Marine Biology and Ocean Environment Vocabulary

Vocabulary flashcards covering foundational concepts in marine biology, historical expeditions, ocean floor bathymetry, seawater chemical properties, and physical oceanography circulation systems.

Biological Oceanography

The branch of ocean science that focuses on large-scale (ocean-scale) processes and their effects on marine life.

Marine Biology

The scientific study of organisms that inhabit the seas and oceans.

Plankton

Organisms that drift with ocean currents and are unable to swim effectively against them.

Nekton

Active, free-swimming marine organisms capable of moving independently against ocean currents.

Neuston

Organisms that inhabit the surface micro-layer at the air-sea interface.

Life Habits of Marine Organisms

Classifications of marine organisms based on their spatial distribution and movement capabilities within pelagic and benthic marine zones.

Azoic Theory

A 19th-century hypothesis formulated by Edward Forbes asserting that no marine life could exist below a depth of $550\,m$.

Edward Forbes

A 19th-century naturalist (1815–1854) who surveyed the Mediterranean aboard the Beacon and proposed the Azoic theory.

Challenger Expedition

The first major oceanographic expedition (1872–1876), led by Wyville Thomson and John Murray, which traveled $110{,}840\,km$ and identified $4{,}717$ new species.

Prince Albert I of Monaco

An early marine oceanographer (1848–1922) who founded the Monaco Oceanographic Institute and led research voyages across the Mediterranean and eastern Atlantic.

Hypothesis

A testable statement or proposed explanation formulated to answer a scientific question.

Ocean Bathymetry

The underwater topography of the ocean floor, characterized by continental shelves, slopes, abyssal plains, ridges, and trenches.

Abyssal Plain

A flat region of the deep-ocean basin formed as fine sediment settling from suspension covers underlying crustal irregularities.

Mid-Ocean Ridge

A continuous underwater mountain range located at divergent plate boundaries where new oceanic crust forms via seafloor spreading.

Subduction Zone

A convergent boundary where one tectonic plate plunges beneath another into the mantle, forming deep ocean trenches and volcanic arcs.

Ocean Trench

A steep-sided, narrow depression on the seafloor ranging from $6$ to $11\,km$ deep (averaging $3.5$–$5\,km$), created by subduction.

Transform Fault

A tectonic plate boundary where plates slide horizontally past one another.

Water Molecule Polarity

The unequal distribution of electron charge in a water molecule, yielding a partial negative charge near oxygen and partial positive charges near hydrogen.

Hydrogen Bond

An intermolecular attraction formed between the oppositely charged ends of adjacent polar water molecules.

Salinity

The concentration of dissolved salts in water, measured in grams of salt per kilogram of water (ppt or $\%$), typically $33$–$37\,\%$ in the open ocean.

Principle of Constant Composition

The rule stating that the ratios between major dissolved ions in seawater remain constant throughout the global ocean, regardless of total salinity.

Estuary

A partially enclosed coastal body of water where seawater mixes with freshwater input from rivers.

Compensation Depth

The depth in the water column where gross primary production through photosynthesis equals respiration rate, resulting in zero net productivity.

Thermocline

A layer of water where temperature changes rapidly with increasing depth.

Pycnocline

A ocean layer where water density increases rapidly with depth.

Oxygen Minimum Zone

A subsurface water zone where dissolved oxygen levels drop sharply due to organic decomposition accumulating near the thermocline/pycnocline.

Coriolis Effect

The apparent deflection of moving air and water caused by Earth's rotation, bending paths to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

Ekman Transport

The net movement of a water column set in motion by wind, deflected at a $90^\circ$ angle relative to wind direction due to the Coriolis effect.

Ocean Gyre

A large, circular surface current system produced by planetary wind patterns and the Coriolis effect.

Upwelling

The process in which wind and Coriolis forces push surface waters away from a coastline, bringing cold, nutrient-rich deep water to the surface.

Thermohaline Circulation

Deep-ocean circulation driven by density differences resulting from variations in water temperature and salinity.