Marine Biology

Complex biological communities and the physical environments they inhabit in the ocean, including coral reefs, deep-sea vents, open ocean pelagic zones, and coastal wetlands. These ecosystems are defined by abiotic factors such as light, temperature, salinity, and pressure, which shape the organisms that can survive there.

The division of the ocean into distinct vertical and horizontal zones based on depth, light penetration, and distance from shore. The major depth zones are the epipelagic (sunlight), mesopelagic (twilight), bathypelagic (midnight), abyssopelagic (abyssal), and hadopelagic (trench) zones.

The process by which corals expel the symbiotic zooxanthellae algae living in their tissues when subjected to environmental stress, particularly elevated water temperatures. Without these algae, corals lose their color and their primary source of nutrition, often leading to death if conditions persist.

The interconnected networks of feeding relationships in ocean ecosystems, beginning with primary producers like phytoplankton and seagrasses, passing through herbivorous zooplankton and small fish, and extending to apex predators such as sharks, orcas, and tuna.

The production and emission of light by living organisms through chemical reactions, most commonly involving the molecule luciferin and the enzyme luciferase. In the deep sea where sunlight cannot penetrate, bioluminescence is used for communication, predation, camouflage, and mate attraction.

The ongoing decrease in the pH of ocean water caused by the absorption of excess atmospheric carbon dioxide. When CO2 dissolves in seawater it forms carbonic acid, which reduces the availability of carbonate ions that marine organisms need to build calcium carbonate shells and skeletons.

Designated regions of the ocean where human activities such as fishing, mining, and drilling are restricted or prohibited to conserve biodiversity, protect critical habitats, and allow depleted populations to recover. MPAs vary from fully no-take reserves to multiple-use zones.

Close, long-term biological interactions between two or more different species in the ocean, which can be mutualistic (both benefit), commensal (one benefits, the other is unaffected), or parasitic (one benefits at the other's expense). Marine symbioses are among the most ecologically important relationships on Earth.

A global system of ocean currents driven by differences in water density caused by variations in temperature and salinity. Often called the global ocean conveyor belt, this circulation redistributes heat around the planet and plays a crucial role in regulating global climate and transporting nutrients.

Regions of the ocean that support exceptionally high species diversity and endemism, often coinciding with complex habitats like coral reefs, seamounts, and upwelling zones. These hotspots are critical for global biodiversity but are often disproportionately threatened by human activities.