《自然》（20230824出版）一周論文導讀

Nature,  24 August 2023, Volume 620 Issue 7975, 

《自然》2023年8月24日，第620卷，7975期

物理學Physics

Poton transport through nanoscale corrugations in two-dimensional crystalsn

二維晶體中納米級波紋的質子輸運

▲ 作者：O. J. Wahab, E. Daviddi, B. Xin, P. Z. Sun, E. Griffin, A. W. Colburn, D. Barry, M. Yagmurcukardes, F. M. Peeters, A. K. Geim, M. Lozada-Hidalgo & P. R. Unwin

▲ 鏈接：https://www.nature.com/articles/s41586-023-06247-6

▲ 摘要：

研究者使用高分辨率掃描電化學電池顯微鏡發現，雖然質子通過機械剝離的單層石墨烯和六方氮化硼的滲透不能歸因于任何結構缺陷，但納米尺度的二維膜的非平坦性極大地促進了質子的運輸。

掃描電化學電池顯微鏡觀察到的質子電流的空間分布顯示出明顯的不均勻性，這種不均勻性與納米尺度的皺紋和其他應變積累的特征密切相關。

研究結果強調了納米尺度的形貌是質子通過二維晶體傳輸的重要參數，二維晶體通常被認為是平面的，并且表明應變和曲率可以作為額外的自由度來控制二維材料的質子滲透率。

▲ Abstract：

Here, using high-resolution scanning electrochemical cell microscopy, we show that, although proton permeation through mechanically exfoliated monolayers of graphene and hexagonal boron nitride cannot be attributed to any structural defects, nanoscale non-flatness of two-dimensional membranes greatly facilitates proton transport. The spatial distribution of proton currents visualized by scanning electrochemical cell microscopy reveals marked inhomogeneities that are strongly correlated with nanoscale wrinkles and other features where strain is accumulated. Our results highlight nanoscale morphology as an important parameter enabling proton transport through two-dimensional crystals, mostly considered and modelled as flat, and indicate that strain and curvature can be used as additional degrees of freedom to control the proton permeability of two-dimensional materials.　

Mixed-dimensional moiré systems of twisted graphitic thin films

扭曲石墨薄膜的混合維渦流系統

▲ 作者：Dacen Waters, Ellis Thompson, Esmeralda Arreguin-Martinez, Manato Fujimoto, Yafei Ren, Kenji Watanabe, Takashi Taniguchi, Ting Cao, Di Xiao & Matthew Yankowitz

▲ 鏈接：https://www.nature.com/articles/s41586-023-06290-3

▲ 摘要：

將具有相對扭轉角的原子薄范德華晶體堆疊形成的摩爾條紋可以產生顯著的新物理性質。研究者通過在薄塊石墨晶體上輕微旋轉單層石墨烯片來構建雙門控器件，并對其進行輸運測量，發現摩爾流勢改變了整個石墨薄膜的電子特性。

在零磁場和小磁場中，輸運是由柵極可調諧的摩爾和石墨表面態的組合介導的，以及共存的半金屬體態，它們對柵極沒有反應。在高場下，由于石墨的兩個最低朗道帶的獨特性質，石墨的摩爾流勢與石墨體態發生雜化。

這些朗道帶有助于形成單一的準二維雜化結構，在這種雜化結構中，摩爾態和塊狀石墨態不可避免地混合在一起。研究建立了第一種新型混合維摩爾材料扭曲石墨烯-石墨。

▲ Abstract：

Moiré patterns formed by stacking atomically thin van der Waals crystals with a relative twist angle can give rise to notable new physical properties. Here, we perform transport measurements of dual-gated devices constructed by slightly rotating a monolayer graphene sheet atop a thin bulk graphite crystal. We find that the moiré potential transforms the electronic properties of the entire bulk graphitic thin film. At zero and in small magnetic fields, transport is mediated by a combination of gate-tuneable moiré and graphite surface states, as well as coexisting semimetallic bulk states that do not respond to gating. At high field, the moiré potential hybridizes with the graphitic bulk states due to the unique properties of the two lowest Landau bands of graphite. These Landau bands facilitate the formation of a single quasi-two-dimensional hybrid structure in which the moiré and bulk graphite states are inextricably mixed. Our results establish twisted graphene–graphite as the first in a new class of mixed-dimensional moiré materials.

地理學和地球物理學

Geography & Geophysics

A global rise in alluvial mining increases sediment load in tropical rivers

全球沖積采礦增加熱帶河流沉積物負荷

▲ 作者：Evan N. Dethier, Miles Silman, Jimena Díaz Leiva, Sarra Alqahtani, Luis E. Fernandez, Paúl Pauca, Seda ?amalan, Peter Tomhave, Francis J. Magilligan, Carl E. Renshaw & David A. Lutz

▲ 鏈接：

https://www.nature.com/articles/s41586-023-06309-9

▲ 摘要：

全球熱帶地區河流中越來越多的黃金和礦產開采活動已經導致生態系統退化，并威脅到人類健康。這種河流礦產開采涉及河道走廊的密集挖掘和沉積物處理，改變了河流形態，并向下游釋放了多余的沉積物。懸浮沉積物負荷的增加會降低水的清晰度，造成淤積，從而可能導致魚類患病和死亡、水質惡化和對人類基礎設施造成損害。

雖然已在地方尺度上對河流采礦進行了調查，但沒有對其實際足跡和對水文系統的影響進行全球綜合，因此對其全部環境后果一無所知。研究者收集并分析了一個跨度37年的衛星數據庫，顯示了全球范圍內普遍存在的、不斷增加的河流礦產開采。

研究者確定了49個國家的396個礦區，集中在幾乎普遍被采礦衍生沉積物改變的熱帶水道。在173條受采礦影響的河流中，80%的懸浮沉積物濃度是采礦前水平的兩倍多。

在采礦影響大型河流（>50米寬）的30個國家中，23±19%的大型河流長度被采礦產生的沉積物改變，這是一個全球性的影響，代表35,000公里的河流，占所有大型熱帶河流長度的約6%。研究結果強調了熱帶河流系統中與采礦相關退化的普遍性和強度。

▲ Abstract：

Increasing gold and mineral mining activity in rivers across the global tropics has degraded ecosystems and threatened human health. Such river mineral mining involves intensive excavation and sediment processing in river corridors, altering river form and releasing excess sediment downstream. Increased suspended sediment loads can reduce water clarity and cause siltation to levels that may result in disease and mortality in fish, poor water quality and damage to human infrastructure. Although river mining has been investigated at local scales, no global synthesis of its physical footprint and impacts on hydrologic systems exists, leaving its full environmental consequences unknown. We assemble and analyse a 37-year satellite database showing pervasive, increasing river mineral mining worldwide. We identify 396 mining districts in 49 countries, concentrated in tropical waterways that are almost universally altered by mining-derived sediment. Of 173 mining-affected rivers, 80% have suspended sediment concentrations (SSCs) more than double pre-mining levels. In 30 countries in which mining affects large (>50m wide) rivers, 23±19% of large river length is altered by mining-derived sediment, a globe-spanning effect representing 35,000 river kilometres, 6% (±1%s.e.) of all large tropical river reaches. Our findings highlight the ubiquity and intensity of mining-associated degradation in tropical river systems.

The break of earthquake asperities imaged by distributed acoustic sensing

分布式聲傳感成像的地震顆粒破碎

▲ 作者：Jiaxuan Li, Taeho Kim, Nadia Lapusta, Ettore Biondi & Zhongwen Zhan

▲ 鏈接：https://www.nature.com/articles/s41586-023-06227-w

▲ 摘要：

利用全球地震陣列對大逆沖地震進行破裂成像，揭示了與頻率相關的破裂特征，但高頻輻射作用仍不清楚。對更豐富的地殼地震的類似觀測可以提供關鍵的限制條件，但如果沒有超密集的局部陣列，這種情況很少見。

研究者采用分布式聲傳感技術對高頻地震破裂輻射體進行成像。通過將一條100公里長的暗光纖電纜轉換成一個10000通道的地震陣列，為2021年美國加州羚羊谷6.0級矩震拍攝了四個高頻子事件的圖像。

在將研究結果與長周期矩釋放和動態破裂模擬進行比較后，作者認為，成像的子事件是由于斷層凸起的斷裂-斷層上更強的點或針-實質上調節了整體破裂行為。在級聯序列中，斷層凸起的斷裂可以促進原本衰落的斷裂傳播。研究強調了如何利用廣泛存在的光纖網絡作為高頻地震天線，系統地研究區域性中等規模地震的破裂過程。結合動態破裂模型，可以提高對地震破裂動力學的認識。

▲ Abstract：

Rupture imaging of megathrust earthquakes with global seismic arrays revealed frequency-dependent rupture signatures, but the role of high-frequency radiators remains unclear. Similar observations of the more abundant crustal earthquakes could provide critical constraints but are rare without ultradense local arrays. Here we use distributed acoustic sensing technology to image the high-frequency earthquake rupture radiators. By converting a 100-kilometre dark-fibre cable into a 10,000-channel seismic array, we image four high-frequency subevents for the 2021 Antelope Valley, California, moment-magnitude 6.0 earthquake. After comparing our results with long-period moment-release and dynamic rupture simulations, we suggest that the imaged subevents are due to the breaking of fault asperities—stronger spots or pins on the fault—that substantially modulate the overall rupture behaviour. An otherwise fading rupture propagation could be promoted by the breaking of fault asperities in a cascading sequence. This study highlights how we can use the extensive pre-existing fibre networks12 as high-frequency seismic antennas to systematically investigate the rupture process of regional moderate-sized earthquakes. Coupled with dynamic rupture modelling, it could improve our understanding of earthquake rupture dynamics.

生態學Ecology

Landscape-scale benefits of protected areas for tropical biodiversity

熱帶生物多樣性保護區的景觀效益

▲ 作者：Jedediah F. Brodie, Jayasilan Mohd-Azlan, Cheng Chen, Oliver R. Wearn, Mairin C. M. Deith, James G. C. Ball, Eleanor M. Slade, David F. R. P. Burslem, Shu Woan Teoh, Peter J. Williams, An Nguyen, Jonathan H. Moore, Scott J. Goetz, Patrick Burns, Patrick Jantz, Christopher R. Hakkenberg, Zaneta M. Kaszta, Sam Cushman, David Coomes, Olga E. Helmy, Glen Reynolds, Jon Paul Rodríguez, Walter Jetz & Matthew Scott Luskin

▲ 鏈接：https://www.nature.com/articles/s41586-023-06410-z

▲ 摘要：

聯合國最近同意大規模擴大全球保護區（PAs），以減緩生物多樣性的下降。研究者測試了東南亞巨大多樣性的保護區是否有助于其邊界內外的脊椎動物保護。保護區增加了鳥類多樣性的各個方面。

大型保護區還與鄰近未受保護景觀中哺乳動物多樣性的顯著增強有關。研究結果與保護區引發的溢出效應一致，而不是導致其他地方的生態條件惡化。這些發現支持了聯合國到2030年實現保護區覆蓋率30%的目標，表明保護區在其邊界內和更廣泛的景觀中都與更高的脊椎動物多樣性相關。

▲ Abstract：

The United Nations recently agreed to major expansions of global protected areas (PAs) to slow biodiversity declines. Here we test whether PAs across mega-diverse Southeast Asia contribute to vertebrate conservation inside and outside their boundaries. Reserves increased all facets of bird diversity. Large reserves were also associated with substantially enhanced mammal diversity in the adjacent unprotected landscape. Rather than PAs generating leakage that deteriorated ecological conditions elsewhere, our results are consistent with PAs inducing spillover that benefits biodiversity in surrounding areas. These findings support the United Nations goal of achieving 30% PA coverage by 2030 by demonstrating that PAs are associated with higher vertebrate diversity both inside their boundaries and in the broader landscape.

PDiverse values of nature for sustainability

可持續發展的不同自然價值

▲ 作者：Unai Pascual, Patricia Balvanera, Christopher B. Anderson, Rebecca Chaplin-Kramer, Michael Christie, David González-Jiménez, Adrian Martin, Christopher M. Raymond, Mette Termansen, Arild Vatn, Simone Athayde, Brigitte Baptiste,etc

▲ 鏈接：https://www.nature.com/articles/s41586-023-06406-9

▲ 摘要：

盡管《昆明-蒙特利爾全球生物多樣性框架》和聯合國可持續發展目標等協議將自然價值觀納入行動，但主流環境和發展政策仍然優先考慮一些價值觀，特別是與市場相關的價值觀，而忽視了人們與自然聯系并從自然中受益的其他方式。可以說，“價值觀危機”是生物多樣性喪失和氣候變化、流行病出現和社會環境不公正等相互交織的危機的基礎。

生物多樣性和生態系統服務政府間平臺在5萬多份科學出版物、政策文件以及土著和地方知識來源的基礎上，評估了有關自然的各種價值和評估方法的知識，以深入了解它們在政策制定中的作用，并更充分地將其納入決策。運用這一證據，提出了以價值為中心的方法組合，以提高估值并解決吸收障礙，最終利用變革性變革，實現更公正和可持續的未來。