International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, China.
Shengsi County Aquaculture Service Center, Zhoushan, China.
Sci Total Environ. 2024 Jun 20;930:172561. doi: 10.1016/j.scitotenv.2024.172561. Epub 2024 Apr 17.
Environmental stressors such as salinity fluctuations can significantly impact the ecological dynamics of mussel beds. The present study evaluated the influence of hyposalinity stress on the detachment and survival of attached mussels by simulating a mussel farming model in a laboratory setting. Byssus production and mechanical properties of thread in response to varying salinity levels were assessed, and histological sections of the mussel foot were analyzed to identify the changes in the byssus secretory gland area. The results showed that hyposalinity stress (20 and 15 psu) led to a significant decrease in mussel byssus secretion, delayed initiation of new byssus production, and reduced plaque adhesion strength and breaking force of byssal threads compared to the control (30 psu) (p < 0.05). The complete suppression of byssal thread secretion in mussels under salinity conditions of 10 and 5 psu, leading to lethality, indicates the presence of a blockade in byssus secretion when mussels are subjected to significant physiological stressors. Histological analysis further demonstrated a decrease in the percentage of foot secretory gland areas in mussels exposed to low salinities. However, contrary to expectations, the study found that mussels did not exhibit marked detachment from ropes in response to the reduced salinity levels during one week of exposure. Hyposalinity stress exposure reduced the byssal secretion capacity and the mechanical properties of threads, which could be a cause for the detachment of suspension-cultured mussels. These results highlight the vulnerability of mussels to hyposalinity stress, which significantly affects their byssus mechanical performance.
环境胁迫因子，如盐度波动，会显著影响贻贝床的生态动态。本研究通过在实验室模拟贻贝养殖模型，评估低盐胁迫对附着贻贝脱落和存活的影响。评估了贻贝在不同盐度下产生足丝和足丝纤维力学性能的变化，并对贻贝足部组织切片进行分析，以确定足丝分泌腺面积的变化。结果表明，低盐胁迫（20 和 15 psu）会导致贻贝足丝分泌显著减少，新足丝产生延迟，与对照组（30 psu）相比，贻贝斑块附着强度和足丝纤维断裂力降低（p<0.05）。在盐度为 10 和 5 psu 的条件下，贻贝足丝分泌完全被抑制，导致死亡，表明当贻贝受到重大生理胁迫时，足丝分泌受到抑制。组织学分析进一步表明，暴露在低盐环境下的贻贝足部分泌腺面积百分比下降。然而，与预期相反的是，研究发现，在暴露于低盐水平一周的时间内，贻贝并没有明显从绳索上脱落。低盐胁迫会降低贻贝的足丝分泌能力和纤维的力学性能，这可能是悬浮养殖贻贝脱落的原因。这些结果强调了贻贝对低盐胁迫的脆弱性，这会显著影响它们的足丝力学性能。
