Skip navigation
SuUB logo
DSpace logo

  • Home
  • Institutions
    • University of Bremen
    • City University of Applied Sciences
    • Bremerhaven University of Applied Sciences
  • Sign on to:
    • My Media
    • Receive email
      updates
    • Edit Account details

Citation link: https://doi.org/10.26092/elib/3250

Publisher DOI: https://doi.org/10.1016/j.chemgeo.2005.07.017
Price_Pichler_Distribution, speciation and bioavailability of arsenic in a shallow-water submarine hydrothermal system_2005_accepted-version.pdf
OpenAccess
 
by-nc-nd 4.0

Distribution, speciation and bioavailability of arsenic in a shallow-water submarine hydrothermal system, Tutum Bay, Ambitle Island, PNG


File Description SizeFormat
Price_Pichler_Distribution, speciation and bioavailability of arsenic in a shallow-water submarine hydrothermal system_2005_accepted-version.pdf2 MBAdobe PDFView/Open
Authors: Price, Roy 
Pichler, Thomas  
Abstract: 
Shallow-water hydrothermal vent systems can introduce large amounts of potentially toxic elements, such as arsenic (As), into coastal marine environments. The first step in understanding and describing the potential impact of these elements throughout hydrothermally influenced coastal ecosystems is to determine the element's distribution and speciation, which in turn influences the availability of the toxin for biological uptake. Shallow submarine hot springs near Ambitle Island, Papua New Guinea, are discharging as much as 1.5 kg per day of arsenic directly into a coral-reef ecosystem. We have investigated the bioavailability of the As throughout Tutum Bay by studying vent fluid, seawater, pore water, precipitates, and sediments. In addition to measuring As abundance, As speciation (As(III), As(V), and the methylated species DMA and MMA) was determined in various waters. The As concentration for discrete mineral phases in vent precipitates and sediments was determined by sequentially extracting arsenic from the easily extractable, carbonate, Fe-oxyhydroxide or hydrous ferric oxide (HFO), and residual fractions, each of which have a different bioavailability.

Diffuse venting seems to play a critical role on the distribution of As throughout Tutum Bay surface sediments, which have a mean As concentration of 527 ppm while excluding the vent precipitates (range = 1483 to 52 ppm). Up to 54 ppm As were extracted from the easily extractable fraction of surface sediments (mean = 19.7 ppm), using a K2HPO4/KH2PO4 buffer at pH = 7.2. Arsenic from this fraction is considered to be the most available for biological processes, and therefore the most dangerous for biota. However, sequential extraction shows that 98.6% of the As in vent precipitates, and a mean of 93.3% in surface sediments (range = 88.2% to 96.3%), is coprecipitated with the hydrous ferric oxide (HFO) fraction. Thus, the bulk of the As being discharged into Tutum Bay is scavenged by the HFO, and should remain stable unless the physicochemical conditions surrounding the oxides change. In surface seawaters of Tutum bay, we found as much as four times the average seawater concentration of As (8.4 μg/L compared to ∼2 μg/L). The abundance of As in seawater just above the sediment/water interface is near normal, although As(III) in both surface and bottom seawater throughout Tutum Bay is substantially enriched compared to average seawater.

Hydrothermal venting therefore provides bioavailable As by two major pathways throughout Tutum Bay: 1) easily-exchangeable As from hydrothermally influenced sediments to as far away as 200 m from focused venting, and 2) in surface seawaters, which may allow for biological uptake by phytoplankton and transfer up the food web.
Keywords: Arsenic speciation; Shallow-water hydrothermal venting; sequential extraction; Bioavailability
Issue Date: 15-Dec-2005
Publisher: Elsevier Science
Project: National Science Foundation grant 
Grant number: BE: CBC# 0221834
Journal/Edited collection: Chemical Geology 
Issue: 1-3
Start page: 122
End page: 135
Volume: 224
Type: Artikel/Aufsatz
ISSN: 1872-6836
Secondary publication: yes
Document version: Postprint
DOI: 10.26092/elib/3250
URN: urn:nbn:de:gbv:46-elib82165
Institution: andere Institution 
Appears in Collections:Forschungsdokumente

  

Page view(s)

405
checked on May 9, 2025

Download(s)

39
checked on May 9, 2025

Google ScholarTM

Check


This item is licensed under a Creative Commons License Creative Commons

Legal notice -Feedback -Data privacy
Media - Extension maintained and optimized by Logo 4SCIENCE