Marine Sciences I – Comprehensive Vocabulary Review

A vocabulary set covering major concepts, processes, organisms, and tools discussed throughout the Marine Sciences I lecture slides, suitable for comprehensive exam review.

Hydrogen Bond

Weak electrostatic attraction between the positive hydrogen of one water molecule and the negative oxygen of another, giving water many unique properties.

Astragalus Bone

Distinctive double-roller ankle bone shared by whales and even-toed ungulates, key evidence of their evolutionary relationship.

Ekman Transport

Net movement of surface water 90° to the right of the wind in the Northern Hemisphere (left in the Southern) caused by Coriolis deflection.

Geostrophic Gyre

Large oceanic circulation pattern where Coriolis force balances the horizontal pressure gradient, forming rotating “hills” of water.

Passive Continental Margin

Tectonically quiet continental edge facing a diverging plate boundary, with broad shelf and little seismic activity.

Active Continental Margin

Tectonically active continental edge near a convergent plate boundary, marked by narrow shelf, volcanism, and earthquakes.

Submarine Canyon

Steep-walled valley cut into continental shelf and slope, often ending in deep-sea sediment fans.

Turbidity Current

Dense, sediment-laden underwater avalanche that flows down continental slopes and carves submarine canyons.

Abyssal Plain

Extremely flat, sediment-covered area of the deep-ocean floor found between continental margins and mid-ocean ridges.

Seamount

Submarine mountain rising ≥1000 m above surrounding seafloor but not reaching the surface, usually volcanic in origin.

Guyot

Flat-topped seamount formed when a volcanic island erodes to sea level and later subsides.

Hydrothermal Vent

Seafloor hot spring at mid-ocean ridges where mineral-rich, super-heated water emerges and supports chemosynthetic life.

Ringwoodite

High-pressure mantle mineral that can store water within Earth’s deep interior, evidence for deep Earth water reservoirs.

Hadley Cell

Atmospheric circulation cell between the equator and 30° latitude characterized by rising equatorial air and descending subtropical air.

Inter-Tropical Convergence Zone (ITCZ)

Belt of low pressure near the equator where trade winds converge, bringing heavy rainfall and shifting seasonally.

Coriolis Effect

Apparent deflection of moving objects due to Earth’s rotation: right in the Northern Hemisphere, left in the Southern.

Western Boundary Current

Fast, deep, narrow warm current on the western side of ocean basins (e.g., Gulf Stream).

Eastern Boundary Current

Wide, shallow, slow cold current on the eastern side of ocean basins (e.g., California Current).

Upwelling

Vertical movement of deep, cold, nutrient-rich water to the surface, enhancing biological productivity.

El Niño

Warm phase of ENSO when weakened trade winds allow warm Pacific water to spread eastward, suppressing upwelling off South America.

Thermohaline Circulation

Global deep-ocean circulation driven by differences in water density due to temperature and salinity.

North Atlantic Deep Water (NADW)

Cold, saline water mass formed in the North Atlantic that sinks and flows southward as part of the conveyor belt.

Antarctic Bottom Water (AABW)

Densest water mass on Earth formed around Antarctica, spreading northward along the seafloor.

SOFAR Channel

Sound-fixing and ranging layer (~1000 m depth) where sound speed minimum allows long-distance sound propagation.

Heat Capacity of Water

Amount of heat required to raise 1 g of water by 1 °C (1 cal), unusually high compared with most substances.

Latent Heat of Vaporization

Energy absorbed (540 cal g⁻¹) during water’s change from liquid to vapor without temperature change.

Salinity

Total mass of dissolved salts in seawater, usually expressed in parts per thousand (≈35 ‰).

Forchhammer’s Principle

Proportions of major dissolved salts in seawater remain nearly constant everywhere, despite salinity differences.

Pycnocline

Ocean layer where water density increases rapidly with depth, usually due to a temperature drop (thermocline).

Cabbeling

Process where mixing two water masses of identical density but different T/S yields water that is denser, causing sinking.

Continental Drift

Hypothesis by Alfred Wegener proposing that continents move across Earth’s surface, precursor to plate tectonics.

Seafloor Spreading

Process by which new oceanic crust forms at mid-ocean ridges and moves outward, evidenced by magnetic striping.

Transform Fault

Plate boundary where plates slide horizontally past each other, often offsetting mid-ocean ridges (e.g., San Andreas).

Hot Spot

Stationary mantle plume producing volcanic chains as tectonic plates move overhead (e.g., Hawaiian Islands).

Oceanic Ridge

Continuous submarine mountain range at divergent plate boundaries where new lithosphere forms.

Carbonate Compensation Depth (CCD)

Depth below which calcium carbonate dissolves faster than it accumulates, preventing carbonate sediment burial.

Residence Time

Average time an element remains in the ocean, calculated as amount divided by input (or output) rate.

Biological Pump

Process transporting carbon and nutrients from the surface to deep ocean via sinking organic material.

HNLC Region

Ocean area with High Nutrients but Low Chlorophyll where iron or silica limits phytoplankton growth.

Henry’s Law

Solubility of a gas in liquid is proportional to the gas’s partial pressure above the liquid (C = K_H · P).

Total Alkalinity (TA)

Sum of all proton acceptors minus donors in seawater; primary buffer against pH change.

Dissolved Inorganic Carbon (DIC)

Total concentration of CO₂, H₂CO₃, HCO₃⁻, and CO₃²⁻ in seawater.

Ocean Acidification

Decrease in ocean pH due to absorption of anthropogenic CO₂, lowering carbonate ion concentration.

Saturation State (Ω)

Ratio of ion product [Ca²⁺][CO₃²⁻] to solubility product K_sp; Ω < 1 favors carbonate dissolution.

Bjerrum Plot

Graph showing proportions of CO₂ species (CO₂, HCO₃⁻, CO₃²⁻) as a function of pH.

Isotope

Atoms of the same element with different numbers of neutrons (e.g., ¹²C vs ¹³C).

δ¹³C Notation

Per-mil deviation of ¹³C/¹²C ratio in a sample relative to a standard (PDB).

Suess Effect

Decline in δ¹³C of atmospheric and oceanic CO₂ due to fossil-fuel emissions depleted in ¹³C.

Fractionation Factor (ε)

Isotopic enrichment expressed in per mil between two substances or phases during a process.

Trophic Level Enrichment

Increase of ~3–4 ‰ in δ¹⁵N with each step up a food web, useful for dietary studies.

Paleocene–Eocene Thermal Maximum (PETM)

Rapid global warming event ~56 Ma marked by a large negative carbon-isotope excursion and ocean acidification.

Bathymetry

Measurement and mapping of seafloor depth and topography.

Echo Sounding

Technique using sound pulses to measure two-way travel time and determine water depth.

Multibeam Sonar

System emitting multiple sound beams to produce high-resolution swath maps of seafloor.

Satellite Altimetry

Measurement of sea-surface height from space to infer seafloor features via gravitational anomalies.

Stromatolite

Layered sedimentary structure formed by cyanobacterial mats; earliest evidence of life (~3.5 Ga).

Hydrothermal Chemosynthesis

Production of organic matter from inorganic chemicals (e.g., H₂S) by bacteria at hydrothermal vents, independent of sunlight.

Megavirus

Extra-large virus infecting protists or amoebas (e.g., Mimivirus), sometimes harboring its own virophages.

Virophage

Small virus that infects and parasitizes larger viruses inside host cells.

Marine Snow

Continuous shower of organic particles falling from surface waters to the deep sea, major food source below photic zone.

Coccolithophore

Single-celled algae that produce calcium-carbonate plates (coccoliths) and influence global carbonate cycles.

Diatom

Silica-walled phytoplankton with pill-box frustules, major contributors to marine primary production.

Dinoflagellate

Flagellated planktonic protists, some photosynthetic, some bioluminescent, others causing harmful red tides.

Prochlorococcus

Tiny cyanobacterium, Earth’s most abundant photosynthetic organism, dominating oligotrophic tropical oceans.

TEX₈₆

Organic geochemical proxy using archaeal lipids to estimate past sea-surface temperatures.

Milankovitch Cycle

Periodic change in Earth’s orbital parameters (eccentricity, obliquity, precession) influencing climate and sediment cycles.

Magnetostratigraphy

Dating method using patterns of geomagnetic polarity reversals recorded in rocks or sediments.

Foraminifera

Marine protozoans with calcium-carbonate shells useful as paleoceanographic proxies and sediment constituents.

Calcareous Ooze

Deep-sea sediment composed >50 % of calcium-carbonate microfossils (foraminifera, coccoliths).

Siliceous Ooze

Deep-sea sediment composed >50 % of biogenic silica from diatoms or radiolarians.

Red Clay

Fine, iron-oxide-rich pelagic sediment accumulating in the deepest, remote ocean basins.

Hjulström Diagram

Graph showing velocity needed to erode, transport, and deposit particles of different sizes.

Terrigenous Sediment

Material derived from land (rivers, wind, glaciers) deposited in the marine environment.

Eolian Transport

Movement of sediments by wind, delivering fine dust to oceans over great distances.

Ice-Rafted Debris

Sediment transported by icebergs and released upon melting, indicating past glacial activity.

Manganese Nodule

Authigenic concretion of manganese and other metals forming on abyssal plains.

Symbiosis

Close ecological relationship between two species; includes mutualism, commensalism, and parasitism.

Serial Endosymbiosis Theory

Hypothesis that eukaryotic organelles (mitochondria, chloroplasts) originated from symbiotic bacteria.

Great Oxygenation Event

Rise in atmospheric O₂ ~2.4 Ga produced by photosynthetic cyanobacteria, transforming Earth’s atmosphere.

Cymothoa exigua

Isopod “tongue-eating” parasite replacing fish tongues and feeding on host blood/mucus.

CCD Rise

Upward shift of the carbonate compensation depth during high CO₂ periods, causing deeper carbonate dissolution.

Latent Heat of Fusion

Energy absorbed (80 cal g⁻¹) when ice melts without temperature change.

Surface Tension

Cohesive force at water’s surface due to hydrogen bonding, resisting penetration and shaping droplets.

Stokes Law

Equation describing the settling velocity of small spherical particles in a fluid, important for sedimentation.

Ekman Spiral

Layered deflection of water velocity with depth under steady wind, each layer turning relative to the one above.

Gyre Hill

Mound of water that forms at center of subtropical gyres due to converging Ekman transport.

Walker Circulation

Zonal atmospheric cell over the Pacific influencing ENSO; ascending air in the west, descending in the east during normal conditions.

Ammonite

Extinct Mesozoic cephalopod with coiled shell, related to modern squid and octopus.

Tridacna gigas

Giant clam hosting symbiotic dinoflagellate algae, largest living bivalve.

Leuconoid Sponge

Most complex sponge body type with extensively branched canals and chambers for efficient filtration.

Fringing Reef

Coral reef directly attached to a shoreline of a volcanic island or continent.

Barrier Reef

Coral reef separated from land by a lagoon, formed as island subsides.

Atoll

Ring-shaped coral reef enclosing a lagoon, marking final stage of Darwin’s reef subsidence model.

Calcification

Biological precipitation of CaCO₃ by organisms; consumes alkalinity and releases CO₂.

Aragonite

Metastable form of calcium carbonate produced by corals and pteropods; more soluble than calcite.

Whale Fall

Decomposing whale carcass on deep seafloor that supports specialized ecological communities.

Marine Snow

(Duplicate removed)

Biogeochemical Cycle

Movement of chemical elements between living organisms and the physical environment.

Supralittoral Zone

Area above high-tide line periodically splashed but not regularly submerged, part of coastal classification.

Ocean Drilling Program (ODP/ IODP)

International scientific initiative coring ocean sediments to study Earth history and processes.