北极公路之旅揭示关键地下网络。
内容总结：
【北极科考揭示地下真菌网络关键作用，或成应对气候变化新钥匙】
2025年6月，生物学家迈克尔·范·努兰驾驶越野车驶入北美最北端的阿拉斯加道顿公路。在永昼的极地阳光下，他和"地下网络保护协会"的科研团队开启了一项紧迫任务：探寻冻土之下隐藏的真菌王国。
看不见的"生命互联网"
在看似荒芜的苔原下，绵延数十英尺的菌根真菌网络如同天然互联网，通过丝状菌丝连接植物根系，输送水分和养分。团队首席科学家托比·基尔斯指出："真菌正像'农民'般管理着地上植物，它们是重塑土壤、支撑生态系统的关键角色。"最新显微成像技术揭示，数十万独立菌丝能智能融合成高效营养输送网，根据资源分布动态调整生长路径。
冻土下的"碳炸弹"
研究显示，全球菌根真菌每年封存碳量相当于人类年碳排放量的36%。阿拉斯加苔原上层三米冻土约锁存1万亿吨碳，是亚马逊雨林总碳量的10倍。但随着气候变暖，冻土融化正在激活深层碳库。微生物分解千年冻土释放的温室气体，可能使北极从碳汇转变为碳源。
与时间赛跑的测绘行动
团队运用机器学习分析全球2.5万份土壤样本，预测出全球菌根真菌多样性热点。阿拉斯加北坡正是重点区域之一。在四天科考中，研究人员跨越150英里苔原，采集540份土壤样本。初步检测显示，在记录的354种真菌中，253种是新发现物种，其中约75%可能是该地区特有。
全球行动的起点
该组织已在79个国家展开合作，从哈萨克斯坦草原到太平洋环礁，不同生态系统中真菌都展现出独特生态功能。2026年夏季，团队将重返阿拉斯加监测冻土碳通量。科学家警告，目前不到10%的真菌热点位于保护区内，而气候变化的影响无远弗届。
"过去我们忽视了真菌系统的测绘与保护，"基尔斯强调，"现在必须争分夺秒——因为地下这些纤细的菌丝，正掌握着地上生命的未来。"
中文翻译：
北极公路之旅：探秘维系生命的地下网络
本文由普利策中心资助。
2025年6月的一个星期二，一辆白色雪佛兰萨博班驶上了北美最北端的公路。阿拉斯加极地夏季的太阳已持续40天未曾落下，还将继续高悬35天。但对于驾驶座上的生物学家迈克尔·范·纽兰来说，时间已然紧迫。
这辆SUV满载着四天野外工作的必需品——沼泽跋涉的橡胶靴、厘米级精度的GPS、从永久冻土中提取土壤样本的钢制套管——沿着道尔顿公路轰鸣前行。这条公路像一条沥青与砾石缝合的线，穿过阿拉斯加北部海岸的苔原。窗外，不见树木的景象暗示着一片荒芜，但表象具有欺骗性。绵延数英里的莎草和羽绒般厚实的苔藓，构成了季节性驯鹿、灰熊、麝牛以及大约200种鸟类盛宴的基础。
范·纽兰更感兴趣的是地下发生的事。在那里，真菌菌丝构成的庞大系统——从微观导管到纱线般粗细的"动脉"——向四面八方水平延伸数十英尺。通过连接植物根系并循环养分，这个密集的网络化支架维持着地表之上的生命。
"有些人只把泥土看作泥土。但它是一个活生生的、会呼吸的系统，"非营利组织"地下网络保护协会"的首席数据科学家范·纽兰说。"你在森林中看到的复杂性——层层叠叠的树冠，不同种类的鸟类和昆虫……你脚下正踩着一个同样复杂、甚至可能更复杂的地下系统。"
这个系统的构建者正是范·纽兰研究的对象：菌根真菌。这是一群在进化上关系疏远、栖息于土壤的微生物，它们不断生长的附属物从周围环境中汲取养分和水分。这些环境包括附近的植物。真菌苍白的、线状的"菌丝"在土壤中穿行，直到找到植物根系与之连接。随后，双方可以进行交易。植物从真菌那里获得其自身根系难以触及的稀缺氮和磷；真菌则获取植物的碳，以进一步生长并定殖土壤。
自被发现以来的一个世纪里，菌根真菌曾被视为植物根系的寄生虫，后来又被看作服务于植物利益的被动基础设施。但近十年来利用机器人技术和先进成像技术的研究表明，它们是掌控自身命运并影响他人命运的活跃"商人"。
"你可以把真菌想象成某种在地面上'种植'植物的农夫，"阿姆斯特丹自由大学的进化生物学家、SPUN的首席科学家兼主任托比·基尔斯说。她于2021年共同创立了该组织。菌根真菌引导养分在"高速公路"上流通，并重塑土壤结构，以支持整个生态系统的生命。如今，"我们更多地视真菌为真正重要的独立行动者，"基尔斯说。"这颠覆了我们理解地下的方式。"
随着真菌网络进入视野，与我们对动植物的了解相比，一个仍然知之甚少的方面是其全球生物多样性和生物地理分布。菌根真菌可能有两万到五万个物种，每个物种都有其独特的技巧，利用酶、酸和采水结构来连接不同植物并获取养分。为了填补这一认知空白，在2025年发表于《自然》杂志的一篇模型中，范·纽兰及其同事利用机器学习处理了来自全球的2.5万个土壤样本，产生了超过28亿条真菌DNA序列。他们利用这些数据预测了菌根"热点"的位置——即物种多样性高且稀有度高的地区。
正是这个模型将范·纽兰吸引到了北极。根据分析，这片位于普拉德霍湾油田和北极国家野生动物保护区之间的阿拉斯加苔原地带，很可能是一个菌根热点。因此，范·纽兰带领一个研究团队对该地区土壤进行采样；他和其他SPUN研究人员还将在全球其他预测热点地区采样，包括热带岛屿、茂密森林和山脉。如果这些地点蕴藏着稀有、独特的土壤真菌，那么每一铲泥土都可能揭示新物种。
该团队的发现可能具有全球意义。每年，菌根真菌储存的碳相当于全球碳排放量的三分之一以上。包括阿拉斯加苔原在内的北方永久冻土，在其顶部三米土壤中封存了大约1万亿公吨碳——大约是整个亚马逊雨林（地表上下）碳总量的10倍。因此，保护这些广阔的真菌网络是应对气候变化的关键工具。
"过去我们确实忽视了测绘、监测和保护真菌系统，"基尔斯说，"但现在情况正在改变。"
但我们对菌根的认识来得太晚了。气候变化已经在动摇这个地区。真菌群落对气温升高、湿度增加、野火频率和强度上升以及永久冻土融化做出反应。SPUN预测的菌根热点中，只有不到10%位于受保护的土地内，而即使是受保护的土地也无法完全免受气候变化影响。为了在保护工作中为土壤真菌争取空间，他必须为他的模型收集更多实地证据，并识别将受影响的稀有物种。
这就是为什么范·纽兰和其他研究人员一直在竞相对全球的菌根真菌热点进行采样。他担心，如果不了解是哪些菌根"角色"承担着我们的碳负担，我们将无法保护它们，从而也无法保护我们自己。当科学家们冒险进入偏远地区时，他们正在发现地下真菌的细微脉络以令人惊讶的方式决定着地上生命的未来。
奠定基础
在为期四天、行程150英里的苔原考察的第三天清晨6点，我在死马镇加入了SPUN团队。死马镇是阿拉斯加北坡北部海岸的一个油田服务小镇。当我们沿着道尔顿公路颠簸前行时，他们向我介绍了最近的情况。第一天以轮胎漏气开始，以完成10个地点采样结束。第二天，车辆完好无损，四位研究人员组成的团队又采集了14份潮湿、巧克力色的沼泽泥土样本。
我们向南驶出小镇，将车停在路边停车带，从团队前一天结束的地方继续工作。在前往当天第一个采样点的短途徒步中，范·纽兰跪下来向我介绍菌根。他剥开一丛矮柳树旁厚厚的苔藓，切下一块冰冷的土块。他将切下的土块托在掌心，指着那些类似爆米花的小白色团块。
"这些都是（菌根）菌丝紧紧缠绕在细根周围的地方，"他说。"然后从这里，它们向外延伸出菌丝网络。"菌丝是构成真菌体（菌丝体）的单个丝状体。这些真菌管状体由坚硬的细胞构成，含有几丁质——与昆虫外骨骼中发现的化合物相同。它们可以细到不可思议。菌丝通常只有五微米宽——大约是人类头发宽度的十分之一，比植物的根尖窄得多。通过觅食、钻入缝隙、利用土壤中的气穴和潮湿区域，菌丝能够获取灌木无法获取的养分。
至少研究人员过去是这么认为的。菌丝内部发生的一切微小到看不见。最终能够看到它的能力正在彻底改变这个领域。
2025年2月，基尔斯的生态学家团队与来自阿姆斯特丹AMOLF研究所的汤姆·清水领导的生物物理学家团队合作，利用机器人技术追踪了营养物质在培养皿中生长的菌丝内的流动情况。视频看起来像是城市通勤的延时摄影。营养物质通过菌丝隧道双向流动。随着真菌延伸出更多菌丝，分支网络脉动着，逐渐扩展成一张吞噬养分的"蕾丝"。如果菌丝生长得再稀疏一点，网络就会效率低下；再密集一点，则会变得不经济。
"这项研究的精确度非常惊人，"阿尔伯塔大学的森林生态学家贾斯汀·卡斯特说，她未参与此项研究。"我听到一位同事形容它是杰作。"
成像技术揭示了数十万个独立的真菌尖端如何形成一个高效的网络。在无尽的养分搜寻中，菌丝侵入空白空间。当丝状体相互碰撞时，它们会融合。当一条菌丝路线回报的养分太少时，真菌会及时止损，将生长转向别处。
这些菌丝网络生长在人们能想象到的最远离野外的地方：阿姆斯特丹实验室的培养皿中。然而，最终的图像终于使它们的相互作用变得可见。"感觉几乎就像你是一个躲在树后的灵长类动物学家，"最近获得麦克阿瑟奖和泰勒环境成就奖的基尔斯说。
2022年，她聘请了具有地理空间数据工作经验的范·纽兰，以帮助将这些微观交换与全球循环联系起来。"迈克尔能够看到更大的图景，理解所有这些相互作用如何共同创造了我们在景观中看到的一切，"基尔斯说。"这是一种不可思议的技能。"
范·纽兰在研究生和博士后期间进行野外工作并设计受控的实验室实验，以揭示真菌与植物之间错综复杂的相互作用，为数十年来证明土壤真菌是植物多样性重要驱动力的研究增添了新内容。当相邻的植物相似时，比如两种北极灌木，它们必须区分如何获取生态系统中稀缺的资源。他已经证明，每种植物的真菌使其能够在地下进行战略性区分。
植物"在争夺资源，而它们的大部分资源实际上是通过菌根真菌来调停的，"研究类似相互作用的卡斯特说。
数以万计的菌根物种代表着巨大的变异，研究人员通常将其分为两种主要类型。外生菌根真菌在高纬度地区占主导地位，它们通过用菌丝套住根细胞，向植物输送难以获取的土壤氮。而更偏向热带、聚集在赤道附近的丛枝菌根真菌，则将其微观菌丝刺穿根细胞，以交易其专长领域的磷。每一类真菌内部还存在更多差异，它们还可以为植物提供维生素和矿物质，如钙和锌。
马克·贝兰 / 《量子》杂志
关于个体系统积累的研究表明，植物与其真菌不能分开理解。"我在生态学领域初出茅庐时就在思考地上和地下系统如何相互作用，但对我来说，它们似乎完全不可分割，"范·纽兰说。"以一种菌根类型为主的森林，其养分生态流动与以另一种类型为主的森林完全不同，这在很大程度上似乎是不同共生关系如何运作的结果，以及哪些真菌更擅长做某些事情。"
换句话说，植物之间的竞争实际上是真菌之间的竞争。而在北极土壤中，他说，这些竞争性的伙伴关系可能"拥有地球上一些最稀有的菌根真菌群落"。
碳炸弹
36岁的范·纽兰乐于接受挑战。作为一名长期的运动员，他童年时在后院搭建过越野摩托车坡道，并为西雅图大学参加过越野跑。2019年，他在不列颠哥伦比亚省完成了50英里的超级马拉松。在阿拉斯加之行的第三天上午过半时，他的竞争精神再次浮现。SPUN在2023年前往哈萨克斯坦的一次考察采集了57份土壤样本。范·纽兰想要60份。
一份样本包含九个土芯，每个土芯采集点距离一个中心点15米，该中心点距离公路约半英里。SPUN的地理空间数据科学家金苏·埃尔汉斯蹲下，将7英寸长的金属圆筒锤入土壤。叮。叮。叮。有时土壤松软潮湿；有时则结块或冰冷。"有个冻土块，"埃尔汉斯边说边用拇指按压一些顽固的、已装袋的永久冻土。土芯中含有植物根系、真菌以及土壤中生活的任何其他东西——这是地下生命的快照，也是特定地点、特定时刻生物多样性的普查。
在每个采样点，合作者、费尔班克斯阿拉斯加大学的微生物学家马里奥·马斯卡雷拉会标记精确的GPS坐标，识别地表植物种类，并将探针插入土壤以测量温度和湿度。实验室随后将分析每个地点的土壤养分，并从样本中提取DNA序列，以寻找未被发现真菌物种。
这一天，我们继续向南行驶50英里，穿过北坡，进入布鲁克斯山脉。我们驶过麝牛、结冰的池塘，以及阿拉斯加高压原油管道穿过的芬芳山丘。第三天结束时，团队到达了第39个地点，一个俯瞰库帕鲁克河的斜坡草地——距离目标还差21个地点，而只剩下一天时间。
最后一天以苔原上预期的刺骨寒冷开始：浓雾下华氏30度（约摄氏-1度）。然而这是六月，夏季早已开始。我们跋涉过及小腿深的融雪，来到一个更干燥的地点供团队采样。去年夏天成堆的草状莎草在我们周围枯萎。"它没有气味，"马斯卡雷拉说，"但我敢肯定我们现在吸入了大量甲烷。"
漫长冬季后，早已死亡的植物、动物和真菌正在解冻，使其中的碳可以被微生物分解者获取。这些分解者消化复杂的有机物质，并释放出更简单的气体：二氧化碳、甲烷和一氧化二氮——这些都是温室气体。随着气候变化对北极的影响加剧，更深层的永久冻土正以这种方式被激活。微生物不再将它们的盛宴局限于去年的收获：它们还能释放被封冻了数千年的碳。
微生物真菌是理解这些碳去向的关键。在数十年将真菌视为寄生虫或被动管道之后，对其功能日益增多的认识已促使研究人员将菌根视为气候研究中缺失的一环。2023年，范·纽兰和基尔斯帮助估算了真菌每年储存的碳量：丛枝菌根储存39.3亿吨，外生菌根储存90.7亿吨——合计占全球每年二氧化碳排放总量的36%。
马克斯·利维
"正是生与死的循环创造了巨大的土壤碳输入，"范·纽兰说。"这是一个活着的和正在死去的基础设施。"
但如此高的生产力是复杂的。每一类真菌中特定物种的作用千差万别。真菌学家发现，有些真菌物种是出色的分解者。在这些分解者中，有些能有效地储存死碳，而另一些则将其大部分排放到空气中。"分类学身份确实很重要，"研究北极植物-微生物相互作用的阿默斯特学院生态学家丽贝卡·休伊特说。"谁在那里真的会影响功能。"
在阿拉斯加，随着地面变暖，哪些物种——碳储存者还是碳泄漏者——将会繁盛，这对全球气候意味着什么，仍然是一个悬而未决的问题。有些真菌会繁盛。另一些则会消亡。"赢家"可能决定北极是否会成为导致地球变暖的碳源。
在第54号地点，当我们徒步返回SUV时，范·纽兰思考着这项工作的更大影响。他怀疑苔原真菌"具有特定的特性"，能更有效地捕获碳。"一旦我们确定了这里独特的菌根物种，我们将能够将它们与我们为该地区估算的碳吸收量联系起来，"他说。
马克斯·利维
团队在第55号地点停车后暂停吃午餐。范·纽兰从驾驶座上俏皮地提出贿赂："如果我们达到60个（地点），我们就可以去商店"——普拉德霍湾综合商店，研究人员可以在那里购买北极熊明信片和"道尔顿公路幸存者"贴纸。他们重新振作起来。
我们接近高地的山麓丘陵，向着一道东西走向、像大陆衣领般的8000英尺高峰攀登。沼泽让位于更厚的苔藓和更蓬乱的灌木。范·纽兰可能对稀有真菌潜力的任何疑虑，都随着每一英里和每一个采样点而消散。布鲁克斯山脉和普拉德霍湾冰冷的海岸线在功能上使苔原的植物-真菌伙伴关系与阿拉斯加其他地区隔绝开来。
"我们知道大的山脉会形成地理屏障，从而导致隔离和独特物种的进化，进而形成该地独特的共生伙伴关系，"他说。"这让我思考，它们的故事将会是什么？"
立下界标
下午4点，我们到达了第60号地点。范·纽兰将车停在一个宽阔的停车带，我们徒步几分钟来到一个朝西、覆盖着棉草的山坡。每个人各司其职——GPS定位、植物识别和土壤采样——然后轮流敲击钢套管，获取最后一个土芯。
60个地点，每个地点9个土芯：四天内540份样本。"我为这种干劲感到自豪，"当最后一团苔原土壤进入最后一个样本袋后，范·纽兰说。"这次考察将产生惊人的数据。"
四个月后，即2025年11月，范·纽兰通过电子邮件向我发送了初步结果。每个采样点平均包含约75种不同的外生菌根真菌物种。物种组成从北到南发生了显著变化。在研究人员记录的354个不同物种中，有253个是以前未知的。
该地区似乎是稀有、特有真菌的热点地区。他们检测到的物种中，大约每四个就有三个在其他地方从未发现过。尽管从理论上讲，有些可能存在于未采样的苔原地区——比如西伯利亚某地——但范·纽兰怀疑，许多物种将被证明是该地区特有的。这些植物和真菌被夹在山与海之间，如同在偏远的岛屿上，孤独却又共同地协同进化了数百万年。
"在地图上看到是一回事。但身临其境才真正体会到这些生态系统有多么独特，"他说。"我们发现了许多未命名的物种。"
失去稀有真菌可能意味着失去它们所扮演的独特角色，并可能进一步破坏生态系统的稳定。"人们想象着保护亚马逊雨林，"范·纽兰说。"但对于土壤来说，这很难。土壤的'亚马逊'在哪里？"
它们可能遍布世界各地。阿拉斯加的北坡只是SPUN研究人员计划探访的数十个潜在真菌热点之一。该组织与79个国家的研究人员合作。基尔斯每年参加四到五次考察，经常带着她的孩子。在哈萨克斯坦，SPUN希望了解真菌如何帮助草原植物抵御干旱。在中太平洋的巴尔米拉环礁，树木及其真菌伙伴渗入珊瑚碎石，并与入侵的椰子树竞争。在非洲南部的莱索托，真菌似乎有助于防止农田侵蚀。"我们去的每个地方都有不同的故事，"范·纽兰说。每个地点的生物多样性数据可以反馈到SPUN的模型中，以改进热点预测。
有些地点值得重访。2026年夏季，范·纽兰和他的团队将返回死马镇，测量碳进出苔原土壤的通量。生态学家不知道永久冻土融化将对地球的碳平衡产生什么影响。但随着每年无情的极昼回归，新的碳库进入了土壤中最无畏的菌丝的触及范围。科学家们渴望知道菌根将如何处理它。真菌将为那些有足够耐心倾听的人提供答案。
英文来源：
An Arctic Road Trip Brings Vital Underground Networks into View
Introduction
This story was supported by the Pulitzer Center.
One Tuesday in June 2025, a white Chevy Suburban set off down the northernmost highway in North America. The sun of Alaska’s polar summer hadn’t set in 40 days, and it wouldn’t set again for another 35. But for Michael Van Nuland, the biologist in the driver’s seat, time was already running out.
The SUV, packed with four days of fieldwork essentials — rubber boots for mucking in marshes, GPS for centimeter-level precision, a steel tube for extracting soil cores from permafrost — growled along the Dalton Highway, which sews an asphalt-and-gravel seam through the tundra of Alaska’s northern coast. Through the window, the lack of visible trees suggested a barren landscape, but looks are deceiving. The miles of sedge and duvet-thick moss formed the basis of a feast for seasonal caribou, grizzlies, muskox, and roughly 200 bird species.
Van Nuland was more interested in what was happening underground, where sprawling systems of fungal threads — from microscopic ducts to arteries thick as yarn — extended dozens of feet horizontally in all directions. By connecting plant roots and circulating nutrients, this dense, networked scaffold sustained life above the surface.
“Some people just see dirt as dirt. But it’s a living, breathing system,” said Van Nuland, the lead data scientist of the nonprofit Society for the Protection of Underground Networks (SPUN). “The complexity you see in a forest — the layers of canopy, the different species of birds and insects … You’re walking over an equally or possibly even more complex system below ground.”
This system’s architect was the subject of Van Nuland’s study: mycorrhizal fungi, a group of evolutionarily far-flung, soil-dwelling microbes whose ever-growing appendages extract nutrients and water from their surroundings. Those surroundings include nearby plants. The fungi’s pale, thread-like “hyphae” burrow through the soil until they find plant roots to connect with. Then, the parties can trade. From the fungus, the plant accepts scarce nitrogen and phosphorus that its own roots struggle to reach; the fungus takes the plant’s carbon to further grow and colonize the soil.
Across the century since their discovery, mycorrhizal fungi have been considered parasites of plant roots and, later, passive infrastructure that served plants’ interests. But studies from this decade that used advanced techniques in robotics and imaging suggest that they are active merchants that control their fates and influence the fates of others.
“You can think of fungi as sort of farming plants above ground,” said Toby Kiers, an evolutionary biologist at Vrije Universiteit Amsterdam and the chief scientist and director of SPUN, which she co-founded in 2021. Mycorrhizal fungi direct traffic through nutrient superhighways and restructure the soil to support life across entire ecosystems. Now, “we see fungi more as really important actors in their own right,” Kiers said. “It’s flipping the way that we understand the underground.”
As fungal networks come into focus, one thing that remains little known, especially in comparison with our understanding of plants and animals, is their global biodiversity and biogeography. There are likely between 20,000 and 50,000 species of mycorrhizal fungi, each with its own tricks for tapping into different plants and harvesting nutrients using enzymes, acids, and water-mining structures. To address this gap, in a model published in Nature in 2025, Van Nuland and his colleagues had used machine learning to process 25,000 soil samples from around the world, producing more than 2.8 billion fungal DNA sequences. They used the data to predict the locations of mycorrhizal “hot spots” — places with both high diversity and rarity of species.
That model is what drew Van Nuland to the Arctic. According to the analysis, this stretch of Alaskan tundra, sandwiched between the Prudhoe Bay oil fields and the Arctic National Wildlife Refuge, is likely a mycorrhizal hot spot. So Van Nuland brought a team of researchers to sample soil across the region; he and other SPUN researchers will sample more predicted hotspots around the world, including tropical islands, dense forests, and mountains. If these sites harbor rare, unique soil fungi, then each scoop of dirt could reveal new species.
The group’s findings could have global significance. Every year, the scraggles of mycorrhizal fungi store the equivalent of more than one-third of global carbon emissions. Northern permafrost, including in the Alaskan tundra, locks roughly 1 trillion metric tons of carbon in its top three meters of soil — about 10 times the amount of carbon in the entire Amazon rainforest, above and below the surface. Therefore, protection of these vast fungal networks is a key tool for resisting climate change.
“In the past we’ve really neglected to map, monitor, and protect fungal systems,” Kiers said, “and now that’s changing.”
But our recognition of mycorrhizae comes late. Climate change is already destabilizing this area. Fungal communities respond to warmer temperatures, increasing moisture, a growing frequency and intensity in wildfires, and thawing permafrost. Less than 10% of SPUN’s predicted mycorrhizal hot spots fall within protected land, and even protected land is not beyond the reach of climate change. To carve out space for soil fungi in protection efforts, he must gather more evidence for his model on the ground and identify rare species that will be affected.
That’s why Van Nuland and other researchers have been racing to sample hot spots of mycorrhizal fungi across the world. Without knowing which mycorrhizal characters shoulder our carbon burden, he fears, we will fail to protect them and, as a consequence, ourselves. As they venture to remote places, the scientists are discovering surprising ways in which underground wisps of fungi dictate the future of life aboveground.
Laying Groundwork
I joined the SPUN team in Deadhorse, an oilfield-support town on the northern coast of Alaska’s North Slope, at 6 a.m. on day three of a four-day, 150-mile tundra expedition. As we rumbled down the Dalton Highway, they caught me up on recent events. Day one began with a flat tire and ended with 10 sites sampled. On day two, the vehicle remained intact and the gang of four researchers bagged 14 more samples of damp, chocolatey marsh dirt.
We drove south out of town and parked at a roadside pullout to pick up where the team had left off. During our short hike to the day’s first sample site, Van Nuland kneeled to introduce me to mycorrhizae. He peeled back thick moss next to a dwarf willow shrub and cut out a cold clod of dirt. Holding the excised earth in his palm, he pointed to small white clumps resembling popcorn.
“All of these are places where the [mycorrhizal] hyphae are wrapping themselves really intensely around the fine roots,” he said. “Then from this point they’re sending out their hyphal networks.” Hyphae are the individual filaments that make up the fungal body, or mycelium. These fungal tubes are made of rigid cells that contain chitin, the same compound found in insect exoskeletons. They can be impossibly thin. Hyphae are often barely five micrometers wide — about one-tenth the width of a human hair and much narrower than a plant’s root tip. By foraging, burrowing into crevices and tapping into air pockets and moist pools in the soil, hyphae can access nutrients that the shrub cannot.
That’s what researchers had assumed, anyway. What happens inside hyphae is invisibly small. The ability to finally see it is revolutionizing the field.
In February 2025, Kiers’s team of ecologists joined forces with Tom Shimizu’s biophysicists from the AMOLF Institute in Amsterdam to robotically track how nutrients flow within hyphae growing in petri dishes. The videos look like time-lapses of urban commutes. Nutrients streamed in both directions through the hyphal tunnels. As the fungi extended more hyphae, the branching network pulsed and gradually expanded into a nutrient-gobbling lace. If the hyphae were to grow any less densely, the network would be ineffective; any denser, and it would be inefficient.
“The study is phenomenal in its precision,” said Justine Karst, a forest ecologist at the University of Alberta who was not involved in it. “I’ve heard one of my colleagues describe it as a masterpiece.”
The imaging revealed how hundreds of thousands of independent fungal tips form an efficient network. On their endless search for nutrients, hyphae encroached into empty spaces. When filaments bumped into each other, they fused. And when a hyphal route returned too little nourishment, the fungi cut their losses and redirected growth elsewhere.
These mycelial networks grew as far from the wild as one can imagine: in petri dishes in a lab in Amsterdam. Yet the resulting images have finally made their interactions visible. “It feels almost like you’re a primatologist hiding behind a tree,” said Kiers, who was recently awarded a MacArthur fellowship and the Tyler Prize for Environmental Achievement.
In 2022, she hired Van Nuland, who had experience working with geospatial data, to help connect these microscopic exchanges to global cycles. “Michael is able to see this bigger picture of how all of these interactions come together to create what we see across the landscape,” Kiers said. “It’s such an incredible skill.”
Van Nuland spent his graduate school and postdoctoral years doing fieldwork and crafting controlled lab experiments to unravel the intricate interactions between fungi and plants, adding to decades of work showing that soil fungi are important drivers of plant diversity. When neighboring plants are similar, like two Arctic shrubs, they must differentiate how they obtain the scarce resources of the ecosystem. He has shown that each plant’s fungi enable it to strategically differentiate underground.
Plants are “competing for resources, and most of their resources are actually mediated by mycorrhizal fungi,” said Karst, who studies similar interactions.
The tens of thousands of mycorrhizal species represent a huge variation, which researchers typically divide into two main types. Ectomycorrhizal fungi dominate high latitudes, where they can deliver hard-to-access soil nitrogen to plants by lassoing root cells with their hyphae. The more tropical, equator-clustered arbuscular fungi spear their microscopic hyphae through root cells to trade in their area of expertise, phosphorus. Far more distinctions arise within each group of fungi, which can also supply plants with vitamins and minerals, such as calcium and zinc.
Mark Belan/Quanta Magazine
The accumulating studies on individual systems suggest that plants and their fungi cannot be understood separately. “I cut my teeth in ecology thinking about how above- and below-ground systems interact with one another, but to me, they seem completely inseparable,” Van Nuland said. “A forest dominated by one mycorrhizal type has a completely different ecological flow of nutrients than a forest with another type, and a large part of that seems to be the result of how different symbioses work, and which fungi are better at doing certain things than others.”
In other words, competition between plants is actually competition between fungi. And in Arctic soil, he said, those competitive partnerships may “hold some of the rarest communities of mycorrhizal fungi on the planet.”
Carbon Bomb
Van Nuland, 36, relishes a challenge. A longtime athlete, he built dirt-bike ramps in his childhood backyard and ran cross-country for Seattle University. In 2019, he completed a 50-mile ultramarathon in British Columbia. By mid-morning on day three in Alaska, his competitive spirit resurfaced. A SPUN expedition to Kazakhstan in 2023 had bagged 57 soil samples. Van Nuland wanted 60.
One sample consisted of nine soil cores, each taken 15 meters from a central point that was roughly half a mile from the highway. Jinsu Elhance, a geospatial data scientist with SPUN, crouched to hammer the 7-inch-long metal cylinder into the soil. Clink. Clink. Clink. Sometimes the soil was soft and wet; other times, it was chunky or icy. “There’s a frozen puck,” Elhance said as he thumbed some stubborn, bagged permafrost. The cores contained plant roots, fungi and whatever else lives in the soil — a snapshot of life underground and a census of biodiversity in a certain spot at a certain moment in time.
At each sample site, Mario Muscarella, a collaborator and microbiologist at the University of Alaska, Fairbanks, marked the precise GPS coordinates, identified plant species at the surface, and jammed a probe into the earth to measure temperature and moisture. A lab would later analyze each site’s soil nutrients and extract DNA sequences from the samples to search for undiscovered fungal species.
The day carried us 50 more miles south through the North Slope to the Brooks Range. We drove past muskoxen, icy ponds, and fragrant hills traversed by Alaska’s high-pressure crude oil pipeline. At the end of day three, the team reached its 39th site, a sloped meadow overlooking the Kuparuk River — leaving the group 21 sites shy of its target with one day remaining.
The final day began with a stinging cold you’d expect from the tundra: 30 degrees Fahrenheit beneath thick fog. Yet it was June, and summer was well underway. We trudged through calf-deep snowmelt to a drier spot for the team to sample. Heaps of last summer’s grassy sedge lay withered around us. “It’s odorless,” Muscarella said, “but I’m sure that we’re breathing in a ton of methane right now.”
Long-dead plants, animals, and fungi were thawing after a cold winter, making their carbon accessible to microbial decomposers that digest complex organic gunk and belch simpler vapors: carbon dioxide, methane, and nitrous oxide, greenhouse gases all. As climate change tightens its grip over the Arctic, deeper layers of permafrost are activating in this way. Microbes no longer limit their feast to last year’s harvest: They can also liberate carbon that has spent thousands of years in frozen isolation.
Microbial fungi are key to understanding where that carbon is going. After decades of snubbing fungi as parasites or passive tubes, the escalating tally of their functions has led researchers to consider mycorrhizae a missing link in climate studies. In 2023, Van Nuland and Kiers helped estimate how much carbon is stored by fungi annually: 3.93 billion tons by arbuscular and 9.07 billion tons by ectomycorrhizal — a combined value that represents 36% of all carbon dioxide emitted across the planet every year.
Max Levy
“It’s the cycle of life and death that creates a really big soil carbon influx,” Van Nuland said. “It’s a living infrastructure and a dying infrastructure.”
But such productivity is complicated. The role of specific fungi within each group is richly varied. Mycologists are finding that some fungal species are excellent decomposers. Among those decomposers, some store dead carbon efficiently while others burp most of it into the air. “The taxonomic identity can really matter,” said Rebecca Hewitt, an ecologist at Amherst College who studies plant-microbe interactions in the Arctic. “Who is there really affects the function.”
In Alaska, it remains an open question which species — the carbon keepers or the carbon leakers — will thrive as the ground warms, and what that means for the global climate. Some fungi will thrive. Others will perish. The “winners” may dictate whether the Arctic becomes a source of planet-warming carbon.
At site 54, as we hiked back to the SUV, Van Nuland reflected on the larger repercussions of this work. He suspects that tundra fungi “have particular traits” that capture carbon more efficiently. “Once we identify the unique mycorrhizal species here, we’ll be able to connect them to the carbon drawdown that we’re estimating for this area,” he said.
Max Levy
The team paused for lunch after we pulled over at site 55. Van Nuland offered a cheeky bribe from the driver’s seat: “If we hit 60 [sites], we can go to the store” — the Prudhoe Bay General Store, where the researchers could buy polar bear postcards and “DALTON HIGHWAY SURVIVOR” stickers. They found their second wind.
We approached the upland foothills, climbing toward a wall of 8,000-foot peaks that run east-to-west like a continental collar. Marsh gave way to thicker moss and shaggier shrubs. Any doubts Van Nuland may have had about the potential for rare fungi faded with every mile and site. The Brooks Range and icy coastline of Prudhoe Bay have functionally isolated the tundra’s plant-fungus partnerships from the rest of Alaska.
“We know that big mountain ranges create geographic barriers and therefore lead to isolation and the evolution of unique species, and therefore unique symbiosis partnerships in that place,” he said. “It’s got me thinking, what’s their story going to be?”
A Stake in the Ground
We reached site 60 at 4 p.m. Van Nuland parked in a wide pullout, and we hiked for a few minutes to a west-facing hill blanketed in cottongrass. Each person tackled familiar chores — GPS, plants and soil — and then took turns swinging at the steel tube for the final core.
Sixty sites, at nine cores per site: 540 samples in four days. “I’m proud of the hustle,” Van Nuland said after the last clod of tundra soil entered the last sample bag. “Amazing data is going to come out of this expedition.”
Four months later, in November 2025, Van Nuland emailed me the preliminary results. Each of the sampling sites contained, on average, about 75 different species of ectomycorrhizal fungi. The composition of species shifted strongly from north to south. Of the 354 different species the researchers logged, 253 were previously unknown.
The region appears to be a hot spot for rare, endemic fungi. Roughly three of four species they detected have been found nowhere else. Although some may theoretically exist in unsampled tundra — in a place like Siberia, maybe — Van Nuland suspects that many of the species will prove to be endemic to this region. These plants and fungi have been left to co-evolve, alone but together, for millions of years, wedged between mountain and sea as if on a remote island.
“Seeing it on a map is one thing. But being there really drove home just how unique these ecosystems are,” he said. “There were a lot of unnamed species that we found.”
Losing rare fungi could mean losing the unique role they play, and could further destabilize the ecosystem. “People picture protecting the Amazon rainforest,” Van Nuland said. “But for soil, it’s hard. Where are the Amazons of the soil?”
They may be all over the world. Alaska’s North Slope is just one of the dozens of possible fungal hot spots that SPUN researchers plan to visit. The organization works with researchers across 79 countries. Kiers joins four of five trips per year, often with her children. In Kazakhstan, SPUN wants to learn how fungi help grassland plants withstand drought. On the Palmyra Atoll in the central Pacific, trees and their fungal partners infiltrate coral rubble and compete with invasive coconut palms. In Lesotho in southern Africa, fungi seem to help thwart erosion on agricultural land. “Each place that we’ve gone to has a different story,” Van Nuland said. The biodiversity data from each site can feed back into SPUN’s model to improve the hot spot predictions.
Some sites are worth revisiting. In summer 2026, Van Nuland and his team will return to Deadhorse to measure the flux of carbon in and out of the tundra soil. Ecologists don’t know what thawing permafrost will do for Earth’s carbon balance. But as relentless daylight returns each year, new pools of carbon appear within reach of the soil’s most intrepid hyphae. The scientists yearn to know what mycorrhizae will do with it. The fungi will provide answers to those patient enough to listen.