Introduction to Marine Science BIOL 1202

Introduction to Marine Science (BIOL 1202)

• Course name: Introduction to Marine Science (BIOL 1202)
• Instructor: Lauren Rowsey
• Class date: January 10, 2025
• Class number: 3, History of Oceanography II

Objectives

• Navigation recap
• The scientific method
• Ocean history II: transition to marine science

Navigation Recap

• Latitude: Lines running horizontally around the Earth.
• Longitude: Lines running vertically around the Earth.
• Determining longitude: Calculate difference between local time and the time at your starting point using the chronometer and rotation rate (15° per hour).

How to Remember the Difference

• Latitude: Imagined lines that run east to west and are measured in degrees. Latitude is determined by the angle between the horizon and the North Star. The equator is 0°.
• Longitude: Imagined lines that run north to south and are measured in degrees. Longitude is determined by the time difference between your location and Greenwich Mean Time. 0° longitude runs through Greenwich, England.

How do you know your Longitude?

• Earth rotates at a rate of 15° per hour.
• Calculate the time difference between your local time and the time at your starting point (e.g., Greenwich Mean Time).
• If your local time is ahead of the starting point's time, you are east of the starting point.
• If your local time is behind the starting point's time, you are west of the starting point.

Latitude and Longitude Practice

• Angle between the North Star and the horizon: 14°
• Local time: 3:30 pm
• Ship's chronometer: 10:00 am (Greenwich Mean Time)
• Latitude = 14° North (determined from the sextant)
• Longitude calculation: Time difference of 5.5 hours between local and Greenwich time. Multiplied by 15°/hour= 82.5° East.

What Part of the World Are You Located In?

• The position determined from the example problem would be in the eastern part of the world.

2. The Scientific Method

• Science is a process of asking questions about the natural world and discovering patterns, then making predictions that are formalized in the scientific method.
• This method comprises observations, hypotheses, testing, and predictions to develop a theory that explains phenomena.
• Observations: Occurrences we can measure with our senses.
• Hypothesis: A testable statement about how or why things happen in nature (if-then statement).
• Predictions: Anticipate, in advance of testing, what results will occur under specified conditions (if-then).
• Testing: Experiments and further observations to verify or alter hypotheses.
• Theory: A well-substantiated explanation of a natural world phenomenon developed over many years of testing and verification.
• Good practice is to come up with alternative hypotheses or ideas and not get overly attached to a single idea. Testing and observations can lead to rejecting a hypothesis.

3. Ocean History II: Transition to Marine Science

James Cook

• Considered one of the first marine scientists.
• Voyages between 1768 and 1779, circling the globe twice.
• Produced detailed charts of New Zealand, the Great Barrier Reef, and Hawaii, using these charts for WWII.
• Used a chronometer to determine longitude and make accurate maps.
• Sampled subsurface ocean temperatures, marine life, wind, currents, depth, and sediments.

Matthew Maury

• US Navy Depot of Charts and Instruments
• Used ship logs to study global patterns of surface winds and currents
• Compiled sailing directions to decrease travel time.
• Book about winds and ocean currents.

Challenger Expedition

• First complete expedition for marine science.
• Academics at the University of Edinburgh conceived the expedition, and the British Navy provided the ship and crew.
• The scientists were in charge.
• Traveled over 127,600 km across all oceans except the Arctic.
• Studied the physical, chemical, and biological aspects of the ocean.
• Investigated the hypothesis that life below 549 m was impossible.
• 6 scientists worked for 3.5 years on the expedition.

Challenger Results

• Measured salinity, water temperature, and water density.
• Discovered life at great depths.
• Rejected the hypothesis that life could not exist at great depths.
• Found over 4,717 species.
• John Murray's detailed report was the foundation of oceanography.

20th and 21st Centuries: New Technology

• Introduced echo sounders, measuring depth of ocean floors.
• Showed that ocean bottoms are rugged and variable.
• Deep-sea drilling (with the Glomar Challenger) confirmed sea floor spreading and plate tectonics.

Deep-Sea Vehicles

• Human-operated submersibles and remotely operated vehicles (ROVs) allowed exploration of the deepest parts of the ocean.

Remote Sensing

• Satellites are used for ocean studies.
• Satellites are used to determine temperature, ice cover, colour of water (estimate chlorophyll), topography of the ocean surface, and position (with GPS).
• They were first used in 1978.

Ocean Observatories

• Continuous measurements and the use of data via submerged cables or satellite transmission from moored buoys.
• Neptune: a joint U.S.-Canadian venture.

Floats and Buoys

• Moored buoys are deployed in various locations, including the Gulf of Maine.
• Argo floats were used to study long-term ocean variability (temperature and salinity).

Do We Still Need to Go to Sea?

• Technology has provided global ocean patterns.
• Technology hasn't replaced hands-on measurements.
• Not all marine science happens on ships.

Take Home Messages

• Transition to scientific oceanography.
• The Challenger report is the basis of the field.
• Development of oceanographic institutions and funding agencies.
• Large teams of specialists working together on extensive projects.
• Development of new technologies enabled collection of data and global oceanographic data on an unprecedented scale.

Next Class

• Topic: Plate Tectonics I
• Suggested Reading: Chapters 2, sections 2.1-2.3.