2016 SoE Marine Chapter - Pressures - Climate Change - Dissolved oxygen and oxygen minimum zones

Brief description

The Marine chapter of the 2016 State of the Environment (SoE) report incorporates multiple expert templates developed from streams of marine data. This metadata record describes the Expert Assessment "Pressures on the marine environment associated with climate change - oceanic dissolved oxygen and oxygen minimum zones in shelf and offshore regions". The full Expert Assessment, including figures and tables (where provided), is attached to this record. Where available, the Data Stream(s) used to generate this Expert Assessment are accessible through the "On-line Resources" section of this record. ---------------------------------------- DESCRIPTION OF THE PRESSURE The ocean is undergoing physical and chemical changes as carbon dioxide and other greenhouse gases in the atmosphere rise. These changes are warming the upper ocean, altering the upper ocean density structure and acidifying the oceans (see ocean sections). Oxygen is consumed in aerobic respiration and most marine ecosystems are composed of aerobic organisms that need oxygen to survive. Due to aerobic respiration, the dissolved oxygen concentrations in the ocean are lowest in the intermediate water (300 m to 1000 m). In coastal regions with limited circulation the biological consumption of oxygen can lower oxygen considerably. Global warming is projected to reduced the dissolved oxygen and lead to expansion of areas with low oxygen (Cocco et al., 2013). DATA STREAM(S) USED IN EXPERT ASSESSMENT Offshore data from around Australia from the latest CARS compilation (CARS2009a v1.1, as of 12 July 2010). See http://www.marine.csiro.au/atlas/ ---------------------------------------- 2016 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details] • 2016 • Assessment grade: Low impact Assessment trend: Unclear Confidence grade: Evidence and consensus too low to make an assessment Confidence trend: Evidence and consensus too low to make an assessment Comparability: Grade and trend are somewhat comparable to the 2011 assessment • 2011 • Assessment grade: Very good Assessment trend: Stable Confidence grade: Limited evidence or limited consensus Confidence trend: Limited evidence or limited consensus ---------------------------------------- CHANGES SINCE 2011 SOE ASSESSMENT Unclear what data were used in the 2011 assessment; the 2016 assessment is based on the latest CARS compilations and so includes observations added to CARS 2011-2016.

Lineage

Statement: QUALITY OF DATA USED IN THE ASSESSMENT The CARS dissolved oxygen and nitrate data reflect a compilation of all ocean observations. To improve the robustness of the results we only show the annual mean values.

Notes

Purpose
To describe the pressures on the marine environment associated with climate change and oceanic dissolved oxygen and oxygen minimum zones in shelf and offshore regions for use in the Marine chapter of the 2016 State of the Environment report.