Starting in early April, NASA satellites began to detect a patch of brownish, blue-green water lingering off the coasts of New Jersey, Delaware, Maryland, and Virginia. The colors and patterns were most intense in the shallow coastal zone where the waters of Raritan Bay, Delaware Bay, and Chesapeake Bay merged with the Atlantic Ocean—an area known as the Mid-Atlantic Bight .
从四月初开始，美国宇航局的卫星开始探测到新泽西州、特拉华州、马里兰州和弗吉尼亚州海岸附近有一片褐色、蓝绿色的水域。拉里坦湾、特拉华湾和切萨皮克湾的水域与大西洋交汇处的浅海岸带的颜色和图案最为浓郁，该地区被称为中大西洋湾。
It’s a part of the ocean that remote sensing scientists typically describe as being “noisy” or “dirty” because rivers often discolor coastal waters with plumes of suspended sediment, water stained with colored dissolved organic matter , and an array of microscopic and aquatic plant life. All of this can mingle with ephemeral phytoplankton blooms , sometimes in mucky waters against a varied backdrop of seagrass, sand flats, and rocky sea bottoms.
这是海洋的一部分，遥感科学家通常将其描述为“嘈杂”或“肮脏”，因为河流经常因悬浮沉积物的羽流、被有色溶解有机物污染的水以及一系列微观和水生植物而使沿海水域变色。所有这些都可能与短暂的浮游植物繁殖混合在一起，有时会出现在海草、沙坪和岩石海底的各种背景下的浑浊水域中。
This mix creates optical complexity that has long made it harder for scientists to distinguish and categorize phytoplankton blooms in shallow coastal zones compared to the deeper, darker, more uniform waters of the open ocean. Yet with the arrival of missions like PACE (Plankton, Aerosol, Cloud, Ocean Ecosystem), which launched in 2024 and measures more wavelengths of light than previous ocean color missions, scientists are growing increasingly confident in identifying phytoplankton blooms even in optically complex coastal areas.
这种混合造成了光学上的复杂性，长期以来，与更深、更暗、更均匀的公海水域相比，科学家们更难区分和分类浅海沿海地区的浮游植物繁殖。然而，随着 2024 年启动的 PACE（浮游生物、气溶胶、云、海洋生态系统）等任务的到来，它测量的光波长比以前的海洋颜色任务更多，科学家们对识别浮游植物繁殖越来越有信心，即使是在光学复杂的沿海地区。
Multiple NASA satellites—including PACE, Aqua, and Terra—have captured images of colorful water in recent weeks. While some of the color visible in the images may be due to outflows from coastal rivers and sediment churned up by spring storms, “there are likely phytoplankton blooms happening,” said Anna Windle, a research scientist at NASA’s Goddard Space Flight Center supporting the PACE science team. “Diatoms typically dominate blooms early in the spring, but we are seeing some signs of coccolithophores mixed in as well,” she said. PACE data helped confirm that at least some of the greens and blues offshore are phytoplankton blooms by mapping chlorophyll in the region on the same day.
最近几周，美国宇航局的多颗卫星（包括 PACE、Aqua 和 Terra）捕捉到了彩色水体的图像。虽然图像中可见的一些颜色可能是由于沿海河流的流出和春季风暴搅动的沉积物造成的，但支持 PACE 科学团队的 NASA 戈达德太空飞行中心的研究科学家安娜·温德尔 (Anna Windle) 表示，“浮游植物很可能会大量繁殖”。 “硅藻通常在早春的花朵中占主导地位，但我们也看到了一些颗石藻混合的迹象，”她说。 PACE 数据通过在同一天绘制该地区的叶绿素图，帮助确认至少一些近海的绿色和蓝色是浮游植物的大量繁殖。
Diatoms are a class of phytoplankton that often experience explosive growth in their population in the spring when the combination of river runoff, increased sunlight, and seasonal shifts in winds and currents brings upwellings of cool, nutrient-rich water to the surface. Diatom-dominated blooms typically appear greenish in natural-color satellite imagery.
硅藻是一类浮游植物，在春季，当河流径流、阳光增加以及风和水流的季节性变化将凉爽、营养丰富的水涌到地表时，硅藻的数量通常会出现爆炸性增长。在自然色卫星图像中，以硅藻为主的花朵通常呈绿色。
Coccolithophore-dominated blooms generally have a brighter, chalkier, more turquoise look to them. The milky appearance is a product of the coccolithophores—tiny plant-like organisms that live in the upper layers of the ocean and surround themselves with scaly platings called coccoliths made of calcite , or calcium carbonate.
以颗石藻为主的花朵通常具有更明亮、更白垩、更绿松石色的外观。乳白色的外观是颗石藻的产物，颗石藻是一种微小的植物状生物，生活在海洋的上层，周围覆盖着由方解石或碳酸钙制成的称为颗石的鳞片。
These highly reflective hubcap-shaped scales are only a few thousandths of a millimeter thick, but coccolithophores are found in such massive numbers during blooms that their plates play a key role in global biogeochemical cycles. The organisms are responsible for about one-half of modern precipitation of calcium carbonate in the ocean, according to one estimate . Off the Mid-Atlantic, coccolithophore blooms generally occur in the late spring or summer, after surface water temperatures have warmed and diatom blooms have lowered nutrient levels somewhat.
这些高度反射的轮毂盖形状的鳞片厚度只有千分之几毫米，但在开花期间发现了大量的颗石藻，以至于它们的板在全球生物地球化学循环中发挥着关键作用。据一项估计，现代海洋中碳酸钙降水量的一半左右是由这些生物体造成的。在大西洋中部附近，颗石藻水华通常发生在春末或夏季，此时地表水温变暖，硅藻水华在一定程度上降低了营养水平。
Phytoplankton are to the ocean what grasses and ground cover are to land: primary producers, a key food source for other life, and the main carbon recyclers for the marine environment. Diatoms, coccolithophores, algae, and other forms of phytoplankton are floating organisms that absorb sunshine, sponge up nutrients such as nitrogen and phosphorus, and create their own food through photosynthesis .
浮游植物对于海洋就像草和地被植物对于陆地一样：初级生产者、其他生物的关键食物来源以及海洋环境的主要碳回收者。硅藻、颗石藻、藻类和其他形式的浮游植物是漂浮的生物，它们吸收阳光，吸收氮和磷等营养物质，并通过光合作用创造自己的食物。
The ocean surface is typically quite nutrient-rich in the spring after cold winter weather and winds have mixed the water vertically, bringing nutrients upwards. “But over time, as big spring phytoplankton blooms grow, they deplete the nutrients,” said Rutgers University oceanographer Oscar Schofield. “Unless big river outflows or storms replenish the nutrients, we’ll likely see this bloom start to decline in the coming weeks.”
在寒冷的冬季天气之后的春季，海洋表面通常营养丰富，并且风垂直混合水，将营养物质向上输送。 “但随着时间的推移，随着春季浮游植物大量繁殖，它们会耗尽营养，”罗格斯大学海洋学家奥斯卡斯科菲尔德说。 “除非大河流流出或暴风雨补充养分，否则我们可能会在未来几周内看到这种水华开始减少。”
NASA Earth Observatory image by Michala Garrison, using MODIS data from NASA EOSDIS LANCE and GIBS/Worldview . Story by Adam Voiland.
NASA 地球观测站图像，由 Michala Garrison 拍摄，使用来自 NASA EOSDIS LANCE 和 GIBS/Worldview 的 MODIS 数据。亚当·沃伊兰的故事。