What impact does effective ballast water treatment have on marine biodiversity?

Effective ballast water treatment has a significant impact on marine biodiversity by preventing the spread of non-native species. Ballast water is taken on by ships to maintain stability and balance during transit, often containing a mix of microorganisms, plants, and animals from its original location. If not treated, this ballast water can introduce invasive species into new environments, which can outcompete native species for resources, disrupt local ecosystems, and lead to a decline in native biodiversity.

By implementing effective treatment methods that kill or remove these organisms before the ballast water is discharged, ships are less likely to introduce harmful non-native species into the marine environment. This helps preserve local biodiversity and maintain healthier ecosystems, ensuring that the balance of native species is supported and that the ecological integrity of local waters is upheld.

The other options do not accurately address the primary function and benefits of ballast water treatment as it pertains to marine biodiversity. Enhancing biodiversity or altering water salinity are not direct outcomes of treatment practices targeting non-native species. Also, asserting that there is no impact fails to recognize the critical ecological consequences of invasive species introductions.