BIO 358-001 1st Edition Lecture 13Outline of Last Lecture I. Rorqual feeding structures II. Echritiidae feeding III. Feeding and conservation IV. Odontocete feedingV. Diving physiology a. Elsner viewb. Kooyman view c. Anaerobic metabolism d. Scholander – forced divese. Elsner – trained dives f. Kooyman – weddel seal intro Outline of Current Lecture I. Diving Physiology ReviewII. Kooyman –Weddell Seal Experiment a. Weddell seal divingb. Oxygen storagec. Aerobic dive limit III. Elephant Seals Current LectureThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Diving Physiology – need access to oxygen (air) access to prey (at depth, on apnea)Diving is mechanical work! That usually takes up more energy… if you measure the diving metabolic rate of marine mammals it is equal to or less than the amount of energy the animal would be using resting. Animals on the verge of asphyxia (elsner)Dives are aerobic (Kooyman) Forced dive (dive reflex) EXTREME! Voluntary diving:- Highly variable dive response Gerald Kooyman – Weddell Seals - Seals rely on holes in the ice, and sit in their holes - Grabbed a seal, drove it far inland to a researcher made ice hole, where humans could survive - Control where the Weddell seal comes up for air - Time-depth recorder (TDR) invented by Kooyman and gentry - Measures depth, worn as a pack on the animal Weddell seal diving: - Shallow exploratory dives ~ 20 minutes- Deep dives, some very long 30-60 minutes; 400-700 meters - Dives were episodic – there was a break during the dive at the surface before it goes on its next dive - Were they aerobic?! Kooyman wanted to know. Where oxygen is stored: - Lung- Blood (hemoglobin) - Muscle (myoglobin- smaller than hemoglobin but grabs onto oxygen with a heme group)Where is it stored in a diving marine mammals? - Lungs – NO – well not a lot- Blood – YES – blood volume is increased, increased hematocrit (# of Red Blood Cells) o Human hematocrit 30-45, weddel seal 60 - Muscle – YES – increased myoglobin content Aerobic Dive Limit (ADL) - Maximum breath hold time possible without an increase in lactic acid during or after a dive- Lactic acid is evidence of anaerobic metabolism - ADL = (Body mass X O2/mass)/Diving MR - Total onboard oxygen/ rate of oxygen usage - Minutes = unit Kooyman measured oxygen by placing a dome over the hole ADL for Weddell Seal = 24 minutes. Dives longer than 20-30 minutes = lactic acid in blood (anaerobic) What are they doing when there is no human interaction – strapped TDRs on 22 Weddell seals –brings back TDR’s and analyzes data In the wild – only 3-8 percent of dives are longer than the ADL When they go over their ADL they have to spend extended time at the surface to recover and get rid of lactate debt. Why would you want to stay within the aerobic dive limit and limit surface interval time? - Longer foraging time – spend more time at depth Why would you go anaerobic? - Abundant food source - An Ice hole freezes or there’s another seal in your ice holeWeddell seals in the wild are NOT on the verge of Asphyxia Northern Elephant Seals – Mirounga angustirostris (males 4-5 m; 3600 kg) - 1 month on land – moult – get rid of all of their hair - 1 month on land - breed - 10 months at sea – pelagic animals - Burney Le Boef and Dan Costa Dive Profile: - Prolonged Continuous diving – diving ALL of the time - 3 dives per hour – each 20 minutes long – only 2 to 3 minutes of any hour at the surface – spend 90% of their life at sea UNDERWATER - submarine mammals - sleep underwater - record – 140 minutes – 1500 meters!!!!! - What is the ADL for an elephant seal – never been directly measured – o 30 for small femaleso 50 for large meals- elephant seals routinely dive longer than the calculated ADL ( suggesting either diving MR is lower than resting or enhanced ability to utilize on-board O2) - they can handle really low oxygen levels. - Evidence for aerobic dives – dive record of elephant seals does not show time where they are at the surface. Why dive so deep? - Feeding: gain about 1 kg per day- Predator avoidance: avoid great white sharks, or killer whales - Energy conservation: diving MR lower than or equal to resting MR How do you find your prey, how do you determine how deep you are? How do you know where to go or how to go