The Permian–Triassic mass extinction (PTME) interval is marked by major excursions in both inorganic and organic carbon (C) isotopes. Carbon cycle models predict that these trends were driven by large increases in productivity, yet organic C–rich rocks are not recorded in most PTME shelf sedimentary successions. Anomalous C-rich facies have been reported from rare abyssal plains records now exposed in Japan and New Zealand, where black shales at the PTME are extraordinarily organic-rich units. We examined organic matter at the Waiheke, New Zealand, section, and results show that these deposits are dominated by lamalginites composed of unicellar solitary or colonial phytoplankton produced during algal blooms that falls as “marine snow.” We modeled the impact of ash fall from eruptions in the Siberian Traps large igneous province and argue that they fertilized the Panthalassa Ocean with P and Fe, leading to a marine “snowstorm” and significant C drawdown marking this major biobloom during the PTME.The Permian–Triassic mass extinction (PTME) was the most severe loss of marine and terrestrial diversity in the Phanerozoic (Bond and Grasby, 2017). Extinction drivers remain debated but are generally considered to have been related to impacts of the Siberian Traps large igneous province (SLIP; Dal Corso et al., 2022). A large negative shift in both organic and inorganic carbon (C) isotope records at the marine extinction level reflects disruption of the global C cycle and contemporaneous changes in productivity. Models suggest that the shift back from this negative C isotope excursion involved increased productivity and C burial (e.g., Schobben et al., 2020; Cui et al., 2021) under anoxic open-ocean conditions (Wignall and Twitchett, 1996). However, enhanced productivity and global C burial are not recorded in shallow shelf and slope successions of latest Permian to earliest Triassic age, which have low organic matter (OM) content, despite extensive anoxia (e.g., Grasby et al., 2019; Müller et al., 2022). The discrepancies between C cycle models and the rock record create a quandary over the interpretation of the C isotope record. The occurrence of “carbonaceous claystone” at the PTME boundary in obducted slices of ocean crust in Japan hints at anomalous organic deposition in the abyssal plains of Panthalassa during the PTME (Isozaki, 1997; Suzuki et al., 1998). Similar deposits from southern Panthalassa are also exposed in New Zealand (Grasby et al., 2021). Here, we show that these deep-sea organic-rich deposits are lamalginites, formed from phytoplankton, which suggest that an open-ocean biobloom occurred during the PTME. As mid-ocean productivity is generally nutrient limited, given the distance from terrestrial input, a transient biobloom is difficult to explain.Deposition of atmospherically transported volcanic ash is an important source of bioavailable macro- and micronutrients to the mid-ocean. Longman et al. (2021) estimated that 31% of ash-bound P is released from volcanic ash to seawater, and the high Fe content (1–10 wt% FeO) also makes ash a significant source of micronutrients (e.g., Duggen et al., 2010; Xu and Weber, 2021). We modeled the degree of ocean fertilization from SLIP volcanism and show its role as a likely driver of the PTME bioblooms.Records of the abyssal plains prior to the Jurassic are extremely rare because of subduction. We examined an outcrop of pelagic sedimentary rocks deposited across the Permian–Triassic boundary (PTB) at the Island Bay section on Waiheke Island, New Zealand (Aotearoa) (Hori et al., 2011; Grasby et al., 2021), located at 36°46.131′S, 175°00.200′E (World Geodetic System 1984 datum). This slice of obducted ocean floor (Fig. 1) records deposition at a paleolatitude of ~34°S (Kodama et al., 2007). Now exposed in an intertidal outcrop, pillow lavas are overlain by organic-lean Upper Permian to Lower Triassic siliceous mudstones and cherts of the Kiripaka Formation (Hori et al., 2011). While paleolongitude is more difficult to ascertain, the absence of terrestrial material and the chert-dominated strata all indicate a deep, open-ocean, abyssal plain sedimentary environment far from continental influence (Hori et al., 2011). These strata host three unique black shale units (units 5, 7, and 9 in Fig. 2; Grasby et al., 2021) that strongly contrast with bounding cherts. The lowest black shale unit (5) is 20 cm thick and spans the PTME. Trace metal and pyrite framboid data from unit 5 suggest that transient euxinic bottom-water conditions developed in the southern Panthalassa Ocean at the PTME, coincident with the globally recognized negative carbon isotope excursion and SLIP eruption (Grasby et al., 2021).Organic matter and its thermal maturity were characterized for 12 newly collected organic-rich samples using reflected light microscopy (Zeiss Axioimager II) equipped with the Diskus-Fossil system. Rock samples were mounted in cold-setting epoxy, which was then polished. The standard reference for reflectance measurement was yttrium-aluminum-garnet, with a 0.906% reflectance under oil immersion.We modeled P and Fe emissions from the SLIP using a binomial multiplicative cascade, reflecting the fractal nature of LIP eruptions (Grasby et al., 2020). Given uncertainty in eruption length, we modeled SLIP as a series of total potential eruption periods (32, 64, 128, 256, and 512 k.y.). For each eruption period, 100 randomly generated model runs were used to produce a statistical range of results. Ash production was estimated based on Olgun et al. (2011), whereby parameters included: 1:4 ratio of volcaniclastics to lava volume (2.6 × 106 km3), 5% proportion of ash to volcaniclastics, and a mafic ash density of 2400 kg/m3. Further details are provided in the Supplemental Material.1Previously reported total organic carbon (TOC) contents of the Waiheke section (Grasby et al., 2021) range from 0.21 to 0.55 wt% (mean = 0.30 wt%), except for the lower black shale (unit 5), where TOC ranges from 0.63 to 9.05 wt % (mean = 4.6 wt%). The thin black shales of units 7 and 9 have TOC values of 0.36 wt% and 0.32 wt%, respectively. Pyrolysis results showed negligible S2 yield, indicating high thermal maturity. Petrographic examination revealed that OM is dominantly marine, bituminized lamalginite that preserves the thin lamellar shape of precursor algae (Fig. 3A). Terrestrially sourced OM (e.g., vitrinite and inertinite) was not observed. Pore-filling pyrobitumen (Fig. 3B) occurs as infill of pore spaces in thin, fine-grained laminae, but it is a minor component of OM, such that TOC dominantly reflects marine algal-matter content. The mean random bitumen reflectance (%BRo) of the lamalginites is 1.2% ± 0.03%, and that of pyrobitumen is 1.8% ± 0.07%. The maximum burial temperature and later thermal alteration events (171 °C and 228 °C, respectively) were estimated using the Barker and Pawlewicz (1994) equation. Using the thermal maturation for the lamalginite, the initial mean and maximum in-place TOC (marine algal content) were determined to be 7.3 wt% and 14.5 wt%, respectively, based on the equation of Jarvie (2012).Using our model, an example realization (in this case for Fe) for dissolved nutrient loading to the oceans as a function of SLIP eruption rate is shown in Figure 4A. Results from the 100 model runs for each assumed total eruption time gave a range of mean P and Fe fluxes of 5690–91,000 Gmol P/k.y. and 122–1950 Gmol Fe/k.y., respectively (Fig. 4B).At Waiheke, the low TOC content (mean = 0.30 wt%) of sediments other than black shales is consistent with the deep-ocean setting. In contrast to these background conditions, the black shales deposited during the PTME have estimated original mean TOC content of 7.3 wt%, with a maximum of 14.5 wt%, representing extraordinarily high values for abyssal plain sediments.Organic-rich black shale preservation across the PTME is not unique to this southern Panthalassa site. Black shales reported in sections that represent paleo-equatorial to mid-northern-latitude abyssal plains, now exposed in accretionary complexes of the Chichibu belt and Mino-Tamba terrane of Japan, have been interpreted as evidence for deep-water anoxia at the PTME (Isozaki, 1997). The Japanese records are characterized by deep-water cherts that are replaced in the uppermost Permian section by a siliceous claystone, and then a thin black shale unit that initiates at the PTME and extends into the basal Griesbachian (Isozaki, 1997; Suzuki et al., 1998; Yamakita et al., 1999; Takahashi et al., 2009). The TOC content of the black shales is up to 8 wt% in the Kinkazan area, 3.3 wt% in the Akkamori section (Takahashi et al., 2009), and 7 wt% in the Hisuikyo, Hozukyo, and Kenzan sections, with a mean of 2.56 ± 0.97 wt% (Yamakita et al., 1999). Thus, anomalous organic-rich rocks appear to have been deposited over an extensive area of the Panthalassa abyssal plains during the PTME (from a least mid-southern to mid-northern latitudes). While increased anoxia (Wignall and Twitchett, 1996), which has been shown to have been global by U isotope records (Lau et al., 2016), could explain the preservation of OM, high productivity is required to explain such anomalously high TOC levels in pelagic sediments.The organic-rich black shales deposited across the PTB at Waiheke are dominated by lamalginite (Fig. 3). Found in Middle Proterozoic to recent sediments (Pickel et al., 2017), lamalginites are composed of unicellular solitary or colonial algae phytoplankton. In marine environments, lamalginite is mainly composed of dinoflagellate and acritarch cysts. Export of this low-density labile OM occurs as “marine snow.” Modern marine snow is generally composed of clay as well as organic-derived debris such as the tests of microorganisms, zooplankton fecal pellets, and bacteria (Macquaker et al., 2010). Marine snow accumulation rates are an interplay between rates of biologic production and decomposition of OM en route to the seafloor (e.g., Fowler and Knauer, 1986). Thus, lamalginites typically form during phytoplankton blooms, which enable rapid transport of organic material through the water column.The thermal maturation of our samples is too high for preservation of biomarkers. However, cholestane/stigmastane ratios in Japanese organic-rich shales indicate a much higher contribution of zoo- and phytoplankton to OM as compared to typical Phanerozoic records (Suzuki et al., 1998), consistent with our observations at Waiheke, where OM is dominated by algal material. Given the distal deep-water setting of the Waiheke section, nutrient levels and productivity would be expected to be very low, in accordance with the organic-lean siliceous sediments bounding the PTME horizon. While anoxia would lead to enhanced OM preservation, as previously interpreted (e.g., Isozaki, 1997), we suggest that the lamalginite deposits at the PTME have their origins in bio-blooms. The volume of OM suggests extremely high rates of primary productivity—a veritable marine snowstorm. Such enhanced productivity would require a major nutrient flux to the Panthalassa Ocean, but one that was transient, in order to explain the anomalous organic-rich layers across the PTME in contrast to the OM-lean siliceous sediments deposited before and after the PTME. The estimate of sedimentation rates (0.5 m/m.y.) presented by Hori et al. (2011) constrains the thickest OM-rich bed to record at most 200 k.y. of deposition.Primary production in modern oceans is largely confined to narrow shelf regions along western continental margins, and equatorial belts, where upwelling supplies nutrients to the euphotic zone (Boyd et al., 2014). In contrast, oligotrophic subtropical oceans have very low productivity that is almost entirely dependent on near-surface recycling of macronutrients N and P. High-nutrient, low-chlorophyll regions, covering ~40% of world oceans, have productivity limited by the micronutrient Fe (Watson, 2001).The increased nutrient flux driving a bio-bloom could come from enhanced continental weathering and runoff, enhanced upwelling of nutrient-rich waters to the photic zone, or enhanced atmospheric loading. The absence of terrestrial OM in our samples along with the distal oceanic setting make direct nutrient loading from increased continental weathering unlikely. Suzuki et al. (1998) argued for increased upwelling in the open ocean during the PTME. However, upwelling is largely restricted to western continental margins (due to Coriolis-driven eastern boundary currents) and equatorial zones (due to Coriolis-driven divergent flow) (e.g., Smith, 1995). While changes in wind shear could have increased equatorial upwelling in some Japanese sections, this is unlikely to account for increased productivity in the midlatitude setting of Waiheke Island. The widespread occurrence of organic-rich sediments across Panthalassa must have involved a broader ocean-wide influence on primary production for up to 200 k.y. Frogner et al. (2001) showed that the instantaneous dissolution of aerosols adsorbed to volcanic ash releases high amounts of P and Fe fast enough to support primary production. Hg concentration spikes and Δ199Hg anomalies at Waiheke Island support the interpretation that enhanced SLIP volcanism was concurrent with lamalginite deposition (Grasby et al., 2021).The huge scale of basaltic fissure eruptions of the SLIP was capable of injecting ash into the stratosphere (Glaze et al., 2017). Such basaltic ash is more reactive than silicic ash (Jones and Gislason, 2008), ensuring that the SLIP-generated fertilization of the global oceans was likely substantial. In modern time, examples of nutrient release from ash driving bioblooms include the rapid increase (within weeks) of chlorophyll-a in surface waters following the eruptions of Miyake-jima in Japan (Uematsu et al., 2004) and Kasatochi in the Aleutian Islands, United States (Hamme et al., 2010). Volcanic ash has similarly been suggested to have caused major bioblooms in the Late Ordovician (Longman et al., 2021).Our model results showed a mean range of P and Fe flux of 5690–91,000 Gmol P/k.y. and 122–1950 Gmol Fe/k.y., respectively, and a maximum range of 173,000–559,000 Gmol P/k.y. and 3708–11,970 Gmol Fe/k.y., respectively (dependent on total eruption period of SLIP as in Fig. 4B). In comparison, modern P and Fe dust deposition into the oceans is estimated to be 32,000 and 5700 Gmol/k.y., respectively (Paytan and McLaughlin, 2007; Xu and Weber, 2021). Thus, our results suggest that SLIP nutrient loading would have been in the same order of magnitude as background emissions, at a minimum doubling macro- and micronutrient dust loads to the oceans. Increased P loading is consistent with the globally observed decrease in δ15N values across the PTME (Grasby et al., 2019), as higher P flux would drive enhanced atmospheric N2 fixation to maintain the 16:1 Redfield N/P ratio. What remains uncertain is why anomalous organic-rich sediments are mainly observed in abyssal plains records across the PTME and not on continental shelves. While anoxic conditions on shelf areas might have been expected to foster organic-rich deposition, the high temperatures experienced in shelf seas may have increased organic remineralization (Wignall, 2015). In a similar sense, preservation bias may be important, where deep-sea records better record a transient biobloom event. The impact of additional nutrient flux on marine productivity would also have been highly variable, controlled by the degree of local deficiency. For instance, Xu and Weber (2021) suggested that the modern Fe supply can range from a strong surplus in areas of upwelling to a strong deficit in subtropical gyres, such that the impact of nutrient loading would be selectively higher in nutrient-deficient open-ocean regions.We demonstrated that extraordinarily TOC-rich sediments deposited in deep-ocean settings across the PTME were formed of thick algal deposits, implying the occurrence of major biobloom events creating marine “snowstorms.” Our nutrient flux model indicated that the SLIP could have significantly increased P and Fe loading rates to Panthalassa. We suggest that volcanic ash loading can explain the anomalous occurrence of organic-rich deposits in typically nutrient-starved regions of the deep ocean. The surviving ocean-floor records indicate that these layers were extensive and likely constituted a major carbon burial site, as required by models (e.g., Cui et al., 2021) to explain recovery in the δ13C record after the PTME. The organic-poor nature of most contemporary shelf records remains an enigma.This work benefited from Natural Environment Research Council grant NE/J01799X/1 to D.P.G. Bond.

中文翻译：

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二叠纪-三叠纪大规模灭绝期间的海洋暴风雪

二叠纪-三叠纪大灭绝（PTME）间隔的特点是无机和有机碳（C）同位素的重大偏移。碳循环模型预测，这些趋势是由生产力大幅提高驱动的，但大多数 PTME 陆架沉积序列中并未记录富含有机碳的岩石。日本和新西兰现已暴露的罕见深海平原记录中报告了异常的富含碳相，其中 PTME 的黑色页岩是极其富含有机物的单元。我们对新西兰怀赫科地区的有机物进行了检查，结果表明，这些沉积物主要是由单胞孤生或群落浮游植物组成的层藻，这些浮游植物是在藻类大量繁殖期间产生的，这些浮游植物以“海洋雪”的形式落下。我们模拟了西伯利亚地盾大型火成岩省喷发造成的火山灰影响，并认为火山灰为 Panthalassa 海洋提供了磷和铁的肥料，导致海洋“暴风雪”和显着的碳下降，标志着 PTME 期间的这一主要生物华期。 –三叠纪大规模灭绝（PTME）是显生宙海洋和陆地多样性最严重的丧失（Bond 和 Grasby，2017）。灭绝驱动因素仍然存在争议，但普遍认为与西伯利亚地盾大型火成岩省的影响有关（SLIP；Dal Corso 等人，2022）。海洋灭绝水平上有机和无机碳（C）同位素记录的大幅负变化反映了全球碳循环的破坏和生产力的同期变化。模型表明，在缺氧的公海条件下（Wignall 和 Twitchett，1996），这种负 C 同位素偏移的转变涉及生产率的提高和 C 埋藏（例如，Schobben 等人，2020 年；Cui 等人，2021 年）。然而，尽管存在广泛的缺氧，但在二叠纪晚期至三叠纪早期的浅层陆棚和斜坡序列中，并未记录到生产力提高和全球碳埋藏量的提高，这些浅层陆架和斜坡序列的有机质（OM）含量较低，尽管存在广泛的缺氧（例如，Grasby等人，2019年；Müller等人）等，2022）。C循环模型和岩石记录之间的差异给C同位素记录的解释带来了困境。日本洋壳俯冲切片中 PTME 边界处出现的“碳质粘土岩”暗示着 PTME 期间 Panthalassa 深海平原出现了异常有机沉积（Isozaki，1997；Suzuki 等，1998）。新西兰也暴露出来自 Panthalassa 南部的类似矿床（Grasby 等，2021）。在这里，我们发现这些深海富含有机物的沉积物是由浮游植物形成的层藻，这表明在 PTME 期间发生了公海生物华。由于海洋中部的生产力通常受到养分的限制，考虑到与陆地输入的距离，短暂的生物华很难解释。大气中输送的火山灰的沉积是海洋中部生物可利用的大量和微量营养素的重要来源。朗曼等人。（2021）估计，31％的灰烬结合的磷从火山灰释放到海水中，高铁含量（1-10wt％FeO）也使灰烬成为微量营养素的重要来源（例如，Duggen等人，2010） ；徐和韦伯，2021）。我们模拟了 SLIP 火山活动对海洋的施肥程度，并展示了其作为 PTME 生物华的可能驱动因素的作用。由于俯冲作用，侏罗纪之前的深海平原的记录极其罕见。我们检查了新西兰怀赫科岛（Aotearoa）岛屿湾部分跨越二叠纪-三叠纪边界（PTB）沉积的中上层沉积岩露头（Hori 等人，2011 年；Grasby 等人，2021 年），位于南纬 36°46.131′，东经 175°00.200′（世界大地测量系统 1984 年基准）。这片仰俯洋底（图 1）记录了古纬度约 34°S 的沉积物（Kodama 等人，2007 年）。现在暴露在潮间带露头中的枕状熔岩被贫有机的上二叠统至下三叠统的硅质泥岩和 Kiripaka 组的燧石所覆盖（Hori 等，2011）。虽然古经度更难以确定，但陆地物质的缺失和以燧石为主的地层都表明，这里存在着远离大陆影响的深海、开放海洋、深海平原沉积环境（Hori et al., 2011）。这些地层拥有三个独特的黑色页岩单元（图 2 中的单元 5、7 和 9；Grasby 等人，2021），与边界燧石形成强烈对比。最低的黑色页岩单元 (5) 厚 20 厘米，横跨 PTME。5 号机组的痕量金属和黄铁矿框架数据表明，PTME 的 Panthalassa 洋南部形成了短暂的微生底水条件，与全球公认的负碳同位素偏移和 SLIP 喷发相一致（Grasby 等人，2021）。 有机物质使用配备 Diskus-Fossil 系统的反射光显微镜 (Zeiss Axioimager II) 对 12 个新收集的富含有机物样品进行了热成熟度表征。岩石样品安装在冷固化环氧树脂中，然后进行抛光。反射率测量的标准参考是钇铝石榴石，在油浸下的反射率为 0.906%。我们使用二项式乘法级联对 SLIP 的 P 和 Fe 排放进行建模，反映了 LIP 喷发的分形性质（Grasby 等人， 2020）。考虑到喷发长度的不确定性，我们将 SLIP 建模为一系列总的潜在喷发周期（32、64、128、256 和 512 ky）。对于每个喷发期，使用 100 次随机生成的模型运行来生成统计结果范围。灰烬产量是根据 Olgun 等人估计的。(2011)，参数包括：火山碎屑与熔岩体积的比例为 1:4 (2.6 × 106 km3)，火山碎屑中火山灰的比例为 5%，镁铁质灰密度为 2400 kg/m3。补充材料中提供了更多详细信息。1之前报道的 Waiheke 部分的总有机碳 (TOC) 含量（Grasby 等人，2021 年）范围为 0.21 至 0.55 wt%（平均值 = 0. 30 wt%），但下部黑色页岩（单元 5）除外，其 TOC 范围为 0.63 至 9.05 wt%（平均值 = 4.6 wt%）。7 号和 9 号单元的薄层黑色页岩的 TOC 值分别为 0.36 wt% 和 0.32 wt%。热解结果显示 S2 产量可以忽略不计，表明热成熟度较高。岩相学检查显示，OM 主要是海洋沥青化的角藻岩，保留了前体藻类的薄层状形状（图 3A）。没有观察到来自陆地的 OM（例如镜质体和惰质体）。孔隙填充焦沥青（图 3B）作为薄的细粒纹层中孔隙空间的填充而出现，但它是 OM 的次要成分，因此 TOC 主要反映海洋藻类物质的含量。片状沥青的平均随机沥青反射率 (%BRo) 为 1.2% ± 0.03%，焦沥青的平均随机沥青反射率为 1.8% ± 0.07%。使用 Barker 和 Pawlewicz (1994) 方程估算了最高埋藏温度和后来的热蚀变事件（分别为 171 °C 和 228 °C）。根据 Jarvie (2012) 的方程，利用菱镁矿的热成熟，初始平均和最大原地 TOC（海洋藻类含量）分别确定为 7.3 wt% 和 14.5 wt%。图 4A 显示了海洋溶解养分负荷与 SLIP 喷发率函数的示例实现（本例中为 Fe）。每个假设总喷发时间的 100 次模型运行结果给出了平均 P 和 Fe 通量范围分别为 5690-91,000 Gmol P/ky 和 ​​122-1950 Gmol Fe/ky（图 4B）。除黑色页岩外的沉积物的 TOC 含量（平均值 = 0.30 wt%）与深海环境一致。与这些背景条件相反，PTME 期间沉积的黑色页岩估计原始平均 TOC 含量为 7.3 wt%，最大值为 14.5 wt%，对于深海平原沉积物来说是非常高的值。 PTME 并不是这个南部 Panthalassa 遗址所独有的。代表古赤道至中北纬深海平原的部分报告的黑色页岩，现在暴露在日本秩父带和美浓-丹波地体的增生杂岩中，已被解释为 PTME 深水缺氧的证据。矶崎新，1997）。日本记录的特点是深水燧石在二叠纪最上部被硅质粘土岩所取代，然后是薄薄的黑色页岩单元，起始于 PTME 并延伸到基底 Griesbachian（Isozaki，1997；Suzuki 等，2017）。 ，1998 年；Yamakita 等人，1999 年；Takahashi 等人，2009 年）。金华山地区黑色页岩 TOC 含量高达 8 wt%，Akkamori 剖面为 3.3 wt%（Takahashi 等，2009），Hisuikyo、Hozukyo 和 Kenzan 剖面为 7 wt%，平均值为 2.56 ± 0.97 wt%（Yamakita 等，1999）。因此，富含有机物的异常岩石似乎在 PTME 期间（从至少中南纬度到中北纬度）沉积在 Panthalassa 深海平原的大片区域。虽然缺氧增加（Wignall 和 Twitchett，1996）可以解释 OM 的保存，而 U 同位素记录已证明缺氧是全球性的（Lau 等人，2016），但需要高生产力才能解释如此异常高的 TOC 水平怀赫科 PTB 沉积的富含有机物的黑色页岩主要成分为斜角藻（图 3）。层藻类发现于中元古界至近代沉积物中（Pickel 等，2017），由单细胞孤生或群生藻类浮游植物组成。在海洋环境中，片藻主要由甲藻和原胞囊组成。这种低密度的不稳定 OM 以“海洋雪”的形式输出。现代海洋雪通常由粘土以及有机碎片组成，例如微生物、浮游动物粪便颗粒和细菌的测试（Macquaker 等，2010）。海洋积雪速率是生物生产速率和有机质在到达海底的过程中分解速率之间的相互作用（例如，Fowler 和 Knauer，1986）。因此，层状藻通常在浮游植物大量繁殖期间形成，这使得有机物质能够通过水柱快速运输。我们样品的热成熟度对于生物标记物的保存来说太高了。然而，日本富含有机物页岩中的胆甾烷/柱头烷比率表明，与典型的显生宙记录相比，浮游动物和浮游植物对 OM 的贡献要高得多（Suzuki 等，1998），这与我们在 OM 占主导地位的 Waiheke 的观察结果一致由藻类物质。鉴于怀赫科部分的远端深水环境，根据 PTME 地平线周围的贫有机硅质沉积物，预计营养物水平和生产力将非常低。虽然缺氧会导致 OM 保存增强，如之前的解释（例如，Isozaki，1997），但我们认为 PTME 的菱镁矿沉积物起源于生物华。OM 的体积表明初级生产力极高——一场名副其实的海洋暴风雪。这种生产力的提高需要大量营养物质流入泛海海洋，但这种营养物质流动是短暂的，以便解释 PTME 上的异常富含有机物层，与 PTME 前后沉积的贫有机质硅质沉积物形成鲜明对比。Hori 等人提出的沉降率估计值 (0.5 m/my)。(2011) 限制最厚的富含 OM 的沉积层最多记录 200 ky。现代海洋的初级生产主要局限于西部大陆边缘和赤道带的狭窄陆架区域，那里的上升流向真光带提供营养物质 (Boyd等人，2014）。相比之下，贫营养副热带海洋的生产力非常低，几乎完全依赖于常量营养元素 N 和 P 的近地表循环。高营养、低叶绿素区域覆盖了世界海洋的 40%，其生产力受到微量营养元素 Fe 的限制（Watson， 2001）。驱动生物繁荣的营养通量增加可能来自于大陆风化和径流的增强，营养丰富的水域向透光区的上涌增强，或大气负荷的增强。我们的样本中缺乏陆地有机质，加上远端海洋环境，使得大陆风化增加带来的直接养分加载不太可能。铃木等人。（1998）主张 PTME 期间公海上升流增加。然而，上升流主要限于西部大陆边缘（由于科里奥利驱动的东部边界流）和赤道地区（由于科里奥利驱动的辐散流）（例如，Smith，1995）。虽然风切变的变化可能会增加日本某些地区的赤道上升流，但这不太可能解释怀赫科岛中纬度地区生产力的增加。Panthalassa 广泛存在的富含有机物的沉积物一定对整个海洋的初级生产产生了更广泛的影响，影响范围长达 200 ky Frogner 等人。(2001)表明，吸附在火山灰上的气溶胶瞬间溶解，释放出大量的磷和铁，速度足以支持初级生产。怀赫科岛的汞浓度峰值和 Δ199Hg 异常支持了这样的解释，即 SLIP 火山活动增强与斜藻沉积同时发生（Grasby 等人，2021）。SLIP 大规模的玄武岩裂隙喷发能够将火山灰注入平流层（Glaze等人，2017）。这种玄武岩灰比硅灰更具反应性（Jones 和 Gislason，2008 年），这确保了 SLIP 产生的全球海洋肥化作用可能是巨大的。现代，火山灰驱动生物华释放养分的例子包括日本三宅岛（Uematsu et al., 2004）和阿留申群岛 Kasatochi 喷发后地表水中叶绿素-a 的迅速增加（几周内） ，美国（Hamme 等人，2010）。同样，火山灰也被认为在奥陶纪晚期引起了主要的生物华（Longman et al., 2021）。我们的模型结果显示，P 和 Fe 通量的平均范围为 5690–91,000 Gmol P/ky 和 ​​122–1950 Gmol Fe /ky，最大范围分别为 173,000–559,000 Gmol P/ky 和 ​​3708–11,970 Gmol Fe/ky（取决于 SLIP 的总喷发周期，如图 4B 所示）。相比之下，现代进入海洋的磷和铁尘埃沉积量估计分别为 32,000 Gmol/ky 和 ​​5700 Gmol/ky（Paytan 和 McLaughlin，2007 年；Xu 和 Weber，2021 年）。因此，我们的结果表明，SLIP 养分负荷与背景排放量处于同一数量级，至少使海洋中的宏观和微量营养素粉尘含量增加一倍。磷负荷的增加与全球观察到的整个 PTME δ15N 值的下降一致（Grasby 等人，2019），因为较高的磷通量将推动大气中 N2 固定的增强，以维持 16:1 的 Redfield N/P 比。目前仍不确定的是，为什么富含有机物的异常沉积物主要在 PTME 的深海平原记录中观察到，而不是在大陆架上观察到。虽然陆架区域的缺氧条件可能会促进富含有机物的沉积，但陆架海经历的高温可能会增加有机物的再矿化（Wignall，2015）。从类似的意义上说，保存偏差可能很重要，因为深海记录可以更好地记录短暂的生物华事件。额外的养分通量对海洋生产力的影响也存在很大差异，并受到当地营养缺乏程度的控制。例如，Xu和Weber（2021）提出，现代铁供应范围可以从上升流区域的强烈过剩到亚热带环流的严重短缺，这样，在营养物缺乏的开放地区，营养物负荷的影响会选择性地更高。我们证明，在 PTME 深海环境中沉积的极其富含 TOC 的沉积物是由厚厚的藻类沉积物形成的，这意味着发生了造成海洋“暴风雪”的重大生物华事件。我们的养分通量模型表明，SLIP 可以显着增加 Panthalassa 的 P 和 Fe 负载率。我们认为，火山灰负载可以解释深海典型营养匮乏区域富含有机物沉积物的异常出现。幸存的海底记录表明，这些层范围广泛，可能构成了主要的碳埋藏地点，按照模型（例如 Cui 等人，2021）的要求来解释 PTME 后 δ13C 记录的恢复。大多数当代货架记录的有机贫乏性质仍然是一个谜。这项工作受益于自然环境研究委员会授予 DPG Bond 的 NE/J01799X/1 资助。例如，Xu和Weber（2021）提出，现代铁供应范围可以从上升流区域的强烈过剩到亚热带环流的严重短缺，这样，在营养物缺乏的开放地区，营养物负荷的影响会选择性地更高。我们证明，在 PTME 深海环境中沉积的极其富含 TOC 的沉积物是由厚厚的藻类沉积物形成的，这意味着发生了造成海洋“暴风雪”的重大生物华事件。我们的养分通量模型表明，SLIP 可以显着增加 Panthalassa 的 P 和 Fe 负载率。我们认为，火山灰负载可以解释深海典型营养匮乏区域富含有机物沉积物的异常出现。幸存的海底记录表明，这些层范围广泛，可能构成了主要的碳埋藏地点，按照模型（例如 Cui 等人，2021）的要求来解释 PTME 后 δ13C 记录的恢复。大多数当代货架记录的有机贫乏性质仍然是一个谜。这项工作受益于自然环境研究委员会授予 DPG Bond 的 NE/J01799X/1 资助。例如，Xu和Weber（2021）提出，现代铁供应范围可以从上升流区域的强烈过剩到亚热带环流的严重短缺，这样，在营养物缺乏的开放地区，营养物负荷的影响会选择性地更高。我们证明，在 PTME 深海环境中沉积的极其富含 TOC 的沉积物是由厚厚的藻类沉积物形成的，这意味着发生了造成海洋“暴风雪”的重大生物华事件。我们的养分通量模型表明，SLIP 可以显着增加 Panthalassa 的 P 和 Fe 负载率。我们认为，火山灰负载可以解释深海典型营养匮乏区域富含有机物沉积物的异常出现。幸存的海底记录表明，这些层范围广泛，可能构成了主要的碳埋藏地点，按照模型（例如 Cui 等人，2021）的要求来解释 PTME 后 δ13C 记录的恢复。大多数当代货架记录的有机贫乏性质仍然是一个谜。这项工作受益于自然环境研究委员会授予 DPG Bond 的 NE/J01799X/1 资助。