Ocean health can be broadly defined based on factors that affect productivity, species diversity, and resilience such as adaption to climate change. In other words, the ability of marine ecosystems to thrive and support human livelihoods. GOOS contributes to ocean health studies by monitoring ocean acidification, biodiversity and habitat, and water quality.
Each year, about one quarter of excess human carbon dioxide (CO2) emissions are absorbed by the ocean
. That absorption has helped decrease the rate of atmospheric warming but has the unfortunate side effect of making the ocean more acidic. Ocean acidity increases the amount of energy needed by many small ocean organisms in constructing their carbonate shells and structures, and in some places will make it impossible for these organisms to live. (original image)
Since 1950 the number of worldwide fisheries that are fully exploited has increased dramatically
. As a consequence, we are seeing ocean ecosystems shift towards lower trophic levels – for example, from predators such as tuna to prey fish such as herring. (original article)
Heating of the ocean reduces the solubility of oxygen, critical for most ocean life. Areas with poorer water quality resulting from reduced oxygen levels
are projected to grow in size over time. In some areas, increased ocean stratification (i.e., layering) will have negative impacts on ocean productivity. (original article)
Cumulative Human Impact on Ocean Ecosystems
Human activity, including climate change, shipping, fishing activity, pollution and others, has been estimated to have an impact over much of the ocean (Halpern et al., 2008).
At right is a global map of cumulative human impact across 20 ocean ecosystem types. Areas of very high impact are color coded as dark red (e.g., Eastern Caribbean, North Sea, near Japan). Very low impact areas are colored in blue (e.g., northern Australia).