BIO358-001 1st Edition Lecture 19Outline of Last Lecture I. Methods of Tracking divesII. D-TagIII. Right Whale D-Tag StudyIV. Beaked Whale D-Tag Study Outline of Current Lecture I. Answers to questions Current Lecture(1) What are some of the anthropogenic sources of sound in the ocean?- shipping- commercial recreational – fishing - high resolution imaging- explosives- air guns (2) Is noise in the ocean increasing? If so, by how much, and why?-increase in 3Db per decibel in certain parts – northern hemisphere – due to shipping (3) Which frequency of sounds (low or high) travels farther in the ocean? What is a good marinemammal example of a long-range acoustic signal travel through the ocean?- Low frequency travels much better than high frequency (ships make low frequency)- Subwoofer sound goes through the whole room- Higher frequencies need to be pointed right at you to hear it. These 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.- Low frequency sounds can travel VERY far in the ocean (3) True/False. Seismic airguns and sonar are high-amplitude sounds. - True (4) What is the largest source of anthropogenic sounds in the ocean?- Shipping - Seismic is getting there (5) A concern about increasing levels of shipping noise is “acoustic masking”. What does this term mean?- It is getting too loud for communication - Animals unable to use communication space when ships go by (6) Is there any evidence that exposure to chronic noise causes physiological changes in anyorganism?- Rats – exposed chronically to noise throughout life – adrenals higher in mass than expected, other organs, less heavy than expected. Smaller young, young that do not thrive as well. - Heart rate and behavior from resting to non-resting with exposure to noise - Stress – increase in adrenals and thyroid – measure steroid levels in fecal samples of whales. Trained dogs to smell whale poop… -(7) Please be able to discuss the study that was able to infer that shipping noise might impact right whale stress levels (Rolland et al.2012).- Frequency in Hz - Shipping after 9/11 shipping turned off for a few days – reduction of noise –- Fecal glucocorticoid metabolites before and after 9/11 – drop from before and after 9/11– substantial drop in glucocorticoid metabolites in whale fecal samples (9) What is the largest source of noise from large ships?- The propeller cutting through the water - “propeller cavitation” makes hole in the water and the water caves in to that hole making noise. -(10) Is the IMO (International Maritime Organization) taking steps to reduce ship noise? Please also know that the European Union has proposed that shipping noise (and other anthropogenic sources) be identified as a “marine pollutant”.- Engineering project – to reduce ship noise- Long term solution, ships last 3 decades(11) True/False. Marine shipping is expected to decrease by 50% by 2030. - False (12) In a general sense, how do seismic air guns work?- Large boat tows an array of air guns (used to use dynamite) - Massive air compressors that send air to gun- Highly compressed air hits water and expands and then contracts and makes a controlled explosion - Signal every 12-10 seconds - Hydrophones to hear the return sound and how it changes - Data produced – shows if there is gas/hydrocarbon on the seafloor (13) Do seismic air gun pulses travel far in the ocean? If so, what magnitude of distance can theytravel?- Yes- Kilometers- Long distances - 3900 km (14) Is there any evidence that any marine mammal might change any aspect of its behavior in the presence of seismic air gun activity?- Fin whales – before survey – number of calls higher than after the survey and they moved from where they wanted to be. - Sperm whales – change in foraging rate – massive reduction in “buzz” rate which indicates feeding – reduced feeding, as you move closer to the air gun array. (15) Oil and gas seismic exploration in the mid-Atlantic – think about what some of the potentialimpacts are on marine mammals. Is there the potential problem of cumulative effects?- Chronic stress – smaller calf sizes?- Difficulty communicating for mating and feeding- Disruption of migration pathways - Disruption of body weight due to disruption of feeding - Cumulative effects –not much research done – more
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