On the premise of crop rotation, is there similarly a plant or organism able to provide nutrients into its environment that exists in water biomes?

Question

I know of the simple concept of crop rotation, and being able to use certain plants to replenish soil, and was wondering if there is a plant or organism that can or does function similarly but in water. I also know there are some plants that are more resilient (and even function or thrive) in soils high in certain compounds and metals (or, conversely lacking in certain nutrients or conditions), that are otherwise detrimental for other plants or organisms. I am therefore also wondering which plants or organisms function similarly, but again--in water, rather than on land. I have a particular interest in saltwater environments, but also would like to know if there is something in freshwater environments that provides this function.

Answer 1

Yes! In aquatic ecosystems, there are organisms that function similarly to how crop rotation replenishes soil nutrients on land. In freshwater systems, certain nitrogen-fixing cyanobacteria and aquatic legumes like Azolla can enrich the water with nitrogen, supporting other plants and algae. In saltwater environments, species such as seagrasses and salt-tolerant algae can contribute organic matter and nutrients to sediments, improving conditions for other organisms. Additionally, filter-feeding animals like mussels and oysters recycle nutrients by concentrating and depositing them in the sediment, indirectly “fertilizing” the surrounding habitat. Overall, these organisms help maintain nutrient balance and support productivity in aquatic ecosystems, much like crop rotation does for terrestrial soils.

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