Final Exam ESCI

Mixed Layer

Wind driven surface currents that change in response to weather conditions; produces a well-mixed layer with a uniform temperature.

Pycnocline

Middle layer where density increases rapidly with depth, including thermohaline and halocline.

Thermocline

Layer where temperature changes with depth.

Halocline

Layer where salinity changes with depth.

Deep Layer

Beneath the pycnocline, characterized by cold and dark conditions, increasing density with depth, and slow water movement.

Gyre

Large systems of rotating ocean currents.

Continuity

Connection with no sharp breaks, where ocean currents keep moving and fluid replaces older fluid.

Polynya

Area of open water surrounded by sea ice, often caused by a heat source that prevents freezing.

Deep Water

Formed in salty and cold areas, causing dense water to sink to the ocean's bottom.

Diurnal Tide

One high and one low tide per day with little difference between the two.

Semi-Diurnal Tide

Two highs and two lows per day with a significant difference between the highs and lows.

Mixed Semidiurnal Tide

A tide pattern with varying heights: lower high tide, higher high tide, lower low tide, and higher low tide.

Microtidal

Tide with a height difference of less than 2 meters.

Mesotidal

Tide with a height difference between 2 to 4 meters.

Macrotidal

Tide with a height difference of more than 4 meters.

Tidal Bore

Wave of incoming tide.

Tidal Amplitude

Height difference between high and low tide in a specific area.

High Tide Flooding

Overflow of ocean water during high tide that covers low-lying areas, increasing due to climate change.

Ecosystem

Subdivision of Earth’s systems where organism communities interact with each other and their physical environment.

Autotroph

Producers that gain energy from photosynthesis or chemosynthesis.

Heterotroph

Consumers that obtain energy by eating other organisms.

Photosynthesis

Process by which autotrophs gain energy from light.

Trophic Level

Position that an organism occupies in a food chain, food web, or ecological pyramid.

Phytoplankton

Primary producer in the photic zone.

Zooplankton

Primary consumer that drifts with currents.

Plankton

Organisms that drift with currents.

Nekton

Organisms that are denser than water and use muscles to swim.

Pelagic

Refers to the open sea away from the coast.

Benthic

Refers to the bottom of the ocean.

Adaptation

Genetically controlled trait that enhances an organism's chances for survival and reproduction.

Neutrally Buoyant

An organism that neither floats nor sinks.

Decomposers

Organisms that break down organic material, such as dead organisms.

Chemotrophs

Organisms that make their own food through chemosynthesis.

Ecological Efficiency

Fraction of total energy at one trophic level that is transformed into energy at the next.