Optical assessment of impact and recovery of sedimentary pH profiles in ocean acidification and carbon capture and storage research. (July 2015)

• Record Type: Journal Article
• Authors: Queirós, Ana M.; Taylor, Peter; Cowles, Adam; Reynolds, Andy; Widdicombe, Stephen; Stahl, Henrik
• Is Part Of: International journal of greenhouse gas control. Volume 38(2015:Jul.)
• Page Start: 110
• Page End: 120
• Publication Date: 2015-07
• Subjects: Acidification -- Benthic -- Biogeochemistry -- CCS -- Fluorophore -- pH; Greenhouse gases -- Environmental aspects -- Periodicals; Air -- Purification -- Technological innovations -- Periodicals; Gaz à effet de serre -- Périodiques; Gaz à effet de serre -- Réduction -- Périodiques; Air -- Purification -- Technological innovations; Greenhouse gases -- Environmental aspects; Periodicals; 363.73874605
• DOI: 10.1016/j.ijggc.2014.10.018
• Languages: English
• ISSNs: 1750-5836

Abstract

Highlights: pH profiling methods often fall short of marine OA and CCS experimental needs. A new optical sensor application (MOPP) helps to meet these needs. MOPP identified distinct impact and recovery patterns in different sediment types. Patterns depend on sediment characteristics, i.e. buffering capacity and permeability. CCS and OA impact assessment thus require consideration of these differences. Abstract: Available methods for measuring the impact of ocean acidification (OA) and leakage from carbon capture and storage (CCS) on marine sedimentary pH profiles are unsuitable for replicated experimental setups. To overcome this issue, a novel optical sensor application is presented, using off-the-shelf optode technology (MOPP). The application is validated using microprofiling, during a CCS leakage experiment, where the impact and recovery from a high CO2 plume was investigated in two types of natural marine sediment. MOPP offered user-friendliness, speed of data acquisition, robustness to sediment type, and large sediment depth range. This ensemble of characteristics overcomes many of the challenges found with other pH measuring methods, in OA and CCS research. The impact varied greatly between sediment types, depending on baseline pH variability and sediment permeability. Sedimentary pH profile recovery was quick, with profiles close to control conditions 24 h after the cessation of the leak. However, variability of pH within the finer sediment was still apparent 4 days into the recovery phase. Habitat characteristics need therefore to be considered, to truly disentangle high CO2 perturbation impacts on benthic systems. Impacts on natural communities depend not only on the pH gradient caused by perturbation, but also on other processes that outlive the perturbation, adding complexity to recovery.