Mahaffey et al, 2023, MCCIP reports, "Climate Change Impacts on Dissolved Oxygen Concentration in Marine and Coastal Waters around the UK and Ireland" Flashcards
Why is oxygen the most important gas in the marine environment?
Oxygen is essential for respiration by almost all marine life.
How much have dissolved oxygen concentrations in the global ocean declined since the 1960s?
They have declined by 2%
What is the main driver for the decline in dissolved oxygen in near coastal regions?
Excessive nutrient loading or eutrophication.
What has been attributed as the cause for the observed global decline in dissolved oxygen?
Ocean warming.
What do climate models predict about the future rates of oxygen decline?
Future rates of oxygen decline will increase globally in response to warming.
At what concentration is water considered hypoxic?
When oxygen concentrations are less than 2 mg/litre (equivalent to ~64 µmol/kg).
What are the effects of the development of oxygen deficiency in the marine ecosystem?
It can have deleterious effects, increasing severity with the onset of hypoxia or anoxia.
Where is the intensity and impact of dissolved oxygen depletion particularly apparent?
In coastal and shelf seas.
What has been the main factor for seasonally focused depletion of oxygen in the North Sea?
Approximately one-third due to warming and two-thirds due to enhanced oxygen consumption.
What is the confidence level regarding the direction of change in dissolved oxygen in UK coastal and shelf seas?
Medium level of confidence.
What is the global confidence level regarding the ongoing decline in dissolved oxygen concentrations due to warming?
High level of confidence.
What is the confidence level on the future of dissolved oxygen dynamics on a regional scale relevant to UK marine waters?
Medium level of confidence.
What is a key challenge in studying dissolved oxygen trends?
Determining the mechanisms driving spatial and temporal trends in dissolved oxygen.
What hampers the assessment of oxygen deficiency in UK coastal and shelf waters?
Lack of long-term data outside of the North Sea.
What technology can improve detection of future oxygen depletion?
Autonomous ocean gliders and instrumented moorings.
