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Trophic Level Decoupling Drives Future Changes
in Phytoplankton Bloom Phenology
作者: Ryohei YamaguchiKeith B. RodgersAxel TimmermannKarl SteinSarah SchluneggerDaniele BianchiJohn P. Dunne, and Richard D. Slater 
期刊: Nature Climate Change

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.
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

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 (]
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.
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。
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.
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

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.
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

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.
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

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.
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。
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.
Multiproduct Biorefinery from Marine
Thraustochytrids Towards a Circular Bioeconomy
作者:Adarsha Gupta, Colin J. Barrow, and Munish Puri
期刊:Trends in Biotechnology

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.
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

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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