Fate of ocean oxygenation in a warming world

Oxygen is critical to the health of all higher life. In the oceans dissolved oxygen concentrations have declined by 2% since 1960, and are expected to continue to decline into the future in relation to man-made climate change. Future deoxygenation, along with overfishing, threatens the sustainability of economically important fisheries and marine ecosystems and will impact global biogeochemical cycles. It is therefore crucial that we obtain a well-informed view about what the future may hold.

Current model simulations that predict the future carry considerable uncertainties; they do not all agree and grossly underestimate the document decrease of the last 50 years. This suggests the models are missing key interactions, calling for urgent action and a dedicated and inclusive scientific approach.

FARGO provides such an approach by addressing why, and to what extent, seawater dissolved oxygen concentrations may change in a warming world. FARGO will study dissolved oxygen concentrations in the Pacific Ocean, the largest low-oxic water body in the current ocean, through an innovative and dedicated research programme incorporating a novel multi-proxy approach feeding IPCC-type climate model simulations across key warm time intervals:
i- warmer climates across the closure of the American sea-way (4-15 million years);
ii- warmer climates as future analogue (mid-Pliocene Warm Period, 3.3 to 3 million years ago);
iii- Pleistocene warm intervals (interglacials of the last ca. 800,000 years).

FARGO is structured into two phases: Phase I (years 1-4), and Phase II (years 5-7). The focus of the first four years is analytical, to advance method development and reconstruct time-series of oxygen concentrations and associated processes that drive changes (seawater warming, stratification, productivity, ventilation). The material FARGO will use to create these time-series involves the shells of microorganisms called foraminifera. Some species float near the ocean surface, called planktonic foraminifera, and can be used to assess the presence of subsurface oxygen minimum zones, seawater temperatures, etc. Species that live on or in sediments at the bottom of the ocean are termed benthic foraminifera and can be used to reconstruct bottom water oxygen concentrations and ventilation. FARGO will use sediments from the International Ocean Discovery Program to determine if there have been changes in the natural extent and intensity of the shallow Pacific Ocean OMZ oxygen minimum, or 'dead', zones (e.g. areas where oxygen levels are too low to support aerobic life), during the key warm intervals. The original time-series will feed the IPCC-type climate model simulations and provide robust tests to investigate if the simulations are realistic and correct for the specific time periods, and identify routes to improve the model simulations. Utilizing these improvements, FARGO will carry out simulations for future, including 1.5 and 2 degree warming scenarios.

To raise awareness of ocean deoxygenation FARGO plans several bespoke impact and engagement activities aimed at scientific peers, policy makers, and the general public. To slow/reduce deoxygenation and protect our marine environment FARGO plans to work with government (Scottish and UK) to develop regional legislation to manage nutrient inputs from aquaculture and agriculture of UK waters.

Who might benefit from this research, and how might they benefit?

FARGO's aim is to deliver a step-change in our understanding of the longer-term oxygen cycle and drivers of change. FARGO will deliver a substantial and lasting impact by providing critical information about the marine oxygen cycle and different drivers, to improve model simulations of the future. The research therefore underpins pathways for solutions to safeguard the ocean.
The outputs and outcome of FARGO will be of benefit to a wide community, including academic and non-academic users of the research. The work will contribute to future assessments of the climate system and is of relevance to government agencies (e.g. European Union, NERC, DEFRA, CEFAS), policy forming bodies (International Panel on Climate Change), and NGOs (World Ocean Network, Commonwealth Foundation, Greenpeace, United Nations). In addition the work will strongly complement and have relevance to several of NERC's strategic research areas, including climate change, biodiversity, geosciences, marine environments, as well as existing NERC programmes such as Ocean Acidification, International Ocean Discovery Program (IODP-UK).

Who? Policy makers:
Future global ocean deoxygenation has been identified as one of the most serious issues affecting marine environments, which will impact local environments, economically important fisheries and global biogeochemical cycles. About ten percent of the world population is dependent on fisheries and aquaculture, with the majority working in developing countries. Fisheries provide 16 per cent of global animal protein, highlighting the economic importance.

How? FARGO will organize a workshop, inviting UK stakeholders (scientists, politicians, fisheries, economists, NGO's) to seminar sessions, with specific emphasis on UK waters, to be held at the Scottish Parliament, followed by a debate, to be held at the Scottish Parliament (hosted by MSP Liam McArthur; see letter of support), coincident with a public exhibition. I plan to work with SPICe (Scottish Parliament Information Centre) on the potential to develop legislation to manage nutrient inputs in aqua- and agri-culture (runoff from agriculture delivers high nutrient loadings in coastal areas), through their academic fellowship scheme. FARGO's phase II, which features simulations of the future (including analogue mPWP), will build towards strong international engagements (WWF, IPCC).

Who? General public.
How? The PI, with Dynamic Earth Edinburgh (see letter of support) will create an exhibition 'An underwater Back to the Future adventure with microfossils', showing a magnified view of the ecology of foraminifera, radiolarians, coccolithophores and diatoms, their evolution through time, how their emergence shaped our planet, and how they are instrumental in informing us about past environments and future predictions. Dr. Hermione Cockburn, scientific director of Dynamic Earth, has furthermore offered to host several outreach activities over the duration of the grant. We will organise family friendly hands-on activities during October half term, with themes on how marine animals cope with environmental change, solubility of gasses and photosynthesis. Dynamic Earth has between 750 to 1000 visitors each day during these activities. 2020 will be the Year of Scotland's Coast and Waters. We will hold an evening lecture, including panel discussion, during the Edinburgh International Science Festival (April) that will be appropriate to a general audience, and excellent venue to promote and discuss our research.