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Less oxygen is available under water, so aerobic bacteria and fungi fail to colonize the submerged debris effectively. In addition, cool temperatures retard bacterial and fungal growth. This causes slow decomposition, and thus the plant debris gradually accumulates to form peat and eventually muskeg.
Baikal seals mate in the water towards the end of the pupping season. With a combination of delayed implantation and a nine-month gestation period, the Baikal seals' overall pregnancy is around 11 months. Pregnant females are the only Baikal seals to haul out during the winter. The males tend to stay in the water, under the ice, all winter.
In species like the spiny dogfish and other sharks and rays, a spiracle exists near the top of the head that pumps water into the gills when the animal is not in motion. [5] In some fish, capillary blood flows in the opposite direction to the water, causing countercurrent exchange. The muscles on the sides of the pharynx push the oxygen ...
Photosynthetic oxygen evolution is the fundamental process by which oxygen is generated in the earth's biosphere. The reaction is part of the light-dependent reactions of photosynthesis in cyanobacteria and the chloroplasts of green algae and plants. It utilizes the energy of light to split a water molecule into its protons and electrons for ...
This is an accepted version of this page This is the latest accepted revision, reviewed on 28 February 2025. Taxonomic group of semi-aquatic mammals Pinnipeds Temporal range: Latest Oligocene – Holocene, 24–0 Ma Pre๊ ๊ O S D C P T J K Pg N Clockwise from top left: Grey seal (Halichoerus grypus), Steller sea lion (Eumetopias jubatus), New Zealand fur seal (Arctocephalus forsteri ...
Phocid seals do not have particularly large lung volumes, and they normally exhale at the start of a dive to reduce buoyancy and avoid nitrogen uptake under pressure. The lungs progressively collapse during the dive, starting with the alveoli, where gas exchange takes place, and re-expand during the ascent, so some gas exchange may be possible ...
Blubber from whales and seals contains omega-3 fatty acids and vitamin D. [15] Without the vitamin D, for example, the Inuit and other natives of the Arctic would likely suffer from rickets. There is evidence blubber and other fats in the arctic diet also provide the calories needed to replace the lack of carbohydrates which are found in the ...
Dives during the winter are also deeper and longer than those in the summer. It is known that the hooded seal is generally a solitary species, except during breeding and molting seasons. During these two periods, they tend to fast as well. The seals mass annually near the Denmark strait around July, at the time of their molting periods, to mate.