过度捕捞导致了海洋生物数量的减少。

Overfishing has caused a significant ___decline in marine life populations.

由于缺乏维护，公园的美观度明显下降了。

There was a noticeable ___diminution in the park's beauty due to lack of maintenance.

他不断付出的努力被轻视，这让他感到自己的价值被低估。

The constant ___diminishing of his efforts made him feel undervalued.