Ocean Acidification

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“The Pacific Partnership on Ocean Acidification (PPOA) is empowering Pacific Island communities to face the challenges posed by ocean acidification. PPOA works directly with stakeholders at all levels, from school children to women’s groups, village leaders and policy-makers. By building Pacific capacity to confront ocean acidification, PPOA supports Pacific communities to monitor their own coastal ocean chemistry, develop national policies to address ocean acidification and apply Pacific traditional ecological knowledge to adapt their coastal ecosystems to become more resilient to the threat of ocean acidification.”

Dr Duncan McIntosh, PPOA Project Manager at the Secretariat of the Pacific Regional Environment Programme

Summary

The Pacific Partnership on Ocean Acidification (PPOA) is a four-year collaborative project between the Secretariat of the Pacific Regional Environment Programme SPREP, the University of the South Pacific (USP) and the Pacific Community (SPC) with the goal of building resilience to ocean acidification in the Pacific Islands. The project’s pilot sites are in Fiji, Kiribati and Tokelau and activities focus on research and monitoring, capacity-building and awareness-raising, policy support and implementing practical adaptation actions. Financial support is provided by the New Zealand Ministry of Foreign Affairs and Trade and the Principality of Monaco.

The issue

Small island developing states (SIDS), such as nations in the Pacific Island region, are highly exposed to the impacts of climate change and ocean acidification, given their close proximity to the marine environment and their reliance on marine resources for livelihoods and infrastructure.

In particular, the Pacific Islands are especially vulnerable to the effects of ocean acidification. For example, as the ocean acidifies it becomes more difficult for coral reefs to calcify, resulting in net dissolution. As the coral structure erodes, the reef becomes a less effective force against wave and storm erosion, and it is harder to keep up with sea level rise.

In addition, the tourism infrastructure and fisheries industries in the Pacific Islands rely heavily on healthy coral reefs. Therefore, the impacts of ocean acidification in the region strongly affect community resilience and economic well-being.

The response

The OceanNETs project explores an approach for carbon dioxide removal in a Norwegian fjord

How can carbon dioxide (CO2) be removed from the atmosphere and stored safely and permanently in the ocean? This question is being investigated by scientists from seven nations led by GEOMAR Helmholtz Centre for Ocean Research Kiel in an experiment just starting in the Raunefjord near Bergen, Norway. In mesocosms, free-floating, experimental enclosures, they are exploring whether the ocean can absorb additional CO2 from the atmosphere through the addition of alkaline minerals – known as ocean alkalinisation – and what influence this has on marine communities. The study will last until mid-July and takes place as part of the Ocean-based Negative Emission Technologies (OceanNETs) project funded by the European Union.

The target is clear: In the Paris Agreement, the global community agreed to limit global warming to well below 2° Celsius and to make efforts to keep it below 1.5° Celsius. This can only be achieved if we drastically reduce our greenhouse gas emissions and take measures to actively remove carbon dioxide (CO₂) from the atmosphere again – in other words, create “negative emissions”. To what extent the ocean can support this and what risks and side effects might occur is currently being investigated by an international 43-member research team led by GEOMAR Helmholtz Centre for Ocean Research Kiel in a study south of Bergen, Norway.

For the long-term experiment, the researchers are using mesocosms developed at GEOMAR, which are a type of oversized test tube, 20 metres long and two metres in diameter. In the sealed containers, the pH value of the seawater is raised by the addition of alkaline minerals. This so-called alkalinization not only counteracts ocean acidification, it also enhances the ocean’s potential to take up and store CO₂. Regular sampling and measurements document the chemical and biological changes in the mesocosms over a period of about eight weeks.

The investigated approach simulates a natural process: In nature, minerals from rocks and soils are partially responsible for maintaining the alkalinity of seawater. In the experiment, slaked lime – representing calcium-based minerals – and magnesium silicate – representing siliceous minerals – are used for alkalinization, because they dissolve easily in water and are free of impurities often contained in minerals. The experiment aims to clarify how effectively this sequesters additional CO₂, which of the two substances produces better results and, most importantly, how ocean alkalinization affects marine life.

“We need to work on ways to actively mitigate climate change. The problem is becoming more and more pressing. Even if we manage to reduce CO₂ emissions fast and radically, there will still remain CO₂ emission we cannot avoid,” says Professor Dr. Ulf Riebesell, marine biologist at GEOMAR and project leader of the study. “With our research, we want to help develop safe and sustainable solutions which can remove carbon dioxide from the atmosphere. In doing so, it is important to ensure that negative impacts on the marine environment are prevented.”

Mesocosm studies are particularly suitable for investigating the effects of changes in seawater chemistry without affecting the marine environment. The sealed structure of the “giant test tubes” allows conditions in the enclosed water to be altered in a controlled manner. Mesocosms contain natural communities and are exposed to real environmental conditions during experiments, so that close-to-natural conditions can be simulated. This is not possible in the laboratory.

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Arctic Ocean, Indian Ocean, North Atlantic Ocean, North Pacific Ocean, Project, Protect and restore ecosystems and biodiversity, South Atlantic Ocean, South Pacific Ocean, Unlock ocean-based solutions to climate change

The International Alliance to Combat Ocean Acidification (OA Alliance) is a voluntary initiative of governments and non-government members representing nearly 300 million people and 366,414 kilometres of coastline.

Members of the OA Alliance include a wide diversity of national, state, municipal, and sovereign Tribal, indigenous, and First Nation governments along with many dedicated affiliate partners like NGOs, seafood industry leaders, and local academia. Through the Alliance, they are exploring and promoting efforts that increase biodiversity, adaptive capacity, and resilience by translating knowledge into policy actions by national, regional and subnational governments.

Start Date: 01/01/2021

End Date: 31/01/2023

This project is hosted by the programme Ocean Acidification Research for Sustainability.

Contact

Jessie Turner: Jessie@OAalliance.org

The initiative is one of the actions in the LIFE IP Urban Klima 2050 project, which comprises a series of measurement platforms on the Basque coast to track climate change in the sea.

Observing and monitoring the Basque coastal ocean is essential to study the effects of climate change in this area. AZTI has been involved in this since 1986, when it began installing a variety of platforms for monitoring climate change in the sea. 

Its most recent action has been to install a new pH sensor for monitoring ocean acidification off the coast of the Basque Region. The action is part of the LIFE IP Urban Klima 2050 project, and is supported by the Department of the Environment at the Provincial Government of Gipuzkoa and Naturklima.

The sensor is installed at around 3 kilometres from the coast, 50 metres below sea level, and provides regular data on changes in pH in the Bay of Biscay. This makes it possible to make accurate, reliable estimates of ocean acidification levels at the location. This acidification is a direct result of CO2 emissions caused by fossil fuels, which dissolve in the sea, lowering the pH, which affects the growth of marine life such as coralline algae, molluscs, crustaceans, sea snails, coral and some plankton communities.

Mesocosm experiment on Gran Canaria investigates a possible solution for the long-term removal of carbon dioxide from the atmosphere with the help of the ocean.

In a mesocosm experiment just starting on Gran Canaria, scientists from six nations led by GEOMAR Helmholtz Centre for Ocean Research Kiel are investigating to what extent the ocean can help absorb more carbon dioxide (CO2) from the air and what impacts this has on marine life. The experiment is taking place as part of the EU project Ocean-based Negative Emission Technologies (OceanNETs). The project, which has been running since July 2020, aims to provide an integrated assessment of targeted measures for CO2 removal in the ocean.

The human-induced increase in carbon dioxide (CO₂) concentration in the atmosphere continues. With well-known consequences: The climate is changing, extreme weather events are increasing in many places, with sometimes dramatic effects on humans and nature. According to current estimates by the Intergovernmental Panel on Climate Change (IPCC), the goal of limiting global warming to as close to 1.5° Celsius as possible decided in the Paris Agreement, can no longer be achieved without active removal of CO₂. The Ocean-based Negative Emission Technologies (OceanNETs) project, funded by the European Union and coordinated at GEOMAR Helmholtz Centre for Ocean Research Kiel, is investigating to what extent ocean-based approaches could contribute to achieving this goal.

In the long term, most of the carbon dioxide (CO₂) released by humans will be recaptured by the weathering of rocks on land and stored in the ocean as dissolved bicarbonate. However, it will take up to ten thousand years for the human CO₂ footprint to be largely wiped out again via this process. Too long to play a significant role in addressing climate change in the coming decades. Unless this process could be actively accelerated. Whether this is possible and how the marine communities react to it is currently being investigated by 50 scientists from six nations under the leadership of GEOMAR in a mesocosm experiment on Gran Canaria.

In oversized test tubes, so-called mesocosms, deployed in on-shore waters the researchers are simulating accelerated weathering through the addition of minerals, as they are also introduced into the oceans through natural weathering of rocks. For every kilogram of dissolved rock minerals, this approach can bind about half a kilogram of additional CO₂ in the seawater. In the nine mesocosms, different amounts of minerals were added with the corresponding amount of CO₂. The concentration gradient set in this way should provide information about possible thresholds for the environmental compatibility of accelerated weathering. In addition to the long-term storage of CO₂ in the seawater, the approach known as ocean alkalinisation has the co-benefit of counteracting ocean acidification. The on-going acidification of seawater is a consequence of continued CO₂ emissions. About a quarter of the CO₂ released annually by humans dissolves in the ocean and reacts with the water to form carbonic acid – with serious consequences for marine life.

“The goal of our experiment is to investigate the potential risks and side effects of ocean alkalinisation on marine communities, but also to capture any positive effects by curbing ocean acidification”, explains Prof. Ulf Riebesell, marine biologist at GEOMAR Helmholtz Centre for Ocean Research Kiel and head of the study. “In addition, we hope to gain insights into how effectively and safely ocean alkalinisation could be used as a method of CO₂ removal.”

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