ENSCI 100 – Exam 3 Study Guide

A series of flashcards covering essential concepts for the ENSCI 100 exam, focusing on ocean processes, climate effects, thermohaline circulation, and key definitions.

What is the pycnocline?

The layer where density rapidly increases with depth, transitioning between surface and deep ocean; includes thermocline/halocline.

What happens to density as depth increases in the ocean?

Density generally decreases.

Why do gyres form garbage patches?

Circular currents trap and concentrate debris in the center of the gyre.

Is the ocean a carbon sink or source?

The ocean is a carbon sink as it absorbs CO₂ from the atmosphere.

What is upwelling?

Movement of cold, nutrient-rich deep water to the surface.

What is coastal runoff?

Water from land carrying pollutants, fertilizer, and debris into oceans.

What is the solubility pump?

CO₂ dissolves in cold, dense water and sinks, storing carbon deep in the ocean.

What is the biological pump?

Phytoplankton fix carbon, which sinks as organic matter to the deep ocean.

What are HNLC regions?

Areas with high nutrients (N, P) but low productivity due to iron limitation.

What is thermohaline circulation?

Global 'conveyor belt' driven by temperature and salinity, moving heat, oxygen, and nutrients.

What causes thermohaline circulation?

Density differences due to temperature and salinity.

What are the impacts of weakened thermohaline circulation?

Less heat to poles resulting in cooler polar regions, less oxygen in deep ocean, and reduced CO₂ absorption leading to more atmospheric warming.

What characterizes the Surface Zone of the ocean?

Warm, mixed, low density, interacting with the atmosphere.

What distinguishes the Pycnocline?

A rapid density increase with temperature decreases (thermocline) and salinity changes.

What defines the Deep Zone of the ocean?

Cold, dense, stable, with high oxygen capacity.

What drives wind-driven circulation?

Wind and Coriolis forces, moving heat across the surface.

What is the role of the solubility pump in carbon storage?

Cold water dissolves CO₂, which sinks and stores carbon long-term.

How does the biological pump operate?

Photosynthesis leads to sinking organic carbon, moving about 50% of surface carbon downward.

What is the difference between short-wave and long-wave energy?

Short-wave refers to incoming solar energy, while long-wave refers to outgoing heat energy.

What happens when land ice melts?

It raises sea level.

What is thermal expansion?

Warmer water causes particles to spread out, increasing volume.

How do climate impacts manifest due to ocean changes?

Increased flooding, longer droughts, heavier rainfall, and possible changes in storm intensity.

What affects thermohaline circulation besides temperature and salinity?

Freshwater input from glaciers can reduce density and slow circulation.

What defines climate forcing?

Any factor that changes Earth’s energy balance, such as CO₂.

What is the greenhouse effect?

Shortwave energy from the sun enters the Earth, while longwave energy is trapped by greenhouse gases.

What are the Milankovitch Cycles?

Natural variations in Earth's orbit and tilt affecting climate over thousands of years.

What is solubility stress in oceans?

Warmer water leads to less CO₂ absorption.

What is biological pump stress?

Less phytoplankton leads to reduced carbon storage.

What does ocean acidification entail?

The increase of CO₂ leads to carbonic acid formation, lowering pH and harming shell organisms.

How does the water cycle relate to storms?

Warmer air can hold more water, leading to heavier rain and flooding.