The Living Ocean

Maintaining momentum is crucial as nations build a treaty to safeguard the high seas, argue Glen Wright, Julien Rochette, Kristina M. Gjerde and Lisa A. Levin.

The exploration of ocean worlds in the outer Solar System offers the opportunity to search for an independent origin of life, and also to advance our capabilities for exploring and understanding life in Earth’s oceans.

Plastic pollution is caused exclusively by humans. It poses growing global threats to both the ocean and society, and requires urgent action. Using psychological principles can motivate and implement change by connecting symptoms and sources.

Ocean uptake of CO₂ slows the rate of anthropogenic climate change but comes at the cost of ocean acidification. Observations now show that the seasonal cycle of CO₂ in the ocean also changes, leading to earlier occurrence of detrimental conditions for ocean biota.

As the United Nations prepares a historic treaty to protect the oceans, scientists highlight what’s needed for success.

Coral reefs are complex ecosystems that are populated by diverse microorganisms. In this Review, Vega Thurberet al. summarize the diversity of reef viruses that infect corals and their associated microbiota, and highlight their roles in coral disease and reef decline.

Incorporating marine biomes into the planetary boundaries framework promotes integrated understanding of biophysical limits and earth system governance.

Size, morphology, silica content and life cycle of diatoms affect their contribution to the export of carbon to the deep ocean, suggests a literature review.

This Review Article discusses the role of bacteriophages in the marine environment, including interactions with their bacterial hosts and their impact on biogeochemical cycling, and a hypothesis to explain successional host–phage dynamics in marine systems.

Metal dissolution from atmospheric aerosol deposition plays an important role in enhancing and inhibiting phytoplankton growth and community structure. Here, the authors review the impacts of trace metal leaching from natural and anthropogenic aerosols on marine microorganisms over short and long timescales.

There has been about a forty per cent reduction in the transport of carbonate ions to the deep North Atlantic Ocean since preindustrial times, severely endangering cold-water corals.

Using transcriptome data from marine subsurface sediments, expressed microbial enzymes are shown to be potential targets for secretion by Bacteria, Archaea and Fungi, providing insights into nutrient cycling in the subsurface environment.

The effects of biological similarity on geochemical signals recorded in planktonic foraminiferal tests used in paleo-reconstructions remains unclear. Here, the authors embed species-specific vital effect offsets in evolutionary models and show how shared evolutionary history shapes δ¹³C, but not δ¹⁸O values.

Latitudinal differences in the global distribution of pelagic and demersal teleost fish predators can be explained by the relative inflow of energy at the base of each food chain.

Marine protected areas aim to conserve biodiversity and habitat. However continued high emissions causing changes in sea-surface temperatures and oxygen levels are likely to disrupt many ecosystems protected by MPAs.

Infection of the alga Emiliania huxleyi with its virus EhV results in the increased release of extracellular vesicles that impact viral decay and infection, suggesting that EhV exploits these extracellular vesicles for efficient viral infection during algal blooms.

The drivers of North Atlantic phytoplankton bloom have been debated for decades, partially owing to incomplete sub-surface observations. Here, Mignot et al. use robotic sensors to provide detailed observations of developing blooms and to explore the drivers of different phases of plankton growth.

Laboratory experiments with the brine shrimp Artemia salina illustrate the potential for turbulence generated by the diurnal vertical migrations of aggregations of centimetre-scale zooplankton to affect the physical and biogeochemical structure of oceanic water columns.

Combining data on sea-surface chlorophyll-a with a regional ocean model and diatom abundance from sediment grabs, the authors determine the strength of pelagic–benthic coupling across the George V region in East Antarctica.

The ocean is a key part of the climate system but is often neglected in individual country priorities. Analysis of Nationally Determined Contributions reveals 70% include marine issues. The level of inclusion varies dependent on country factors including vulnerability to rising seas.

Protists are an important part of the marine food web. In this Review, Caronet al. summarize recent insights from transcriptomic studies of cultured and free-living protists and discuss how these findings highlight the functions and interactions of these single-celled eukaryotes in the global oceans.

The Great Barrier Reef has migrated rapidly in response to sea-level changes since the last glacial period, suggesting resilience to environmental stress over this interval, according to a reconstruction of reef accretion.

The sensitivity of mussel larvae to ocean acidification, particularly during the time of shell formation, remains uncertain. Here, the authors show that larvae can elevate calcium carbonate saturation state beneath their shell to enhance calcification, but this ability is compromised by ocean acidification.

Global patterns of upper-ocean plankton phenology are described and found to vary strongly by latitude and productivity regime, with insolation having a globally overarching role.

Tourism is a significant contributor to the global economy, with potentially large environmental impacts. Origin and destination accounting perspectives are used to provide a comprehensive assessment of global tourism’s carbon footprint.

Marine aquaculture has the potential to improve food security. A global analysis shows that space in coastal areas is unlikely to limit the potential for aquaculture.

Marine ecosystems and their stored carbon are threatened by warming and marine heatwaves. During a 2010–2011 heatwave, around a third of a Western Australian seagrass ecosystem suffered damage, potentially releasing 2–9 Tg CO₂ in the following years.

Much of the methane produced by the deep subseafloor biosphere is consumed by anaerobic methane oxidation with sulfate in continental shelf sediments, according to a global map and calculated budgets of methane fluxes and degradation.