Department of Microbiology, The University of Tennessee Knoxville, Knoxville, Tennessee, USA.
NIEHS/NSF Great Lakes Center for Fresh Waters and Human Health, Bowling Green State University, Bowling Green, Ohio, USA.
Environ Microbiol Rep. 2023 Feb;15(1):3-12. doi: 10.1111/1758-2229.13122. Epub 2022 Sep 12.
Billions of years ago, the Earth's waters were dominated by cyanobacteria. These microbes amassed to such formidable numbers, they ushered in a new era-starting with the Great Oxidation Event-fuelled by oxygenic photosynthesis. Throughout the following eon, cyanobacteria ceded portions of their global aerobic power to new photoautotrophs with the rise of eukaryotes (i.e. algae and higher plants), which co-existed with cyanobacteria in aquatic ecosystems. Yet while cyanobacteria's ecological success story is one of the most notorious within our planet's biogeochemical history, scientists to this day still seek to unlock the secrets of their triumph. Now, the Anthropocene has ushered in a new era fuelled by excessive nutrient inputs and greenhouse gas emissions, which are again reshaping the Earth's biomes. In response, we are experiencing an increase in global cyanobacterial bloom distribution, duration, and frequency, leading to unbalanced, and in many instances degraded, ecosystems. A critical component of the cyanobacterial resurgence is the freshwater-marine continuum: which serves to transport blooms, and the toxins they produce, on the premise that "water flows downhill". Here, we identify drivers contributing to the cyanobacterial comeback and discuss future implications in the context of environmental and human health along the aquatic continuum. This Minireview addresses the overlooked problem of the freshwater to marine continuum and the effects of nutrients and toxic cyanobacterial blooms moving along these waters. Marine and freshwater research have historically been conducted in isolation and independently of one another. Yet, this approach fails to account for the interchangeable transit of nutrients and biology through and between these freshwater and marine systems, a phenomenon that is becoming a major problem around the globe. This Minireview highlights what we know and the challenges that lie ahead.
数十亿年前，地球的水域主要由蓝藻菌所主宰。这些微生物的数量庞大，它们通过光合作用产生的氧气，引发了一个新的时代——大氧化事件的开始。在接下来的整个地质年代中，随着真核生物（如藻类和高等植物）的兴起，蓝藻菌将其全球有氧能力的一部分让给了新的光合自养生物，它们与蓝藻菌一起存在于水生生态系统中。然而，尽管蓝藻菌在地球的生物地球化学历史上是最臭名昭著的成功故事之一，但科学家们至今仍在试图揭开它们成功的秘密。如今，人类世又迎来了一个由过度营养输入和温室气体排放驱动的新时代，这些又在重塑地球的生物群系。作为回应，我们正在经历全球蓝藻水华分布、持续时间和频率的增加，导致生态系统失去平衡，在许多情况下退化。蓝藻菌复苏的一个关键组成部分是淡水-海洋连续体：它将水华及其产生的毒素输送出去，前提是“水往低处流”。在这里，我们确定了促成蓝藻菌卷土重来的驱动因素，并在环境和人类健康的背景下讨论了未来的影响，沿着水生连续体。这篇综述探讨了被忽视的淡水到海洋连续体的问题以及营养物质和有毒蓝藻水华沿着这些水域移动的影响。海洋和淡水研究在历史上是相互孤立和独立进行的。然而，这种方法没有考虑到营养物质和生物通过这些淡水和海洋系统相互交换的情况，这种现象在全球范围内正在成为一个主要问题。这篇综述强调了我们所知道的和未来的挑战。
