Ocean Oxygen Loss Could Be Worse Than Models Predict
The oceans are losing their life-sustaining oxygen. That’s what data from the last 50 years show, and what predictive computer models indicate for the future. The problem? There’s a mismatch, and that suggests to researchers in Germany that oceans may be on a path to losing oxygen faster than realized.
A study published in the journal Nature Geoscience by researchers at the GEOMAR Helmholtz Centre for Ocean Research Kiel found that current computer models underestimate recent observed declines in ocean oxygen – calling into question their ability to exactly predict the future.
The problem, they write, is that warming oceans affect oxygen concentrations in many ways. At higher temperatures, less oxygen can stay dissolved in water, but that only explains a small slice of oxygen loss so far. What current simulations fail to account for is how warming also changes ocean circulation patterns, according to the study. Because deep currents mix the world’s oceans, changes in those currents and circulations patterns also affect oxygen. This, they say, is where current science cannot yet predict the future very closely.
A Cautionary Tale of Seafood Traceability
An Associated Press investigation reported that a major seafood distributor has been selling fresh, “local” fish from the other side of the world.
It offers a cautionary tale as more large brands try to ensure traceability of seafood supplies.
According to the piece, the distributor, Sea To Table, says it works directly with United States docks to ensure the seafood that its sells is domestic, wild and “traceable.” New York-based, it is a growing company that had $13 million in sales last year, with chefs and other brands as customers.
But AP reporters, using stake-outs, time-lapse cameras, interviews and DNA testing, found that at least some of its seafood couldn’t be from where the company claimed and likely came from the Indian Ocean or western central Pacific. Sea To Table wasn’t working directly with docks or fishers, but with wholesalers or import markets, the article said. The owner of one of its suppliers told the AP: “Can things get mixed up? It could get mixed up. Is it an intentional thing? No, not at all.”
Eat Forage Fish, but Not Too Much
Wild herring, sardines and other small forage fish may be the sustainable foods of the future – but they are not a limitless resource.
Who should consume them and for what purpose? These are open questions illustrated by a pair of studies released by different teams of researchers at the University of Washington this week.
In one paper, a large review of environmental studies of all kinds of protein sources found that industrial beef and farmed catfish have the biggest environmental downsides. Meanwhile, small wild-caught fish, such as sardines and herring, and farmed oysters and other mollusks have the lowest. With food demand projected to grow worldwide this century, the researchers say that policies need to better compare environmental consequences for different animal proteins.
But a separate paper published this week in Nature Sustainability notes that populations of wild forage fish, such as anchovy and herring, are likely to face pressures by 2050 as demand grows. That’s largely because these species not only provide protein for humans but are also used as aquaculture feed, a rapidly growing industry. As aquaculture grows so will pressure on these small, environmentally friendly fish.