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Also called rough fish. See also coarse fish. Trawling – is fishing with a large bag-like net, called a trawl, which is drawn along behind a boat called a trawler. The net can be dragged along the sea bottom in order to target demersal fish, or pulled through clear water in order to target pelagic fish.
Zooplankton and salps play a large role in the active transport of fecal pellets. 15–50% of zooplankton biomass is estimated to migrate, accounting for the transport of 5–45% of particulate organic nitrogen to depth. [40] Salps are large gelatinous plankton that can vertically migrate 800 meters and eat large amounts of food at the surface.
In zoology, deep-sea gigantism or abyssal gigantism is the tendency for species of deep-sea dwelling animals to be larger than their shallower-water relatives across a large taxonomic range. Proposed explanations for this type of gigantism include necessary adaptation to colder temperature, food scarcity, reduced predation pressure and ...
The variation in salinity is smaller, typically between 34.5 and 35 psu. [5] The density ranges from 1023 to 1027 g/L of seawater. [5] These changes in temperature, salinity, and density induce stratification which create ocean layers. These different water masses affect gradients and mixing of nutrients and dissolved gasses.
Upwelling intensity depends on wind strength and seasonal variability, as well as the vertical structure of the water, variations in the bottom bathymetry, and instabilities in the currents. In some areas, upwelling is a seasonal event leading to periodic bursts of productivity similar to spring blooms in coastal waters.
Removal of piscivorous fish can change lake water from clear to green by allowing phytoplankton to flourish. [24] In the Eel River, in Northern California, fish (steelhead and roach) consume fish larvae and predatory insects. These smaller predators prey on midge larvae, which feed on algae. Removal of the larger fish increases the abundance of ...
The pelagic food web, showing the central involvement of marine microorganisms in how the ocean imports nutrients from and then exports them back to the atmosphere and ocean floor. A marine food web is a food web of marine life. At the base of the ocean food web are single-celled algae and other plant-like organisms known as phytoplankton.
Fish larvae are part of the zooplankton that eat smaller plankton, while fish eggs carry their own food supply. Both eggs and larvae are themselves eaten by larger animals. [2] [3] Fish can produce high numbers of eggs which are often released into the open water column. Fish eggs typically have a diameter of about 1 millimetre (0.039 in).