Algae, beautiful yet dangerous

The Shenzhen Bay in Nanshan District is highly eutrophic and recently, a thick patchy algae bloom was discovered in Talent Park. This bloom covered most water bodies, and investigations are under way to trace its causes and find solutions. The bloom was likely caused by a combination of extreme drought conditions, hyper-salinity due to poor tidal exchange, and high nutrient inflow from a humanmade freshwater canal.

位于南山区的深圳湾是一个富营养化严重的海湾，近期，在人才公园发现了成片而厚实的赤潮，这片赤潮覆盖了大部分水域。目前调查正在进行以追踪其原因并找到解决方法。本次赤潮的产生与极端的干旱条件、潜在不良的潮汐交换导致的高盐度水体，及可能来自人工淡水运河的高营养物质有关。

A thick patchy algae bloom was discovered in Talent Park recently. Matteo Convertino

近期，在人才公园发现了成片而厚实的赤潮。

Tracking microalgae is crucial to detect whether water bodies have exceeded risk thresholds, whether the algae is blooming, or worse, if the water contains toxic pathogens associated with the emergence of blooms. After analyzing the algae in Talent Park, which consisted mostly of chlorellas, diatoms, and leptolyngbya (a cyanobacteria species), no apparent signs of toxicity were found. However, there were observations of dead birds and fish and high nitrogen and phosphorus levels. Therefore, it is highly recommended not to touch the water due to the potential for skin irritation and toxicity.

追踪微藻对于检测水体是否超过风险阈值、赤潮是否会爆发，或者水体是否含有与赤潮发生有关的有害病原体至关重要。在分析了人才公园的赤潮后，发现其主要由小球藻、硅藻和细鞘丝藻（一种蓝藻物种）组成，虽然没有发现明显的毒性迹象，却伴随有鸟和鱼的死亡，以及水体高氮和高磷水平的情况。这有可能造成人类皮肤刺激和中毒情况，因此强烈建议不要接触发生赤潮时的海水。

Algae blooms can be seen near Talent Park's bridge where there is lighting at night. Photo by Bowen 

人才公园桥的附近可以看到赤潮现象，光线有可能促进了藻类进行光合作用的生长。

Multispectral drones can be used to trace blooms and define red areas that are active and potentially more risky. Red pixels identify locations where oxygen levels are potentially very low, which harms biodiversity. These active blooms coincide with areas close to night illumination such as those close to Talent Park's bridge. The light may have contributed to the growth of photosynthetic algaes.

多光谱无人机可以用来追踪赤潮，并定义藻类活跃、有更大的风险爆发赤潮的红色区域。红色像素标识出不利于生物生存的氧气水平非常低的位置。此次赤潮发生区域与靠近夜间照明的区域相重叠，如人才公园桥的附近，这表明光线有可能促进了藻类进行光合作用的生长。

Algal blooms of dinoflagellates were observed recently in the Dapeng peninsula. Courtesy of Shenzhen Marine Environmental Monitoring Center.

近期，在大鹏半岛可以观察到鞭毛藻爆发现象。

Recently, other colorful but harmful algal blooms of dinoflagellates were observed in the Dapeng peninsula: red algae during the day and neon-blue bioluminescent at night. Although these blooms have bright colors and artsy patterns, they can be potentially harmful.

最近，在大鹏半岛也观察到其他五颜六色但有害的鞭毛藻爆发现象：白天看起来是红藻，晚上看到的则是霓虹蓝的生物发光体。虽然这些藻类有明亮的颜色和艺术性的图案，但它们可能是有潜在危害的。

Eutrophication, which results from excessive nutrients, can be caused by dramatic shifts in nutrients, fresh and salt-water flows, sediment, biodiversity, and temperatures. The growth of algae is often a complex combination of slow and fast changes acting together that lead to eutrophication. When this becomes frequent and persistent, it can alter ecosystems, result in carbon emissions, species death, poor water quality, and emerging pathogenic toxins that can severely harm local species as well as people.

富营养化是由过多的营养物质造成的，该现象可以由营养物质、淡水和盐水流量、沉积物、生物多样性和温度的剧烈变化引起。藻类的生长往往是缓慢和快速变化共同作用的复杂过程，最终导致富营养化。当这种情况变得频繁且长久时就会改变生态系统，导致碳的排放、物种死亡、水质变差以及出现病原体毒素等现象，从而严重危害当地物种以及人类生活。

Park staff members remove algaes from the seawater in Talent Park in Nanshan District recently. Matteo Convertino

人才公园的管理人员在打捞藻类。

Balanced freshwater-saltwater flows, habitat connections, water treatment, protection and restoration of coastal vegetation, fish and other wildlife, ecosystem monitoring, and responsible recreation are necessary solutions to maintain a well-functioning biodiversity in which species support each other. Prevention is crucial, and everyone should join efforts to build better aquatic ecosystems.

平衡的淡水-海水流动、生境的连通性、污水处理、保护和恢复沿海植被、鱼类和其他野生动物、生态系统监测和游客负责任的娱乐活动等，是维持功能良好且互相支持的生物多样性所需要的方案。保护生物多样性预防是至关重要的，每个人都应该为建设更好的水生生态系统而努力。