Erika Xim Paola Santos BSBA (Marketing) – III Aqua Sci – 2 Film Commentary of “Our Planet: Fresh Water” I’ve always loved watching documentaries about wildlife and ecosystems. As a kid, I used to appreciate National Geographic more than cartoon channels. While, watching the film, “Our Planet: Fresh Water”, the kid in me was re-awakened but the fascination in learning something new about wildlife still remains. Fresh water is very crucial nowadays, which is why freshwater ecosystems are valuable. While the earth consists mainly of about 70% water, only a minute fraction consists of fresh water. As said in the documentary, only 1% is within reach and still, most of the fresh water are trapped in glaciers. Freshwater ecosystems also provide as breeding grounds for species of animals like the threatened Pacific salmon which returns to the rivers of the Andes to lay their eggs. They also thrive with plants such as the macarenia, as well as seagrass, which manatees and other aquatic animals graze on. Insect species such as the giant mayfly also stay 3 years underwater as larvae. Freshwater systems also act as the drinking water source of animals like elephants. Along with hippos and buffalos, they also rely on these waters to keep themselves cool. People also use freshwater bodies for their livelihood as they breed freshwater fishes. Marine ecosystems do not differ that much as with freshwater ecosystems, and there are actually marine animals that go to freshwater bodies depending in cold seasons or during breeding season or until they hit maturity. The main difference lies in the salinity levels where marine ecosystems have higher salinity levels such as in the open oceans and seas. The Pacific salmon mentioned earlier lay their eggs in rivers, after which their young stay in freshwater until they reach maturity and migrate to the open seas. Manatees also stay in seas during the summer but have winter homes in rivers during the cold seasons because the waters are warmer. The basic principles in aquatic systems is that it is composed of thriving living things such as plants and animals, and there are certain non-living factors in play as well. These plants like the seagrass are the food sources or sometimes the breeding ground of some animals. In an ecosystem, there is also a food chain. Just as in the rivers of Andes where the torrent ducks feed on the larvae of mayflies as their source of nutrients. The Pacific salmon also visit these waters and leap up waterfalls, or straight in the mouths of awaiting Alaskan bears. The non-living factors include the temperature of the water, which are crucial for the adaptation of some notable species, light for the growth of plants, and nutrients for survival. There is also the interaction with terrestrial animals, as well as people. I learned a lot from watching the documentary. I was filled with fascination and interest as I learn new things I didn’t know beforehand. What I was most surprised was about the formation of Lake Eyre or the Kati Thanda in the middle of the desert of Australia. It’s quite a mystery how it only forms once a decade when heavy rains pour over the desert and flood the lowermost areas. Even more puzzling is how animals learn about the lake as pelicans travel down to feed on fishes and reproduce until the lake dries out and not return after another decade has passed. I was also overwhelmed by the reality of our ecosystems being threatened due to human activities that contribute to global warming and pollution. It was also saddening how there is a scarcity of freshwater in wildlife such that elephants have to dig deeper to drink water since the streams have dried out due to dams built by people. I’m concerned how they get dehydrated especially since elephant species are starting to get fewer in number. Buffalos and hippos also have to make do with mud instead of abundant water to cool themselves. I felt helpless to see how they are mud-soaked and packed tightly due to the scarcity of water, and their tempers rising as the temperature also rises. I hope we get educated about freshwaters ecosystems and how they are valuable especially to the aquatic plants and animals so we can lessen pollution and find ways to address global warming. After all, these are the only homes they know and go to.