For decades, an oxygen-depleted dead zone that is harmful to sea life has appeared in the Gulf of Mexico in a region off the coasts of Louisiana and Texas. This year, it's larger than average, federal scientists announced in a report Thursday.

This year, the dead zone in the Gulf of Mexico entered into the top third of largest dead zones in records that go back 38 years, (..)

The 2024 zone in the Gulf is about 6,705 square miles, which is an area roughly the size of New Jersey.

The latest measurement is about 1,000 square miles larger than NOAA's prediction in June, calculated using discharge from the Mississippi River and nutrient runoff data from the U.S. Geological Survey.

Out of sight, out of mind

In presentations of mCDR strategies, the deep ocean is routinely depicted schematically as a black, featureless abyss, without acknowledgement that the receiving environments for carbon disposal are biodiverse, heterogeneous, and provide critical ecosystem functions. Up until the 1970s, plans for retrieving minerals from the deep seabed likewise included no recognition of the potential harm caused to species living there. While such impacts now motivate many DSM debates, proposals for mCDR continue to rely on an outdated view of the deep ocean as a place where waste can be dumped far from sight and without consequences.

Research into the risks associated with DSM has informed a counter-narrative to the emergency framing and “climatism” used by proponents of deep-seabed mineral extraction. A similar counter-narrative has yet to receive comparable attention in current debates on the feasibility and safety of mCDR but is very much needed. Consideration of a wide array of risks associated with large-scale mCDR interventions and consequences for marine ecosystems and environments is rapidly becoming essential as business interests outpace science and policy development. Like DSM, mCDR needs to be carefully considered not in relation to narrowly framed numerical climate targets, but within a holistic framework including potential far-reaching impacts on marine life, deep-ocean ecosystems and social equity.

Ocean acidification refers to a reduction in the pH of the ocean over an extended period of time, caused primarily by uptake of carbon dioxide (CO2) from the atmosphere.

For more than 200 years, or since the industrial revolution, the concentration of carbon dioxide (CO2) in the atmosphere has increased due to the burning of fossil fuels and land use change. The ocean absorbs about 30 percent of the CO2 that is released in the atmosphere, and as levels of atmospheric CO2 increase, so do the levels in the ocean. (...)

Climate impacts are triggering a host of novel bio- and geoengineering interventions to save coral reefs. This Comment challenges heroic scientific assumptions and advocates for a more systemic, evidence-based approach to caring for coral reefs.

For example, evidence shows that resilience and recovery are an inherent feature of natural ecosystems. The assumption that human intervention can deliver a better outcome is not supported by data: a synthesis of 400 studies of post-disturbance recovery shows no consistent benefits with human restoration compared to natural recovery^9^. Disturbed ecosystems undoubtedly display recovery debt, that is, “deficits in biodiversity and functions”^10^. But passive recovery as a natural process supports continued functioning and, most importantly, avoids further human disturbance.

Recent evidence from the northern Great Barrier Reef supports nature’s un-aided capacity to recover in the short term, with coral cover jumping from 10%, the lowest ever recorded, to a record high of 36% in just six years following the last major bleaching event. It was not coral reseeding or biophysical interventions that delivered this outcome over vast spatial scales, but natural recruitment and regrowth. Unfortunately, current and future heatwaves will continue to kill these regrown corals, rendering this natural success ephemeral. Yet to date, there is little evidence that the ecological dynamics that enabled this regrowth will cease to exist, or that active interventions — which have the stated goal of increasing cover of the same fast-growing corals — can have any population-wide impact^11^.

(...)Therefore, rather than being preoccupied with how to intervene, the scientific community can prudently step back and consider how to have less, not more, influence on nature.

A deliberate reduction of human influence on natural systems is not careless withdrawal, but a radical acceptance of our limited capacity to predict and influence specific outcomes within complex natural systems. (...)

Something remarkable has happened to A23a, the world's biggest iceberg.

For months now it has been spinning on the spot just north of Antarctica when really it should be racing along with Earth's most powerful ocean current.

Scientists say the frozen block, which is more than twice the size of Greater London, has been captured on top of a huge rotating cylinder of water.

For three decades it was a static "ice island". It didn't budge. It wasn't until 2020 that it re-floated and started to drift again, slowly at first, before then charging north towards warmer air and waters.

Prof Taylor showed how a current that meets an obstruction on the seafloor can - under the right circumstances - separate into two distinct flows, generating a full-depth mass of rotating water between them.

A23a is a perfect illustration once again of the importance of understanding the shape of the seafloor.

A23a's behaviour can be explained because the ocean bottom just north of South Orkney is reasonably well surveyed.

That's not the case for much of the rest of the world.

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The International Seabed Authority (ISA) has elected Leticia Carvalho of Brazil as its next secretary general, as pressure mounts for a pause on efforts to mine the sea floor for minerals for use in the energy transition.

Carvalho told The Guardian last month that rules governing deep-sea mining will take time and that no mining application should be approved before they are complete.

Canada’s The Metals Company (TMC) has said it is seeking a licence by year-end to extract minerals from the ocean floor.

The rush to complete the mining code was triggered by the Pacific island state of Nauru saying it would submit a mining licence application on behalf of TMC, which triggered the so-called “two-year rule” in 2021.

That rule allows mining applications to be submitted within two years, whether the mining code has been finalised or not.

Summary:

This video discusses the importance of both open ocean cleanup and river interception in addressing plastic pollution.

The speaker argues that open ocean cleanup is necessary to address the problem of plastic accumulation in remote areas of the ocean, such as the Great Pacific Garbage Patch. This is important because plastic pollution in the ocean harms marine life and contributes to climate change.

The speaker also argues that river interception is necessary to prevent plastic from entering the ocean in the first place. This is important because rivers are a major source of plastic pollution in the ocean.

The speaker concludes by saying that both open ocean cleanup and river interception are important and that they can be done at the same time.

An international research team deployed the unmanned submersible, ‘Ran,’ underneath 350-meter-thick ice. They got back the very first detailed maps of the underside of a glacier, revealing clues to future sea level rise.

Ran, an autonomous underwater vehicle (AUV), was programmed to dive into the cavity of Dotson Ice Shelf, West Antarctica, and scan the ice above it with an advanced sonar. An ice shelf is a mass of glacial ice, fed from land by tributary glaciers, that floats in the sea above an ice shelf cavity. For 27 days, the submarine travelled a total of over 1,000 kilometers back and forth under the glacier, reaching 17 kilometers into the cavity.

Some things are as expected. (...)

But the researchers also saw new patterns on the glacier base that raise questions. (...)

“The maps that Ran produced represent a huge progress in our understanding of Antarctica’s ice shelves. We’ve had hints of how complex ice-shelf bases are, but Ran uncovered a more extensive and complete picture than ever before. The imagery from the base of Dotson Ice shelf helps us interpret and calibrate what we see from the satellites,” said Karen Alley.

There are more than an estimated 3000 World War II shipwrecks across the Pacific Ocean. After years of decay, some of the wrecks are spilling thousands of tons of oil and fuel into the sea.

The scale and complexity of the Southern Ocean can be hard to comprehend. But our new paper may help. It summarises the present state of understanding of the Southern Ocean, how it is changing, and where the knowledge gaps lie.

Scientists and others regularly voyage to the Southern Ocean’s furthermost icy reaches – but more research is needed. The scientific and broader community must join together to advance Southern Ocean science and protect this vital natural asset.

We are currently in the UN Decade of Ocean Science, which aims to improve predictions of ocean and climate change. Improved understanding of the Southern Ocean is vital to this effort.

An analysis of the shape and composition of the microparticles suggests they may originate from clothes, indicating that wastewater runoff from washing machines could be polluting deep-sea corals living in previously thought to be "pristine waters".

The University College Cork study, funded by the Marine Research Institute, focused on the Porcupine Bank Canyon and north-eastern Porcupine Seabight.

The team analysed samples from depths of 605m to 2,126m from these marine conservation sites.

The study is published in Marine Pollution Bulletin: Microplastics and cellulosic microparticles in North Atlantic deep waters and in the cold-water coral Lophelia pertusa