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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Ocean acidification | 7/9 | https://en.wikipedia.org/wiki/Ocean_acidification | reference | science, encyclopedia | 2026-05-05T07:35:46.998480+00:00 | kb-cron |
==== United Kingdom commercial fisheries ==== The shellfish industry is an important part of the United Kingdom economy. In 2013, the shellfish industry contributed 37% of total landings by value. England and Scotland are the highest producers of shellfish within the United Kingdom. It has been found that annually fishers catch 66,000 t and 61,000 t. In terms of value, the wild-captured shellfish are worth 203 million pounds per year. However, ocean acidification is causing a decrease in the growth of many shellfish species. This is causing a drastic economic loss in the United Kingdom economy. It is predicted that by 2100 there will be an economy-wide economic loss of shellfish production in the United Kingdom. The direct potential loss ranges from 14 to 28 percent of fishery output. That is a total loss of about 23 to 88 million pounds. The financial losses vary regionally due to different patterns of wild-caught shellfish and the exploitation of species with differing sensitivities to ocean acidification. Shellfish resources in the United Kingdom will require regional, national, or international solutions to reduce the impacts of ocean acidification on shellfish species and stabilize the economy.
==== US commercial fisheries ====
The value of fish caught from US commercial fisheries in 2007 was valued at $3.8 billion and of that 73% was derived from calcifiers and their direct predators. Other organisms are directly harmed as a result of acidification. For example, decrease in the growth of marine calcifiers such as the American lobster, ocean quahog, and scallops means there is less shellfish meat available for sale and consumption. Red king crab fisheries are also at a serious threat because crabs are also calcifiers. Baby red king crab when exposed to increased acidification levels experienced 100% mortality after 95 days. In 2006, red king crab accounted for 23% of the total guideline harvest levels and a serious decline in red crab population would threaten the crab harvesting industry.
== Possible responses ==
=== Climate change mitigation ===
Reducing carbon dioxide emissions (i.e. climate change mitigation measures) is the only solution that addresses the root cause of ocean acidification. For example, some mitigation measures focus on carbon dioxide removal (CDR) from the atmosphere (e.g. direct air capture (DAC), bioenergy with carbon capture and storage (BECCS)). These would also slow the rate of acidification. Approaches that remove carbon dioxide from the ocean include ocean nutrient fertilization, artificial upwelling/downwelling, seaweed farming, ecosystem recovery, ocean alkalinity enhancement, enhanced weathering and electrochemical processes. All of these methods use the ocean to remove CO2 from the atmosphere to store it in the ocean. These methods could assist with mitigation but they can have side-effects on marine life. The research field for all CDR methods has grown a lot since 2019. In total, "ocean-based methods have a combined potential to remove 1–100 gigatons of CO2 per year". Their costs are in the order of US$40–500 per ton of CO2. For example, enhanced weathering could remove 2–4 gigatons of CO2 per year. This technology comes with a cost of US$50–200 per ton of CO2.
=== Carbon removal technologies which add alkalinity ===
Some carbon removal techniques add alkalinity to the ocean and therefore immediately buffer pH changes which might help the organisms in the region that the extra alkalinity is added to. The two technologies that fall into this category are ocean alkalinity enhancement and electrochemical methods. Eventually, due to diffusion, that alkalinity addition will be quite small to distant waters. This is why the term local ocean acidification mitigation is used. Both of these technologies have the potential to operate on a large scale and to be efficient at removing carbon dioxide. However, they are expensive, have many risks and side effects and currently have a low technology readiness level.
==== Ocean alkalinity enhancement ==== Ocean alkalinity enhancement (OAE) is a proposed "carbon dioxide removal (CDR) method that involves deposition of alkaline minerals or their dissociation products at the ocean surface". The process would increase surface total alkalinity. It would work to increase ocean absorption of CO2. The process involves increasing the amount of bicarbonate (HCO3-) through accelerated weathering (enhanced weathering) of rocks (silicate, limestone and quicklime). This process mimics the silicate-carbonate cycle. The CO2 either becomes bicarbonate, remaining in that form for more than 100 years, or may precipitate into calcium carbonate (CaCO3). When calcium carbonate is buried in the deep ocean, it can hold the carbon indefinitely when utilizing silicate rocks. Enhanced weathering is one type of ocean alkalinity enhancement. Enhanced weathering increases alkalinity by scattering fine rock particles. This can happen on land and in the ocean (even though the outcome eventually affects the ocean). In addition to sequestering CO2, alkalinity addition buffers the pH of the ocean therefore reducing ocean acidification. However, little is known about how organisms respond to added alkalinity, even from natural sources. For example, weathering of some silicate rocks could release a large amount of trace metals at the weathering site. Cost and energy consumed by ocean alkalinity enhancement (mining, pulverizing, transport) is high compared to other CDR techniques. The cost is estimated to be US$20–50 per ton of CO2 (for "direct addition of alkaline minerals to the ocean"). Carbon sequestered as bicarbonate in the ocean amounts to about 30% of carbon emissions since the Industrial Revolution. Experimental materials include limestone, brucite, olivine and alkaline solutions. Another approach is to use electricity to raise alkalinity during desalination to capture waterborne CO2.