环境条件和养殖模式对大型经济类海藻砷吸收和转化的影响

Edible marine macroalgae is a very important marine resource for the coastal cities in China. Marine macroalgae is capable for accumulating large amount of arsenic from the seawater, and it is so called “Arsenic Bank” in the marine ecosystem. Arsenosugars are considered as the “non-toxic” arsenic speciation and it is the major arsenic form in marine macroalgae. From the recent findings, arsenosugar could be metabolized in human, thus its potential health risk cannot be underestimated. Environmental parameters (e.g. phosphate concentration, N:P ratio, temperature, ORP, and mixing process) and marine-culture patterns (e.g. algae mono-culture, algae and shellfish mix-culture, harvesting scheme) may play important roles on the uptake and transformation of As in macroalgae, however the mechanisms are still hidden. The current project application aims to have a field investigation of two local edible marine macroalgae species (Gracilaria lemaneaformis and Porphyra haitanensis) around Nan’ao Island, in order to study As uptake and translocation in the two marine species under the influence of different environmental parameters and marine-culture patterns. Moreover, it is to have a mechanistic study on the As uptake and transformation in the two marine species under different phosphate concentration gradients and the rising temperature in the laboratory. The ultimate goal is to understand the mechanism of the As uptake and transformation in marine macroalgae, thus to predict the impact of eutrophication and global warming on the quality and safety of edible marine macroalgae.

大型食用类海藻是我国沿海地区的重要海洋经济资源。由于它可以从海水中富集大量的砷，因此被称为海洋的“砷库”。虽然砷在海藻体内多以“无毒”的砷糖形式存在，但砷糖在人体代谢过程中的潜在长期健康风险不容忽视。环境条件（磷酸盐浓度、氮磷比、水温、氧化还原条件、水体混合速率等）及养殖模式（藻类单养、藻贝混养、收割批次）是决定海藻中砷浓度和形态的关键因子，但目前关于这些因子对藻类吸收和转化砷的影响机制尚不清楚。本项目拟对我国主要的食用类海藻养殖基地南澳岛进行实地研究，揭示不同环境条件及养殖模式下海藻对砷吸收和转化的规律。通过在实验室调节磷酸盐浓度、氮磷比及温度等条件，研究海藻对砷吸收和转化的机制。结合实地和实验室研究结果，阐明环境条件及养殖模式对于海藻吸收和转化砷的影响机制，并进一步预测近岸海域富营养化与温度升高对海产品质量和安全的影响。

大型食用类海藻是我国沿海地区的重要海洋经济资源。由于它可以从海水中富集大量的砷，因此被称为海洋的“砷库”。虽然砷在海藻体内多以“无毒”的砷糖形式存在，但砷糖在人体代谢过程中的潜在长期健康风险不容忽视。环境条件（磷酸盐浓度、氮磷比、水温、氧化还原条件、水体混合速率等）及养殖模式（藻类单养、藻贝混养、收割批次）是决定海藻中砷浓度和形态的关键因子，但目前关于这些因子对藻类吸收和转化砷的影响机制尚不清楚。通过本项目的研究（1）认清环境条件和养殖模式对坛紫菜和龙须菜吸收和转化砷的影响，不同养殖模式（插杆和浮筏养殖）对于坛紫菜砷的含量未见显著差异，且不同批次紫菜中的砷形态分布都主要以砷糖形式存在；（2）通过对南澳海区坛紫菜养殖区域的连续多年的研究发现，气候条件变化对大型海藻的产量影响尤为突出，但对于大型海藻吸收和转化砷未见显著的影响；（3）通过室内模拟实验，验证了磷酸盐对于坛紫菜吸收砷的影响，海水中磷酸盐升高不仅可以抑制大型海藻对砷的吸收，还可以促进无机砷向有机砷转化，研究成果将为海洋食品安全，以及可持续绿色海洋养殖提供科学参考依据。