shifts in phytoplankton community composition.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Polar biology 19 (1998), S. 286-288 
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The formation of resting spores in diatoms is a common phenomenon in neritic environments. Here we report on resting spores of the genus Chaetoceros associated with a layer of increased chlorophyll fluorescence, at a depth of more than 200 m, north of Brabant Island and in Wilhelmina Bay, southeast coast of the Gerlache Strait (64°41.0′S, 62°0.5′W). Six species of Chaetoceros were identified by the morphology and size of the resting spores. Given that Chaetoceros spp., both in vegetative cells and as resting spores, are commonly found in Antarctic coastal surface waters, their location at depth could represent the pelagic “waiting” or “seeding” populations mentioned for other environments.
    Type of Medium: Electronic Resource
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  • 6
  • 7
    Publication Date: 2024-02-07
    Description: The Andvord fjord in the West Antarctic Peninsula (WAP) is known for its productivity and abundant megafauna. Nevertheless, seasonal patterns of the molecular diversity and abundance of protistan community members underpinning WAP productivity remain poorly resolved. We performed spring and fall expeditions pursuing protistan diversity, abundance of photosynthetic taxa, and the connection to changing conditions. 18S rRNA amplicon sequence variant (ASV) profiles revealed diverse predatory protists spanning multiple eukaryotic supergroups, alongside enigmatic heterotrophs like the Picozoa. Among photosynthetic protists, cryptophyte contributions were notable. Analysis of plastid-derived 16S rRNA ASVs supported 18S ASV results, including a dichotomy between cryptophytes and diatom contributions previously reported in other Antarctic regions. We demonstrate that stramenopile and cryptophyte community structures have distinct attributes. Photosynthetic stramenopiles exhibit high diversity, with the polar diatom Fragilariopsis cylindrus, unidentified Chaetoceros species, and others being prominent. Conversely, ASV analyses followed by environmental full-length rRNA gene sequencing, electron microscopy, and flow cytometry revealed that a novel alga dominates the cryptophytes. Phylogenetic analyses established that TPG clade VII, as named here, is evolutionarily distinct from cultivated cryptophyte lineages. Additionally, cryptophyte cell abundance correlated with increased water temperature. Analyses of global data sets showed that clade VII dominates cryptophyte ASVs at Southern Ocean sites and appears to be endemic, whereas in the Arctic and elsewhere, Teleaulax amphioxeia and Plagioselmis prolonga dominate, although both were undetected in Antarctic waters. Collectively, our studies provide baseline data against which future change can be assessed, identify different diversification patterns between stramenopiles and cryptophytes, and highlight an evolutionarily distinct cryptophyte clade that thrives under conditions enhanced by warming. IMPORTANCE The climate-sensitive waters of the West Antarctic Peninsula (WAP), including its many fjords, are hot spots of productivity that support multiple marine mammal species. Here, we profiled protistan molecular diversity in a WAP fjord known for high productivity and found distinct spatiotemporal patterns across protistan groups. Alongside first insights to seasonal changes in community structure, we discovered a novel phytoplankton species with proliferation patterns linked to temperature shifts. We then examined evolutionary relationships between this novel lineage and other algae and their patterns in global ocean survey data. This established that Arctic and Antarctic cryptophyte communities have different species composition, with the newly identified lineage being endemic to Antarctic waters. Our research provides critical knowledge on how specific phytoplankton at the base of Antarctic food webs respond to warming, as well as information on overall diversity and community structure in this changing polar environment
    Type: Article , PeerReviewed
    Format: text
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  • 8
  • 9
    Publication Date: 2023-01-30
    Description: The Antarctic Circumpolar Current is the world's largest current system connecting all major ocean basins of the global ocean. Its flow, driven by strong westerly winds, is constricted to its narrowest extent in the Drake Passage, located between South America and the Antarctic Peninsula. Due to the remoteness of the area, harsh weather conditions and strong bottom currents, sediment recovery is difficult and data coverage is still inadequate. Here, we report on the composition of 51 surface sediments collected during the R/V Polarstern PS97 expedition (February-April 2016) across the western and central Drake Passage, from the Chilean/Argentinian continental margin to the South Shetland Islands and the Bransfield Strait (water depth: ∼100-4000 m). We studied microfossils (diatoms), bulk sediment composition and geochemical proxies (biogenic opal, organic carbon, calcium carbonate, carbon and nitrogen stable isotopes, sterols and photosynthetic pigments), and evaluated how they respond to, and reflect oceanic domains and polar to subpolar frontal systems in this region. Our multi-proxy approach shows a strong relationship between the composition of surface sediments and ocean productivity, terrigenous input, intensity of ocean currents, and ice proximity, clearly differentiating among 4 biogeographical zones. The Subantarctic Zone was characterized by warmer-water diatoms, high carbonate (〉45%) and low organic carbon contents (avg. 0.26%), as well as low concentrations of pigments (avg. 1.75 μg/g) and sterols (avg. 0.90 μg/g). A general N-S transition from carbonate-rich to opal-rich sediment was observed at Drake Passage sites of the Polar Front and Permanently Open Ocean Zone. These sites were characterized by low organic carbon content (0.22%), high relative abundances of heavily silicified diatoms (≥60% Fragilariopsis kerguelensis), and abundant foraminifera at shallower stations. Approaching the Antarctic Peninsula in the Transitional Zone, an increase in the concentrations of pigments and sterols (avg. 2.57 μg/g and 1.44 μg/g, respectively) and a strong decrease in carbonate content was observed. The seasonal Sea-Ice Zone in the southern section of the study area, had the highest contents of biogenic opal (avg. 14.6%) and organic carbon (avg. 0.7%), low carbonate contents (avg. 2.4%), with the occurrence of sea-ice-related diatoms and sterols. In all zones, terrigenous input was detected, although carbon/nitrogen ratios and δ13Corg suggest a predominance of marine-derived organic matter; lower values of δ13Corg occurred south of the Polar Front. The new results presented here constitute a highly valuable reference dataset for the calibration of microfossil and geochemical proxies against observational data and provide a useful regional baseline for future paleo-research.
    Keywords: diatoms; Drake Passage; organic carbon; Photosynthetic pigments; sterols; surface sediments
    Type: Dataset
    Format: application/zip, 3 datasets
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  • 10
    Publication Date: 2023-06-27
    Keywords: ANT-XXXI/3; Bransfield Strait; Calcium carbonate; Carbon, organic, total; Carbon/Nitrogen ratio; Chlorophyll a, per unit mass total organic carbon; Chlorophyll a/phaeopigments ratio; Chlorophyll a per unit sediment mass; DEPTH, sediment/rock; diatoms; Diatoms, total valves, per unit sediment dry mass; Drake Passage; Elevation of event; Event label; GBG; GC; Giant box corer; Giant box grab; GKG; Gravity corer; Latitude of event; Longitude of event; MUC; MultiCorer; Nitrogen, total; Opal, biogenic silica; organic carbon; Phaeopigments, per unit mass total organic carbon; Phaeopigments per unit sediment mass; Photosynthetic pigments; Pigments, per unit mass total organic carbon; Pigments per unit sediment mass; Polarstern; PS97; PS97/015-2; PS97/020-1; PS97/021-1; PS97/022-1; PS97/024-2; PS97/027-1; PS97/042-1; PS97/044-1; PS97/045-1; PS97/046-6; PS97/048-1; PS97/049-2; PS97/052-3; PS97/053-1; PS97/054-2; PS97/055-2; PS97/056-1; PS97/059-1; PS97/060-1; PS97/061-1; PS97/062-1; PS97/065-2; PS97/067-2; PS97/068-2; PS97/069-1; PS97/071-2; PS97/072-2; PS97/073-2; PS97/074-1; PS97/077-1; PS97/079-1; PS97/080-2; PS97/083-1; PS97/084-2; PS97/085-2; PS97/086-2; PS97/089-2; PS97/093-3; PS97/094-1; PS97/095-1; PS97/096-1; PS97/097-1; PS97/114-1; PS97/122-2; PS97/128-1; PS97/129-2; PS97/131-1; PS97/132-2; PS97/134-1; PS97/135-1; PS97/139-1; Scotia Sea; Siliciclastics; South Pacific Ocean; sterols; Sterols, per unit mass total organic carbon; Sterols per unit sediment mass; surface sediments; δ13C, organic carbon; δ15N
    Type: Dataset
    Format: text/tab-separated-values, 665 data points
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