Soil fertilitySoil fertility refers to the ability of soil to sustain agricultural plant growth, i.e. to provide plant habitat and result in sustained and consistent yields of high quality. It also refers to the soil's ability to supply plant/crop nutrients in the right quantities and qualities over a sustained period of time. A fertile soil has the following properties: The ability to supply essential plant nutrients and water in adequate amounts and proportions for plant growth and reproduction; and The absence of toxic substances which may inhibit plant growth e.
Soil pHSoil pH is a measure of the acidity or basicity (alkalinity) of a soil. Soil pH is a key characteristic that can be used to make informative analysis both qualitative and quantitatively regarding soil characteristics. pH is defined as the negative logarithm (base 10) of the activity of hydronium ions (H+ or, more precisely, H3O+aq) in a solution. In soils, it is measured in a slurry of soil mixed with water (or a salt solution, such as 0.01M CaCl2), and normally falls between 3 and 10, with 7 being neutral.
Latitudinal gradients in species diversitySpecies richness, or biodiversity, increases from the poles to the tropics for a wide variety of terrestrial and marine organisms, often referred to as the latitudinal diversity gradient. The latitudinal diversity gradient is one of the most widely recognized patterns in ecology. It has been observed to varying degrees in Earth's past. A parallel trend has been found with elevation (elevational diversity gradient), though this is less well-studied.
Ecosystem modelAn ecosystem model is an abstract, usually mathematical, representation of an ecological system (ranging in scale from an individual population, to an ecological community, or even an entire biome), which is studied to better understand the real system. Using data gathered from the field, ecological relationships—such as the relation of sunlight and water availability to photosynthetic rate, or that between predator and prey populations—are derived, and these are combined to form ecosystem models.
OmbrotrophicOmbrotrophic ("cloud-fed"), from Ancient Greek ὄμβρος (ómvros) meaning "rain" and τροφή (trofí) meaning "food"), refers to soils or vegetation which receive all of their water and nutrients from precipitation, rather than from streams or springs. Such environments are hydrologically isolated from the surrounding landscape, and since rain is acidic and very low in nutrients, they are home to organisms tolerant of acidic, low-nutrient environments. The vegetation of ombrotrophic peatlands is often bog, dominated by Sphagnum mosses.
Raised bogRaised bogs, also called ombrotrophic bogs, are acidic, wet habitats that are poor in mineral salts and are home to flora and fauna that can cope with such extreme conditions. Raised bogs, unlike fens, are exclusively fed by precipitation (ombrotrophy) and from mineral salts introduced from the air. They thus represent a special type of bog, hydrologically, ecologically and in terms of their development history, in which the growth of peat mosses over centuries or millennia plays a decisive role.
ZooplanktonZooplankton are the animal component of the planktonic community (the "zoo-" prefix comes from ζῷον). Plankton are aquatic organisms that are unable to swim effectively against currents. Consequently, they drift or are carried along by currents in the ocean, or by currents in seas, lakes or rivers. Zooplankton can be contrasted with phytoplankton, which are the plant component of the plankton community (the "phyto-" prefix comes from φῠτόν). Zooplankton are heterotrophic (other-feeding), whereas phytoplankton are autotrophic (self-feeding).
Correlation does not imply causationThe phrase "correlation does not imply causation" refers to the inability to legitimately deduce a cause-and-effect relationship between two events or variables solely on the basis of an observed association or correlation between them. The idea that "correlation implies causation" is an example of a questionable-cause logical fallacy, in which two events occurring together are taken to have established a cause-and-effect relationship. This fallacy is also known by the Latin phrase cum hoc ergo propter hoc ('with this, therefore because of this').
Lake stratificationLake stratification is the tendency of lakes to form separate and distinct thermal layers during warm weather. Typically stratified lakes show three distinct layers: the epilimnion, comprising the top warm layer; the thermocline (or metalimnion), the middle layer, whose depth may change throughout the day; and the colder hypolimnion, extending to the floor of the lake. Every lake has a set mixing regime that is influenced by lake morphometry and environmental conditions.
Woody plantA woody plant is a plant that produces wood as its structural tissue and thus has a hard stem. In cold climates, woody plants further survive winter or dry season above ground, as opposed to herbaceous plants that die back to the ground until spring. Woody plants are usually trees, shrubs, or lianas. These are usually perennial plants whose stems and larger roots are reinforced with wood produced from secondary xylem. The main stem, larger branches, and roots of these plants are usually covered by a layer of bark.
