Introduction to Marine Science (BIOL 1202) - History of Oceanography II - Jan 10, 2025 PDF

Introduction to Marine Science (BIOL 1202) Lauren Rowsey Class 3: History of Oceanography II January 10, 2025 Objectives 1. Navigation recap 2. The scientific method 3. Ocean history II: transition to marine science 1. Navigation recap How to...

Introduction to Marine Science (BIOL 1202) Lauren Rowsey Class 3: History of Oceanography II January 10, 2025 Objectives 1. Navigation recap 2. The scientific method 3. Ocean history II: transition to marine science 1. Navigation recap How to remember the difference? How do you know your longitude? Remember…earth rotates! Rotation rate of Earth 15° per hour (360° per 24 h) Calculate difference between your local time and the time at your place of departure (“clock time” on chronometer) If your local time is ahead of clock time, you are EAST of your starting point If your local time is behind clock time, you are WEST of starting point. Navigation practice You measure an angle of 14° between the North Star and the horizon with your sextant. Your local time is 3:30 pm and your ship’s chronometer tells you that it is 10:00 am in Greenwich. What is your latitude and longitude? Online: www.pollev.com/unbintromarine Text: UNBINTROMARINE to 22333 Navigation Practice Latitude: 14 degrees north (simply measurement of sextant) Longitude: Start by calculating difference between local time and chronometer: You are 5.5 hours ahead of Greenwich = you are EAST of Greenwich Multiple time by rate of rotation 5.5 hr * 15 °/hr = 82.5 degrees E Online: www.pollev.com/unbintromarine Text: UNBINTROMARINE to 22333 What part of the world are you located in?? 2. The scientific method Poll Everywhere How would you define ‘science’? Science Science is a process We ask questions about the natural world and discover underlying patterns Make predictions about the future Process is formalized as the scientific method Observations Testing Prediction Hypothesis Theory Science Scientific Method Observations: occurrences we can measure with our senses Observations Testing Prediction Hypothesis Theory Scientific Method Observations: occurrences we can measure with our senses Scientific Method Hypothesis: a testable statement about how or why things happen in nature Different than predictions – if, then statement Observations Testing Prediction Hypothesis Theory Scientific Method Hypothesis: a testable statement about how or why things happen in nature Different than predictions – if, then statement It is good practice to come up with multiple, alternative hypotheses i.e., do not become too attached to a single explanation We can reject a hypothesis if observations of our tests show it was incorrect We can find support for our hypothesis if the results of our tests are consistent with it But we never ‘prove’ a hypothesis is correct! Scientific Method / Test Poll Everywhere What are some alternative hypotheses for why cunner might go dormant? And how could we test them? Scientific Method Theory: a well-substantiated explanation of some aspect of the natural world. Only formalized after many years of testing and verification. Observations Testing Prediction Hypothesis Theory Scientific Method Any questions about the scientific method? 3. Ocean history II: Transition to marine science James Cook Can be considered 1st marine scientist Voyages from 1768-1779 Circled the globe twice He made very detailed charts New Zealand, Great Barrier Reef, Hawaii His charts of the Pacific Islands were used in WWII Able to determine longitude using a chronometer and make accurate maps Sampled subsurface temperatures Fig. 1.10 and marine life; measured winds, currents, depth and sediment Charting global winds and ocean currents Matthew Maury: US Navy Depot of Charts and Instruments Used ships’ logs to figure out worldwide patterns of surface winds and currents en.wikipedia.org Published sailing directions to shorten passage times as well as a book about winds and currents “The physical geography of the seas” Joined confederacy during US Civil War; troubling views on slavery  1st oceanographic trip around the world Challenger Expedition 1872-1876 First expedition completely for marine science Conceived by academics at University of Edinburgh British Navy provided ship & crew But the scientists were in charge! Traveled 127,600 km All oceans except Arctic earthobservatory.nasa.gov Surveyed the ocean for physical, chemical, and biological features. Scientific method Also investigated the hypothesis in action!! that life below 549 m was impossible HMS Challenger Fig. 1.11b The Challenger remains the longest, continuous scientific oceanographic expedition Challenger: Sampling 6 scientists 3.5 years of sampling water, netting fish, and dredging sediment ¼ of 243 crew abandoned the ship en.wikipedia.org 8 died or went mad “driven to distraction by the mind-numbing routine of years of dredging” John Murray: the father of John Murray modern oceanography Challenger: Results Salinity, temperature, water density measurements Found life at great depths Reject the hypothesis that life could not exist below 549 m Discovered 4717 species John Murray wrote the 50 volume Challenger Report This report was the foundation of oceanography What about the Arctic Ocean?! Polar oceanography began with Fridtjof Nansen Set sail from Norway on the Fram to get caught in the ice (1893-96) With crew of 13, drifted in ice pack for almost 4 years! Covering a distance >1600 km Missed North Pole but revealed the Arctic was covered by a free moving ice pack (no continent) Fig. 1.12 20th & 21st Centuries: new technology In 1925, a German vessel used echo sounders for the first time in oceanography Bounces sound waves off ocean bottom Showed ocean bottom was variable and rugged Fig. 3.1 Deep sea drilling Ocean drilling uncovers Earth’s past Deep-drilling ship: Glomar Challenger (1968) Could drill ocean bottom at 6 km depth This ship’s work helped confirm sea floor spreading and plate tectonics (stay tuned for our next class….!) There have been several replacement ships over the years R/V Chikyu Deep-sea vehicles Allow us to explore deepest depths of ocean Human operated submersibles Alvin (WHOI) Deepsea Challenger Remotely operated vehicles (ROVs) Nereus Remote sensing Satellites are an important tool in ocean studies First dedicated oceanographic satellite in 1978 Can measure temperature, ice cover, colour (estimate chlorophyll), topography of ocean surface, and position (GPS) Fig. 1.14. NASA A-train satellites Ocean observatories Continuous measurements Data sent via submerged cables or satellite transmission from moored buoys NEPTUNE: joint US-Canadian venture http://www.neptunecanada.ca Float and buoys Moored buoys in various parts of the world, including Gulf of Maine http://oceandata.gmri.org/data/recent.html Argo floats to study long-term ocean variability (temperature, salinity) Do we still need to go to sea? New technology has allowed us a global perspective on oceanographic patterns BUT hasn’t replaced hands-on measurements and observations And not all marine science happens on ships! Take-home Messages Transition to scientific oceanography Challenger Report as foundation of field Rise of oceanographic institutions and funding agencies Large teams of specialists working on large projects Development of new technology Collection of global data at unprecedented scales Next Class Topic: Plate Tectonics I Suggested Reading: Ch. 2, Sections 2.1-2.3