Marine Ecosystems The types of marine ecosystems are: Coastal waters - constitute the interface between the marine and the freshwater environments, and between the continents and the oceans. Estuaries - are broad portions of rivers or streams near their outlet, influenced by the marine water body into which they flow.
Marine waters cover two-thirds of the surface of the Earth. In some places the ocean is deeper than Mount Everest is high; for example, the Mariana Trench and the Tonga Trench Marine ecosystems the western part of the Pacific Ocean reach depths in excess of 10, metres 32, feet.
Within this ocean habitat live a wide variety of organisms that have evolved in response to various features of their environs. Origins of marine life The Earth formed approximately 4. As it cooled, water in the atmosphere Marine ecosystems and the Earth was pummeled with torrential rainswhich filled its great basins, forming seas.
The primeval atmosphere and waters harboured the inorganic components hydrogenmethaneammoniaand water. These substances are thought to have combined to form the first organic compounds when sparked by electrical discharges of lightning.
Some of the earliest known organisms are cyanobacteria formerly referred to as blue-green algae.
Evidence of these early photosynthetic prokaryotes has been found in Australia in Precambrian marine sediments called stromatolites that are approximately 3 billion years old. Although the diversity of life-forms observed in modern oceans did not appear until much later, during the Precambrian about 4.
During the Cambrian Period about million to million years ago a major radiation of life occurred in the oceans. Fossils of familiar organisms such as cnidaria e.
The first fossil fishes are found in sediments from the Ordovician Period about million to million years ago. Changes in the physical conditions of the ocean that are thought to have occurred in the Precambrian—an increase in the concentration of oxygen in seawater and a buildup of the ozone layer that reduced dangerous ultraviolet radiation—may have facilitated the increase and dispersal of living things.
The marine environment Geography, oceanography, and topography The shape of the oceans and seas of the world has changed significantly throughout the past million years.
According to the theory of plate tectonicsthe crust of the Earth is made up of many dynamic plates. When two plates divergemagma from the mantle wells up and cools, forming new crust; when convergence occurs, one plate descends—i.
Examples of both processes are observed in the marine environment. Oceanic crust is created along oceanic ridges or rift areas, which are vast undersea mountain ranges such as the Mid-Atlantic Ridge.
Excess crust is reabsorbed along subduction zoneswhich usually are marked by deep-sea trenches such as the Kuril Trench off the coast of Japan. The shape of the ocean also is altered as sea levels change. During ice ages a higher proportion of the waters of the Earth is bound in the polar ice capsresulting in a relatively low sea level.
When the polar ice caps melt during interglacial periods, the sea level rises. These changes in sea level cause great changes in the distribution of marine environments such as coral reefs. For example, during the last Pleistocene Ice Age the Great Barrier Reef did not exist as it does today; the continental shelf on which the reef now is found was above the high-tide mark.Abstract.
Marine ecosystems are centrally important to the biology of the planet, yet a comprehensive understanding of how anthropogenic climate change is affecting them has been poorly developed. Marine ecosystem, complex of living organisms in the ocean environment.
Marine organisms are not distributed evenly throughout the oceans. Variations in characteristics of the marine environment create different habitats and influence what types of organisms will inhabit them.
The availability of. Marine ecosystems are home to a host of different species ranging from planktonic organisms that form the base of the marine food web to large marine mammals.
Many species rely on marine ecosystems for both food and shelter from predators. Marine ecosystems include: the abyssal plain (areas like deep sea coral, whale falls, and brine pools), polar regions such as the Antarctic and Arctic, coral reefs, the deep sea (such as the community found in the abyssal water column), hydrothermal vents, kelp forests, mangroves, the open ocean, rocky shores, salt marshes and mudflats, and sandy shores.
Marine ecosystems are home to a host of different species ranging from planktonic organisms that form the base of the marine food web to large marine mammals.
Many species rely on marine ecosystems for both food and shelter from predators. Marine ecosystem: Marine ecosystem, complex of living organisms in the ocean environment. Marine waters cover two-thirds of the surface of the Earth. In some places the ocean is deeper than Mount Everest is high; for example, the Mariana Trench and the Tonga Trench in the western part of the Pacific Ocean reach.