The Second World Ocean Assessment (WOA II)
The Second World Ocean Assessment (WOA II) is the major output of the second cycle of the Regular Process for Global Reporting and Assessment of the States of the Marine Environment, including Socioeconomic Aspects. It is the newest outcome of the only integrated assessment of the world’s ocean at the global level covering environmental, economic and social aspects.
WOA II is a collective effort of interdisciplinary writing teams made up of more than 300 experts from around the world, including scientists from the Plymouth Marine Laboratory and the University of Plymouth. It provides scientific information on the state of the marine environment in a comprehensive and integrated manner to support decisions and actions for the achievement of Sustainable Development Goals, in particular goal 14, as well as the implementation of the United Nations Decade of Ocean Science for Sustainable Development.
The report catalogues a swathe of impacts on what UN secretary general António Guterres said was the planet’s “life support system”.
Sea levels were rising, coasts were eroding, waters were heating and acidifying and the number of deoxygenated “dead zones” was rising.
Martin Edwards and Michael Moore from Plymouth Marine Laboratory who contributed to the section on human health and the oceans said “there is strong evidence of an increase in the spread of pathogens related to climate warming (e.g., Vibrio) and there is some evidence related to an increase in some harmful algal bloom species related to climate warming is some regional areas around the world. Increasingly the spread of non-indigenous species have also started to be considered as one of the major threats to global marine ecosystems through impacts on the ecosystem’s structure, function and services.
Marine litter was present in all marine habitats, the report said, and overfishing was costing societies billions. About 90% of mangrove, seagrass and marsh plant species were threatened with extinction, the report said.
The report said there had been progress in protecting more marine areas, but there were still many scientific knowledge gaps to be filled.
Specifically for the pelagic environment, climate change during the course of the twenty-first century is expected to continue to drive changes in the upper ocean that have an impact on the diversity and productivity of plankton assemblages on the regional to global scales.
- These changes include an expansion of the subtropical gyres, ocean warming and acidification, decreases in salinity, increases in vertical stratification and decreases in inorganic nutrient supplies to the euphotic zone in the open ocean. Predicted biological responses to those changes on a global scale include the following:
- Primary production is likely to decrease and the relative abundance of picophytoplankton is likely to increase at the expense of microplankton diatoms. These trends are likely to propagate through food webs resulting in decreases in the ocean’s carrying capacity for fisheries and in its capacity to sequester carbon through the biological pump.
- Plankton food webs in the polar oceans and coastal upwelling regions will be the most affected by ocean acidification, owing to the high solubility of CO2 in cold waters.
Get the report here: https://www.un.org/regularprocess/woa2launch