Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, Av. Diagonal 645, Barcelona E-08028, Spain.
Department of Marine Biology and Oceanography, Institute of Marine Sciences (ICM-CSIC), Pg. Marítim de la Barceloneta, 37-49, Barcelona E-08003, Spain.
Environ Sci Technol. 2021 Jan 5;55(1):468-477. doi: 10.1021/acs.est.0c05795. Epub 2020 Dec 6.
Critical research is needed regarding harmful algal blooms threatening ecosystem and human health, especially through respiratory routes. Additional complexity comes from the poorly understood factors involved in the physical production of marine aerosols coupled with complex biogeochemical processes at ocean surfaces. Here-by using a marine aerosol generation tank-five bubble-bursting experiments (with contrasting incubation times and, likely, physiological microalgal states) were run to investigate simultaneously the concentrations of the toxins, synthesized by a natural cf. bloom, in suspension in the water and in the atmosphere. The first two experiments (EXP1-2) were run with moderate levels of cf. cell numbers (ca. 10 cells·L) and total toxin in suspension (4 × 10 pg·L) obtained at an early phase of the bloom. After 0.75-4 h incubation, toxin concentration in the aerosols accounted for 49-69 pg·L. By striking contrast, three experiments (EXP3-5)-conducted with samples collected two weeks later with higher cell abundances and higher toxin concentration in the seston (respectively, about 1 × 10 cells·L and 2 × 10 pg·L) and incubated for 21 h-showed about 15-fold lower atmospheric concentrations (3-4 pg·L), while important foam accumulation was observed in the water surface in the tank. Offline spectroscopic analysis performed by proton-nuclear magnetic resonance spectroscopy showed that the particulate organic carbon in the water was drastically different from that of bubble-bursting aerosols from the tank experiments-suggesting a selective transfer of organic compounds from seawater into the atmosphere. Overall, the results suggest that aerosol production and diffusion of marine toxins in the atmosphere are regulated by complex interactions between biological processes and air-sea aerosol production dynamics.
需要对威胁生态系统和人类健康的有害藻类大量繁殖进行关键性研究，尤其是通过呼吸道途径。另外，海洋气溶胶的物理产生涉及到许多人们尚未了解的因素，再加上海洋表面复杂的生物地球化学过程，使得情况更加复杂。在这里，我们通过一个海洋气溶胶发生箱，进行了五个气泡破裂实验（具有不同的孵化时间，可能会导致生理微藻状态不同），同时研究了悬浮在水中和大气中的毒素浓度。前两个实验（EXP1-2）是在中水平的 cf. 细胞数量（约 10 个细胞·L）和悬浮总毒素（4×10 pg·L）的情况下进行的，这些数值是在大量繁殖的早期阶段获得的。经过 0.75-4 h 的孵化后，气溶胶中的毒素浓度占 49-69 pg·L。相比之下，另外三个实验（EXP3-5）是在两周后用含有更高细胞丰度和更高悬浮毒素浓度（分别为约 1×10 个细胞·L 和 2×10 pg·L）的样本进行的，孵化时间为 21 h，气溶胶中的大气浓度约低 15 倍（3-4 pg·L），同时在水箱的水面上观察到了大量的泡沫积聚。离线光谱分析通过质子核磁共振光谱法进行，结果表明，水中的颗粒有机碳与水箱实验中气泡破裂气溶胶的颗粒有机碳有很大的不同，这表明有机化合物从海水中选择性地转移到了大气中。总的来说，这些结果表明，海洋毒素在大气中的气溶胶产生和扩散受到生物过程和海气气溶胶产生动力学之间复杂相互作用的调节。
