Ecosystems are everywhere and we hardly even notice. Even we, humans are a part of it. However, ecosystems are not exclusive to terrestrial regions since ecosystems are present even in the shallowest rivers to the great depths of the ocean. Aquatic ecosystems differ from terrestrial ecosystems because of course they are underwater. Nevertheless, both of these ecosystems are still composed of abiotic and biotic components. In aquatic ecosystems several species of marine and freshwater plants and animals are found. There various kinds of fish, turtles, dolphins, crabs, kelps seaweeds, mangroves and others that are present and they make up for the biotic part of the ecosystem. Also often found in ecosystems are of course water, soil, stones, and sand. These composes the abiotic part of the ecosystem along with other factors like temperature, salinity, and one of the most important of all is sunlight. These factors are not independent of each other but instead interwoven to a complex net of relationships. A great number of symbiotic relationships interplay in these ecosystems in order to maintain balance. One of this relationships would be mutualism in which both organisms benefit from this relationship. An example of this relationship is between the clownfish and the sea anemone. Another type symbiosis is commensalism. Commensalism is a form of symbiosis in which only organism benefits without harming the other. The hermit crab and the barnacles that grow in its shell is a good example of commensalism. Predation is also another type of this relationship. In predation one organism is eaten by another. Sharks eating smaller fishes, electric eels that uses electricity to sting their prey are some examples. Sometimes these relationships extend up to the terrestrial ecosystems like when crocodile hunts for zebras and other animals near rivers or when some birds hunt for fishes. This reminds us that terrestrial and aquatic ecosystems are interconnected and never inseparable. There are two types of aquatic ecosystem: marine and freshwater. Marine ecosystems cover more than 70% of the earth’s surface. They are distinguished from freshwater ecosystems based on the salinity. Marine ecosystems have and average salinity of more 35 ppt compared to freshwater ecosystems have 0 to 5 ppt. Marine ecosystems can be divided into many zones depending upon water depth and shoreline features. The oceanic zone is the vast open part of the ocean where animals such as whales, sharks, and tuna live. The benthic zone consists of substrates below water where many invertebrates live. The intertidal zone is the area between high and low tides; in this figure it is termed the littoral zone. On the other hand freshwater ecosystems cover only 0.80% of the earth’s surface and it is divide to into two: Lentic which has slow moving water, including pools, ponds, and lake and Lotic with faster moving water, for example streams and rivers. Aquatic ecosystems are important source of biodiversity. It is home for a diverse types plant animals life. These ecosystems are sources of food and water, they help in preventing droughts and floods, supports in soil formation and nutrient cycle, and they have also cultural impacts. Due to their importance this ecosystems this ecosystems should be protected. Terrestrial ecosystems cannot exist on its own and needs the aquatic ecosystem in order to sustain life. In total I have learned that each member of an ecosystem is important since they are all important. They exist in an intricate web of relationships where sometimes some are harmed or eaten. But that is the way that nature maintains balance. I also learned that aquatic ecosystems are as important as terrestrial ecosystems. Even though we don’t belong in aquatic ecosystems we surely can’t live without them.

Retrieved from: http://serc.carleton.edu/microbelife/topics/marinesymbiosis/index.html http://www.environment.gov.au/topics/water/water-information/aquatic-ecosystems http://environment.nationalgeographic.com/environment/freshwater/aquatic-ecosystems/