--- title: "Ocean Ecosystems" description: "Understand ocean ecosystems as interconnected systems where living things (producers, consumers, decomposers) and non-living factors (temperature, salinity, light, currents) all interact, and that cha" canonical: https://lightmysky.com/learn/science/ocean-ecosystems-mt_w4OYcWJs6H source: https://lightmysky.com/learn/science/ocean-ecosystems-mt_w4OYcWJs6H.md retrieved: 2026-10-19 --- > **Agent view.** This is the Markdown twin of the page, for tools and assistants. > When to use this site, and the call that answers each job: https://lightmysky.com/agent-instructions.md > API description (OpenAPI 3.1): https://lightmysky.com/openapi.json · Authentication: https://lightmysky.com/auth.md > Pricing: https://lightmysky.com/pricing.md · Catalog: https://lightmysky.com/llms.txt · Full catalog: https://lightmysky.com/llms-full.txt > Every machine-readable file on this domain: https://lightmysky.com/.well-known/ai-catalog.json > Ask for Markdown with `Accept: text/markdown`, a `.md` address, or `?mode=agent`. # Ocean Ecosystems Understand ocean ecosystems as interconnected systems where living things (producers, consumers, decomposers) and non-living factors (temperature, salinity, light, currents) all interact, and that changes to one part affect the whole system Subject: Science · Area: Ocean Life · Ages 9 to 11 Page: https://lightmysky.com/learn/science/ocean-ecosystems-mt_w4OYcWJs6H ## Ready when they can - Describe an ocean ecosystem as a system of living and non-living parts that interact - Name key non-living factors that affect ocean life: temperature, salinity, light, currents - Explain how a change in one factor (like temperature) cascades through the whole ecosystem ## Lesson: The Ocean Is One Big System You already know how ocean food webs connect living things, and how light fades from the sunlight zone to the twilight zone to the midnight zone. An ocean ecosystem is the whole picture: living parts like plankton, fish, and whales, plus non-living parts like temperature, salinity, light, and currents, all interacting together. Four non-living factors matter most. Temperature is how warm or cold the water is. Salinity is how much salt is dissolved in the water. Light is how much sunlight reaches that depth. Currents are moving rivers of water that carry heat, nutrients, and even tiny drifting plankton across the ocean. *(drawing: Warmer water starts a chain. Less food for tiny ocean life means less food for fish, and less food for fish means less food for whales.)* **Example.** Off the coast of Peru, a current sometimes brings warmer water than usual. The warm water has fewer nutrients, so tiny drifting plankton struggle to grow. Fish that eat plankton go hungry and swim elsewhere. Seabirds and sea lions that eat those fish go hungry too. One change in temperature moved through the whole ecosystem. **Tip.** When you study an ecosystem, ask what happens next. A change in one factor, like temperature, rarely stays in one place. It moves through the food web until it touches almost everything. **Recap.** An ocean ecosystem is a web of living things and non-living factors like temperature, salinity, light, and currents, and a change in any one part ripples through the whole system. ## Practice 8 questions on this page, each with its working shown. ## Needs first - [Ocean Food Webs](https://lightmysky.com/learn/science/ocean-food-webs-mt_OnV_DTp5i8) - [Ocean Depth Zones](https://lightmysky.com/learn/science/ocean-depth-zones-mt_sQpIV0-qY7) - [Changing Environments](https://lightmysky.com/learn/science/changing-environments-mt_Wyd-l-6H7G) ## Opens up - [Matter Cycling in Ecosystems](https://lightmysky.com/learn/science/matter-cycling-in-ecosystems-mt_0ajzcoKAKw) - [Coral Bleaching & Acidification](https://lightmysky.com/learn/science/coral-bleaching-and-acidification-mt_EXO1bJ3G_v) - [Ocean Pollution & Harm](https://lightmysky.com/learn/science/ocean-pollution-and-harm-mt_J6uccv2Bo4) - [Oceans & Climate](https://lightmysky.com/learn/science/oceans-and-climate-mt_KRNU0IOKfO)