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Gross primary production (GPP) is the amount of chemical energy, typically expressed as carbon biomass, that primary producers create in a given length of time.Some fraction of this fixed energy is used by primary producers for cellular respiration and maintenance of existing tissues (i.e., "growth respiration" and "maintenance respiration").
However, in aquatic ecosystems, primary producers are consumed by herbivores at a rate four times greater than in terrestrial ecosystems. [22] Although this topic is highly debated, researchers have attributed the distinction in herbivore control to several theories, including producer to consumer size ratios and herbivore selectivity.
Food chain in a Swedish lake. Osprey feed on northern pike, which in turn feed on perch which eat bleak which eat crustaceans.. A food chain is a linear network of links in a food web, often starting with an autotroph (such as grass or algae), also called a producer, and typically ending at an apex predator (such as grizzly bears or killer whales), detritivore (such as earthworms and woodlice ...
The ecological efficiency of an ecosystem is as a result often no better than an approximation. On the other hand, an approximation may be enough for most ecosystems, where it is important not to get an exact measure of efficiency, but rather a general idea of how energy is moving through its trophic levels.
As ecosystems age this supply diminishes, making phosphorus-limitation more common in older landscapes (especially in the tropics). [20]: 287–290 Calcium and sulfur are also produced by weathering, but acid deposition is an important source of sulfur in many ecosystems. Although magnesium and manganese are produced by weathering, exchanges ...
Primary production in most ecosystems is dominated by the process of photosynthesis, In which organisms synthesize organic molecules from sunlight, H 2 O, and CO 2. [3] Aquatic primary productivity refers to the production of organic matter, such as phytoplankton, aquatic plants, and algae, in aquatic ecosystems, which include oceans, lakes ...
Local experts will explain the many contributions moths and frogs make to the environment.
Temperature is an important abiotic factor in lentic ecosystems because most of the biota are poikilothermic, where internal body temperatures are defined by the surrounding system. Water can be heated or cooled through radiation at the surface and conduction to or from the air and surrounding substrate. [ 6 ]