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Dissolved oxygen

The lowest dissolved oxygen between 100 and 1000 metres in the World Ocean Atlas 2023 climatology. Open-ocean oxygen, not the coastal dead-zone pins on Pollution.

NOAA WOA23 · minimum dissolved oxygen · 100-1000 m

The lowest dissolved oxygen between 100 and 1000 metres in the World Ocean Atlas 2023 climatology. Open-ocean oxygen, not the coastal dead-zone pins on Pollution.
Map: Fix Planet from NOAA World Ocean Atlas 2023 dissolved-oxygen data, 1965-2022. The colour is the minimum between 100 and 1000 metres, in micromoles per kilogram. Boundaries: Natural Earth.

What it is

The map is the minimum of the World Ocean Atlas 2023 dissolved-oxygen field between 100 m and 1000 m, in micromoles per kilogram. WOA23, from NOAA NCEI, is an objectively analysed climatology for 1965-2022. IPCC SROCC reports that open-ocean oxygen in the upper 1000 m fell about 0.5-3.3% over 1970-2010, and that oxygen-minimum zones expanded about 3-8%.

Why it is on this shelf

Pollution’s “Dead zones” figure is a coastal hypoxia compilation (after Diaz / Breitburg context). Chlorophyll stays on Pollution as a biomass proxy. This card answers a different question: where is the open-ocean oxygen field low, and what does the WOA climatology show? Do not merge the two.

How to read it

Darker colour is a lower minimum in that depth range. The field is a long-term mean, not a single cruise and not a forecast. Oxygen-minimum zones are mid-depth layers in the open ocean. Coastal dead zones, often driven by nutrients, sit on the Pollution page. The WOA23 oxygen documentation describes the climatology. IPCC SROCC is the assessment of the multi-decadal decline.

Sources

Open source map →