National Institute of Biology, Marine Biology Station Piran, Fornače 41, 6330 Piran, Slovenia; International Postgraduate School Jožef Stefan, Jamova cesta 39, 1000 Ljubljana, Slovenia.
Istituto Nazionale di Oceanografia e di Geofisica Sperimentale - OGS, via Piccard 54, 34151 Trieste, Italy.
Harmful Algae. 2020 Mar;93:101773. doi: 10.1016/j.hal.2020.101773. Epub 2020 Feb 28.
Pseudo-nitzschia H. Peragallo (1900) is a globally distributed genus of pennate diatoms that are important components of phytoplankton communities worldwide. Some members of the genus produce the neurotoxin domoic acid, so regular monitoring is in place. However, the identification of toxic members in routine samplings remains problematic. In this study, the diversity and seasonal occurrence of Pseudo-nitzschia species were investigated in the Gulf of Trieste, a shallow gulf in the northern Adriatic Sea. We used time series data from 2005 to 2018 to describe the seasonal and inter-annual occurrence of the genus in the area and its contribution to the phytoplankton community. On average, the genus accounted for about 15 % of total diatom abundance and peaked in spring and autumn, with occasional outbreaks during summer and large inter-annual fluctuations. Increased water temperature and decreased salinity positively affected the presence of some members of the genus, while strong effects could be masked by an unsuitable definition of the species complexes used for monitoring purposes. Therefore, combining morphological (TEM) and molecular analyses by sequencing the ITS, 28S and rbcL markers, eight species were identified from 83 isolated monoclonal strains: P. calliantha, P. fraudulenta, P. delicatissima, P. galaxiae, P. mannii, P. multistriata, P. pungens and P. subfraudulenta. A genetic comparison between the isolated strains and other strains in the Mediterranean was carried out and rbcL was inspected as a potential barcode marker in respect to our results. This is the first study in the Gulf of Trieste on Pseudo-nitzschia time series from a long-term ecological research (LTER) site coupled with molecular data. We show that meaningful ecological conclusions can be drawn by applying integrative methodology, as opposed to the approach that only considers species complexes. The results of this work will provide guidance for further monitoring efforts as well as research activities, including population genetics and genomics, associated with seasonal distribution and toxicity profiles.
假多甲藻 H. 佩拉戈洛（Pseudo-nitzschia H. Peragallo）（1900 年）是一种分布广泛的羽纹硅藻属，是世界范围内浮游植物群落的重要组成部分。该属的一些成员会产生神经毒素软骨藻酸，因此需要定期监测。然而，在常规采样中鉴定有毒成员仍然存在问题。在这项研究中，我们调查了亚得里亚海北部的里雅斯特湾（Trieste）的假多甲藻属的物种多样性和季节性发生情况。我们使用了 2005 年至 2018 年的时间序列数据来描述该属在该地区的季节性和年际发生情况及其对浮游植物群落的贡献。平均而言，该属约占总硅藻丰度的 15%，在春季和秋季达到峰值，偶尔在夏季出现爆发，年际波动较大。水温升高和盐度降低对该属某些成员的存在产生了积极影响，而由于用于监测目的的物种复合体定义不当，可能会掩盖强烈的影响。因此，通过对 ITS、28S 和 rbcL 标记进行序列分析，结合形态学（TEM）分析，从 83 个分离的单克隆株中鉴定出 8 个种：P. calliantha、P. fraudulenta、P. delicatissima、P. galaxiae、P. mannii、P. multistriata、P. pungens 和 P. subfraudulenta。对分离株与地中海其他株之间的遗传比较进行了检查，并检查了 rbcL 是否可以作为潜在的条形码标记符，以根据我们的结果进行检查。这是里雅斯特湾（Trieste）首个从长期生态研究（LTER）站点获得的假多甲藻时间序列的研究，同时结合了分子数据。我们表明，通过应用综合方法可以得出有意义的生态结论，而不是仅考虑物种复合体的方法。这项工作的结果将为进一步的监测工作以及与季节性分布和毒性特征相关的种群遗传学和基因组学等研究活动提供指导。
