Nitrous Oxide and Methane Dynamics in a Coral Reef Lagoon Driven by Pore Water Exchange: Insights from Automated High‐Frequency Observations

Authors

Chiara O'Reilly, Southern Cross University - Coffs Harbour, Australia
Isaac R. Santos, Southern Cross University - Coffs Harbour, Australia
Tyler Cyronak, Southern Cross University - Lismore, AustraliaFollow
Ashly McMahon, Southern Cross University - Coffs Harbour, Australia
Damien T. Maher, Southern Cross University - Lismore, Australia

ORCID

0000-0003-3556-7616

Document Type

Article

Publication Title

Geophysical Research Letters

ISSN

0094-8276

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.

DOI

10.1002/2015GL063126

Volume

42

Issue

8

First Page

2885

Last Page

2892

Comments

©2015. American Geophysical Union. All Rights Reserved.

Additional Comments

ARC grant #s: LE120100156, DE140101733, DE150100581, DP120101645

NSUWorks Citation

Chiara O'Reilly, Isaac R. Santos, Tyler Cyronak, Ashly McMahon, and Damien T. Maher. 2015. Nitrous Oxide and Methane Dynamics in a Coral Reef Lagoon Driven by Pore Water Exchange: Insights from Automated High‐Frequency Observations .Geophysical Research Letters , (8) : 2885 -2892. https://nsuworks.nova.edu/occ_facarticles/1037.