Fishy Deep-Sea Designs!

Home , Anglerfish, Barracudina, Mesopelagic zone, Pelagic zone

Mountains in the Sea Exploration

Fishy Deep-sea Designs!

Focus Students will predict where scientists will find cer- Adaptations of fishes living in the mesopelagic tain species of fish living along the Hudson Shelf and bathypelagic zones of the deep ocean Valley and in Hudson Canyon in the upcoming expedition. Grade Level 7 - 9 Materials  Overhead of map of Hudson Shelf Valley and Focus Questions Hudson Canyon (http://woodshole.er.usgs.gov/project- How do the characteristics of seawater at 200 pages/newyork/ or http://pubs.usgs.gov/factsheet/fs114-99/ meters differ from those at 1000 meters? How fs114-99.html might fishes living between 200 meters and 1000  Student Worksheet, included in this lesson – 1 meters of water differ from those living at depths per student greater than 1000 meters?  Internet access for students  Optional: the 28-minute video “Night Life: Learning Objectives Creatures of the Deep” created by the New Students will learn about the physical location England Aquarium and Bermuda Underwater of deep water habitats along the Hudson Shelf Exploration Institute (to order call the New Valley and in Hudson Canyon. England Aquarium at 617-973-5288 or access their website at [email protected]) Students will learn the basic characteristics of the  mesopelagic and bathypelagic zones with regard Optional: the 26-minute video “Marine to depth, temperature, pressure, light level and Bioluminescence: Secret Lights in the Sea” food availability. produced by Harbor Branch Oceanographic Marine Science Educational Series (to order Students will understand how fish living in the call 772-465-2400 x692 for telephone orders, mesopelagic and bathypelagic zones have adapt- email at [email protected] or via their website ed to survive in each respective habitat. http://www.hboi.edu/index_04.html  Representative images of mesopelagic and Students will learn that many fishes are biolumi- bathypelagic fishes (can be accessed from mul- nescent. tiple sources listed in Resources section)  Bucket (with handle) of water Students will learn why fishes bioluminescence.  Ice  Thermometer Students will learn about a variety of deepwater fishes through independent research. Mountains in the Sea – Grades 7-9 (Life Science) Focus: Adaptations of fishes in mesopelagic and bathypelagic zones oceanexplorer.noaa.gov

Teaching Time is not sufficient enough to support plant growth, One hour for introduction (two hours if videos are the availability of food, as compared to the epi- included) pelagic zone, is much reduced. Only about 20% One week for student independent research of the food produced in the epipelagic zone makes its way to underlying waters of the meso- Seating Arrangement pelagic zone. Individually It is in the mesopelagic zone that a transition Maximum Number of Students between the warm surface waters of the epipe- 36 lagic and the constant cold temperatures of the bathypelagic zones (see below) occurs. This tran- Key Words sition in temperature is called a thermocline. At Photic 200 meters, the temperature averages roughly 23 Aphotic degrees Celsius and then declines linearly with Epipelagic zone depth to about 4 degrees Celsius at 1000 meters. Mesopelagic zone Animals that migrate through the mesopelagic Bathypelagic zone zone experience quite a bit of change in temper- Twilight zone ature, while animals that tend to stay at the same Midnight zone depths experience far fewer fluctuations. Bioluminescence Counterillumination Since pressure increases with depth (one atmosphere per 10 meters or 14.6 pounds per square Background Information inch per 10 meters), organisms living in the meso- The ocean is divided into three zones based on pelagic zone are under a quite a bit of pressure! depth. The upper 200 meters of the ocean is The pressure at 200 meters is equivalent to 21 termed the photic zone. This zone is penetrated atmospheres or 307 pounds per square inch and by sunlight and plants thrive. Food is relatively at 1000 meters is equivalent to 101 atmospheres abundant. This region is also called the epipe- or 1475 pound per square inch. lagic zone and this term refers to the upper layer of the open ocean or “top pelagic” zone in the Fishes of the Mesopelagic Zone ocean. Many midwater fishes have light organs, or photophores, that produce light. The biological The Mesopelagic Zone production of light is called bioluminescence. Immediately below the epipelagic zone lies the Bioluminescence has evolved in many different mesopelagic zone and this zone extends from species and this suggests its importance to surviv- 200 meters to 1000 meters in depth. This zone is al in the deep sea. There are several reasons why also called the middle pelagic zone. In the meso- an organism may produce light. Some of these pelagic zone, dim light still exists but not at high strategies are listed below, with an example of an enough levels to support plant growth. This zone organism that uses that strategy. has yet another name and has been coined the “twilight” zone which refers to the dissipation of Counterillumination or “To Hide”: Many animals that light with increasing depth. At the lower depths move up and down in the twilight zone have light of the twilight zone, light penetration becomes producing organs on their ventral surfaces. They minimal and darkness abounds. Since the sunlight are able to increase the light level of their ven- available to the depths of the mesopelagic zone trally-located lights as they move into shallower, Mountains in the Sea – Grades 7-9 (Life Science) oceanexplorer.noaa.gov Focus: Adaptations of fishes in mesopelagic and bathypelagic zones

light-richer waters and dim them as they descend large mouths relative to their body size, unhinge- into deeper waters. In this manner, they become able jaws that can be opened wide to swallow somewhat invisible to predators swimming above prey, and large teeth. If a rare meal swims by, a or below them. A fish using counterillumination hungry midwater fish does not want to miss an would have a ventral surface that blends in with opportunity to dine! the lighter waters above when viewed from a predator from below. This is very similar to coun- In the twilight zone, there are numerous fishes tershading (animals with lighter ventral surfaces that are black or red. At depth, these fishes are and darker backs, or dorsal surfaces) but uses not visible. The black animals absorb all colors of light to achieve the same effect. Shining tube- light available and the red animals appear black shoulders and bristlemouths both have ventrally- as well; there is no red light to reflect and their located lights! bodies absorb all other available wavelengths of light. Thus red and black animals predominate. Attracting a Mate: Many organisms have species- Since the color blue penetrates best in water, specific light patterns and in some, specific to there simply are not that many blue animals in the a certain sex. In a dark environment, this is a midwater regions of the ocean; their entire bod- great way to get a date! Anglerfish and lantern ies would reflect the blue light and they would be fish both are thought to produce light to attract a highly visible to predators. mate. Fishes in the midwater zone can typically be Attracting Prey: Some organisms have lighted body grouped into two distinct categories; those that swim parts that they use to attract prey. Gulper eels up to the epipelagic zone at night (vertical migra- have a light at the end of their tail. It is thought tors) and those that remain at particular depths that this animal might use the light to attract prey within the mesopelagic zone. Midwater fishes that to its humongous mouth. make vertical migrations are typically black or silver, have large eyes to capture available light, a large Escape Tactic: Some organisms will use light to mouth, photophores and small body size. They also temporarily distract or divert predators. Some tend to have well-developed swim bladders, muscles animals will shoot out “clouds” of light. The goal and bones; all structures that aid in migration. Fishes is for the light to confuse or distract a predator, that do not migrate tend to be black, red or silver, while the “un-lighted” animal attempts to escape. have large eyes, and have large mouths, photophores and small body size. They tend to lack a The use of photophores for counterillumination is swim bladder, however, and they have weak bones a characteristic, in particular, that characterizes and flabby muscles. mesopelagic fishes. Therefore, if you observe a fish with photophores on its ventral surface, the Bathypelagic Zone fish is very likely to be a vertical migratory fish Below depths of 1000 meters lies a world of per- and uses counterillumination as a survival strat- petual darkness. The depths below 1000 meters egy. comprise the bathypelagic or “deep pelagic” zone. Due to its constant darkness, this zone is Most mesopelagic fishes are quite small; food also called the midnight zone. Only about 5% of is scare and the limited resources available do the food produced in the epipelagic zone makes not support large body sizes. Bristlemouths and it way down to the bathypelagic zone. Food is a lanternfish are the most abundant in this zone. scarce commodity in the midnight zone. Since food is scare, many midwater fishes have

Mountains in the Sea – Grades 7-9 (Life Science) Focus: Adaptations of fishes in mesopelagic and bathypelagic zones oceanexplorer.noaa.gov

The temperature in the bathypelagic zone, unlike pressure, light level and food availability in that of the mesopelagic zone, is constant. The the mesopelagic and bathypelagic zones temperature in this zone never fluctuates far from might be. a chilling 4 degrees Celsius. The pressure in the 4. Describe the temperature, pressure, light bathypelagic zone is extreme and at depths of level and food availability in the mesope- 4,000 meters, reaches over 5850 pounds per lagic and bathypelagic zones to students. square inch! Though quite a harsh environment, 5. Use a bucket of water to demonstrate pres- the bathypelagic zone comprises the single larg- sure. Ask a student to lie down on his/her est habitat on Earth. back at the front of the classroom. Ask the student to breathe in and out. Now gently Fishes of the Bathypelagic Zone place a bucket of water on the student’s lung In the bathypelagic zone, bioluminescence is as area. Hold onto the handle of the bucket to prevalent as in the mesopelagic zone. However, provide support. Ask the student to breathe in the complete darkness of the bathypelagic and to tell the class if it was more or less dif- zone, there is no need for countershading and ficult to inhale with a bucket of water sitting bioluminescence is not used for this purpose. on top of their chest. Ask the entire class Bathypelagic fishes tend to have fewer photo- how it might feel to breathe with 50, 100 phores than mesopelagic fishes and the photo- and 1000 buckets of water sitting on top of phores tend to be on the head and sides of the their lungs. fishes in bathypelagic fishes whereas mesopelag- 6. Fill the bucket with ice. ic fishes often have photophores on their ventral 7. Use the bucket of ice water to convey tem- surfaces. perature. Have a student come to the front of the class and submerge their hand in the Fishes of the midnight zone usually have no need ice water. Ask them how it feels and whether for large, sensitive eyes and the eyes of these they would like to take a bath in water just fishes are often absent or reduced. Since food is as cold. so scarce, energy conservation is the name of the 8. Take a temperature reading of the ice water game! Most of the fishes are sluggish or tend to using a thermometer and convey reading to stay in one place. They have watery, flabby mus- the class. Relate temperature reading to tem- cles, weak skeletons, no scales and poorly devel- perature in mesopelagic and bathypelagic oped systems (nervous, respiratory and diges- zones. tive). Almost all of the bathypelagic fishes lack a 9. Ask students to describe the fishes they think swimbladder. Most bathypelagic fishes have huge would live in the mesopelagic and bathype- mouths, are small and have black bodies. lagic zones. 10. Describe the characteristics of mesopelagic Learning Procedure and bathypelagic fishes and record the char- 1. Introduce students to the Hudson Shelf Valley acteristics on the board. and Hudson Canyon by showing them the 11. Give each student a Student Worksheet overhead of the region. and provide approximately 20 minutes for 2. Show students how the oceans have been students to complete the worksheet. divided into three zones (epipelagic, meso- 12. Tell students that they should closely pelagic and bathypelagic) based on depth. observe the structure of the fishes on their Draw a diagram on the board or use an worksheets and hypothesize whether each overhead. fish would be found in the mesopelagic or 3. Ask students what they think the temperature, bathypelagic zone. Students should explain

Mountains in the Sea – Grades 7-9 (Life Science) oceanexplorer.noaa.gov Focus: Adaptations of fishes in mesopelagic and bathypelagic zones

their hypothesis in the allotted space beside tribution of animals in the Pacific, students each fish. can access great photographs and some 13. Discuss the worksheet with students. good, basic information. The Monterey 14. Show students representative images of Bay Canyon has been studied extensively fishes from both habitats. (Hatchetfish and and may serve as a valuable model when lanternfish are good examples from the students are trying to guess where scien- mesopelagic zone; gulper eels, deep sea tists may find certain fish living in Hudson anglerfish and deep sea bristlemouths are Canyon. good examples from the bathypelagic zone.) 15. If you choose to show one or both videos, The BRIDGE Connection show videos to students. Go to the BRIDGE website at http://www.vims.edu/ 16. Provide students with the list of fishes from bridge/ the mesopelagic and bathypelagic zone Under the Navigation side bar click on Human below. Allow them to select one fish and Activities to learn more about the technology used research the habitat requirements of the to study deep sea environments. fish. Students should include the following in their report: a picture of the fish, the size of The “ME” Connection the fish, the depth(s) where the fish can be If the bathypelagic zone of the ocean represents found, the general habitat requirements of over 80% of all habitats on Earth, why might it the fish and special adaptations for survival. be important to study this habitat? How might Also require that students include the genus discoveries in this deep sea habitat affect your and species of the fish they research and life someday? describe; many of the fishes listed below include several different species that will Connections to Other Subjects differ in habitat (i.e., some anglerfishes are Art found in the mesopelagic zone while others Using art materials, create a canyon habitat. are found in the bathypelagic zone). Place fishes at the proper depths within the habitat. Note: This builds on the evaluation tool listed Anglerfish below. Bristlemouth Lanternfish Mathematics Hatchet fish One atmosphere is equivalent to 14.7 pounds Gulper eel per square inch. At the surface of the ocean, Viperfish one atmosphere of pressure exists due to the Fangtooth atmosphere above the water. Pressure in the Dragonfish ocean then increases one atmosphere with every Barracudina increase in 10 meters of depth. How many Longnose lancetfish pounds per square inch of pressure would exist at Sabertooth fish 200 meters? At 1000 meters?

Evaluation Note: Descriptions of some of these ani- Using art materials (construction paper, aluminum mals can be found on the Monterey Bay foil, glow-in-the dark paint, etc.), have students Aquarium’s website http://www.mbayaq.org/efc/ create a three-dimensional model, to scale, of the living_species/. Although this site provides dis- fish they researched.

Mountains in the Sea – Grades 7-9 (Life Science) Focus: Adaptations of fishes in mesopelagic and bathypelagic zones oceanexplorer.noaa.gov

Extensions For More Information Have students visit the http://oceanexplorer.noaa.gov Paula Keener-Chavis, Director, Education Programs website to find out more about the New England NOAA Office of Ocean Exploration Seamount Expedition. Hollings Marine Laboratory 331 Fort Johnson Road, Charleston SC 29412 Resources 843.762.8818 Websites for student research: 843.762.8737 (fax) http://www.mbayaq.org/efc/living_species/ [email protected] http://www.mbari.org/ http://www.biolum.org Acknowledgements http://www.bioscience-explained.org/EN1.1/features.html This lesson plan was produced by Stacia http://www.pbs.org/wgbh/nova/abyss/ Fletcher, South Carolina Aquarium, Charleston, http://oceanlink.island.net/oinfo/deepsea/deepsea.html SC for the National Oceanic and Atmospheric http://people.whitman.edu Administration. If reproducing this lesson, please http://www.seasky.org/monsters cite NOAA as the source, and provide the follow- http://www.divediscover.whoi.edu ing URL: http://www.nationalgeographic.com http://oceanexplorer.noaa.gov http://www.marine.whoi.edu/ships/alvin/alvin.htm http://www.ocean.udel.edu/deepsea http://www.pbs.org/wgbh/nova/abyss/life/extremes.html http://www.whoi.edu/WHOI/VideoGallery/vent.html

National Science Education Standards Content Standard A: Science as Inquiry • Abilities necessary to do scientific inquiry • Understandings about scientific inquiry

Content Standard C: Life Science • Structure and function in living systems • Populations and ecosystems

Content Standard D: Earth and Space Science • Structure of the Earth system

Mountains in the Sea – Grades 7-9 (Life Science) oceanexplorer.noaa.gov Focus: Adaptations of fishes in mesopelagic and bathypelagic zones

Student Handout

In which zone, the mesopelagic or bathypelagic, do you think you would find the following fishes? Use your knowledge of both zones and the structure of each fish to formulate your hypothesis. Explain why you chose the mesopelagic or bathypelagic zone for each fish in the space provided to the right.

Fish name: Lantern fish Mesopelagic or bathypelagic? ______Please explain your choice below.

Fish name: Gulper eel Mesopelagic or bathypelagic? ______Please explain your choice below.

Fish name: Bristlemouth (species #1) Mesopelagic or bathypelagic? ______Please explain your choice below.

Fish name: Bristlemouth (species #2) Mesopelagic or bathypelagic? ______Please explain your choice below.

Mountains in the Sea – Grades 7-9 (Life Science) oceanexplorer.noaa.gov Focus: Adaptations of fishes in mesopelagic and bathypelagic zones

Student Handout Teacher Answer Key

Fish name: Lantern fish Mesopelagic or bathypelagic? ______Please explain your choice below.

Large eye, abundant photophores on belly

Fish name: Gulper eel Mesopelagic or bathypelagic? ______Please explain your choice below.

Small eye, huge mouth, no photophores on

Fish name: Bristlemouth (species #1) Mesopelagic or bathypelagic? ______Please explain your choice below.

Small eye, large mouth, fewer photophores than bristle mouth pictured below

Fish name: Bristlemouth (species #2) Mesopelagic or bathypelagic? ______Please explain your choice below.

Large eye, abundant photophores on belly, smaller mouth than bristlemouth pictured above