Oceans & Coastal Margins is a core part of IB Geography. Revise the key concepts and common mistakes below, then lock them in with the free games.
ENSOEl Niño-Southern Oscillation: coupled ocean-atmosphere mode of variability in the tropical Pacific.
El NiñoWarm phase of ENSO with weakened trade winds and warmer eastern Pacific.
La NiñaCool phase of ENSO with strengthened trade winds and cooler eastern Pacific.
Thermohaline circulationGlobal ocean conveyor belt driven by temperature and salinity gradients.
UpwellingVertical movement of cold, nutrient-rich water to the surface supporting major fisheries.
TeleconnectionLinkage of weather patterns across great distances, e.g. ENSO effects on Indian monsoon.
Coral bleachingLoss of symbiotic zooxanthellae from coral polyps under thermal stress, leaving skeletons white.
Ocean acidificationReduction in ocean pH (around 8.2 to 8.1 since 1750) as oceans absorb CO₂.
Thermal expansionIncrease in ocean volume as water warms, contributing about half of recent sea-level rise.
Eustatic changeWorldwide sea-level change due to variation in water volume.
Isostatic changeLocal sea-level change due to vertical land movement.
MangrovesSalt-tolerant coastal forests acting as nurseries, sediment traps and storm buffers.
Constructive wavesLow, long waves with stronger swash than backwash, building beaches.
Destructive wavesHigh, short waves with stronger backwash than swash, eroding beaches.
Questions where students often pick the tempting wrong answer — make sure you know the right one: