Search results
Results from the WOW.Com Content Network
The related term Aufwuchs (German "surface growth" or "overgrowth", pronounced [ˈaʊ̯fˌvuːks] ⓘ) refers to the collection of small animals and plants that adhere to open surfaces in aquatic environments, such as parts of rooted plants. Periphyton serves as an important food source for invertebrates, tadpoles, and some fish.
The primary plant in freshwater marshes are emergent plants. Emergent plants are plants with soft stems and are highly adapted to live in saturated soils. [ 1 ] Freshwater marshes have a lengthy growing season and contain high nutrient levels in the water and substrate, which contribute to an overall high net primary production. [ 9 ]
The term was first proposed and used by the German biologist Ernst Haeckel in 1891 in his article Plankton-Studien where he contrasted it with plankton, the aggregate of passively floating, drifting, or somewhat motile organisms present in a body of water, primarily tiny algae and bacteria, small eggs and larvae of marine organisms, and protozoa and other minute consumers.
The biotic characteristics are mainly determined by the organisms that occur. For example, wetland plants may produce dense canopies that cover large areas of sediment—or snails or geese may graze the vegetation leaving large mud flats. Aquatic environments have relatively low oxygen levels, forcing adaptation by the organisms found there.
Algae grow very quickly and communities may represent fast changes in environmental conditions. [35] In addition to community structure, responses to freshwater stressors are investigated by experimental studies that measure organism behavioural changes, altered rates of growth, reproduction or mortality. [6]
These rapid plant movements differ from the more common, but much slower "growth-movements" of plants, called tropisms. Tropisms encompass movements that lead to physical, permanent alterations of the plant while rapid plant movements are usually reversible or occur over a shorter span of time.
The medusae of most species are fast-growing, and mature within a few months then die soon after breeding, but the polyp stage, attached to the seabed, may be much more long-lived. Jellyfish have been in existence for at least 500 million years, [ 1 ] and possibly 700 million years or more, making them the oldest multi-organ animal group.
[82] [15] [14] This means that the plants alter the ecosystem around them. This adjusting occurs in both physical and chemical forms. This adjusting occurs in both physical and chemical forms. Many seagrass species produce an extensive underground network of roots and rhizome which stabilizes sediment and reduces coastal erosion . [ 83 ]