Volume 11 Issue 1, January 2018

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.

Making sense of exoplanet observations requires better understanding of terrestrial atmospheres in our solar system, especially for Venus. We need to not just intermittently explore, but continuously monitor these atmospheres — like we do for Earth.

A combination of two anoxygenic pathways of photosynthesis could have helped to warm early Earth, according to geochemical models. These metabolisms, and attendant biogeochemical feedbacks, could have worked to counter the faint young Sun.

Tectonic controls on atmospheric oxygenation are frequently invoked — but whether geochemical records support these ties is an unsettled question.

The composition of the oceans is altered by hydrothermal circulation. These chemical factories sustain microbial life, which in turn alters the chemistry of the fluids that enter the ocean. A decade of research details this complex interchange.

The slowdown in surface warming in the early twenty-first century has been traced to strengthening of the Pacific trade winds. The search for the causes identifies a planetary-scale see-saw of atmosphere and ocean between the Atlantic and Pacific basins.

The elemental ratios of marine phytoplankton and organic matter vary widely across ocean biomes, according to a catalogue of biogeochemical data, suggesting that climate change may have complex effects on the ocean’s elemental cycles.

Advances in high-precision isotopic analysis have provided key constraints on the origin and early evolution of the Earth and Moon. Measurements of the isotopes of tungsten provide the most stringent constraints on this history.

A compilation of hundreds of palaeoclimate records highlighted the extent of regional variability during the past 2,000 years, and therein the uniqueness of recent warming.

Ancient hydrothermal deposits formed in the Martian subsurface may be the best targets for finding evidence for ancient life on Mars, and clues about the origin of life on Earth.

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.

Wind power for energy generation is projected to decrease in northern mid-latitudes and increase in the tropics and Southern Hemisphere, suggests an analysis of climate model simulations utilizing an industry wind turbine power curve.

Extratropical feedbacks between climate and aerosols from landscape fire and biogenic secondary organic aerosols are significant, according to a global aerosol model that is constrained by observations.

Iceberg melt is the largest annual freshwater source in a south Greenland fjord, with release largely below 20 m depth, according to iceberg-model simulations. Furthermore, iceberg melt peaks later in the year than other sources of freshwater.

Amplification of the methane cycle by anyoxygenic photosynthesis could have warmed early Earth and countered the faint young Sun, geochemical modelling suggests. A combination of H₂-based and Fe²⁺-based photosynthesis acts to enhance methane fluxes.

The faults in creeping segments of subduction zones are weaker than those in locked segments, according to analyses of stress orientations and GPS data from subduction zones globally.

A water-rich layer of partial melt marks the base of the lithosphere in the equatorial Atlantic Ocean, according to analyses of seismic data.

Volcanism in the western US may result from warm oceanic mantle beneath the Pacific Ocean being drawn eastwards by mantle flow induced by the sinking of Farallon slabs, according to numerical model simulations.

Collisions of large differentiated impactors during the late stages of Earth’s accretion may have heterogeneously mixed projectile material into the Earth, explaining observed chemical and isotopic heterogeneities in mantle materials.