 marine ecosystems, the estuaries, first the contents, the definition of estuaries, productivity of estuaries, plants and animal life present in estuaries, an impact of human on the estuarine water. So the estuaries, estuaries are actually the places where marine and freshwater they meet with each other. So we can say the estuaries are actually the places where marine water is diluted or the salt concentration is diluted. In simple words, if we talk, different rivers where they flow ultimately will be a part of an ocean, a part of a sea. So the position on which the river or any other water, fresh water body will go and meet with the ocean where the waters are located, the specific location is called the estuaries. So if we look at the estuaries, then in the estuaries, fresh water and marine water are mixed up. I mean, here fresh water and marine water are the two properties where they meet. That is why the animals, that is, the salt or marine water in the estuarine environment do not exist. In this way, the salt in the fresh water is also diluted. So it is actually the ideal environment for the aquatic organisms. The productivity of estuarine waters, if we talk about estuarine waters, they have very high productivity. So the productivity here is very high. Different types of algae are growing there. Different types of algae are present. Different types of aquatic plants are growing there. Now if we look at the productivity in which algae plants are growing, why they are growing there? There are two reasons for that. Number one, the nutrients from the ocean are also coming along with the water waves or the tides. Similarly, the nutrients of fresh water, they are also coming along with the fresh water. So the nutrients on both sides are available here for the growth of different types of algae or the aquatic plants. So if we look at the diversity of animals and plants, so at this position, a great number of different types of algae are there. Different types of plants are there. The plants are there, mainly they are submerged or emerging plants. Different types of plants are growing here and they are making the vegetation. So the second one is about animals. If we talk about animals, different types of invertebrates are there. Different types of invertebrates if we talk about them, they are also called the nurseries of the different types of animals. So the nurseries are the ones where a huge number of organisms are growing. Because the estuarine water that is having highest diversity in the aquatic ecosystem, in the aquatic ecosystem, the diversity is found in the estuarine water. It means that large number of invertebrates are there, large number of vertebrates are there. In invertebrates, if we look at different types of invertebrates, molluscs, anelites, and other types of arthropods are there. Different types of peristations, crabs, shrimps, different types of fishes are there. So different types of fishes are there. Similarly, different types of birds are also there. So the birds who are feeding the fish are also present in the estuarine water. So what is the impact of human and estuarine water? They have exploited these estuaries. So what have these estuaries done to humans? They have exploited them. Now what are the estuaries done on different positions? Is it drained? Is it filled? Is it divided in different compartments? So that the fish can be harbored from there. So now when the natural system over-exploits it, ultimately they are being damaged by the human. So apart from this, the human is being designed for its recreational purposes. Because of which the estuaries are either damaged badly. So because of which the overall population of plants and animals is also decreasing there. The other impacts are the pollution caused by oil spillage. The pollution caused by oil spillage is present there. Especially when the oil is draining, the exploration of the oil near estuaries will have a direct impact on the estuarine flora and fauna. Similar to the estuarine. Now when the estuarine is drained, the flowing water will ultimately impact the life of the plants and animals present in the estuarine water. So the estuarine will kill the different types of plants and animals present there.