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Article
Nitrous Oxide and Methane Dynamics in a Coral Reef Lagoon Driven by Pore Water Exchange: Insights from Automated High‐Frequency Observations
Geophysical Research Letters
  • Chiara O'Reilly, Southern Cross University - Coffs Harbour, Australia
  • Isaac R. Santos, Southern Cross University - Coffs Harbour, Australia
  • Tyler Cyronak, Southern Cross University - Lismore, Australia
  • Ashly McMahon, Southern Cross University - Coffs Harbour, Australia
  • Damien T. Maher, Southern Cross University - Lismore, Australia
Document Type
Article
Publication Date
4-28-2015
Keywords
  • Methane,
  • Nitrous oxide,
  • Radon,
  • Submarine groundwater discharge,
  • Coral reef
Abstract

Automated cavity ring down spectroscopy was used to make continuous measurements of dissolved methane, nitrous oxide, and carbon dioxide in a coral reef lagoon for 2 weeks (Heron Island, Great Barrier Reef). Radon (222Rn) was used to trace the influence of tidally driven pore water exchange on greenhouse gas dynamics. Clear tidal variation was observed for CH4, which correlated to 222Rn in lagoon waters. N2O correlated to 222Rn during the day only, which appears to be a response to coupled nitrification‐denitrification in oxic sediments, fueled by nitrate derived from bird guano. The lagoon was a net source of CH4 and N2O to the atmosphere and a sink for atmospheric CO2. The estimated pore water‐derived CH4 and N2O fluxes were 3.2‐fold and 24.0‐fold greater than the fluxes to the atmosphere. Overall, pore water and/or groundwater exchange were the only important sources of CH4 and major controls of N2O in the coral reef lagoon.

Comments

©2015. American Geophysical Union. All Rights Reserved.

Additional Comments
ARC grant #s: LE120100156, DE140101733, DE150100581, DP120101645
ORCID ID
0000-0003-3556-7616
DOI
10.1002/2015GL063126
Citation Information
Chiara O'Reilly, Isaac R. Santos, Tyler Cyronak, Ashly McMahon, et al.. "Nitrous Oxide and Methane Dynamics in a Coral Reef Lagoon Driven by Pore Water Exchange: Insights from Automated High‐Frequency Observations" Geophysical Research Letters Vol. 42 Iss. 8 (2015) p. 2885 - 2892 ISSN: 0094-8276
Available at: http://works.bepress.com/tyler-cyronak/21/