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  • Fitzsimmons, Jessica N.  (3)
  • Biodiversity Research  (3)
  • 1
    Online Resource
    Online Resource
    The biogeochemical cycling of iron, copper, nickel, cadmium, manganese, cobalt, lead, and scandium in a California Current experimental study
    Wiley ; 2018
    In:  Limnology and Oceanography Vol. 63, No. S1 ( 2018-03)
    Details
    In: Limnology and Oceanography, Wiley, Vol. 63, No. S1 ( 2018-03)
    Abstract: A 3‐day shipboard incubation experiment was conducted in the California Current System in July 2014 to investigate the cycling of iron (Fe), copper (Cu), nickel (Ni), cadmium (Cd), manganese (Mn), cobalt (Co), lead (Pb), and scandium (Sc) under a range of light and particle conditions. Filtered ( 〈 0.2 μm) and unfiltered treatments were incubated under the following light conditions: Dark, light (“UV”), and light without the ultraviolet (UV) wavelengths (“noUV”). The experiment was sampled for carbon and Fe uptake rates, dissolved trace metal concentrations (Fe, Cu, Ni, Cd, Mn, Co, Pb, Sc), Fe and Cu speciation, size‐fractionated concentrations of Cd and Fe, and diatom community composition from DNA sequencing. Exposure to UV light increased phytoplankton Fe uptake in the first 24 h of the incubation relative to the noUV treatment, suggesting that a fraction of the ambient ligand‐bound Fe was photoreactive. Fe‐binding organic ligand production was observed in the unfiltered light treatments in association with increasing chlorophyll a , and evidence for Cu‐binding ligand production in these treatments was also observed. Biological uptake of Cd and Co was observed along with scavenging of dissolved Pb. Manganese appeared to be rapidly oxidized by Mn‐oxidizing bacteria with concomitant drawdown of dissolved Ni. Scandium displayed similar trends to Fe, reinforcing the limited observations of the physicochemical similarities between these two elements in seawater. Overall, this study highlights distinct impacts of photochemical processes, scavenging, and biological effects on marine trace metal cycling in an environment characterized by seasonal upwelling.
    Type of Medium: Online Resource
    ISSN: 0024-3590 , 1939-5590
    URL: Issue
    URL: Article
    DOI: 10.1002/lno.v63.S1
    DOI: 10.1002/lno.10751
    Language: English
    Publisher: Wiley
    Publication Date: 2018
    detail.hit.zdb_id: 2033191-5
    detail.hit.zdb_id: 412737-7
    SSG: 12
    SSG: 14
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    Online Resource
  • 2
    Online Resource
    Online Resource
    Testing the Canyon Hypothesis: Evaluating light and nutrient controls of phytoplankton growth in penguin foraging hotspots along the West Antarctic Peninsula
    Wiley ; 2020
    In:  Limnology and Oceanography Vol. 65, No. 3 ( 2020-03), p. 455-470
    Details
    In: Limnology and Oceanography, Wiley, Vol. 65, No. 3 ( 2020-03), p. 455-470
    Abstract: Biological hotspots along the West Antarctic Peninsula (WAP) are characterized by high phytoplankton productivity and biomass as well as spatially focused penguin foraging activity. While unique physical concentrating processes were identified in one of these hotspots, understanding the mechanisms driving the blooms at these locations is of high importance. Factors posited to explain the blooms include the upwelling of macronutrient‐ and micronutrient‐enriched modified Upper Circumpolar Deep Water (mUCDW) and the depth of the mixed layer influencing overall light availability for phytoplankton. Using shipboard trace‐metal clean incubation experiments in three different coastal biological hotspots spanning a north‐south gradient along the WAP, we tested the Canyon Hypothesis (upwelling) for enhanced phytoplankton growth. Diatoms dominated the Southern region, while the Northern region was characterized by a combination of diatoms and cryptophytes. There was ample concentration of macronutrients at the surface and no phytoplankton growth response was detected with the addition of nutrient‐enriched mUCDW water or iron solution to surface waters. For all treatments, addition of mUCDW showed no enhancement in phytoplankton growth, suggesting that local upwelling of nutrient‐enriched deep water in these hotspots was not the main driver of high phytoplankton biomass. Furthermore, the dynamics in the photoprotective pigments were consistent with the light levels used during these incubations showing that phytoplankton are able to photoacclimate rapidly to higher irradiances and that in situ cells are low light adapted. Light availability appears to be the critical variable for the development of hotspot phytoplankton blooms, which in turn supports the highly productive regional food web.
    Type of Medium: Online Resource
    ISSN: 0024-3590 , 1939-5590
    URL: Issue
    URL: Article
    DOI: 10.1002/lno.v65.3
    DOI: 10.1002/lno.11313
    Language: English
    Publisher: Wiley
    Publication Date: 2020
    detail.hit.zdb_id: 2033191-5
    detail.hit.zdb_id: 412737-7
    SSG: 12
    SSG: 14
    Location Call Number Limitation Availability
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    Online Resource
  • 3
    Online Resource
    Online Resource
    Elevated trace metal content of prokaryotic communities associated with marine oxygen deficient zones
    Wiley ; 2017
    In:  Limnology and Oceanography Vol. 62, No. 1 ( 2017-01), p. 3-25
    Details
    In: Limnology and Oceanography, Wiley, Vol. 62, No. 1 ( 2017-01), p. 3-25
    Abstract: Little is known about the trace metal content of marine prokaryotes, in part due to their co‐occurrence with more abundant particulate phases in the upper ocean, such as phytoplankton and biogenic detritus, lithogenic minerals, and authigenic Mn and Fe oxyhydroxides. We attempt to isolate these biomass signals in particulate data from the US GEOTRACES Eastern Pacific Zonal Transect (cruise GP16) in the Eastern Tropical South Pacific (ETSP), which exhibited consistent maxima in P and other bioactive trace metals, and minima in particulate Mn, in the oxygen deficient zones (ODZs) of 13 stations. Nitrite maxima and nitrate deficits indicated the presence of denitrifying prokaryotic biomass within ETSP ODZs, and deep secondary fluorescence maxima at the upper ODZ boundaries of 10 stations also suggested the presence of low‐light, autotrophic communities. ODZs were observed as far west as 99°W, more than 2300 km from the South American coast, where eolian lithogenic and lateral/resuspended sedimentary inputs were negligible, presenting a unique opportunity to examine prokaryotic metal stoichiometries. ODZ particulate P maxima can rival gyre mixed layer biomass concentrations, are highly sensitive to oxygen, and are in excess of amounts scavengable by local Fe oxyhydroxides and acid–volatile sulfides. Even after correction for lithogenic and ferruginous–scavenged metals, ODZ P‐maxima are often enriched in Cd, Co, Cu, Ni, V, and Zn, exhibiting particulate trace metal ratios to P that exceed mixed layer biomass ratios by factors of 2–9. ODZ prokaryotic communities may be largely hidden, TM–rich pools involved in the marine cycles of these bioactive trace metals.
    Type of Medium: Online Resource
    ISSN: 0024-3590 , 1939-5590
    URL: Issue
    URL: Article
    DOI: 10.1002/lno.v62.1
    DOI: 10.1002/lno.10363
    Language: English
    Publisher: Wiley
    Publication Date: 2017
    detail.hit.zdb_id: 2033191-5
    detail.hit.zdb_id: 412737-7
    SSG: 12
    SSG: 14
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
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