Oxygen isotope ratio cycle likely driven by the Lomagundi carbon isotope excursion. Oxygen isotope ratio cycle Oxygen isotope ratio cycles are cyclical variations in the ratio of the abundance of oxygen with an atomic mass of 18 to the abundance of oxygen with an atomic mass of 16 present in some substances, such as polar ice or calcite in ocean core samples, measured with the isotope fractionation. The ratio is linked to water temperature of ancient oceans, which in turn reflects ancient climates. Cycles in the ratio mirror climate changes in geologic history. Oxygen (chemical symbol O) has three naturally occurring isotopes: O, O,
Standard weight in fish common measures of condition used in fisheries assessment and management. Fulton’s condition factor, K, is another measure of an individual fish’s health that uses standard weight. Proposed by Fulton in 1904, it assumes that the standard weight of a fish is proportional to the cube of its length: formula_2 where "W" is the whole body wet weight in grams and "L" is the length in centimeters; the factor 100 is used to bring K close to a value of one. Standard weight in fish Standard weight in fish is the typical or expected weight at a given total length for