Environmental Science 101


The study of the physical and biological aspects of the ocean, including marine ecosystem dynamics, geophysical fluid dynamics (ocean currents, waves), geology of the sea floor, and marine chemical substance cycles.

Marine Ecosystems

- Forest of different mangrove tree species near the coastline.
- Shallow stagnant water is typical.
- Intricate root systems.
Salt Marsh
- Coastal wetlands flooded and drained by tidal salt water.
- Able to prevent flooding, and maintain water quality.
Intertidal Zones
- Visible during low tide and covered by saltwater during high tide.
- High salinity due to evaporation.
- Confluence between streams and ocean.
- Shallow body of water protected from a larger body of water (usually ocean) by sandbars, barrier islands, or coral reefs.
- Two types: Coastal and Atoll.
Coral Reefs
- Composed of large coral colonies of a variety of species living together.
- Barrier reefs – long coral colonies that parallel the coast.
- Atolls – ring-like reefs surrounding islands and seamounts.
Deep Sea and Sea Floor
- Relatively featureless abyssal plain
- Features: seamounts, guyots, hydrothermal vents.
- Fine-grained sediment settles & accumulates to floor of open ocean, far from land.

Fluid Dynamics: Ocean Currents

Surface Ocean Currents: driven by atmospheric circulation.
Ocean Gyres: Large circular currents due to Subtropical High Pressure
Vertical Circulation:
Ekman Spirals:

Fluid Dynamics: Waves

Created by a random distribution of normal pressure of turbulent wind flow over water.
Pressure fluctuation produces normal and tangential stresses which generates waves.
Three types of waves:
- Capillary waves: ripples
- Sea waves: larger-scale, often irregular motions that form under sustained winds
- Swells: sets of waves with common direction and wavelength

Fluid Dynamics: Tides

Daily sea level rise and fall.
Earth’s oceans and crust are gravitationally attracted to the Moon and Sun.
- Gravity creates a “bulges” in ocean and crust on side of Earth facing the Moon, and on side of Earth away the Moon.
Created due to differences in gravitational attraction.
Due to different distances.
Gravitational force is a function of distance.

Sea Floor Geology

Ocean basins are defined geographically by where the oceans are located
Geologically, they are those areas that contain oceanic crust

Continental Margin

Continental Shelf: submerged portion of continent
Continental Slope: sloping edge of continent
Continental Rise: base of Continental Slope; slope begins to flatten out
Canyons: narrow valleys forming due to underwater erosion
Cones: fan-shaped deposits from major river systems

Deep Ocean Floor

Abyssal Plain: relatively featureless plain
Seamounts: submarine volcanoes
Guyots: flat-topped seamounts
Mid-Ocean Ridge: long, linear ridges or area of higher elevation that are zones of active rifting
Trenches: long, linear, deep sea troughs; areas of active subduction

Marine Biogeochemical Cycles

Circuits or pathways by which chemical elements or molecules move through both biotic (“bio-”) and abiotic (“geo-”) reservoirs of an ecosystem
Marine cycles vs. Global cycles