Image Jeremy Bishop | Unsplash

Exploring the linkages between the ocean and biodiversity

On the occasion of the World Oceans Day, 8 June 2022, we reflect on the importance of the ocean, explores the linkages between the ocean and biodiversity, and offers some suggestions on how to protect ocean biodiversity.
Logo of the World Oceans Day 2022

Why is the ocean important?

Across the globe, over 3 billion people rely on the ocean for their livelihoods and more than 350 million jobs are connected to the ocean’s marine and coastal biodiversity [UNCTAD, 2016]. This barely scratches the ocean’s surface regarding the services that marine and oceanic ecosystems provide.

As a driver of global systems that makes life on Earth habitable, the ocean plays a significant role in achieving sustainable development and economic growth as well as providing a broad spectrum of ecosystem services. Some of these services include regulating carbon dioxide emissions and overall temperature, generating and supplying oxygen and clean water, determining weather patterns and precipitation, housing tourism and international trade, preserving underwater cultural heritage and linkages to local communities, providing food and other natural resources and, crucially, serving as a home to an abundance of marine life and biodiversity [FAO, 2020; IPCC, 2019; UNEP, 2021]. It is estimated that the ocean contains between 500,000 and 10 million marine species, many of which have yet to be identified [UN, 2017].

With all of the valuable services and resources that the ocean regulates and provides, which have an estimated annual value of USD 300 billion, it is of the utmost importance that the ocean is carefully and effectively managed in order to achieve the 2050 vision of living in harmony with nature [PDF-674 Kb] and fulfill the Sustainable Development Goals [UNCTAD, 2016].

 Green corals, Chuuk Lagoon, Weno - Marek Okon | Unsplash
     Green corals, Chuuk Lagoon, Weno - Marek Okon | Unsplash

Sustainable Development Goal (SDG) 14: Life Below Water

It is critical for nations around the world to recognize the urgent need for the conservation, protection and sustainable use of marine biodiversity. To accomplish this across United Nations Member States, Sustainable Development Goal 14 aims to “conserve and sustainably use the oceans, seas and marine resources for sustainable development”.

What are the connections between the ocean and biodiversity?

The ocean is intrinsically linked to the biodiversity and enrichment of its marine life and ecosystems. As a result, the ocean and coastal areas are extremely vulnerable to a variety of environmental and anthropogenic phenomena [FAO, 2020; IPCC, 2019; UNEP, 2021]. From the impacts of climate change to plastic pollution and overfishing, there are many unprecedented threats looming over our ocean that are linked to anthropogenic activities.

Climate Change

Climate change has already had a significant impact on ocean and marine ecosystems. In addition to sea levels rising and increases in the frequency and intensity of extreme weather events, ocean warming and ocean acidification have disrupted the chemistry of the ocean’s water and resulted in the destruction of coral reefs as well as the active depletion of the abundance and distribution of marine life in coastal areas, in the open ocean and at the sea floor [IPCC, 2019].

Ocean warming

As of 2019, it was determined that the ocean has absorbed more than 90% of excess heat in the climate system [IPCC, 2019]. This has caused ocean temperatures to rise and is known as ocean warming. The process of ocean warming also results in deoxygenation and sea levels rising [IPCC, 2019]. Combined with the effects of ocean acidification, these events heavily impact the livelihoods of marine ecosystems as well as the species, such as humans, that depend on them [FAO, 2020; IPCC, 2019].

Ocean acidification

Since the 1980s, the ocean has absorbed between 20 to 30% of anthropogenic carbon dioxide emissions [IPCC, 2019]. This has resulted in ocean acidification.

Ocean acidification is a process by which the acidity levels of the ocean’s water increase, primarily resulting from oceanic carbon sequestration, which has adverse effects on marine species distribution and reproductive development [IPCC, 2019]. In addition, coral reefs are extremely vulnerable to changes in the ocean’s chemistry. Known as the rainforests of the sea, it is estimated that over 60% of coral reefs are threatened by ocean acidification, ocean warming, and other anthropogenic events [UN, 2017]. As the ocean has continued to warm and acidify, the frequency of large-scale coral bleaching events has also unfortunately increased [IPCC, 2019]. Together, both ocean warming and ocean acidification have had a direct impact on marine ecosystems and have been amplified by anthropogenic activities.


School of fish in body of water, Red Sea - Francesco Ungaro | Unsplash
     School of fish in body of water, Red Sea - Francesco Ungaro | Unsplash

As ocean ecosystems continue to change, altering the distribution of fish populations and ultimately reducing the global catch potential, communities that are highly dependent on seafood and marine resources may face risks to nutritional health and food security [IPCC, 2019]. In 2010, it was estimated that 37% of the world’s population reside in coastal communities [UNSD, 2016].

Plastic Pollution

Plastic pollution is also a dangerous threat to marine and coastal ecosystems, as it can negatively impact global carbon cycling, marine food chains, aquatic species growth and development, human health and more [UNEP, 2021].

Juvenile fish surrounded by plastic pollution, Indonesia - Naja Bertolt Jensen | Unsplash
   Juvenile fish surrounded by plastic pollution, Indonesia - Naja Bertolt Jensen | Unsplash

Over 800 marine and coastal species are impacted by plastic pollution through ingestion, entanglement and adsorption of toxic, bio-accumulative substances into plastics and an estimated 75 to 199 million tonnes of plastic are found in the ocean [CBD, 2016; UNEP, 2021]. It is clear that the anthropogenic use, production and disposal of plastics must change. At the fifth session of the United Nations Environment Assembly (UNEA-5) in 2022, 175 nations came together with a historic promise to end plastic pollution and forge an international legally binding agreement by 2024. This resolution is intended to address the full lifecycle of plastic, including its production, design and disposal.


Overfishing is another concern threatening the ocean, marine biodiversity and those who depend on it for nutritional resources and food security. Efforts to increase the percentage of marine protected areas have persevered over the past 20 years. However in 2017, it was determined that 34.2% of fish stocks of global marine fisheries were classified as overfished, a 2.8% increase from 2013 [FAO, 2020; FAO, 2016]

Around the world, fish provide more than 3.3 billion people with 20% of their average per capita intake of animal proteins [FAO, 2020]. It is also estimated that 35% of the global harvest produced by fisheries and aquaculture is either wasted or lost annually [FAO, 2020]. According to the Food and Agriculture Organization of the United Nations, to keep up with the projected increase in demands of world fish trade, production, and consumption, the industry can improve the efficiency and sustainability of this sector through the establishment of policies, regulatory frameworks, capacity building, services and infrastructure, as well as physical access to markets [2020].

How can we help protect ocean biodiversity?

Protecting the ocean must remain a priority for nations around the world. With the plethora of services and resources the ocean provides, it is clear that marine biodiversity is critical to the health of both people and our planet. Through the establishment of policies and regulations, we can reduce the impacts of environmental events such as ocean warming and acidification, marine pollution and overfishing [IPCC, 2019; UNEP, 2021; FAO, 2020].

From preventing land-based marine pollution as well as water and plastic pollution to preserving mangroves and coral reefs, there are many actions we can take and promote to conserve and protect the ocean and its abundance of biodiversity. Learn more about actions we can take to protect ocean biodiversity.

Sunset over the ocean, California - NOAA | Unsplash
     Sunset over the ocean, California - NOAA | Unsplash

The Post-2020 Global Biodiversity Framework

To be adopted at the second part of COP-15, the post-2020 global biodiversity framework will play an important role in the conservation, sustainable use and equitable benefit-sharing of marine and coastal biodiversity. Currently, preparations for the framework are advancing, with the Open-Ended Working Group on the Post-2020 Global Biodiversity Framework set to have their fourth meeting from 21 to 26 June 2022 in Nairobi, Kenya.

Resources and events

CBD Secretariat publications and notification

Discover various publications published under the Secretariat of the Convention on Biological Diversity and learn more about marine and coastal biodiversity:

SCBD Technical Series

Upcoming United Nations Observances and Events

Mark your calendars and discover some upcoming and current United Nations observances, initiatives and conferences taking place around the world:

Logo of the World Oceans Day

U.N. World Oceans Day, 8 June 2022


Logo of the Ocean Conference

U.N. Ocean Conference, Lisbon, 27 June-1 July


Logo of the World maritime Day 2022

U.N. World Maritime Day, 29 September 2022


Logo of the United nations Ocean Decade

United Nations Decade of Ocean Science for Sustainable Development (2021-2030)





Logo of the World Oceans Day 2022