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Marine botany is the study of flowering vascular plant species and marine algae that live in shallow seawater of the open ocean and the littoral zone, along shorelines of the intertidal zone, coastal wetlands, and low-salinity brackish water of estuaries. It is a branch of marine biology and botany.
They evolved from terrestrial plants which migrated back into the ocean about 75 to 100 million years ago. [1] [2] In the present day they occupy the sea bottom in shallow and sheltered coastal waters anchored in sand or mud bottoms. [3] There are four lineages of seagrasses [4] containing relatively few species (all in a single order of ...
Marine plants can be found in intertidal zones and shallow waters, such as seagrasses like eelgrass and turtle grass, Thalassia. These plants have adapted to the high salinity of the ocean environment. Light is only able to penetrate the top 200 metres (660 ft) so this is the only part of the sea where plants can grow. [77]
The ocean floor is not all flat but has submarine ridges and deep ocean trenches known as the hadal zone. [6] For comparison, the pelagic zone is the descriptive term for the ecological region above the benthos, including the water column up to the surface. At the other end of the spectrum, benthos of the deep ocean includes the bottom levels ...
The pelagic zone contrasts with the benthic and demersal zones at the bottom of the sea. The benthic zone is the ecological region at the very bottom, including the sediment surface and some subsurface layers. Marine organisms such as clams and crabs living in this zone are called benthos. Just above the benthic zone is the demersal zone.
It is the region of open sea beyond the edge of the continental shelf and includes 65% of the ocean's completely open water. The oceanic zone has a wide array of undersea terrain, including trenches that are often deeper than Mount Everest is tall, as well as deep-sea volcanoes and basins. While it is often difficult for life to sustain itself ...
Dead organisms sink to the bottom of the ocean, depositing layers of shell which over time cement to form limestone. This is the origin of both marine and terrestrial limestone. [57] Calcium precipitates into calcium carbonate according to the following equation: Ca 2+ + 2HCO 3 − → CO 2 + H 2 O + CaCO 3 [112]
It is uncommon to detect deep scattering layers below 1000m. Until recently, sonar has been the predominant method for studying the mesopelagic. [46] The Malaspina Circumnavigation Expedition was a Spanish-led scientific quest in 2011 to gain a better understanding of the state of the ocean and the diversity in the deep oceans. [49]