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THE ROLE OF METAL OXIDE BIOGEOCHEMISTRY ON SEDIMENT NICKEL BIOAVAILABILITY TO BENTHIC BIOTA

Mendonca, Raissa Marques
http://orcid.org/0000-0002-6371-4380
http://rave.ohiolink.edu/etdc/view?acc_num=kent1669107717390113

Abstract Details

2022, PHD, Kent State University, College of Arts and Sciences / Department of Biological Sciences.
Nickel (Ni) is a widespread and persistent contaminant in riverine systems that can impair biological diversity and ecological function. The bioavailability and toxicity of Ni are strongly influenced by its complexation with solid-phase ligands in sediments. Riverine sediments are often vertically stratified with thin oxic layers overlying anoxic horizons, and the distinct physicochemical conditions in these sediment layers modify their Ni binding capacity. In anoxic sediment, reduced sulfur (AVS) is the primary metal ligand, whereas iron (Fe) and manganese (Mn) oxide minerals can be important binding fractions for Ni under oxic conditions. The mixture of competing oxidized and reduced ligands in natural sediments is largely driven by physical conditions and the redox metabolism of the sediment microbial community. However, microbes are concurrently susceptible to the toxic effects of nickel, which can ultimately modify the availability of solid-phase ligands. Current sediment quality criteria consider AVS as the major binding phase for Ni but have not yet incorporated ligands that are present in oxic sediments. The overall objective of this dissertation was to improve our understanding of the role that metal oxides play in regulating Ni bioavailability to benthic organisms in natural sediments. The first study used a field-based approach to evaluate the role of metal oxides on Ni bioavailability to the benthic invertebrate community in riverine sediments exposed to effluent from two mining operations in Thompson, Manitoba, Canada. We found that oxide minerals in natural oxic sediments bind a substantial amount of Ni. Oxic sediment chemistry more strongly represented conditions experienced by benthic invertebrates and the inclusion of oxic solid-phase ligands was critical to refine predictions of Ni bioavailability and its impact on benthic community structure. The second study further investigated the geochemical drivers of Ni sorption to natural sediments across a broader range of sediment types by using lab-based partitioning assays with five geochemically distinct natural sediments. We observed that Ni removal by oxic sediments was rapid and complete. The rate of removal was driven by the pH of the overlying water, while the total amount of Ni removed was related to the affinity of Fe oxides for Ni. The lack of relationship between Ni removal and bulk sediment properties was unexpected, but the relationship between Ni removal and metal oxide affinity (not concentration) provided further evidence that these oxic ligands play a substantial role in the removal of Ni from overlying water. Lastly, the third study evaluated whether sublethal Ni concentrations affect Mn oxidation in the model organism Pseudomonas putida GB-1. This study found that Mn oxidation and biofilm formation are disrupted at a lower Ni concentration than bacterial growth, and revealed a potentially broader indirect effect of Ni exposure to the microbial community. Collectively, this dissertation shows that metal oxides are unquestionably significant scavengers of dissolved Ni in both field and laboratory settings and influence its bioavailability to benthic macroinvertebrates. In addition to being directly toxic to benthic macro- and microbiota, Ni exposure can also affect the amount and distribution of metal oxides in surface sediment by hindering microbial redox processes. Therefore, the inclusion of oxide ligands in bioavailability models seems justified but further mechanistic understanding of Ni sorption to metal oxides is warranted to derive accurate and environmentally relevant binding coefficients. Overall, the systems and interactions studied herein reflect the importance of advancing our understanding of ligands in oxic sediments to improve estimates of metal toxicity in natural waters that inform management, remediation, and protective regulatory efforts.
David Costello (Advisor)
Mark Kershner (Committee Member)
Alison Smith (Committee Member)
Christopher Blackwood (Committee Member)
David Singer (Committee Member)
184 p.
Freshwater Ecology
metal oxides; nickel; biogeochemistry; ecotoxicology; Pseudomonas putida GB-1

Recommended Citations

Citations

  • Mendonca, R. M. (2022). THE ROLE OF METAL OXIDE BIOGEOCHEMISTRY ON SEDIMENT NICKEL BIOAVAILABILITY TO BENTHIC BIOTA [Doctoral dissertation, Kent State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=kent1669107717390113

    APA Style (7th edition)

  • Mendonca, Raissa. THE ROLE OF METAL OXIDE BIOGEOCHEMISTRY ON SEDIMENT NICKEL BIOAVAILABILITY TO BENTHIC BIOTA. 2022. Kent State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=kent1669107717390113.

    MLA Style (8th edition)

  • Mendonca, Raissa. "THE ROLE OF METAL OXIDE BIOGEOCHEMISTRY ON SEDIMENT NICKEL BIOAVAILABILITY TO BENTHIC BIOTA." Doctoral dissertation, Kent State University, 2022. http://rave.ohiolink.edu/etdc/view?acc_num=kent1669107717390113

    Chicago Manual of Style (17th edition)

kent1669107717390113
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This open access ETD is published by Kent State University and OhioLINK.