The Olifants River, Lepelle , iBhalule or Obalule ( Afrikaans : Olifantsrivier ; Portuguese : Rio dos Elefantes ) is a river in South Africa and Mozambique , a tributary of the Limpopo River . It falls into the Drainage Area B of the Drainage basins of South Africa . The historical area of the Pedi people , Sekhukhuneland , is located between the Olifants River and one of its largest tributaries, the Steelpoort River .
29-532: Loskop Dam is a combined gravity and arch type dam located on the Olifants River , near Groblersdal , Mpumalanga , South Africa . It was established in 1939 and has been renovated in 1979. The dam is situated in the Loskop Dam Nature Reserve and it serves mainly for irrigation purposes. The hazard potential of the dam has been ranked high (3). A popular vacation spot that irrigates the majority of
58-498: A calf there on April 11, 1964, returning the species to the area after its extinction in the Transvaal in 1896. The reserve also features other types of rhinoceros , ostriches , leopard , giraffes , blue wildebeest , zebra , among others. Olifants River (Limpopo) The Olifants River has its origin between Breyten and Bethal , Mpumalanga Province . It flows north towards Limpopo Province through Witbank Dam and then
87-414: A group of photosynthetic, eukaryotic organisms that include species with haplobiontic and diplobiontic life cycles. The diplobiontic species, such as Ulva , follow a reproductive cycle called alternation of generations in which two multicellular forms, haploid and diploid, alternate, and these may or may not be isomorphic (having the same morphology). In haplobiontic species only the haploid generation,
116-463: A multicellular gametophyte. All land plants have a diplobiontic common ancestor, and diplobiontic forms have also evolved independently within Ulvophyceae more than once (as has also occurred in the red and brown algae). Diplobiontic green algae include isomorphic and heteromorphic forms. In isomorphic algae, the morphology is identical in the haploid and diploid generations. In heteromorphic algae,
145-998: A sister of the Zygnematophyceae . Since the realization that the Embryophytes emerged within the green algae, some authors are starting to include them. The completed clade that includes both green algae and embryophytes is monophyletic and is referred to as the clade Viridiplantae and as the kingdom Plantae . The green algae include unicellular and colonial flagellates , most with two flagella per cell, as well as various colonial, coccoid (spherical), and filamentous forms, and macroscopic, multicellular seaweeds . There are about 22,000 species of green algae, many of which live most of their lives as single cells, while other species form coenobia (colonies), long filaments, or highly differentiated macroscopic seaweeds. A few other organisms rely on green algae to conduct photosynthesis for them. The chloroplasts in dinoflagellates of
174-674: A slight increase in nitrates could initiate eutrophication . Very high sulphate levels were attributed to coal mining and industry in the upper catchment. The Olifants River's largest tributaries are the Letaba River and the Steelpoort River known as Tubatse River. Other tributaries are the Tongwane , Blyde , Moses , Spekboom , Timbavati , Nkumpi , Ga-Selati , Klaserie , Makhutswi , Mohlapitse River , Lepellane River , Mohwetse River and Ngwaritsi River. Some tributaries, notably
203-519: A smaller scale. On March 6, 1940, the Transvaal Provincial Council established a nature reserve in the area, a popular angling spot for Mozambique tilapia , redbreast tilapia , yellowfish , carp , mudfish , and eel . Boasting a modern RV park and extensive recreational facilities, the reserve covers 12,700 ha. Large game has been bred there since 1948 - indeed, a breeding pair of white rhinoceros were brought there in 1963 to bear
232-468: Is a unicellular, isogamous charophycean alga group that is the closest unicellular relative to land plants. Heterothallic strains of different mating type can conjugate to form zygospores . Sex pheromones termed protoplast-release inducing proteins (glycopolypeptides) produced by mating-type (-) and mating-type (+) cells facilitate this process. The green algae, including the characean algae, have served as model experimental organisms to understand
261-433: The (green) plants (with chloroplasts ) the red algae (with rhodoplasts) and the glaucophytes (with muroplasts). Green algae are often classified with their embryophyte descendants in the green plant clade Viridiplantae (or Chlorobionta ). Viridiplantae, together with red algae and glaucophyte algae, form the supergroup Primoplantae, also known as Archaeplastida or Plantae sensu lato . The ancestral green alga
290-664: The Bushveld , the Loskop Dam was first proposed in 1905 and started as a private cooperative scheme by landowners along the Olifants in 1930, but officially only endorsed by the government in 1934. In 1939, the project was completed under the auspices of the Department of Irrigation (today's Department of Environmental Affairs ) at a cost of R5 million, employing among others Willem J. Grobler, on whose Klipbank Farm his namesake town of Groblersdal
319-606: The Indian Ocean at Xai-Xai north of Maputo . Overgrazing in sections of its middle course result in the river carrying away eroded soil after heavy rains. The Olifants river has become one of the most heavily polluted rivers in South Africa, not by human or industrial waste, but by thriving green algae . A 2013 study in the Kruger Park found that the river was mesotrophic, meaning that nutrient levels were fairly low, though
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#1732872357648348-789: The Klein Olifants River (origin near Hendrina , joins the Olifants River downstream of the Middelburg Dam ), the Elands , Wilge and the Bronkhorstspruit , rise in the Highveld grasslands. The Shingwedzi River flows close to the northeastern side of the Massingir Dam reservoir and joins the left bank of the Olifants about 12 km downstream from the dam wall. Thirty large dams in
377-863: The Loskop Dam and is forced east by the Transvaal Drakensberg , cutting through at the Abel Erasmus Pass and then flowing east further across the Lowveld to join with the Letaba River . It crosses into Gaza Province , Mozambique , after cutting through the Lebombo Mountains by way of the Olifants Gorge, becoming the Rio dos Elefantes , and finally joining the Limpopo River after 40 km before it enters
406-497: The gametophyte is multicellular. The fertilized egg cell, the diploid zygote , undergoes meiosis , giving rise to haploid cells which will become new gametophytes. The diplobiontic forms, which evolved from haplobiontic ancestors, have both a multicellular haploid generation and a multicellular diploid generation. Here the zygote divides repeatedly by mitosis and grows into a multicellular diploid sporophyte . The sporophyte produces haploid spores by meiosis that germinate to produce
435-502: The supralittoral zone , is terrestrial and can in the Antarctic form large carpets on humid soil, especially near bird colonies. Green algae have chloroplasts that contain chlorophyll a and b , giving them a bright green colour, as well as the accessory pigments beta carotene (red-orange) and xanthophylls (yellow) in stacked thylakoids . The cell walls of green algae usually contain cellulose , and they store carbohydrate in
464-708: The Mesostigmatophyceae, Chlorokybophyceae and spirotaenia are only more conventionally basal Streptophytes. The algae of this paraphyletic group "Charophyta" were previously included in Chlorophyta, so green algae and Chlorophyta in this definition were synonyms. As the green algae clades get further resolved, the embryophytes, which are a deep charophyte branch, are included in " algae ", "green algae" and " Charophytes ", or these terms are replaced by cladistic terminology such as Archaeplastida , Plantae / Viridiplantae , and streptophytes , respectively. Green algae are
493-579: The Olifants River Catchment include the following: Green algae The green algae ( sg. : green alga ) are a group of chlorophyll -containing autotrophic eukaryotes consisting of the phylum Prasinodermophyta and its unnamed sister group that contains the Chlorophyta and Charophyta / Streptophyta . The land plants ( Embryophytes ) have emerged deep in the Charophyte alga as
522-413: The class Chlorophyceae undergo closed mitosis in the most common form of cell division among the green algae, which occurs via a phycoplast . By contrast, charophyte green algae and land plants (embryophytes) undergo open mitosis without centrioles . Instead, a 'raft' of microtubules, the phragmoplast , is formed from the mitotic spindle and cell division involves the use of this phragmoplast in
551-427: The form of starch . All green algae have mitochondria with flat cristae . When present, paired flagella are used to move the cell. They are anchored by a cross-shaped system of microtubules and fibrous strands. Flagella are only present in the motile male gametes of charophytes bryophytes, pteridophytes, cycads and Ginkgo , but are absent from the gametes of Pinophyta and flowering plants . Members of
580-435: The fungal species that partner in lichens cannot live on their own, while the algal species is often found living in nature without the fungus. Trentepohlia is a filamentous green alga that can live independently on humid soil, rocks or tree bark or form the photosymbiont in lichens of the family Graphidaceae . Also the macroalga Prasiola calophylla (Trebouxiophyceae) is terrestrial, and Prasiola crispa , which live in
609-580: The genus Lepidodinium , euglenids and chlorarachniophytes were acquired from ingested endosymbiont green algae, and in the latter retain a nucleomorph (vestigial nucleus). Green algae are also found symbiotically in the ciliate Paramecium , and in Hydra viridissima and in flatworms . Some species of green algae, particularly of genera Trebouxia of the class Trebouxiophyceae and Trentepohlia (class Ulvophyceae ), can be found in symbiotic associations with fungi to form lichens . In general
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#1732872357648638-402: The heat of late summer. As their environment dries out, asexual V. carteri quickly die. However, they are able to escape death by switching, shortly before drying is complete, to the sexual phase of their life cycle that leads to production of dormant desiccation-resistant zygotes . Sexual development is initiated by a glycoprotein pheromone (Hallmann et al., 1998). This pheromone is one of
667-511: The light microscope. This process is called conjugation and occurs for example in Spirogyra . Sex pheromone production is likely a common feature of green algae, although only studied in detail in a few model organisms. Volvox is a genus of chlorophytes . Different species form spherical colonies of up to 50,000 cells. One well-studied species, Volvox carteri (2,000 – 6,000 cells) occupies temporary pools of water that tend to dry out in
696-587: The morphology and size are different in the gametophyte and sporophyte. Reproduction varies from fusion of identical cells ( isogamy ) to fertilization of a large non-motile cell by a smaller motile one ( oogamy ). However, these traits show some variation, most notably among the basal green algae called prasinophytes . Haploid algal cells (containing only one copy of their DNA) can fuse with other haploid cells to form diploid zygotes. When filamentous algae do this, they form bridges between cells, and leave empty cell walls behind that can be easily distinguished under
725-417: The most potent known biological effector molecules. It can trigger sexual development at concentrations as low as 10 M. Kirk and Kirk showed that sex-inducing pheromone production can be triggered experimentally in somatic cells by heat shock . Thus heat shock may be a condition that ordinarily triggers sex-inducing pheromone in nature. The Closterium peracerosum-strigosum-littorale (C. psl) complex
754-413: The production of a cell plate . Photosynthetic eukaryotes originated following a primary endosymbiotic event, where a heterotrophic eukaryotic cell engulfed a photosynthetic cyanobacterium -like prokaryote that became stably integrated and eventually evolved into a membrane-bound organelle : the plastid . This primary endosymbiosis event gave rise to three autotrophic clades with primary plastids:
783-427: The walls that divert floodwaters into colliding streams called "heavy rain" with less destructive potential. 650 farms covering around 25.7 ha each use the water, including a small proportion originally reserved for the elderly and disabled. The subtropical climate supports the growth of many crops, but summer tobacco and cotton and winter wheat are the main standbys, as well as table grapes and vegetables on
812-963: Was a unicellular flagellate. The Viridiplantae diverged into two clades. The Chlorophyta include the early diverging prasinophyte lineages and the core Chlorophyta, which contain the majority of described species of green algae. The Streptophyta include charophytes and land plants. Below is a consensus reconstruction of green algal relationships, mainly based on molecular data. Palmophyllophyceae (prasinophyte clade VI) Prasinodermophyceae Ulvophyceae Chlorophyceae Trebouxiophyceae Chlorodendrophyceae Pedinophyceae Prasinophytes Clade VIIA Prasinophytes Clade VIIC Pycnococcaceae Nephroselmidophyceae Mamiellophyceae Pyramimonadales Mesostigmatophyceae Spirotaenia Chlorokybophyceae Streptofilum Klebsormidiophyceae Charophyceae Coleochaetophyceae Zygnematophyceae Mesotaeniaceae s.s. Embryophyta (land plants) The basal character of
841-446: Was founded in 1938 as the canal network's hub. The scheme stretches 64 km to the north of this town, including 148 km on 2 main pipes and 330 km of branch lines irrigating 19,000 ha; 250 km of drainage canals return excess water from farm to river. Most Loskop farms use sprinklers , but a growing portion use central pivot irrigation . An innovative feature of the dam is the use of "breakers," 6-m-high structures above
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