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Compare-Contrast-Connect: Life in the Depth Zones

NGSS Science and Engineering Practices:

NGSS Crosscutting Concepts:

NGSS Disciplinary Core Ideas:

The diversity of life in the ocean is astounding. While most people are familiar with organisms that live near the coastline and can be easily seen, there are many species that live in the open ocean or ‘pelagic’ zone. The pelagic zone can be divided into five zones based on depth: epipelagic, mesopelagic, bathypelagic, abyssopelagic, and hadopelagic (SF Table 9.2).


Even though humans rarely travel to depths below the euphotic zone, we have learned a great deal about species that live in the deep ocean through fishing trawls, underwater construction, and scientific research. However the ocean depths are still an exciting new frontier where new species are continuously discovered. As technology allows humans to go deeper and deeper into the ocean depths, we learn more and more about the organisms that live there. SF Table 9.2 shows some of the species that live in each pelagic zone.


SF Table 9.2. A table showing organisms that live in each of five depth classifications of the pelagic zone (depths in this table are approximate)
Depth Zone Depth (m) Species Examples
Epipelagic 0-200

<p>Moon Jellyfish (<em>Aurelia aurita</em>)</p><br />

<p>Flyingfish (<em>Cheilopogon pinnatibarbatus japonicus</em>)</p><br />

<p>Big Eye Tuna (<em>Thunnus obesus</em>)</p><br />

Mesopelagic 200-1000

<p>Fangtooth (<em>Anoplogaster cornuta</em>)</p><br />

<p>Velvet Whalefish (<em>Barbourisia roufa</em>)</p><br />

Bathypelagic 1000-4000

<p>Pelican Eel (<em>Eupharynx pelecanoides</em>)</p><br />

Abyssopelagic 4000-6000 <p>Deep Sea Anglerfish (<em>Himantolophus</em> sp.)</p><br />
Hadopelagic >6000 <p>Giant Squid (<em>Architeuthis</em> sp.)</p><br />


Question Set: 
  1. Based on SF Table 9.2 and your own research, what adaptations characterize the organisms that live in each of the depth zones?
  2. Consider the adaptations for each depth zone you listed in Question 1. What adaptations are gradual as you move deeper? What adaptations are more abrupt? Why do you think this is?
  3. Which depth zones do the marine organisms come from that you commonly see for sale at the market? Why do you think this is?

Special Feature Type:

Exploring Our Fluid Earth, a product of the Curriculum Research & Development Group (CRDG), College of Education. University of Hawaii, 2011. This document may be freely reproduced and distributed for non-profit educational purposes.