Ocean Tracks Lab: Elephant Seal Migration & Trophic Interactions
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Ocean Tracks Lab In this lab you will have the opportunity to explore the migration routes and behavior of actual tagged and tracked animals in the Pacific Ocean and relate this information to what we’re learning in class about ecology and ecosystems. The Ocean Tracks interactive website allows you, as students, to engage with authentic scientific data through investigations that mirror those currently being conducted by scientists studying the broad-scale effects of climate and human activities on top predators in ocean ecosystems. Using the Ocean Tracks interactive map and data analysis tools, you will explore and quantify patterns in the migratory tracks of marine animals in the northern Pacific Ocean and relate these behaviors to fluctuations and trends in physical oceanographic variables. T he Ocean Tracks project has been funded by the National Science Foundation, and is a collaboration between Education Development Center, Inc. (EDC.org), Scripps Institution of Oceanography, Stanford University, EarthNC (earthnc.com), and the Lifelong Learning Group (lifelonglearninggroup.org). Elephant Seal Tracking E lephant seals are marine mammals. The females give birth to one baby each year and the mother will nurse her baby for about a month before the baby must learn how to swim and hunt on its own. E lephant seals come to California and Mexican beaches every winter to give birth. They stay on land for a few months (December or January through March) while they have their babies and nurse them. E lephant seals then return to the sea to feed. In the spring and summer, they travel thousands of miles while they feed in the ocean. To feed, they dive deep below the ocean surface and eat almost the entire time that they are swimming and migrating. They mainly feed on squid, rays, skates, crabs. S cientists can study where elephant seals travel on their migrations by fastening a tracking device to the seal. The seal then transmits signals back to the scientists who can then map their location and travel routes! Click here to read the background on elephant seals for the lab: Elephant Seal Biology ow it’s time to explore elephant seal migration routes. This data was gathered by tagging and tracking N individual elephant seals. To begin, go to: https://oceantracks.org/map/ Look at your maps. Study the elephant seal “tracks”. ou should see a map of the northern Pacific with the track of one elephant seal mapped in red. You can Y zoom in and out on the map using the + and – buttons on the screen, but be slow and patient with the program as it can get glitchy if you ask it to move too quickly 😊 O ● pen theData & Toolstab in the upper left cornerof the screen ● Click + to expand theTracksmenu. Click on “Tracks” ● Click onElephant Seals: you will then see a listof all the individual elephant seals that were tracked. You can click on any of them to see its tracking data on the map. ● Scroll down to the bottom of the list of all the elephant seals and clickShow All: all the elephant seal tracks should show up on the map on the screen. Helpful tip: ● At any time you can click on any of the active track points on the map to open a track stats window. • You can click on theTrack Summarytab to get thestatistics for the full track. How many elephant seals were tracked (how many individual elephant seals are on the list)? 25 Can you tell from studying the maps where these Northern elephant seals go to mate and give birth? Where? Yes, they all converge at the Elephant Seal Overlook in Point Reyes here do most of these tracked elephant seals go during spring and summer months to feed after giving W birth? In the middle of the ocean What do elephant seals eat? Elephant seals eat rays, skates, fish, squid, and sharks that live near the bottom of the ocean Why do you think that elephant seals travel where they do on their migration routes? T o find an abundance of food. If they travel along the coast or b-line straight to Alaska/Mexico they will not get as much food as they do on the routes they are on now. Trophic Interactions ow we’re going to explore the food webs of elephant seals and think about how trophic interactions N influence their migrations. Click the link below to read the background information on energy movement in ecosystems and food chains in the Ocean Tracks library. This should also serve as excellent review of trophic interactions from our class! Energy Flow and Food Webs Phytoplankton hlorophyll is a green pigment needed by photosynthetic organisms (things like plants that use CO2, water C and sunlight to make sugar). The main photosynthetic organisms in our oceans are phytoplankton! When areas of the ocean have high amounts of chlorophyll, it means that they have LOTS OF PHYTOPLANKTON! F ollow the link below to read about chlorophyll and phytoplankton patterns in the ocean. This reading will help you answer questions in the lab. Chlorophyll in the Ocean lick on the OVERLAYS tab on the left of the screen. Select CHLOROPHYLL and then select the year 2008 C (most of these elephant seals were tracked between 2006-2008) and select August or September (as these are common months that the elephant seals are all out feeding in the ocean). The map will not show you how much chlorophyll (phytoplankton) is found in different parts of the ocean! Your chlorophyll map should look somewhat like this one: F IGURE 1. Major circulation features overlaid on annually averaged surface chlorophyll concentration in the North Pacific Ocean. Highlight the correct answer: Blue and purple colors mean that there are: LOW Green and yellow colors mean that there are: LOW HIGH levels of phytoplankton. HIGH levels of phytoplankton. L ook at your maps and study where most of the tracked seals are swimming in their migrations: Do elephant seals travel on their migrations where there are relatively low levels or mid-high levels of phytoplankton? mid-high levels of phytoplankton BUT…. WAIT!! Do elephant seals eat phytoplankton???? No WHYdo you think that you see a relationship between elephant seal feeding routes and phytoplankton? E lephant Seals move with the current and so do plankton. More energy is spent fighting against the current rather than with it. Therefore, Elephant Seals end up in the same areas of plankton. nother reason could be that where plankton exist, higher animals on the food chain are in the same place. A So, Seals happen to be in the same place since that's where Elephant Seal food is onstruct a realistic elephant seal food chain including phytoplankton with elephant seals at the top. Be C specific in your food chain (for example, don’t just list “fish”, there are thousands of species of fish that feed at many different levels of the food chain). I expect you to do some research and use legit information to build your food chains- look up what these organisms actually feed on and what their prey feeds on, etc. hytoplankton: Microscopic marine algae that perform photosynthesis, forming the foundation of the marine P food chain. Phytoplankton get eaten by ↓↓↓↓↓↓↓↓↓↓↓↓↓ Krill (Euphausia superba): Small, shrimp-like crustaceans that feed on phytoplankton. Krill get eaten by ↓↓↓↓↓↓↓↓↓↓↓↓↓ L anternfish (Electrona antarctica): Mesopelagic fish that consume krill and other small zooplankton. Lanternfish get eaten by ↓↓↓↓↓↓↓↓↓↓↓↓↓ Squid (Psychroteuthis glacialis): Cephalopods that prey on lanternfish and other small fish. Squid get eaten by ↓↓↓↓↓↓↓↓↓↓↓↓↓ Southern Elephant Seal (Mirounga leonina): Top predators that feed on squid (Psychroteuthis glacialis) Great White Sharks reat white sharks also have migration routes that are tracked by scientists! Marine mammals are G important prey of great white sharks. S harks are tracked in many different ways by scientists. Check out these two videos by Monterey Bay Aquarium to watch sharks being tagged using the “Blubber Burrito” method and the dart method. Tagging Great White Sharks White Shark Cafe What are the two main ingredients of a “blubber burrito”? A Sensor and Elephant Seal Blubber What is the main predator of elephant seals in the Pacific Ocean? Great White Sharks Return to your map page which has elephant seal tracks mapped. Now, go toData&Tools🡪Tracks🡪White Sharks. SelectShow Allto view all the great white sharktracks. S tudy your maps. Is there a relationship between elephant seal routes and great white shark routes? Do they overlap? If so, where? They go in opposite directions. Elephant Seals go North and Sharks go south YPOTHESIZE why we see this relationship between the routes of elephant seals and great white sharks. H What do you think is going on here? Be specific. I think Sharks find the water up north to be too cold during winter months since they don’t have the blubber that Elephant Seals do. So they end up going south to find warmth and Elephant Seals use their blubber to their advantage. T he only time they overlap is when Elephant Seals come to mate in the warmer water areas, so the sharks come to feed. 😉 ow let’s take a deep dive into establishing a deeper understanding of elephant seal behavior when N they’re out in the ocean. Select a single elephantseal to focus on(unselect all the other elephantseals so that the track of only one seal is shown on the map). Click on one of its dots (days) on the red track on the map.When you do this, a box should pop up with the elephant seal’s identification number and two tabs at the top of the box: Daily Stats and Track Summary. What is the identification number of the seal that you selected? Elephant Seal 771 What day of the full tracking period did you select? 3/11/2006 Click theTrack Summarytab. How long was this seal tracked for? 2/16/2006 - 5/16/2006, 88 days How far did it travel during the time it was tracked? 5710 km or 3500 miles Select theDaily Statstab. What was the day’s speed? 3.3 km/h or 2 mph ow click “activate track” at the bottom of the pop-up information box for that elephant seal. That should N make the red dots marking the seal’s track become bold. o back to theData & Toolstab, scroll down toToolsand click on it.You should see a number of statistics for G this particular seal and a graph of the elephant seal’s dive depths. T he first thing displayed inToolsis a “play” arrow that says “Show Animal Movement”. You can clickon that to watch your selected elephant seal’s movement on the map over the period of the data collection. L ook at the data for your selected seal & write down the average daily depth for this elephant seal for the period that it was tracked and recorded. Make sure to write down the units in your answer. -565.63m or 1853 ft nderTools, you should see a graph displaying the depth of the seal’s dives. The depth measurement U representsthe maximum daily dive depth. On the divedepth graph, how deep was the deepest dive that your selected elephant seal took? Make sure to check the y-axis for units and write down the units in your answer. -895m or 2936ft ccording to the Guinness Book of World Records, the record for the longest swim by a human holding their A breath and wearing fins is held by Carlos Coste, a Venezuelan swimmer, who swam a super-human 177 meters in 3 minutes and 5 seconds with one breath! To watch Carlos in his record-breaking swim, click here: Longest underwater swim with one breath T he average person can hold their breath for about 30-60 seconds, but elephant seals regularly hold their breath for 20-60 minutes and descend to depths of 1,500 meters (and then have to come all the way back up to the surface)! S o how do these miraculous animals do it? We’ve talked about adaptations in class… think about the adaptions that elephant seals have acquired than enable them to swim for such long periods without breathing. Look back at the Elephant Seal Biology page (link) from the beginning of this lab or your notes from class and read about how elephant seals are able to dive as deep and as long as they do. Discuss three physiological adaptations that enable these amazing organisms to do deep, long dives? Explain these adaptations. DO NOT cut and paste these from the website- please put the answers inyour own words. 1. They have higher levels of myglobin in their muscles. Myglobin is a protein that holds oxygen in the muscle and more of it allows for extended use of that muscle with less oxygen 2. They also exhibit bradycardia which is when the heart rate slows down to a very very low bpm and pumps less oxygen around the body to conserve it in the blood for longer. It also prioritizes oxygen to vital organs and constricts blood vessels in less vital organs. Humans do this too but to a lesser extreme. 3. Their lungs collapse under high pressure which reduces the amount of oxygen that is lost during deep dives through the lungs
