--- title: The ocean: open sea, sunlit zone and the deep dark — a lesson of Mova's school · trees and pragmatics description: «The ocean: open sea, sunlit zone and the deep dark», a lesson of the biology course of Mova's primary school, sentence by sentence with dependency trees and pragmatics. It begins: The ocean is a building of floors made of water: the sunlit zone in the top 200 metres, where there is enough light for --- [Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/corpora/school/biology/8-the-ocean/) [home](https://md.mova.elamur.ai/free/en/) / [corpora](https://md.mova.elamur.ai/free/en/corpora/) / [school](https://md.mova.elamur.ai/free/en/corpora/school/) / [Biology](https://md.mova.elamur.ai/free/en/corpora/school/biology/) / The ocean: open sea, sunlit zone and t… # The ocean: open sea, sunlit zone and the deep dark Lesson 8 of the biology course of Mova's primary school: 17 sentences, each with its syntax tree and pragmatics. The lessons are written for Mova, and their agreed trees are part of Mova corpus 0.4 (CC BY-SA 4.0). How Mova does on its tests: [the lesson at school](https://md.mova.elamur.ai/free/en/school-run/biology/8-the-ocean/). - [0](https://md.mova.elamur.ai/free/en/corpora/school/biology/8-the-ocean/0/) — The ocean is a building of floors made of water: the sunlit zone in the top 200 metres, where there is enough light for plankton to grow, and below it ever darker floors down to the black deep, where the only light is made by animals themselves. - [1](https://md.mova.elamur.ai/free/en/corpora/school/biology/8-the-ocean/1/) — When you snorkel the water looks blue because water soaks up red light first and blue light last, so the deeper you go the bluer and darker it gets, until there is no sunlight at all. - [2](https://md.mova.elamur.ai/free/en/corpora/school/biology/8-the-ocean/2/) — A drop of seawater under the school microscope wriggles with plankton, tiny drifting algae and animals; they are the bottom of the ocean food chain, and the tiny algae among them make about half the oxygen we breathe. - [3](https://md.mova.elamur.ai/free/en/corpora/school/biology/8-the-ocean/3/) — In Jaws one shark terrorises a whole town, but real shark attacks are very rare, most of the 500 or so kinds of shark are smaller than a person, and people catch tens of millions of sharks every year. - [4](https://md.mova.elamur.ai/free/en/corpora/school/biology/8-the-ocean/4/) — In Finding Nemo the anglerfish that chases Marlin and Dory is a good likeness: a big female with a glowing lure on her head, and a real male anglerfish of some kinds is tiny and fuses onto the female for life. - [5](https://md.mova.elamur.ai/free/en/corpora/school/biology/8-the-ocean/5/) — The sunlit zone is the top 200 metres of the ocean, where there is enough light for plant-like plankton to grow, and ocean plankton make about half the oxygen in our air. - [6](https://md.mova.elamur.ai/free/en/corpora/school/biology/8-the-ocean/6/) — Plankton are tiny drifting living things, such as algae, baby fish and copepods; many swim up to the surface at night and sink by day, the biggest daily journey of animals on Earth. - [8](https://md.mova.elamur.ai/free/en/corpora/school/biology/8-the-ocean/8/) — Sharks are fish with skeletons of cartilage; there are over 500 kinds, most smaller than a person, they have lived for over 400 million years, and attacks on people are very rare. - [9](https://md.mova.elamur.ai/free/en/corpora/school/biology/8-the-ocean/9/) — Deep-sea anglerfish lure prey with a light made by bacteria living in the lure, and in some kinds the tiny male fuses onto the much larger female for life. - [10](https://md.mova.elamur.ai/free/en/corpora/school/biology/8-the-ocean/10/) — Giant squid have eyes up to about 27 cm across, among the largest of any animal, and a giant squid was first filmed alive in its deep home only in 2012. - [11](https://md.mova.elamur.ai/free/en/corpora/school/biology/8-the-ocean/11/) — An octopus has no bones, so it can squeeze through any gap bigger than its hard beak; it has 3 hearts, 8 arms and blue blood, and most of its nerve cells are in its arms. - [12](https://md.mova.elamur.ai/free/en/corpora/school/biology/8-the-ocean/12/) — Sperm whales dive over 1,000 metres deep, sometimes over 2,000, hunting squid by echolocation clicks, the loudest sounds made by any animal, and they have the biggest brain of any animal. - [13](https://md.mova.elamur.ai/free/en/corpora/school/biology/8-the-ocean/13/) — Female sea turtles cross oceans to lay eggs on the beach where they hatched, probably finding it partly by sensing Earth's magnetic field, and warmer sand gives more female babies. - [14](https://md.mova.elamur.ai/free/en/corpora/school/biology/8-the-ocean/14/) — Sea turtles eat jellyfish and can mistake floating plastic bags for them; plastic can block the stomach so the turtle feels full and starves, and tiny microplastics have been found from the deepest trenches to Arctic ice. - [15](https://md.mova.elamur.ai/free/en/corpora/school/biology/8-the-ocean/15/) — The Challenger Deep in the Mariana Trench is about 11 km deep, with pressure over 1,000 times that at the surface, and Everest put inside it would have its peak about 2 km under water; yet small fish, shrimp-like animals and microbes still live down there. - [16](https://md.mova.elamur.ai/free/en/corpora/school/biology/8-the-ocean/16/) — Flying fish escape tuna and other hunters by leaping out and gliding on wing-like fins, sometimes over 200 metres, beating their tails on the water to stay up longer. - [17](https://md.mova.elamur.ai/free/en/corpora/school/biology/8-the-ocean/17/) — A squid has 8 arms and 2 longer tentacles, and like an octopus it has 3 hearts. - ← previous: [Antarctica: penguins, seals and the coldest place on Earth](https://md.mova.elamur.ai/free/en/corpora/school/biology/7-antarctica/) - next →: [Coral reefs, rockpools and the seashore](https://md.mova.elamur.ai/free/en/corpora/school/biology/9-coral-reefs-rockpools-and-the-seashore/) - ↑ back to [Biology](https://md.mova.elamur.ai/free/en/corpora/school/biology/)