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  • 1
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    Using Lagrangian-based process studies to test satellite algorithms of vertical carbon flux in the eastern North Pacific Ocean (2015)
    Wiley
    Details
    Publication Date: 2015-10-20
    Description: The biological carbon pump is responsible for the transport of ∼5-20 Pg C yr −1 from the surface into the deep ocean but its variability is poorly understood due to an incomplete mechanistic understanding of the complex underlying planktonic processes. In fact, algorithms designed to estimate carbon export from satellite products incorporate fundamentally different assumptions about the relationships between plankton biomass, productivity, and export efficiency. To test the alternate formulations of export efficiency in remote-sensing algorithms formulated by Dunne et al . [2005], Laws et al . [2011], Henson et al . [2011], and Siegel et al . [2014], we have compiled in situ measurements (temperature, chlorophyll, primary production, phytoplankton biomass and size structure, grazing rates, net chlorophyll change, and carbon export) made during Lagrangian process studies on 7 cruises in the California Current Ecosystem and Costa Rica Dome. A food-web based approach formulated by Siegel et al . [2014] performs as well or better than other empirical formulations, while simultaneously providing reasonable estimates of protozoan and mesozooplankton grazing rates. By tuning the Siegel et al . [2014] algorithm to match in situ grazing rates more accurately, we also obtain better in situ carbon export measurements. Adequate representations of food-web relationships and grazing dynamics are therefore crucial to improving the accuracy of export predictions made from satellite–derived products. Nevertheless, considerable unexplained variance in export remains and must be explored before we can reliably use remote sensing products to assess the impact of climate change on biologically-mediated carbon sequestration. This article is protected by copyright. All rights reserved.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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  • 2
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    Southern Ocean iron enrichment experiment: carbon cycling in high- and low-Si waters (2004)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2004-04-17
    Description: The availability of iron is known to exert a controlling influence on biological productivity in surface waters over large areas of the ocean and may have been an important factor in the variation of the concentration of atmospheric carbon dioxide over glacial cycles. The effect of iron in the Southern Ocean is particularly important because of its large area and abundant nitrate, yet iron-enhanced growth of phytoplankton may be differentially expressed between waters with high silicic acid in the south and low silicic acid in the north, where diatom growth may be limited by both silicic acid and iron. Two mesoscale experiments, designed to investigate the effects of iron enrichment in regions with high and low concentrations of silicic acid, were performed in the Southern Ocean. These experiments demonstrate iron's pivotal role in controlling carbon uptake and regulating atmospheric partial pressure of carbon dioxide.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Coale, Kenneth H -- Johnson, Kenneth S -- Chavez, Francisco P -- Buesseler, Ken O -- Barber, Richard T -- Brzezinski, Mark A -- Cochlan, William P -- Millero, Frank J -- Falkowski, Paul G -- Bauer, James E -- Wanninkhof, Rik H -- Kudela, Raphael M -- Altabet, Mark A -- Hales, Burke E -- Takahashi, Taro -- Landry, Michael R -- Bidigare, Robert R -- Wang, Xiujun -- Chase, Zanna -- Strutton, Pete G -- Friederich, Gernot E -- Gorbunov, Maxim Y -- Lance, Veronica P -- Hilting, Anna K -- Hiscock, Michael R -- Demarest, Mark -- Hiscock, William T -- Sullivan, Kevin F -- Tanner, Sara J -- Gordon, R Mike -- Hunter, Craig N -- Elrod, Virginia A -- Fitzwater, Steve E -- Jones, Janice L -- Tozzi, Sasha -- Koblizek, Michal -- Roberts, Alice E -- Herndon, Julian -- Brewster, Jodi -- Ladizinsky, Nicolas -- Smith, Geoffrey -- Cooper, David -- Timothy, David -- Brown, Susan L -- Selph, Karen E -- Sheridan, Cecelia C -- Twining, Benjamin S -- Johnson, Zackary I -- New York, N.Y. -- Science. 2004 Apr 16;304(5669):408-14.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Moss Landing Marine Laboratories, 8272 Moss Landing Road, Moss Landing, CA 95039-9647, USA. coale@mlml.calstate.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15087542" target="_blank"〉PubMed〈/a〉
    Keywords: Atmosphere ; Biomass ; Carbon/analysis/*metabolism ; Carbon Dioxide/analysis/metabolism ; Chlorophyll/analysis ; Diatoms/growth & development/metabolism ; Ecosystem ; *Iron/analysis/metabolism ; Nitrates/analysis/metabolism ; Nitrogen/analysis/metabolism ; Oceans and Seas ; Photosynthesis ; Phytoplankton/*growth & development/metabolism ; Seawater/chemistry ; *Silicic Acid/analysis/metabolism
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 3
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    Mesoscale eddies drive increased silica export in the subtropical Pacific Ocean (2007)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2007-05-19
    Description: Mesoscale eddies may play a critical role in ocean biogeochemistry by increasing nutrient supply, primary production, and efficiency of the biological pump, that is, the ratio of carbon export to primary production in otherwise nutrient-deficient waters. We examined a diatom bloom within a cold-core cyclonic eddy off Hawaii. Eddy primary production, community biomass, and size composition were markedly enhanced but had little effect on the carbon export ratio. Instead, the system functioned as a selective silica pump. Strong trophic coupling and inefficient organic export may be general characteristics of community perturbation responses in the warm waters of the Pacific Ocean.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Benitez-Nelson, Claudia R -- Bidigare, Robert R -- Dickey, Tommy D -- Landry, Michael R -- Leonard, Carrie L -- Brown, Susan L -- Nencioli, Francesco -- Rii, Yoshimi M -- Maiti, Kanchan -- Becker, Jamie W -- Bibby, Thomas S -- Black, Wil -- Cai, Wei-Jun -- Carlson, Craig A -- Chen, Feizhou -- Kuwahara, Victor S -- Mahaffey, Claire -- McAndrew, Patricia M -- Quay, Paul D -- Rappe, Michael S -- Selph, Karen E -- Simmons, Melinda P -- Yang, Eun Jin -- New York, N.Y. -- Science. 2007 May 18;316(5827):1017-21.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Geological Sciences and Marine Science Program, University of South Carolina, Columbia, SC 29208, USA. cbnelson@geol.sc.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/17510362" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Bacteria/growth & development ; Biomass ; Carbon/analysis ; Chlorophyll/analysis ; Diatoms/*growth & development/physiology ; *Ecosystem ; Hawaii ; Nitrates ; Nitrites/analysis ; Pacific Ocean ; Photosynthesis ; Phytoplankton/growth & development/physiology ; *Seawater/chemistry ; Silicic Acid/analysis ; Silicon Dioxide/*analysis ; Temperature ; *Water Movements ; Zooplankton/growth & development/physiology
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 4
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    Microbial distribution and activity across a water mass frontal zone in the California Current Ecosystem (2012)
    Oxford University Press
    Details
    Publication Date: 2012-08-02
    Description: Ocean fronts with accumulated biomass and organic matter may be significant sites of enhanced microbial activity. We sampled a frontal region (the A-Front) separating oligotrophic and mesotrophic water masses within the California Current Ecosystem (CCE) to assess the influence of frontal hydrography on several microbial parameters. Samples for heterotrophic bacterial, viral and flagellate abundance, dissolved and particulate carbon and nitrogen, transparent particles and bacterial carbon production were collected at 6 depths from the surface to 100 m with 5–9 conductivity/temperature/depth casts along a 26-km northerly transect across the front. Relative to adjacent oligotrophic and mesotrophic waters, the frontal transition displayed peaks in the mean estimates of cell-specific bacterial carbon and bulk bacterial production, particulate organic carbon and particulate organic nitrogen concentrations, and the abundance and size of transparent particles. Bacterial carbon production increased ~5-fold northward from oligotrophic waters to the frontal zone, in agreement with an increase in the frequency of dividing cells, but bacterial abundance was lower than at adjacent stations. This may be partially explained by high chlorophyll, elevated virus:bacteria ratios and low nanoflagellate grazer abundance at the front. Our data suggest that CCE fronts can facilitate intense biological transformation and physical transport of organic matter, in sharp contrast to adjacent low productivity waters, and harbor dynamic microbial populations that influence nutrient cycling.
    Print ISSN: 0142-7873
    Electronic ISSN: 1464-3774
    Topics: Biology
    Published by Oxford University Press
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  • 5
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    Sharp gradients in phytoplankton community structure across a frontal zone in the California Current Ecosystem (2012)
    Oxford University Press
    Details
    Publication Date: 2012-08-02
    Description: Spatial variability of plankton biomass, community composition and size structure was investigated across a strong frontal transition (A-Front) in the southern California Current Ecosystem in October 2008. Depth profiles were taken across a 25-km transect of nine stations sampled semi-synoptically during one night and for 3 days following drifter arrays in the adjacent water masses. Community compositions are compared based on analyses by digital epifluorescence microscopy, flow cytometry and pigment composition by high-pressure liquid chromatography. Our results show three assemblages sharply delineated in space, with plankton at the front being compositionally distinct and biomass elevated relative to either of the adjacent water masses. Depth-averaged chlorophyll a (Chl a ) varied by a factor of 2.3 (0.35–0.81 µg Chl a L –1 ) and autotrophic carbon (AC) varied almost 3-fold (13.6–35.4 µg C L –1 ) across the front. One of the most striking features was a sharp gradient in the distribution of Prochlorococcus (PRO) and Synechococcus (SYN), with PRO located in the warmer oligotrophic waters on the south side of the front and SYN located in the cooler mesotrophic waters to the north. Both PRO and SYN had local biomass minima directly at the front. The peak in phytoplankton biomass at the front was dominated by large (〉20 µm) diatom cells, comprising 71% of the total community biomass. In contrast to previous studies of frontal features in the southern California Current, our study of the A-Front shows strong frontal enhancement of phytoplankton biomass and a shift of phytoplankton size structure towards larger cells.
    Print ISSN: 0142-7873
    Electronic ISSN: 1464-3774
    Topics: Biology
    Published by Oxford University Press
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  • 6
    Electronic Resource
    Electronic Resource
    Coil dimensions of polystyrenes in isorefractive viscous solvents by small-angle neutron scattering (1986)
    s.l. : American Chemical Society
    Macromolecules 19 (1986), S. 1996-2002 
    Details
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ma00161a036
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  • 7
    Electronic Resource
    Electronic Resource
    Egg production by the subtropical copepod Undinula vulgaris (1993)
    Springer
    Marine biology 117 (1993), S. 415-421 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Egg production by Undinula vulgaris, collected off Kaneohe Bay, Hawaii, was measured under field and laboratory conditions on 16 occasions from June to December 1991. In situ rates ranged from 0 to 15.7 eggs female-1 d-1, with a mean of 6.4 eggs female-1 d-1, 2.1% female body carbon d-1. Maximum in situ production was 53 eggs female-1 d-1, 17.2% C d-1. Average egg production (Y, eggs female-1 d-1) was related to the concentration of particulate carbon (X, μg C l-1) by the Ivlev function, Y=13.9[1-e-0.0097 (x-10)], with R 2=0.96. Individuals with the same feeding history produced more eggs at lower temperatures in the laboratory. Egg production was not significantly correlated with dry weight, and no noticeable temporal trend was found. Despite the elevated habitat temperatures (26 to 27°C) of this subtropical copepod, maximum fecundity of U. vulgaris was comparable to, but average rates were lower than, egg production rates of similarly-sized, temperate and borcal species of the genus Calanus. Our results caution against broad extrapolations of the temperature-growth relationship for temperate coastal copepods to species from poorly studied, oligotrophic regions of the oceans.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00349317
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  • 8
    Electronic Resource
    Electronic Resource
    Estimating the grazing impact of marine micro-zooplankton (1982)
    Springer
    Marine biology 67 (1982), S. 283-288 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This paper describes a dilution technique for estimating the micro-zooplankton grazing impact on natural communities of marine phytoplankton. Experiments performed in coastal waters off Washington, USA (October, 1980), yield estimates of micro-zooplankton impact equivalent to 6 to 24% of phytoplankton standing biomass and 17 to 52% of production per day. Indirect evidence suggests that most of this impact is due to the feeding of copepod nauplii and tintinnids; in contrast, non-loricate ciliates, comprising 80 to 90% of numerical abundance, appeared to contribute little to phytoplankton mortality.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00397668
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  • 9
    Electronic Resource
    Electronic Resource
    Ingestion-independent rates of ammonium excretion by the copepod Calanus pacificus (1984)
    Springer
    Marine biology 78 (1984), S. 265-270 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The relationship between food ingested and NH + 4 excretion rate was investigated for female Calanus pacificus collected in August, 1982, from the San Juan Archipelago, Washington State, USA. The copepods were preconditioned to 6 densities of the diatom Thalassiosira weissflogii (0 to 104 cells ml−1) for 30 h before the experiment. The experiment was conducted with nutrients added in excess to maintain equal rates of NH + 4 uptake by the diatoms at all densities. Although ingestion rates of C. pacificus varied from 0 to over 20% of body N d−1 at the different food levels, excretion was a constant 6.6 nM NH + 4 copepod−1 h−1 or about 10% of body N d−1. This ingestion-excretion relationship, which is consistent with previous respiration and fecundity studies, suggests that the ecological dominance of C. pacificus only under conditions of high food abundance may be due to a dramatic increase in its growth efficiency as ingestion increases above the level supporting a constant metabolic rate. The maintenance of a constant level of metabolism during relatively short periods of low food abundance may be advantageous if it allows the copepod to exploit more effectively short-term variability in its food resulting from environmental heterogeneity or vertical migration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00393012
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  • 10
    Electronic Resource
    Electronic Resource
    The structure of Marine Ecosystems: An alternative (1976)
    Springer
    Marine biology 35 (1976), S. 1-7 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In “The Structure of Marine Ecosystems” (1974), Steele developed a simulation model which suggested that the stability of planktonic communities was dependent on a threshold response allowing phytoplankton a refuge in concentration below which herbivorous zooplankton did not feed. Observations from the North Sea were presented to support this hypothesis. In order to more realistically represent the simulated herbivores, Calanus spp., several of Steele's assumptions have been modified. The results of the revised model indicate that feeding thresholds are not essential for the long-term realism and stability of the simulated system and suggest an alternative, ecosystem control through predation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00386669
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