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Portsea Hole
The Portsea Hole is a depression in the seafloor of Port Phillip near Portsea in Victoria, Australia. The undefined area of the depression, generally assessed at , is one of six separate areas that comprise the Port Phillip Heads Marine National Park and is a popular site for divers. Features The Portsea Hole is a remnant section of the drowned valley of the Yarra River, descending sharply from the depth of the surrounding seabed to , exposing changes in the strata of the limestone sides with depth. It is characterized by diverse and abundant fish assemblages as well as a rich benthic community of marine invertebrates, encrusting algae, sponges and soft corals. The Portsea Hole in Port Phillip is about from the Portsea Pier. To the north there is a vertical wall approximately long. The wall has small overhangs which are home to plenty of marine life, including Blue Devil fish. The Portsea Hole is a popular boat dive site for recreational scuba diving Scuba diving is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blue Hole
A blue hole is a large marine cavern or sinkhole, which is open to the surface and has developed in a bank or island composed of a carbonate bedrock (limestone or coral reef). Their existence was discovered in the late 20th century by fishermen and recreational divers. Blue holes typically contain tidally influenced water of fresh, marine, or mixed chemistry. They extend below sea level for most of their depth and may provide access to submerged cave passages. Well-known examples are the Dragon Hole (in the South China Sea) and, in the Caribbean, the Great Blue Hole and Dean's Blue Hole. ''Blue holes'' are distinguished from ''cenotes'' in that the latter are inland voids usually containing fresh groundwater rather than seawater. Description Blue holes are roughly circular, steep-walled depressions, and so named for the dramatic contrast between the dark blue, deep waters of their depths and the lighter blue of the shallows around them. Their water circulation is poor, and the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of living fish species are ray-finned fish, belonging to the class Actinopterygii, with around 99% of those being teleosts. The earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period. Although they lacked a true spine, they possessed notochords which allowed them to be more agile than their invertebrate counterparts. Fish would continue to evolve through the Paleozoic era, diversifying into a wide variety of forms. Many fish of the Paleozoic developed external armor that protected them from predators. The first fish with jaws appeared in the Silurian period, after which many (such as sharks) became formidable marine predators rather than just the prey of arthropods. Mos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protected Areas Of Victoria
Victoria is the smallest mainland state in Australia. it contained separate protected areas with a total land area of (17.26% of the state's area). Of these, 45 were national parks, totalling (11.32% of the state's area). The parks are managed by Parks Victoria, a state government agency. There are also many smaller state areas which are subject to commercial activity such as logging. Coastal and marine parks The state of Victoria has protected approximately 5.3% of coastal waters. In June 2002, legislation was passed to establish 13 marine national parks and 11 marine sanctuaries. Victoria is the first jurisdiction in the world to create an entire system of highly protected marine national parks at the same time. Historic and heritage areas and parks * Beechworth Historic Park * Castlemaine Diggings National Heritage Park * Nyerimilang Heritage Park * Oriental Claims Historic Area * Point Gellibrand Coastal Heritage Park * Steiglitz Historic Park * Walhalla Histo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scuba Diving
Scuba diving is a mode of underwater diving whereby divers use breathing equipment that is completely independent of a surface air supply. The name "scuba", an acronym for "Self-Contained Underwater Breathing Apparatus", was coined by Christian J. Lambertsen in a patent submitted in 1952. Scuba divers carry their own source of breathing gas, usually compressed air, affording them greater independence and movement than surface-supplied divers, and more time underwater than free divers. Although the use of compressed air is common, a gas blend with a higher oxygen content, known as enriched air or nitrox, has become popular due to the reduced nitrogen intake during long and/or repetitive dives. Also, breathing gas diluted with helium may be used to reduce the likelihood and effects of nitrogen narcosis during deeper dives. Open circuit scuba systems discharge the breathing gas into the environment as it is exhaled, and consist of one or more diving cylinders containing breat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraplesiops
''Paraplesiops'' is a genus containing five largely allopatric species of fishes in the longfin, or roundhead, family Plesiopidae, commonly known as blue devils, bluedevils, or blue devilfish because of their colouration. The genus is most similar to the tropical genera '' Plesiops'' and '' Fraudella''. It is restricted to subtropical and temperate rocky and coral reefs in Australian waters. Its species are mostly cryptic, occurring in submarine caves, crevices and under rocky ledges. Species * '' Paraplesiops alisonae'' Hoese and Kuiter, 1984 – Alison's blue devil * '' Paraplesiops bleekeri'' ( Günther, 1861) – eastern blue devil * ''Paraplesiops meleagris'' (Peters, 1869) – southern blue devil * '' Paraplesiops poweri'' Ogilby, 1908 – northern blue devil * '' Paraplesiops sinclairi'' Hutchins, 1987 – western blue devil The western blue devil (''Paraplesiops sinclairi'') is a species of fish in the longfin family Plesiopidae endemic to Western Australia. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soft Coral
Alcyonacea, or soft corals, are an order of corals. In addition to the fleshy soft corals, the order Alcyonacea now contains all species previously known as "gorgonian corals", that produce a more or less hard skeleton, though quite different from "true" corals (Scleractinia). These can be found in suborders Holaxonia, Scleraxonia, and Stolonifera. They are Sessility (zoology), sessile colony (biology), colonial cnidarians that are found throughout the oceans of the world, especially in the deep sea, polar waters, tropics and subtropics. Common names for subsets of this order are sea fans and sea whips; others are similar to the sea pens of related order Pennatulacea. Individual tiny polyp (zoology), polyps form colonies that are normally erect, flattened, branching, and reminiscent of a fan (implement), fan. Others may be whiplike, bushy, or even encrusting. A colony can be several feet high and across, but only a few inches thick. They may be brightly coloured, often purple, r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sponge
Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through them, consisting of jelly-like mesohyl sandwiched between two thin layers of cells. Sponges have unspecialized cells that can transform into other types and that often migrate between the main cell layers and the mesohyl in the process. Sponges do not have nervous, digestive or circulatory systems. Instead, most rely on maintaining a constant water flow through their bodies to obtain food and oxygen and to remove wastes. Sponges were first to branch off the evolutionary tree from the last common ancestor of all animals, making them the sister group of all other animals. Etymology The term ''sponge'' derives from the Ancient Greek word ( 'sponge'). Overview Sponges are similar to other animals in that they are multicellular, he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Algae
Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular microalgae, such as ''Chlorella,'' ''Prototheca'' and the diatoms, to multicellular forms, such as the giant kelp, a large brown alga which may grow up to in length. Most are aquatic and autotrophic (they generate food internally) and lack many of the distinct cell and tissue types, such as stomata, xylem and phloem that are found in land plants. The largest and most complex marine algae are called seaweeds, while the most complex freshwater forms are the ''Charophyta'', a division of green algae which includes, for example, ''Spirogyra'' and stoneworts. No definition of algae is generally accepted. One definition is that algae "have chlorophyll ''a'' as their primary photosynthetic pigment and lack a sterile covering of cells around thei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marine Invertebrate
Marine invertebrates are the invertebrates that live in marine habitats. Invertebrate is a blanket term that includes all animals apart from the vertebrate members of the chordate phylum. Invertebrates lack a vertebral column, and some have evolved a shell or a hard exoskeleton. As on land and in the air, marine invertebrates have a large variety of body plans, and have been categorised into over 30 phyla. They make up most of the macroscopic life in the oceans. Evolution The earliest animals were marine invertebrates, that is, vertebrates came later. Animals are multicellular eukaryotes, and are distinguished from plants, algae, and fungi by lacking cell walls. Marine invertebrates are animals that inhabit a marine environment apart from the vertebrate members of the chordate phylum; invertebrates lack a vertebral column. Some have evolved a shell or a hard exoskeleton. The earliest animals may belong to the genus '' Dickinsonia'', 571 million to 539 million years ago. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benthic Zone
The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "the depths." Organisms living in this zone are called benthos and include microorganisms (e.g., bacteria and fungi) as well as larger invertebrates, such as crustaceans and polychaetes. Organisms here generally live in close relationship with the substrate and many are permanently attached to the bottom. The benthic boundary layer, which includes the bottom layer of water and the uppermost layer of sediment directly influenced by the overlying water, is an integral part of the benthic zone, as it greatly influences the biological activity that takes place there. Examples of contact soil layers include sand bottoms, rocky outcrops, coral, and bay mud. Description Oceans The benthic region of the ocean begins at the shore line (intertida ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limestone
Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms when these minerals precipitate out of water containing dissolved calcium. This can take place through both biological and nonbiological processes, though biological processes, such as the accumulation of corals and shells in the sea, have likely been more important for the last 540 million years. Limestone often contains fossils which provide scientists with information on ancient environments and on the evolution of life. About 20% to 25% of sedimentary rock is carbonate rock, and most of this is limestone. The remaining carbonate rock is mostly dolomite, a closely related rock, which contains a high percentage of the mineral dolomite, . ''Magnesian limestone'' is an obsolete and poorly-defined term used variously for dolomite, for limes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Port Phillip
Port Phillip (Kulin languages, Kulin: ''Narm-Narm'') or Port Phillip Bay is a horsehead-shaped bay#Types, enclosed bay on the central coast of southern Victoria (Australia), Victoria, Australia. The bay opens into the Bass Strait via a short, narrow channel (geography), channel known as The Rip, and is completely surrounded by suburbs and localities (Australia), localities of Victoria's two largest cities — metropolitan Greater Melbourne in the bay's main eastern portion north of the Mornington Peninsula, and the city of Greater Geelong in the much smaller western portion (known as the Corio Bay) north of the Bellarine Peninsula. Geographically, the bay covers and the shore stretches roughly , with the volume of water around . Most of the bay is navigable, although it is extremely shallow for its size — the deepest portion is only and half the bay is shallower than . Its waters and coast are home to Pinniped, seals, whales, dolphins, corals and many kinds of seabirds and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
