Zhejiang Provincial Key Laboratory for Subtropical Water Environment and Marine Biological Resources Protection, Wenzhou University, Wenzhou 325035, China.
Dongtou Fisheries Science and Technology Research Institute, Dongtou, Wenzhou 325700, China.
Harmful Algae. 2017 May;65:19-26. doi: 10.1016/j.hal.2017.04.003. Epub 2017 Apr 15.
The effects of algal blooms on seaweeds have been rarely studied, although harmful algal blooms (HABs) are now normally regarded as worldwide incidents. In the present study, the effects of dense Karenia mikimotoi cells on the growth and photosynthesis of Hizikia fusiformis, a common and commercially cultivated macroalga in coastal waters of the East China Sea (ECS), were studied to understand the possible consequences when the mariculture encountered a dense harmful algal bloom. Furthermore, the counteraction of the latter on the growth and photosynthetic activities of K. mikimotoi was determined to evaluate the contribution of H. fusiformis commercial cultivation to environmental improvements. The results showed that the chlorophyll a (Chl a) contents, maximal photochemical efficiency (F/F) and relative electron transfer rate (rETR) of gas vesicles (specialized leaves), adult and young receptacles of H. fusiformis were all significantly (P<0.05) inhibited compared with the mono-cultured ones. When compared with mono-cultured H. fusiformis (without K. mikimotoi), the Chl a contents in gas vesicles, adult and young receptacles decreased by 20.6%, 17.6% and 33.2% within 2 weeks. Correspondingly, the F/F decreased by 7.9%, 37.4% and 43.7%; the apparent photosynthetic efficiency (α) decreased by 9.4%, 47.1% and 48.3%; and rETR decreased by 19.5%, 52.6% and 68.2%, respectively. The Chl a concentration of the mono-cultured K. mikimotoi (without H. fusiformis) increased to 2247.97μgl from 958.11μgl within 14 d. Those of the co-cultivated ones (with H. fusiformis), however, increased to 1591.31μgl on the 8th day and then decreased rapidly to 254.99 (±37.73) μgl after the next 6 days. Furthermore, compared with the mono-cultured K. mikimotoi cells, the F/F, α and rETR of co-cultivated ones decreased by 9.4%, 36.3% and 30.6%, respectively. The results indicated that the mature sporophytes of H. fusiformis were resistant to dense K. mikimotoi blooms and this resistance was organ-dependent as: gas vesicle>adult receptacles>young receptacles. On the other hand, commercial mariculture of H. fusiformis demonstrated the potential of preventing the occurrence of algal blooms.
赤潮对海藻的影响很少被研究过，尽管有害赤潮（HABs）现在通常被认为是全球事件。在本研究中，研究了密集的米氏凯伦藻细胞对东海（ECS）沿岸海水常见的商业养殖大型海藻条斑紫菜生长和光合作用的影响，以了解当海水养殖遇到密集的有害赤潮时可能产生的后果。此外，还确定了后者对米氏凯伦藻生长和光合作用的拮抗作用，以评估条斑紫菜商业养殖对环境改善的贡献。结果表明，与单一培养的条斑紫菜相比，条斑紫菜气胞、成体和幼体果孢子体的叶绿素 a（Chl a）含量、最大光化学效率（F/F）和相对电子传递率（rETR）均显著降低（P<0.05）。与单一培养的条斑紫菜（不含米氏凯伦藻）相比，气胞、成体和幼体果孢子体的 Chl a 含量在 2 周内分别下降了 20.6%、17.6%和 33.2%。相应地，F/F 下降了 7.9%、37.4%和 43.7%；表观光合效率（α）下降了 9.4%、47.1%和 48.3%；rETR 下降了 19.5%、52.6%和 68.2%。单一培养的米氏凯伦藻（不含条斑紫菜）的 Chl a 浓度从 958.11μg/L 在 14 天内增加到 2247.97μg/L。然而，共培养的 Chl a 浓度在第 8 天增加到 1591.31μg/L，然后在接下来的 6 天内迅速下降到 254.99（±37.73）μg/L。此外，与单一培养的米氏凯伦藻细胞相比，共培养的细胞的 F/F、α和 rETR 分别下降了 9.4%、36.3%和 30.6%。结果表明，条斑紫菜成熟孢子体对密集的米氏凯伦藻赤潮具有抗性，这种抗性与器官有关：气胞>成体果孢子体>幼体果孢子体。另一方面，条斑紫菜的商业养殖具有防止赤潮发生的潜力。
