#aquatic

• Actinenchyma — A structural plant parenchymal tissue, characterized by star-shaped cells with large radiating extensions that leave voluminous intercellular air spaces (lacunae) between them. This special type of tissue is specific to aquatic and marsh plants, having the primary physiological role of facilitating gas circulation and ensuring the buoyancy and respiration of submerged organs in oxygen-deficient environments.
• Actinocarpious — A structural botanical term describing a plant, a carpel, or a fruit whose component elements are arranged in a radiating, symmetric, or star-like manner around a central axis. In historical plant taxonomy, the term was also used to designate a group of aquatic or marsh plants (such as the genus Damasonium, formerly named Actinocarpus) characterized by fruits composed of follicles arranged in a bright star shape.
• Aqua- — A prefixoid or first element of neologistic composition used to introduce a direct reference to water or aquatic environments into compound words; it may also represent the elided form or direct adoption of the Latin term 'aqua'. This structural element forms the basis of many modern concepts in ecology, water sports, general culture, and fluid technology.
• Aquatic herbosa — A complex plant formation composed of herbaceous plants structurally adapted to aquatic or marsh life, either floating or submerged in stagnant or slow-flowing waters. This microstructural ecosystem plays a vital ecological role in the natural purification of hydrographic basins, the fixation of mobile sediments, and the provision of a suitable habitat for the reproduction of various aquatic fauna species.
• Female aquaplaner — The feminine form of the term 'acvaplanist'; a female athlete or recreational water sports enthusiast who glides at high speed across the water while standing balanced on a towed aquaplane. This athlete combines physical strength with elegance of movement to control the board's trajectory under the direct action of hydrodynamic currents.
• Female aquarist — The feminine form of the term 'acvariofil'; a female enthusiast of aquaristics, actively involved in setting up tanks and caring for captive underwater ecosystems; as an adjective, it describes a passion or a female community dedicated to aquatic life. She masters complex aquascaping techniques and biological management to maintain the structural balance of the aquarium.
• Fishkeeping — A passion, constant preoccupation, or hobby consisting of breeding, reproducing, and studying fish, plants, and other aquatic organisms in controlled artificial environments; a branch of miniature bio-ecosystems closely related to aquaristics. This structural discipline involves deep knowledge of water chemistry, the biological nitrogen cycle, and the ecological balance required for species survival in captivity.
• Aquatic — Pertaining to water, relating to water; living, developing, or practiced in water or on its surface. This term describes a structural variety of organisms, ecosystems, plants, or sporting activities whose anatomical, chemical, or operational characteristics are fully or partially adapted to fresh, brackish, or marine liquid environments.
• Aquatic fauna — The totality of vertebrate and invertebrate animal species structurally adapted to live permanently or temporarily in aquatic environments (fresh, brackish, or marine waters). This ecological concept encompasses a diverse range from protozoa and crustaceans to fish, amphibians, and marine mammals, representing a fundamental indicator for assessing biotope quality and the health status of global hydrographic ecosystems.
• Aerenchyma — A fundamental parenchymal plant tissue structurally characterized by the presence of large intercellular spaces, lacunae, or air-filled channels. It is specific to aquatic (hydrophytic) and marsh plants, playing the vital role of ensuring oxygen and gas circulation to submerged organs and facilitating the buoyancy of aerial parts.
• Coenagrionid damselfly — A small, slender-bodied damselfly belonging to the family Coenagrionidae (formerly Agrionidae), structurally characterized by transparent membranous wings folded vertically over the abdomen at rest and often displaying brilliant metallic coloration. These insects are predators, inhabiting areas in close proximity to freshwater lentic or lotic aquatic systems.
• Aldrovanda — A genus of carnivorous aquatic plants belonging to the Droseraceae family, currently represented by a single surviving species, Aldrovanda vesiculosa (commonly known as the waterwheel plant). A rootless, free-floating plant, it captures small aquatic invertebrates using leaves modified into extremely fast mechanical snap-traps, similar to those of the famous Venus flytrap.
• Waterwheel plant — The scientific name of a rare species of aquatic carnivorous plant, endemic to specific wetlands and stagnant freshwaters, commonly known as the waterwheel plant. This structurally unique plant lacks roots, floats freely beneath the water surface, and captures small aquatic invertebrates using leaves modified into snap-traps that close extremely fast when sensitive hairs are triggered.
• Alga — A lower, cryptogamic thallophyte plant with a body unsegmented into true roots, stems, or leaves, containing chlorophyll and other photosynthetic pigments. It lives primarily in aquatic environments or high-humidity spots. Classified into green, brown, or red variants, it plays a vital role in global ecosystems.
• Algotrophism — A form of nutrition or ecological phenomenon characterized by an organism's energetic and metabolic dependence on the consumption of algae; algophagy. In limnic and marine ecosystems, algotrophism represents a foundational mechanism for transferring primary biomass.
• Alisma genus — A genus of herbaceous, perennial, semi-aquatic plants in the family Alismataceae, commonly known as water-plantains; it comprises species adapted to wetlands, lakes, and ditches, globally distributed across temperate regions. These plants feature rhizomatous stems, variable leaves, and branched inflorescences with three-petaled flowers.
• Narrow-leaved water-plantain — A perennial, emergent aquatic plant species in the family Alismataceae, commonly known as narrow-leaved or lanceleaf water-plantain; it grows in shallow water or exposed mud. It is characterized by its narrow, lance-shaped leaves tapering to the petiole, and small pinkish-purple flowers that typically open in the morning.
• Common water-plantain — The type species of perennial herbaceous plants in the genus Alisma, commonly known as common water-plantain or mad-dog weed; it grows in wetlands, shallow pond edges, and wet mud. It features large, broad ovate or heart-shaped leaves resembling terrestrial plantains, and tall branched flowering panicles with tiny pale lilac or white flowers that open in the afternoon.
• Alismataceae — A family of monocotyledonous, herbaceous, perennial, aquatic or marsh plants adapted to life in wetlands and shallow waters. Plants in this family are characterized by laticiferous canals, highly polymorphic leaves arranged in a basal rosette, and 3-merous flowers with distinct green sepals and white or pink petals.
• Alos — An archaic or regional popular name derived from scientific nomenclature (genus Alosa) used to designate various fish species in the Clupeidae family, specifically the Danube shad or its adjacent lineages. This euryhaline migratory fish is structurally characterized by an elongated, hydrodynamic body and silvery scales, studied within population dynamics in European hydrographic basins.