Unveiling the mysteries of the Kermadec Trench

On October 29^(th),2022,scientists from China and New Zealand left Auckland on board the R/V Tansuoyihao to use,for the first time,the full-ocean-depth human-occupied vehicle(HOV)Fendouzhe to systematically explore the Kermadec Trench.The first 1-month-long leg of the voyage was successfully completed on November 25th,2022.The HOV Fendouzhe conducted 16 dives between 5747 and 10010 m in depth,with five dives exceeding 9000 m and two dives to the Scholl Deep,the deepest point of the Kermadec Trench.On November 4th,a first dive to the Scholl Deep was conducted by a scientist(Dr.Kareen Schnabel)from New Zealand National Institute of Water&Atmospheric Research and two pilots(Ms.Yuqing Deng and Mr.Xin Yuan)from the Institute of Deep-sea Science and Engineering,who spent 6 h exploring the Scholl Deep and the adjacent western slope of the trench.This was the first time a female scientist reached the deepest point of this trench.Following a short return to Auckland for re-supply and staff changeover,the second leg of the voyage will be completed before the end of December with another 15 dives planned.

Bio-oxidation of galena particles by Acidithiobacillus ferrooxidans

This paper deals with the bio-oxidation of galena particles （-80 meshes） using Acidithiobacillus ferrooxidans and compares it with Fe^3＋ oxidation. Experimental results show that, at least, 0.00197 mol galena was leached from lOOmL pulp （density of 3.8%） with 39 days＇ bio-oxidation, as compared to 0.00329 mol galena by Fe^3＋ with 9 days＇ oxidation. Because Fe^3＋ was constantly consumed, leaching by Fe^3＋ almost stopped after 9 days. Large amounts of lead sulfate were detected in both bio-oxidation and Fe^3＋ oxidation of galena. A. ferrooxidans followed a unique growth pattern during the bio-oxidation of galena. In the initial 15 days, the bacteria attached themselves to the galena surface with the formation of erosion pits similar in shape and length to those of the bacteria, and there were hardly any bacteria suspended in the solution. After 15 days, suspended bacteria increased. It is thus suggested that A. ferrooxidans may directly oxidize galena.

Sr Isotopes and REEs Geochemistry of Anhydrites from L Vent Black Smoker Chimney, East Pacific Rise 9oN–10oN

High resolution sampling, for Sr isotope and REE analyses, was carried out along a transaction of L vent chimney collected from East Pacific Rise 9oN–10oN. Sr isotopes show these anhydrites are precipitated from a mixture between hydrothermal fluid and seawater. The calculated relative proportion of seawater and hydrothermal fluid shows that the mixing is heterogeneous on the transection of the L vent chimney. Anhydrites from the chimney show uniform chondrite-normalized REE pattern with enrichment of LREE and positive Eu anomaly. While normalized to the REE of end-member hydrothermal fluid, anhydrites also show uniform REE pattern but with negative Eu anomaly and enrichment of HREE. Combining previous studies on REEs of hydrothermal fluids from different hydrothermal systems and the hydrothermal fluid data from this region, we suggested that REE-anion complexing, rather than crystallography controlling, is the main factor that controls the REE partition behavior in the anhydrite during its precipitation from the mixture of hydrothermal fluid and seawater.

Geology, environment, and life in the deepest part of the world’s oceans

The hadal zone,mostly comprising of deep trenches and constituting of the deepest part of the world’s oceans,represents the least explored habitat but one of the last frontiers on our planet.The present scientific understanding of the hadal environment is still relatively rudimentary,particularly in comparison with that of shallower marine environments.In the last 30 years,continuous efforts have been launched in deepening our knowledge regarding the ecology of the hadal trench.However,the geological and environmental processes that potentially affect the sedimentary,geochemical and biological processes in hadal trenches have received less attention.Here,we review recent advances in the geology,biology,and environment of hadal trenches and offer a perspective of the hadal science involved therein.For the first time,we release highdefinition images taken by a new full-ocean-depth manned submersible Fendouzhe that reveal novel species with an unexpectedly high density,outcrops of mantle and basaltic rocks,and anthropogenic pollutants at the deepest point of the world’s ocean.We advocate that the hydration of the hadal lithosphere is a driving force that influences a variety of sedimentary,geochemical,and biological processes in the hadal trench.Hadal lithosphere might host the Earth’s deepest subsurface microbial ecosystem.Future research,combined with technological advances and international cooperation,should focus on establishing the intrinsic linkage of the geology,biology,and environment of the hadal trenches.