The Earth’s surface is nearly 70% water, and of that water over 97% of it is saltwater (McKinney, et al. 2019, 245-246). The interactions between the hydrosphere and the atmosphere indicate the critical need for the ocean to be part of the solution in removing carbon from the atmosphere. There are many technologies, both biological and chemical, that can be utilized within the ocean to capture and sequester carbon. These carbon sequestration solutions not only reduce carbon from the atmosphere, but they can also help improve and conserve biological resources.
An example of a biological approach to carbon sequestration would be to restore coastal blue carbon ecosystems like salt marshes and mangroves. These improvements help store carbon in coastal sediments and can represent around a few hundred million tons of CO2 per year by 2050 (Lebling and Northrop 2020). Large-scale seaweed cultivation can also remove carbon and ocean acidification while providing food and habitat for ocean-life, but also can provide food for humans and ruminant animals. Seaweed can also reduce ruminant animal methane emissions by more than 50% (Lebling and Northrop 2020). In addition to biological approaches, chemical approaches like adding different types of minerals to react with dissolved carbon dioxide, or electrochemical approaches, can also help improve water quality for calcifying species like oysters and other shellfish (Lebling and Northrop 2020). These technologies help reverse ocean acidification that is detrimental to ocean life as well as remove carbon from the atmosphere.
While there are fewer species of organisms in the ocean than on land, there is more biodiversity in the ocean with 32 phyla found in the oceans and just 12 phyla found on land (McKinney, et al. 2019, 109). With nearly 70% of the land’s surface being marine, it will be important to utilize those resources in reducing carbon from the atmosphere. The pH of the ocean has dropped from 8.21 to 8.10 since the start of the Industrial Revolution. On this logarithmic scale, the decrease represents an approximately 30% increase in the acidity of the ocean which is inhibiting the ability of marine life to build shells and skeletons from their ability to extract calcium from the water (Lindsey 2020). This indicates that atmospheric carbon will not only create environmental issues and global warming for terrestrial organism but will also greatly impact the oceans and marine organisms as well. Carbon capture and sequestration technologies will be vital to helping not only reduce our current emissions, but to help reverse some of the massive impacts to the planet.
Do you think that carbon capture and sequestration technologies should be funded if they only sequester carbon permanently, or should additional direct biological benefits be required in addition to the carbon removal aspects?
Figure 1. Possible Uses and Benefits of Cultivated Macroalgae
Source: (Lebling and Northrop 2020).
Author: Logan Callen
Lebling, Katie, and Eliza Northrop. 2020. “Leveraging the Ocean’s Carbon Removal Potential .” World Resources Institute. October 8. Accessed June 30, 2021. https://www.wri.org/insights/leveraging-oceans-carbon-removal-potential.
Lindsey, Rebecca. 2020. “Climate Change: Atmospheric Carbon Dioxide.” Climate.gov. August 14. Accessed June 30, 2021. https://www.climate.gov/news-features/understanding-climate/climate-change-atmospheric-carbon-dioxide.
McKinney, Michael L., Robert M. Schoch, Logan Yonavjak, and Grant A. Mincy. 2019. Environmental Science: Systems and Solutions. 6th ed. Burlington, MA: Jones & Bartlett Learning.