汽水湖の生物相:塩分による直接・間接的な生物相の維持

Salinity strongly affects biota in brackish lakes not only directly through osmotic pressure, but also indirectly through modifying water chemistry and through biological interactions. These salinity effects are summarized as follows: (1) a direct effect through osmotic pressure: the salinity level in brackish systems limits the biota to a set of organisms that can live under these osmotic pressure condition; (2) indirect effect through water chemistry: salinity often affects aspects of water chemistry such as dissolved oxygen and nutrient content, and these impacts often result in mass extinctions and shifts in the distribution of organisms; (3) indirect effects through biological interactions: biota, affected by the above mechanisms often experience further modifications through biological interactions such as predation and competition. These findings strongly suggests that salinity shifts can trigger rapid and large changes in biota, which result from both direct and indirect processes.