Shallow water submarine hydrothermal activity: a case study in the assessment of ocean acidification and fertilization

大多数天然浅水海底热液活动（SWH）沿着海岸线与热液喷发有关，包括用火山气体加热地下水。这些小型海水浴场为真光层提供养分，有助于提高沿海沃茨的总体自然肥力和初级生产力。然而，SWH也分散有毒物质，如汞和砷，并影响酸化。本文以台湾东北部龟山岛海域为研究对象，探讨过去三年来营养盐供应与海洋酸化对海洋初级生产力的影响。这两种类型的热液喷口以颜色区分，温度较高的黄色温泉水从各种大小的硫烟囱中喷出，温度> 110 ° C，而温度较低的无色水直接从安山岩床的裂缝中喷出。N2/Ar和3He/4He比值表明这些火山气体是幔源的。pH值在2.1 - 3.5之间的热液从喷口喷出，影响长达1公里的海洋表面沃茨。相对于正常海水，SHW站点周围的水具有较高浓度的营养盐Si和P，以及微量营养盐Mn和Fe。叶绿素a显示出比正常值高几十到几百倍的高值。我们首次在自然界中发现，SHW促进了浮游植物的生长，并有助于周围沃茨的初级生产力。

Most natural Shallow Water submarine Hydrothermal activates （SWH) along coastlines are related to hydrothermal eruptions involving heating of groundwater with volcanic gas. These SWHs supply nutrients to the euphotic zone, contributing to the overall natural fertility and primary productivity of coastal waters. However, SWHs also disperse toxic materials such as mercury and arsenic, and affect the acidification. We evaluate the impact of "nutrient supply" and "ocean acidification" on the primary production over the last three years in a coastal marine environment, at a SWH area discovered off Gueshandao Island, northeast Taiwan. The two types of hydrothermal vents are differentiated by color, yellow hot spring water with higher temperature >110 °C ejected from sulfur chimneys of various sizes, and colorless water with lower temperature ~80 °C ejected directly from the crevices of the andesitic bedrock. The ratios N2/Ar and 3He/4He suggest that these volcanic gases are mantle-derived. Hydrothermal fluid with pH between 2.1-3.5 erupts from the vents and affects ocean surface waters up to 1 km way. Relative to normal seawater, water around the SHW site has higher concentrations of nutrients Si and P, and micro nutrients Mn and Fe. Chlorophyll a shows high values of several tens to hundreds times greater than normal. We find forthe first time in nature that SHW enhances the growth of phytoplankton and contributes to the primary productivity of the surrounding waters.