1. Phytoplankters are crucial for the marine ecosystem as they form the base of the food chain.
浮游植物对海洋生态系统至关重要，因为它们构成了食物链的基础。

2. The abundance of phytoplankton in the water indicates the health of the aquatic ecosystem.
水中浮游植物的丰富程度反映出水生态系统的健康状况。