Diatoms contributing to new production in surface waters of the northern Bering and Chukchi Seas during summer with reference to water column stratification
Diatoms contributing to new production in surface waters of the northern Bering and Chukchi Seas during summer with reference to water column stratification
复制标题
硅藻对夏季白令海和楚科奇海北部地表水新产量的贡献（参考水柱分层）
DOI：
10.1016/j.pocean.2021.102692
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Hirawake T
中科院分区：
文献类型：
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作者：
Suzuki K;Yoshino Y;Nosaka Y;Nishioka J;Hooker S B;Hirawake T
从春季到夏季，白令海和楚科奇海北方发生了以硅藻为主的浮游植物水华。然而，在夏季水柱经常分层时，对这些沃茨中新生产的硅藻知之甚少。在这项研究中，使用13 C，15 N双同位素示踪技术和扫描电子显微镜，我们评估了硅藻属或种的新生产的表面沃茨的北方白令海和楚科奇海在2013年7月。在白令海峡和楚科奇大陆架观测站，硝酸盐、亚硝酸盐、磷酸盐和硅酸盐的浓度相对较高，而在其他观测站，表层硝酸盐一般都已耗尽。表面铵含量相对较高（0.05-1.52 µM），表明异养生物的高活性。在地表沃茨中，每小时硝酸盐的吸收速率在0.03到3.73 mg N m− 3 h −1之间，而铵的吸收速率在0.04到0.43 mg N m− 3 h −1之间。因此，观察期间的平均f-比率计算为0.62 ± 0.23。我们发现，硝酸盐吸收速率与环境硝酸盐水平呈正相关，表明活动主要是受调节的物理过程中的硝酸盐供应。硅藻角毛藻（主要是C. socialis/gelidus）在数量上占优势。C的贡献。socialis/gelidus（9 ± 4 µm大小）对总有甲浮游植物丰度的影响随着水柱分层的增加而增加，而Thalassiosilaspp. (26± 8 µm）显示了相反的趋势。这些结果是一致的生存策略的小硅藻营养吸收贫营养沃茨通过其较高的细胞表面积体积比。另一方面，海链藻碳生物量在表层沃茨中相对较高，并与f-比值显著相关。我们的结论是，在夏季中心的海链藻在确定新的生产在研究区的表面沃茨中起着关键作用。
Intensive phytoplankton blooms, which mainly consist of diatoms, take place in the northern Bering and Chukchi Seas from spring to summer. Little is known, however, about the diatoms contributing to new production in these waters during summer when the water column is often stratified. In this study, using a13C,15N dual isotope tracer technique plus scanning electron microscopy, we assessed the diatom genera or species contributing to new production in surface waters of the northern Bering and Chukchi Seas in July 2013. Relatively high concentrations of nitrate, nitrite, phosphate, and silicate were observed at Bering Strait and Chukchi Shelf stations, whereas at the other stations surface nitrate was generally depleted. Surface ammonium levels were relatively high (0.05–1.52 µM), suggesting the high activity of heterotrophic organisms. In surface waters, hourly nitrate uptake rates ranged from 0.03 to 3.73 mg N m−3h−1, while the ammonium uptake rates varied between 0.04 and 0.43 mg N m−3h−1. As a result, the meanf-ratio was computed as 0.62 ± 0.23 during observation. We found that the nitrate uptake rates were positively correlated with ambient nitrate levels, indicating that the activity was mainly regulated with the physical process of nitrate supply. The diatomChaetoceros(mainlyC. socialis/gelidus) numerically dominated the surface diatom assemblages. Contributions ofC. socialis/gelidus(9 ± 4 µm in size) to the total armored phytoplankton abundance increased with an increase in the water column stratification, whereasThalassiosilaspp. (26 ± 8 µm) showed the opposite trend. These results were consistent with the survival strategy of small diatoms for nutrient uptake in oligotrophic waters through their higher cell surface area to volume ratios. On the other hand, the carbon biomass ofThalassiosirabecame relatively high in surface waters, and significantly correlated withf-ratio. We conclude that the centric diatomThalassiosiraplays a key role in determining new production in surface waters of the study area during summer.