Which plant can be beneficial in lake bottoms but becomes a nuisance when it grows to the surface?

The plant that can be beneficial in lake bottoms but becomes a nuisance when it grows to the surface is naiads. Naiads play a crucial role in aquatic ecosystems by providing habitat and food for various organisms when they remain submerged. Their presence at the lake bottom can help stabilize sediment and contribute to the overall health of the aquatic ecosystem.

However, when naiads grow excessively and reach the water's surface, they can obstruct navigation, hinder recreational activities, and block sunlight from penetrating deeper waters, which negatively impacts other aquatic plants and animals that rely on light for photosynthesis. This transition from a beneficial presence at the bottom to a problematic overgrowth at the surface illustrates the delicate balance within aquatic ecosystems and the need for careful management of aquatic vegetation to maintain ecological health.

Curly-leaf pondweed, watermilfoil, and lemna have their own unique ecological roles and characteristics but do not embody the specific beneficial-to-nuisance dynamic described in the question as well as naiads do.