IMBeR IPO-China 信息速递
Your news from the Integrated Marine Biosphere Research International Project Office - China
May 2022,
No. 24
IMBeR及其资助部门资讯
IMBeR and Its Sponsors Announcements
In This Issue

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IMBeR and Its Sponsors Announcements
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Editor Picks
IMBeR IPO - China is fully sponsored by ECNU and SKLEC
Editors: GiHoon HONG, Kai QIN and Fang ZUO from IMBeR IPO

Academic adviser: Shan JIANG from SKLEC, ECNU
全球潮汐湿地消长的高分辨率绘图
High-resolution Mapping of Losses and Gains of Earth's Tidal Wetlands
作者: Nicholas J. Murray, Thomas A. Worthington, Pete Bunting, Stephanie Duce, Valerie Hagger, Catherine E. Lovelock, Richard Lucas, Megan I. Saunders, Marcus Sheaves, Mark Spalding, Nathan J. Waltham, and Mitchell B. Lyons
期刊: Science

潮汐湿地被认为会对全球环境变化做出动态响应，但人们对湿地损失被其增益抵消的程度仍知之甚少。我们对卫星数据进行了全球分析，监测了1999年至2019年三种高度相互关联的潮间带生态系统类型——滩涂、潮汐沼泽和红树林的变化。全球已经失去了共计13700平方公里的潮汐湿地，但同时新增的9700平方公里湿地又填补了部分损失，导致20年内最终净损失湿地面积为4000平方公里。我们发现这些消长量的27%与直接人类活动有关，例如将潮汐湿地转为农业用地及对损失湿地进行人为修复。所有其它变化都可归因于间接驱动因素，包括沿海过程和气候变化对其造成的影响。
（实习生周敏编译）
Fig. 1. Representative examples of 1999 to 2019 tidal wetland loss and gain. (A) Losses and gains of tidal flats and tidal marshes after diversion of the main channel in 1996 in the Yellow River delta in China (left). Reference images acquired in 1998 (middle) and 2020 (right). (B) Tidal marsh gain due to Europe’s largest coastal wetland restoration project, UK (left). Reference images acquired in 1999 (middle) and 2018 (right). (C) Mangrove loss due to tectonic subsidence after the Aceh-Andaman earthquake of 2004, Katchal Island, Nicobar Islands (left). Reference images acquired 1992 (middle) and 2019 (right). Imagery data are from USGS (A) and (C) and Google Earth Pro (B). All scale bars are 5 km.
Tidal wetlands are expected to respond dynamically to global environmental change, but the extent to which wetland losses have been offset by gains remains poorly understood. We developed a global analysis of satellite data to simultaneously monitor change in three highly interconnected intertidal ecosystem types—tidal flats, tidal marshes, and mangroves—from 1999 to 2019. Globally, 13,700 square kilometers of tidal wetlands have been lost, but these have been substantially offset by gains of 9700 km2, leading to a net change of −4000 km2 over two decades. We found that 27% of these losses and gains were associated with direct human activities such as conversion to agriculture and restoration of lost wetlands. All other changes were attributed to indirect drivers, including the effects of coastal processes and climate change.
营养水平解耦驱动浮游植物水华物候学的未来变化
Trophic Level Decoupling Drives Future Changes
in Phytoplankton Bloom Phenology
作者: Ryohei Yamaguchi, Keith B. Rodgers, Axel Timmermann, Karl Stein, Sarah Schlunegger, Daniele Bianchi, John P. Dunne, and Richard D. Slater 
期刊: Nature Climate Change

气候变化可以推动海洋生产力发生季节性变化，并对海洋食物网产生影响。然而，这些浮游植物水华物候的变化（起始和峰值时间）及潜在的驱动因素尚不明晰。对此，我们使用了一个含30个模式的气候变化预测大型集合，结果显示大多数海洋区域的水华开始得更早，但不同区域的水华峰值时间变化差异很大。浮游植物生长变化和浮游动物捕食之间的微妙脱钩引起了水华起始时间和峰值时间的变化，而浮游动物捕食的增加（自上而下的控制）在全球大部分海洋的水华峰值时间变化中起着重要作用。在有限的水域，光照限制才是水华起始时间变化的主要控制因素。在热带外地区，到21世纪末，气候变化引起的物候变化将超过其本底的自然变化，这可能会影响海洋食物网中的能量流动。
（实习生周敏编译）
Fig. 2. a,b, Ensemble mean climatology (1990–2020) of phytoplankton bloom initiation (a) and peak timing (b), simulated by GFDL-ESM2M (letters indicate calendar month, January to December). c,d, Ensemble mean trends (1990–2100 under a historical/RCP 8.5 scenario) of bloom initiation (c) and bloom peak timing (d). Positive trends indicate delayed initiation and delayed peak timing. Regions where the trend is statistically insignificant (at the 99% confidence level) are stippled. Black contours superimposed on the maps indicate biome boundaries. e, Biome-averaged changes (2080–2100 minus 1990–2010) in bloom initiation (green) and bloom peak timing (orange). In each ocean basin, ICE, SPSS, STSS, STPS and EQU biomes are assigned in order from the pole (spatial map in Extended Data Fig. 1). Ensemble mean changes are shown as bars and dots on each bar represent the changes of 30 individual members. Stars at the end of a bar indicate that the ensemble mean changes will ‘emerge’, whereby the forced change exceeds the background internal variability by the end of twenty-first century (Methods). Base maps were made with Natural Earth and Cartopy.
Climate change can drive shifts in the seasonality of marine productivity, with consequences for the marine food web. However, these alterations in phytoplankton bloom phenology (initiation and peak timing), and the underlying drivers, are not well understood. Here, using a 30-member Large Ensemble of climate change projections, we show earlier bloom initiation in most ocean regions, yet changes in bloom peak timing vary widely by region. Shifts in both initiation and peak timing are induced by a subtle decoupling between altered phytoplankton growth and zooplankton predation, with increased zooplankton predation (top-down control) playing an important role in altered bloom peak timing over much of the global ocean. Only in limited regions is light limitation a primary control for bloom initiation changes. In the extratropics, climate-change-induced phenological shifts will exceed background natural variability by the end of the twenty-first century, which may impact energy flow in the marine food webs.
恢复湿地生物地貌反馈，恢复世界生物碳热点
Recovering Wetland Biogeomorphic Feedbacks
to Restore the World's Biotic Carbon Hotspots 
作者: Ralph J. M. Temmink, Leon P. M. Lamers, Christine Angelini, Tjeerd J. Bouma, Christian Fritz, Johan Van De Koppel, Robin Lexmond, Max Rietkerk, Brian R. Silliman, Hans Joosten, and Tjisse Van Der Heide
期刊: Science

生物地貌湿地占地表面积的1%，却储存了全球生态系统有机碳的20%。这一不成比例的份额是由泥炭地、红树林、盐沼和海草床的高固碳率和有效储存所推动的，大大超过了海洋和森林生态系统。在此，我们回顾地貌和景观建设植被之间的反馈是如何构成这些特性的基础，以及这一反馈被破坏如何将湿地从碳汇变成碳源。当前，人类活动正导致主要碳储存湿地面积快速下降（以每年1%的速度）。我们的研究结果强调，亟须通过保护手段终止持续损失，并通过创新式恢复手段重建景观形成的反馈，恢复生物地貌湿地作为世界生物碳热点的作用。
（实习生周敏编译）
Fig. 3. Conceptual representation of the formation of carbon-storing biogeomorphic wetlands.
Density-dependent processes underlying biogeomorphic feedbacks can be classified as productivity-stimulating or decomposition-limiting. (A) Peatland formation is initiated through either terrestrialization or paludification. Terrestrialization of aquatic systems by accumulation of organic matter from vascular plants is amplified by productivity-stimulating feedbacks in fens, whereas paludification initiates directly over mineral soil. (B) Once the peat surface rises above the groundwater level, and the peat is large enough to remain waterlogged by retaining rainwater, the resulting bog maintains waterlogged and acidic conditions, resulting in strong decomposition-limiting feedbacks. (C) Vegetated coastal ecosystems (seagrass meadows, mangroves, and salt marshes) generate productivity-stimulating feedbacks that stimulate local production and substrate building. (D) This process can become self-limiting as the system ages because increasing sediment elevation limits further development when this process outpaces sea level rise. This is not a comprehensive representation of all feedbacks. Boxes with vegetation indicate dominant vegetation type in boreal or temperate and tropical wetlands, respectively. [Figure design: Ton A. W. Markus. Symbols are from Integration and Application Network, IAN Image Library (https://ian.umces.edu/imagelibrary)]
Biogeomorphic wetlands cover 1% of Earth’s surface but store 20% of ecosystem organic carbon. This disproportional share is fueled by high carbon sequestration rates and effective storage in peatlands, mangroves, salt marshes, and seagrass meadows, which greatly exceed those of oceanic and forest ecosystems. Here, we review how feedbacks between geomorphology and landscape-building vegetation underlie these qualities and how feedback disruption can switch wetlands from carbon sinks into sources. Currently, human activities are driving rapid declines in the area of major carbon-storing wetlands (1% annually). Our findings highlight the urgency to stop through conservation ongoing losses and to reestablish landscape-forming feedbacks through restoration innovations that recover the role of biogeomorphic wetlands as the world’s biotic carbon hotspots.
凭借恋出生地性确定太平洋大型中上层鱼类的暂定封闭洄游周期和保护区域
Philopatry as a Tool to Define Tentative Closed Migration Cycles and Conservation Areas for Large Pelagic Fishes in the Pacific
作者: Veronica Relano and Daniel Pauly
期刊: Sustainability

大型中上层鱼类穿越太平洋的洄游通常可以通过标记或基因研究来推断。尽管这些技术随着时间的推移不断改进，但仍无法证明大规模的跨洋洄游，通常提出的“路线”并不会出现季节性循环。目前的研究在11种大型中上层鱼类中使用了“恋出生地性”的概念，即动物返回其出生地进行繁殖的趋势。将这一概念应用到对卫星和传统标记、遗传和/或基因组研究推断的种群和亚种群联系等文献综合分析提取出的迁移，就得到了初步的迁移路线和地图。此外，当比较这些推断出的迁移路线和太平洋每个物种的重建渔获量（1950-2016年，哥伦比亚大学 Sea Around Us 计划）时，出现了相似之处，从而加强了由“恋出生地性”得出的迁移周期的准确性。最后，通过叠加11个物种的迁移路线，我们确定了太平洋的某些区域是多个物种迁徙路线的一部分，推动了关于可能的“蓝色走廊”的讨论，这将保护所研究物种的关键迁移路线和种群，对太平洋岛民的渔业、文化和营养摄取是十分重要的。
（实习生周敏编译）
Fig. 4. Tentative migration routes of albacore (Thunnus alalunga) inferred from several sources (see numbers adjacent to the arrows). This suggests two stocks, north and south of the equator. Sources: (1) Bertrand (1999); (2) Harrison et al. (2018); (3) Harley and Williams (2013); (4) Dhurmeea et al. (2016); (5) Farley et al. (2013); (6) Hernandez et al. (2019); (7) Murray (1993); (8) Lewis (1990); (9) Arnold (2001); (10) Childers et al. (2011); (11) Uosaki (2004); (12) Moore et al. (2020); (13) Block et al. (2011). The shaded purple areas refer to breeding grounds. The pink and yellow shaded area refers to the main distribution area of larvae and juveniles, respectively. The insert in the upper right corner shows the catch distribution of albacore from 1950 to 2016 (blue: low; red: high catches).
Migrations of large pelagic fishes across the Pacific are usually inferred from tagging or genetic studies. Even though these techniques have improved over time, they still fail to demonstrate large transoceanic migrations, usually proposing ‘routes’ that do not cycle seasonally. The current study uses the concept of ‘philopatry’ in 11 large pelagic fish species, i.e., the tendency for animals to return to their natal site to reproduce. Tentative migration routes and maps emerge by applying this concept to the movements extracted through a comprehensive review of the literature on satellite and conventional tagging, and population and subpopulation linkages inferred from genetic and/or genomic studies. Moreover, when comparing these proposed migration routes and the mapped reconstructed catch (1950–2016, Sea Around Us) of each species in the Pacific, similarities emerge, reinforcing the accuracy of these migration cycles informed by philopatry. Finally, by superposing the migration routes of our 11 species, we identified areas of the Pacific that are part of the inferred migration routes of multiple species, leading to a discussion of possible ‘blue corridors’ that would protect the studied species’ key migration routes and stocks, which are important for the fisheries, culture and nutrition of Pacific islanders.
21世纪全球海洋记忆的衰退
Global Decline in Ocean Memory over the 21st Century
作者：Hui Shi, Feifei Jin, Robert C. J. Wills, Michael G. Jacox, Dillon J. Amaya, Bryan A. Black, Ryan R. Rykaczewski, Steven J. Bograd, Marisol García-Reyes, and William J. Sydeman
期刊：Science Advances

海洋记忆，即海洋状况的持续性，是气候系统中超越天气时间尺度的可预测性的主要来源。我们的研究表明，通过衡量逐年海洋表面温度异常的持续性，模式预估海洋记忆在未来几十年内将在全球大部分地区稳步下降。海洋记忆的这种全球范围内的下降主要是由上层海洋混合层深度变浅、以应对全球表面变暖造成的；而热力学和动力学反馈可以在很大程度上促进区域性变化。随着混合层深度变浅，随机胁迫在驱动海表面温度异常方面变得更加有效，以牺牲海温中的持续信号为代价增加了其高频噪声。海洋记忆的丢失造成基于海温持续性的海表热状况的有效预报提前期缩短，这可能对预测极端气候和管理气候变化下的海洋生物资源带来前所未有的挑战。
（实习生朱珺月编译）
Fig. 5. Declining year-to-year ocean memory through the 21st century.
(A) Climatological 1-year autocorrelation, A(1), of annual SST anomalies at the end of the 19th century (1870–1899). The magenta lines bound regions of statistically significant A(1) (correlation = 0.3, degree of freedom = 28). (B) Change in A(1) from 1870–1899 to 2071–2100 under SSP5-8.5 scenario. Values are averaged over individual realizations from 20 different climate models from the CMIP6 multimodel ensemble (MME). The magenta lines bound regions of statistically significant A(1) in 2071–2100. Changes outside the gray dotted area are robust (Materials and Methods). White regions over ocean have seasonal or permanent sea-ice cover (Materials and Methods). (C) Global mean A(1) in 30-year rolling windows from observations and CMIP6 simulations from the historical and future (SSP) scenarios. Gray shadings show the range of values across models in percentiles: 25 to 75% (dark) and 5 to 95% (light). The dashed line is the A(1) averaged over the preindustrial control runs from the CMIP6 MME, with an error bar (cadet blue) showing the uncertainty in the MME (MME UNC.) (Materials and Methods). Error bars are also shown to quantify the cross-model spread (purple) and internal variability (salmon) (Materials and Methods). (D to F) Same as (A) to (C) but calculated with the 40-member Community Earth System Model Large Ensemble (CESM1-LE). (D) The climatological A(1) for 1920–1949 period and (E) change in A(1) between 1920–1949 and 2071–2100 in Representative Concentration Pathway (RCP) 8.5 scenario. In (F), the colored dashed line is the global mean A(1) with the fourth-order polynomial detrending, as used for the MME (Materials and Methods). Error bars show uncertainty in the ensemble mean (LE UNC.) and the spread due to internal variability (IV).
Ocean memory, the persistence of ocean conditions, is a major source of predictability in the climate system beyond weather time scales. We show that ocean memory, as measured by the year-to-year persistence of sea surface temperature anomalies, is projected to steadily decline in the coming decades over much of the globe. This global decline in ocean memory is predominantly driven by shoaling of the upper-ocean mixed layer depth in response to global surface warming, while thermodynamic and dynamic feedbacks can contribute substantially regionally. As the mixed layer depth shoals, stochastic forcing becomes more effective in driving sea surface temperature anomalies, increasing high-frequency noise at the expense of persistent signals. Reduced ocean memory results in shorter lead times of skillful persistence-based predictions of sea surface thermal conditions, which may present previously unknown challenges for predicting climate extremes and managing marine biological resources under climate change.
海葵和珊瑚将氧苯酮防晒剂转化为具有光毒性的葡糖苷共轭物
Conversion of Oxybenzone Sunscreen to Phototoxic
Glucoside Conjugates by Sea Anemones and Corals
作者: Djordje Vuckovic, Amanda I. Tinoco, Lorraine Ling, Christian Renicke, John R. Pringle, and William A. Mitch
期刊: Science

据报道，含氧苯酮的防晒霜对珊瑚的毒性引发了人们对生态旅游者使用防晒霜对珊瑚影响的担忧，而且珊瑚资源本就因受全球压力影响而衰退。目前，氧苯酮的毒性机制尚不明确，这阻碍了更安全防晒霜的研发。我们发现，包括紫外线（UV）辐射（290至370纳米）在内的模拟阳光下，氧苯酮会导致海葵的高死亡率。尽管氧苯酮本身可以抵御外线诱导的光氧化，但海葵和一种蘑菇珊瑚都可形成的氧苯酮-葡糖苷共轭物是一种强光氧化剂。海藻共生体封存了这些共轭物，死亡率与动物细胞质中的共轭物浓度相关。离开共生体的海葵死亡率更高，这表明氧苯酮的生态风险对因温度升高而漂白的珊瑚进一步增加。因为许多商业防晒剂含有结构相关的化学品，所以了解代谢物的光毒性应有助于开发对珊瑚安全的产品。
（实习生周敏编译）
Fig. 6. Photosensitization by oxybenzone and related molecules.
(A) Chemical structures of oxybenzone (oxy) and related molecules (red: structural additions to oxybenzone). (B) Light-absorption spectra of compounds 1 and 3 to 5. (C) Allyl-thiourea and sorbic alcohol as probes for reactive species. 1SENS, photosensitizing molecule in its ground state; 3SENS*, photosensitizing molecule in its excited, triplet state. (D) First-order photodegradation rate constants for 10 μM allyl-thiourea with 35 μM of compounds 1 to 5 at pH 8.1 in seawater-strength halide solution (see supplementary materials and methods). Error bars, SEM from three independent experiments.
The reported toxicity of oxybenzone-based sunscreens to corals has raised concerns about the impacts of ecotourist-shed sunscreens on corals already weakened by global stressors. However, oxybenzone’s toxicity mechanism(s) are not understood, hampering development of safer sunscreens. We found that oxybenzone caused high mortality of a sea anemone under simulated sunlight including ultraviolet (UV) radiation (290 to 370 nanometers). Although oxybenzone itself protected against UV-induced photo-oxidation, both the anemone and a mushroom coral formed oxybenzone–glucoside conjugates that were strong photo-oxidants. Algal symbionts sequestered these conjugates, and mortality correlated with conjugate concentrations in animal cytoplasm. Higher mortality in anemones that lacked symbionts suggests an enhanced risk from oxybenzone to corals bleached by rising temperatures. Because many commercial sunscreens contain structurally related chemicals, understanding metabolite phototoxicity should facilitate the development of coral-safe products.
沿海上升流区养分供应对浮游微生物生物多样性及分布的影响
Influence of Nutrient Supply on Plankton Microbiome Biodiversity and Distribution in a Coastal Upwelling Region
作者：Chase C. James, Andrew D. Barton, Lisa Zeigler Allen, Robert H. Lampe, Ariel Rabines, Anne Schulberg, Hong Zheng, Ralf Goericke, Kelly D. Goodwin, and Andrew E. Allen
期刊：Nature Communications

驱动中上层海洋微生物群对环境变化响应的生态和海洋学过程仍是海洋学科的薄弱领域，尤其是在沿海上升流生态系统中。本文表明，在南加州洋流区，沿海上升流的季节性和年际变化可以预测的中上层海洋微生物多样性和群落结构。2014-2020年间季节性采集的样本中，针对原核和真核微生物的核糖体RNA基因测序表明，Nitracline层(水体中硝酸盐浓度随深度变化较快的水层)深度是该地区空间微生物群落结构和生物多样性最可靠的预测因子。由于气候从以强烈分层为特征的暖异常（2014-2016）转变为以更典型的上升流条件为代表的较冷气候条件（2017-2018），对生态造成了显著的变化，光合真核生物变化最为强烈，尤其是硅藻。Nitracline层深度的区域坡面对生物多样性高的近海群落和生物多样性低但生产力高的近岸群落的相对比例具有很强的控制作用。
（实习生朱珺月编译）
Fig. 7. a Map showing the mean alpha diversity for all ASVs for each station. b mean alpha (blue) and gamma diversity (green) per station for all ASVs as a function of distance to shore (km). Shannon index was used as the primary measure of diversity and was calculated as the mean per station per cruise for this analysis. Relationships are fit as a generalized additive model (GAM) with a 95% confidence interval. c map showing the mean alpha diversity for diatoms for each station. d mean alpha (blue) and gamma diversity (green) per station for diatoms as a function of distance to shore (km). Relationships are fit as a generalized additive model (GAM) with a 95% confidence interval (shading). e relative importance of all explanatory variables (mean and coefficient of variation) used to predict mean alpha diversity at a given station. Relationships between environmental variables and diversity were assessed via a generalized linear model with a gaussian fit. Larger circles represent lower AIC values within a column. Circles and their associated AIC values should not be compared across columns. Color represents the correlation coefficient between each explanatory variable and mean alpha diversity. Gray circles represent relationships that are not significant (p > 0.05). Relationships were analyzed between diversity and the mean and coefficient of variation (Coeff. Var.) of environmental variables. Environmental variables included: temperature (Temp), salinity, NO3, PO4, SiO4, chlorophyll a (Chl-a), and nitracline depth (NCD).
The ecological and oceanographic processes that drive the response of pelagic ocean microbiomes to environmental changes remain poorly understood, particularly in coastal upwelling ecosystems. Here we show that seasonal and interannual variability in coastal upwelling predicts pelagic ocean microbiome diversity and community structure in the Southern California Current region. Ribosomal RNA gene sequencing, targeting prokaryotic and eukaryotic microbes, from samples collected seasonally during 2014-2020 indicate that nitracline depth is the most robust predictor of spatial microbial community structure and biodiversity in this region. Striking ecological changes occurred due to the transition from a warm anomaly during 2014-2016, characterized by intense stratification, to cooler conditions in 2017-2018, representative of more typical upwelling conditions, with photosynthetic eukaryotes, especially diatoms, changing most strongly. The regional slope of nitracline depth exerts strong control on the relative proportion of highly diverse offshore communities and low biodiversity, but highly productive nearshore communities.
过渡到密闭空间会影响细菌的游动和逃逸反应
Transitioning to Confined Spaces Impacts
Bacterial Swimming and Escape Response
作者：Jonathan B. Lynch, Nicholas James, Margaret McFall-Ngai, Edward G. Ruby, Sangwoo Shin, and Daisuke Takagi
期刊：Biophysical Journal

共生细菌通常在复杂的环境中游走，然后在宿主有机体中的特权部位定居。已知化学梯度有助于这些细菌的定向运动，引导它们走向最终目的地。然而，人们对物理特征在塑造细菌的路径和定义它们如何穿越给定空间方面的作用知之甚少。有鞭毛的海洋细菌Vibrio fischeri与夏威夷短尾鱿鱼Euprymna scolopes形成二元共生关系，在定植期间必须经过严格的物理限制，在到达最终归宿的途中挤进宽度缩窄到约为2 μm的“瓶颈”组织。利用微流体体外实验，我们发现V.fischeri细胞在进入密闭空间时会改变其行为，拉直其游泳路径并促进从密闭空间中逃脱。使用计算模型，我们将这种逃逸响应归因于两个因素：方向波动的­减少和方向反转之间的不应期。在不对称毛细管中的其他实验证实，V.fischeri即使通过化学吸引进入毛细血管末端，也可以迅速从狭窄的末端逃脱。当狭窄空间的限制接近细胞本身直径时，这种逃避行为明显减弱，从而在化学吸引和逃避物理限制之间取得平衡。我们的研究结果表明，游泳细菌的非平凡分布 (nontrivial distributions)可以在简单的物理梯度空间限制条件下出现。狭小的空间可以作为细菌在复杂环境中进入特定栖息地时的另外关键线索。
（实习生朱珺月编译）
Fig. 8. Confinement promotes channel escape in V. fischeri. (A) Schematic of confinement channels for 2 and 10 μm confinement. (B) Collapsed traces of V. fischeri swimming under 10 μm z confinement over 10 s. (C) Collapsed traces of V. fischeri swimming under 2 μm z confinement over 10 s. Left of vertical black lines is open chamber, right of black lines are confined channels. (D) Selected traces of V. fischeri cells entering noted z confinement. Color denotes time in seconds.
Symbiotic bacteria often navigate complex environments before colonizing privileged sites in their host organism. Chemical gradients are known to facilitate directional taxis of these bacteria, guiding them toward their eventual destination. However, less is known about the role of physical features in shaping the path the bacteria take and defining how they traverse a given space. The flagellated marine bacterium Vibrio fischeri, which forms a binary symbiosis with the Hawaiian bobtail squid, Euprymna scolopes, must navigate tight physical confinement during colonization, squeezing through a tissue bottleneck constricting to ∼2 μm in width on the way to its eventual home. Using microfluidic in vitro experiments, we discovered that V. fischeri cells alter their behavior upon entry into confined space, straightening their swimming paths and promoting escape from confinement. Using a computational model, we attributed this escape response to two factors: reduced directional fluctuation and a refractory period between reversals. Additional experiments in asymmetric capillary tubes confirmed that V. fischeri quickly escape from confined ends, even when drawn into the ends by chemoattraction. This avoidance was apparent down to a limit of confinement approaching the diameter of the cell itself, resulting in a balance between chemoattraction and evasion of physical confinement. Our findings demonstrate that nontrivial distributions of swimming bacteria can emerge from simple physical gradients in the level of confinement. Tight spaces may serve as an additional, crucial cue for bacteria while they navigate complex environments to enter specific habitats.
从海洋破囊壶菌走向循环生物经济的多产品生物炼制
Multiproduct Biorefinery from Marine
Thraustochytrids Towards a Circular Bioeconomy
作者：Adarsha Gupta, Colin J. Barrow, and Munish Puri
期刊：Trends in Biotechnology

海洋环境在很大程度上尚未被开发，关于微藻生物技术的研究持续增多，消费者对健康产品的兴趣也不断增长。破囊壶菌(thraustochytrids)是一种海洋含油原生生物，以其生产的生物活性物质而闻名，在营养品、制药和水产养殖中有着重要的应用。众多高价值的生化物质已被研究，如营养补充剂（omega-3脂肪酸）、角鲨烯、胞外多糖（EPSs）、酶、水产养殖饲料以及生物柴油和色素化合物。我们讨论了破囊壶菌作为生产各种生物活性化合物的可行性，并主张开发生物精炼厂以抵消生产成本。我们预计，未来在细胞制造、脂质组学分析和纳米技术指导下的脂质提取方面的进步将有助于利用这些微生物进行具有成本竞争力的大规模生产。
（实习生朱珺月编译）
Fig. 9. Key figure. Schematic diagram of thraustochytrid fermentation and thraustochytrid products and applications.
Microalgal biotechnology research continues to expand due to largely unexplored marine environments and growing consumer interest in healthy products. Thraustochytrids, which are marine oleaginous protists, are known for their production of bioactives with significant applications in nutraceuticals, pharmaceuticals, and aquaculture. A wide range of high-value biochemicals, such as nutritional supplements (omega-3 fatty acids), squalene, exopolysaccharides (EPSs), enzymes, aquaculture feed, and biodiesel and pigment compounds, have been investigated. We discuss thraustochytrids as potential feedstocks to produce various bioactive compounds and advocate developing a biorefinery to offset production costs. We anticipate that future advances in cell manufacturing, lipidomic analysis, and nanotechnology-guided lipid extraction would facilitate large-scale cost-competitive production through these microbes.
火山引发的辐射和二氧化硫排放的动态反馈导致气候变暖
Volcanic Climate Warming Through Radiative
and Dynamical Feedbacks of SO2 Emissions
作者：Scott D. Guzewich, Luke D. Oman, Jacob A. Richardson, Patrick L. Whelley, Sandra T. Bastelberger, Kelsey E. Young, Jacob E. Bleacher, Thomas J. Fauchez, and Ravi K. Kopparapu
期刊：Geophysical Research Letters

在地球历史的至少最后4亿年中，火山洪水玄武岩喷发与重大气候破坏、海洋缺氧事件和大规模灭绝有关或与之同时发生。以前的研究和最近的历史表明，火山驱动的气候冷却可以通过H2SO4气溶胶反射阳光来实现，而长期气候变暖可以通过二氧化碳排放来实现。我们使用Goddard地球观测系统化学-气候模型来模拟持续4年的火山SO2排放，其规模相当于哥伦比亚河Wapshilla山脊段玄武岩的火山喷发。H2SO4气溶胶引起的短暂冷却期被平流层H2O蒸汽三个数量级的增加所导致的动态和辐射驱动的气候变暖效应所盖过。
（实习生朱珺月编译）
Fig. 10. Zonal mean temperature change of the eruption simulation relative to a baseline and SO4 aerosol optical thickness (AOT). (a) Zonal mean temperature change (K) of the eruption simulation relative to a 20-year average of a baseline simulation as a function of time and (b) the zonal mean temperature change over continental areas only. The −10 K and +10 K contours are highlighted for reference. (c) Zonal average sulfate AOT as a function of time and (d) global area-weighted AOT. The vertical dashed line represents the end of the eruption.
Volcanic flood basalt eruptions have been linked to or are contemporaneous with major climate disruptions, ocean anoxic events, and mass extinctions throughout at least the last 400 M years of Earth's history. Previous studies and recent history have shown that volcanically-driven climate cooling can occur through reflection of sunlight by H2SO4 aerosols, while longer-term climate warming can occur via CO2 emissions. We use the Goddard Earth Observing System Chemistry-Climate Model to simulate a 4-year duration volcanic SO2 emission of the scale of the Wapshilla Ridge member of the Columbia River Basalt eruption. Brief cooling from H2SO4 aerosols is outweighed by dynamically and radiatively driven warming of the climate through a three orders of magnitude increase in stratospheric H2O vapor.
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Disclaimer: This column is a new trial to share cutting-edge research with wider academic community. The Chinese is not an official translation, while the English is invoked from original publication. If there is anything inappropriate, please contact imber@ecnu.edu.cn to correct us or request for a retraction.
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