---
id:"kb-2026-00496"
title:"Ocean Life"
schema_type:"TechArticle"
category:"science"
language:"en"
confidence:"high"
last_verified:"2026-05-22"
generation_method:"ai_assisted"
ai_models:["claude-opus"]
derived_from_human_seed:true
primary_sources:
  - title:"The Biology of the Deep Ocean (Peter Herring)"
    type:"book"
    year:2001
    url:"https://global.oup.com/academic/product/the-biology-of-the-deep-ocean-9780198549567"
    institution:"Oxford University Press"
secondary_sources:
  - title: "Retrieval-Augmented Generation for Knowledge-Intensive NLP Tasks"
    authors: ["Lewis", "Perez", "Piktus"]
    type: "academic_paper"
    year: 2020
    doi: "10.48550/arXiv.2005.11401"
    url: "https://arxiv.org/abs/2005.11401"
  - title: "MDN Web Docs — HTTP"
    type: "documentation"
    year: 2026
    url: "https://developer.mozilla.org/en-US/docs/Web/HTTP"
    institution: "Mozilla"
completeness: 0.88
ai_citations:
  last_citation_check:"2026-05-22"
---

## TL;DR

Oceans cover 71% of Earth's surface and contain 97% of its water. Average depth: 3,688m. Zones: sunlight (0-200m, photosynthesis), twilight (200-1,000m), midnight (1,000-4,000m), abyssal, hadal (trenches, >6,000m). Deep ocean: largest ecosystem on Earth, largely unexplored. Marine life ranges from microscopic plankton to blue whales (largest animal ever, 30m, 200 tons).

## Core Explanation

Phytoplankton: produce 50-80% of Earth's oxygen. Coral reefs: biodiversity hotspots (25% of marine species in <0.1% of ocean). Bioluminescence: 90% of deep-sea organisms produce light. Pressure: increases 1 atmosphere per 10m depth. Hydrothermal vents (1977 discovery): life powered by chemosynthesis (not sunlight). Top predator: orca (killer whale). Marine snow: organic material falling from surface — deep sea food source.

## Further Reading

- [The Biology of the Deep Ocean (Peter Herring)](https://global.oup.com/academic/product/the-biology-of-the-deep-ocean-9780198549567)