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Pediastrum Conchense
''Pediastrum'' is a genus of green algae, in the family Hydrodictyaceae. It is a photoautotrophic, nonmotile coenobial (fixed number of cells) green algae that inhabits freshwater environments. Morphology ''Pediastrum'' is a genus usually look like a green star in the pond or lake. They are coenobial green algae composed of 22 to 27 cells, which are orderly arranged in a circular, flat disk. The diameter of a single coenobium can range from 20 to 80 μm, so they belong to the group of microalgae. Cells in ''Pediastrum'' can be divided into interior cells and peripheral cells by position in the coenobium or their shapes. Some of the species have intracellular cell spaces between interior cells, while some would closely aggregate together. The peripheral cells surround outside the interior cells, and they usually possess bristles, V-liked cutting edges, or wavy projections. Phylogeny The genus of ''Pediastrum'' belongs to the Hydrodictyaceae family, along with '' Psuedopediast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pediastrum Duplex
''Pediastrum duplex'' is a species of fresh water green algae in the genus ''Pediastrum ''Pediastrum'' is a genus of green algae, in the family Hydrodictyaceae. It is a photoautotrophic, nonmotile coenobial (fixed number of cells) green algae that inhabits freshwater environments. Morphology ''Pediastrum'' is a genus usually lo ...''. They form nonmotile coenobia (colonies) with a fixed number of cells. These coenobia are flat and have a circular shape. The cell bodies are polygonal, are granulated and have horn-like projections. They reproduce these autocolonies asexually. The colonies usually contain 8 to 32 cells, with examples of 4, 64 or 128 occurring rarely. Infraspecies ''Pediastrum duplex brachylobum'' ''Pediastrum duplex clathratum'' ''Pediastrum duplex cohaerens'' ''Pediastrum duplex duplex'' ''Pediastrum duplex'' f. ''denticulatum'' Isabella & R.J. Patel ''Pediastrum duplex gracillimum'' ''Pediastrum duplex regulosum'' ''Pediastrum duplex reticulatum'' ''Pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coenobium (morphology)
Coenobium or coenobia may refer to : * Cenobitic monasticism Cenobitic (or coenobitic) monasticism is a monastic tradition that stresses community life. Often in the West the community belongs to a religious order, and the life of the cenobitic monk is regulated by a religious rule, a collection of prece ... (Cenobium, Cenobite), a monastic community in a tradition stressing communal life, as opposite to eremitism * Coenobium (morphology), a colony of cells, notably in algae * ''Coenobia'' (moth) {{dab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zoospore
A zoospore is a motile asexual spore that uses a flagellum for locomotion. Also called a swarm spore, these spores are created by some protists, bacteria, and fungi to propagate themselves. Diversity Flagella types Zoospores may possess one or more distinct types of flagella - tinsel or "decorated", and whiplash, in various combinations. *Tinsellated (straminipilous) flagella have lateral filaments known as mastigonemes perpendicular to their main axis, which allow for more surface area, and disturbance of the medium, giving them the property of a rudder, that is, used for steering. *Whiplash flagella are straight, to power the zoospore through its medium. Also, the "default" zoospore only has the propelling, whiplash flagella. Both tinsel and whiplash flagella beat in a sinusoidal wave pattern, but when both are present, the tinsel beats in the opposite direction of the whiplash, to give two axes of control of motility. Morphological types In eukaryotes, the four main types ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleolimnology
Paleolimnology (from Greek: παλαιός, ''palaios'', "ancient", λίμνη, ''limne'', "lake", and λόγος, ''logos'', "study") is a scientific sub-discipline closely related to both limnology and paleoecology. Paleolimnological studies focus on reconstructing the past environments of inland waters (e.g., lakes and streams) using the geologic record, especially with regard to events such as climatic change, eutrophication, acidification, and internal ontogenic processes. Paleolimnological studies are mostly conducted using analyses of the physical, chemical, and mineralogical properties of sediments, or of biological records such as fossil pollen, diatoms, or chironomids. History Lake ontogeny Most early paleolimnological studies focused on the biological productivity of lakes, and the role of internal lake processes in lake development. Although Einar Naumann had speculated that the productivity of lakes should gradually decrease due to leaching of catchment soils, Augus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleoecology
Paleoecology (also spelled palaeoecology) is the study of interactions between organisms and/or interactions between organisms and their environments across geologic timescales. As a discipline, paleoecology interacts with, depends on and informs a variety of fields including paleontology, ecology, climatology and biology. Paleoecology emerged from the field of paleontology in the 1950s, though paleontologists have conducted paleoecological studies since the creation of paleontology in the 1700s and 1800s. Combining the investigative approach of searching for fossils with the theoretical approach of Charles Darwin and Alexander von Humboldt, paleoecology began as paleontologists began examining both the ancient organisms they discovered and the reconstructed environments in which they lived. Visual depictions of past marine and terrestrial communities have been considered an early form of paleoecology. Overview of paleoecological approaches * Classic paleoecology uses data from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bioindicator
A bioindicator is any species (an indicator species) or group of species whose function, population, or status can reveal the qualitative status of the environment. The most common indicator species are animals. For example, copepods and other small water crustaceans that are present in many water bodies can be monitored for changes (biochemical, physiological, or behavioural) that may indicate a problem within their ecosystem. Bioindicators can tell us about the cumulative effects of different pollutants in the ecosystem and about how long a problem may have been present, which physical and chemical testing cannot. A biological monitor or biomonitor is an organism that provides quantitative information on the quality of the environment around it. Therefore, a good biomonitor will indicate the presence of the pollutant and can also be used in an attempt to provide additional information about the amount and intensity of the exposure. A biological indicator is also the name given ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quaternary
The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ago to the present. The Quaternary Period is divided into two epochs: the Pleistocene (2.58 million years ago to 11.7 thousand years ago) and the Holocene (11.7 thousand years ago to today, although a third epoch, the Anthropocene, has been proposed but is not yet officially recognised by the ICS). The Quaternary Period is typically defined by the cyclic growth and decay of continental ice sheets related to the Milankovitch cycles and the associated climate and environmental changes that they caused. Research history In 1759 Giovanni Arduino proposed that the geological strata of northern Italy could be divided into four successive formations or "orders" ( it, quattro ordini). The term "quaternary" was introduced by Jules Desnoye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin ''creta'', "chalk", which is abundant in the latter half of the period. It is usually abbreviated K, for its German translation ''Kreide''. The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now- extinct marine reptiles, ammonites, and rudists, while dinosaurs continued to dominate on land. The world was ice free, and forests extended to the poles. During this time, new groups of mammals and birds appeared. During the Early Cretaceous, flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Earth b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diagenesis
Diagenesis () is the process that describes physical and chemical changes in sediments first caused by water-rock interactions, microbial activity, and compaction after their deposition. Increased pressure and temperature only start to play a role as sediments become buried much deeper in the Earth's crust. In the early stages, the transformation of poorly consolidated sediments into sedimentary rock (lithification) is simply accompanied by a reduction in porosity and water expulsion (clay sediments), while their main mineralogical assemblages remain unaltered. As the rock is carried deeper by further deposition above, its organic content is progressively transformed into kerogens and bitumens. The process of diagenesis excludes surface alteration (weathering) and deep metamorphism. There is no sharp boundary between diagenesis and metamorphism, but the latter occurs at higher temperatures and pressures. Hydrothermal solutions, meteoric groundwater, rock porosity, permeability, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stauridium
''Stauridium'' is a genus of green algae in the family Hydrodictyaceae.See the NCBI The National Center for Biotechnology Information (NCBI) is part of the United States National Library of Medicine (NLM), a branch of the National Institutes of Health (NIH). It is approved and funded by the government of the United States. The ...br>webpage on Stauridium Data extracted from the References External links Sphaeropleales genera Sphaeropleales {{Chlorophyceae-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monactinus
''Monactinus'' is a genus of green algae in the family Hydrodictyaceae.See the NCBI The National Center for Biotechnology Information (NCBI) is part of the United States National Library of Medicine (NLM), a branch of the National Institutes of Health (NIH). It is approved and funded by the government of the United States. The ...br>webpage on Monactinus Data extracted from the References External links Sphaeropleales genera Sphaeropleales {{Chlorophyceae-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water Net
The water net (genus ''Hydrodictyon'') is a taxon of freshwater green algae in the family Hydrodictyaceae. ''Hydrodictyon'' does well in clean, eutrophic water, and has become a nuisance in New Zealand, where it has been recently introduced. The name ''water net'' comes from the (usually pentagonal or hexagonal) mesh structure of their colonies, which can extend several decimeters. Reproduction in hydrodictyon Algae in the genus can reproduce asexually or sexually. Asexual reproduction takes place by biflagellated (having two flagella) zoospores formed by the thousands inside a cell. However, the zoospores hardly move, as they are packed very densely. The zoospores form a cell wall, become cylindrical in shape, and arrange themselves in a hexagonal pattern, much like the mature tissue. The mother cell disintegrates, releasing the microscopic daughter net. During sexual reproduction, which takes place by iso-gametes (gametes of the same size) even smaller than the zoospores, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
