{"id":5238,"date":"2020-01-02T07:36:00","date_gmt":"2020-01-02T10:36:00","guid":{"rendered":"https:\/\/gia.org.br\/portal\/?p=5238"},"modified":"2021-04-20T11:16:08","modified_gmt":"2021-04-20T14:16:08","slug":"elementor-5238","status":"publish","type":"post","link":"https:\/\/gia.org.br\/portal\/elementor-5238\/","title":{"rendered":"Didymosphenia geminata: A\u00e7\u00e3o incrustante em usinas hidrel\u00e9tricas de energia."},"content":{"rendered":"\t\t
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Por Ra\u00edssa Leite<\/strong><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Didymosphenia geminata<\/em><\/strong>: A\u00e7\u00e3o incrustante em usinas hidrel\u00e9tricas de energia.<\/strong><\/p>

idymosphenia geminata<\/em>, popularmente conhecida como didymo, \u00e9 uma diatom\u00e1cea caracter\u00edstica de \u00e1guas temperadas do hemisf\u00e9rio Norte (Cleve, 1894; Kociolek et al.<\/em>, 2004). Por\u00e9m, nos \u00faltimos anos a esp\u00e9cie passou a expandir sua distribui\u00e7\u00e3o em ritmo acelerado (Spaulding e Elwell, 2007). De acordo com Kilroy (2004), a didymo foi reportada pela primeira vez na Nova Zel\u00e2ndia em 2004. J\u00e1 na Am\u00e9rica do Sul, a esp\u00e9cie foi observada pela primeira vez nas \u00e1guas chilenas da Patag\u00f4nia em 2010 (Segura, 2011) e cinco meses depois na Argentina, no rio Futaleuf\u00fa por Sastre et al.<\/em> (2013). Essa esp\u00e9cie, assim como outras esp\u00e9cies de diatomaceas, utiliza uma estrutura peduncular para se fixar em equipamentos de pesca, de recrea\u00e7\u00e3o e at\u00e9 em cal\u00e7ados (Kilroy, 2004; Bothwell et al.<\/em>, 2009) e em outros organismos, incluindo aves e peixes (Sastre et al.<\/em>, 2013), o que facilita a sua dispers\u00e3o. Essas diatom\u00e1ceas se reproduzem por divis\u00e3o bin\u00e1ria. As fr\u00fastulas (parede celular externa) se dividem, originando assim as c\u00e9lulas filhas, facilitando a dispers\u00e3o das esp\u00e9cies em ambientes aqu\u00e1ticos (Kawecka e Sanecki, 2003; Perkins et al.<\/em>, 2009).<\/p>

As incrusta\u00e7\u00f5es formadas por D. geminata <\/em>ocorrem a partir da produ\u00e7\u00e3o de mucilagem, uma subst\u00e2ncia polim\u00e9rica extracelular (EPS) de colora\u00e7\u00e3o marrom (Thompson et al.<\/em>, 2008; Ravizza, 2015), que auxilia no crescimento e na sobreviv\u00eancia das mesmas devido ao grande acumulo de mat\u00e9ria org\u00e2nica (Andrewartha et al.<\/em>, 2007) (Figura 1).\u00a0<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Figura 1. Aglomera\u00e7\u00e3o de Didymosphenia geminata encontrada em leito de rio. Fonte: ourenvironment.ac.nz\/2018\/07\/25\/didymosphenia-geminata-in-new-zealands ecosystems\/<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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A estrutura peduncular, em conjunto com a mucilagem, possibilita a fixa\u00e7\u00e3o dos organismos mesmo em substratos sujeitos \u00e0 fluxos elevados de \u00e1gua (Callow, 1993; Wetherbee\u00a0et al.<\/em>, 1998). Perkins\u00a0et al.<\/em>\u00a0(2010) identificaram esses ped\u00fanculos nas paredes de concreto do principal canal que transporta a \u00e1gua at\u00e9 a central geradora de energia da UHE de Tarraleah, Tasm\u00e2nia. Segundo Kirkwood\u00a0et al.<\/em>\u00a0(2007), os ped\u00fanculos permanecem fixados ao substrato mesmo ap\u00f3s a morte das c\u00e9lulas que os produzem. As bioincrusta\u00e7\u00f5es ocasionadas pelas diatom\u00e1ceas presentes nos 20 km dos hidrocanais chegaram, segundo estimativas dos autores, a 17,6 toneladas (peso seco) (Perkins\u00a0et al.<\/em>, 2009), sendo capaz de causar redu\u00e7\u00e3o na velocidade de fluxo de \u00e1gua (Andrewartha\u00a0et al.<\/em>, 2010) e, consequentemente, afetando a gera\u00e7\u00e3o de energia. Estudo realizado por Ravizza (2015), utilizando tubos de metais que simulavam os sistemas hidr\u00e1ulicos de uma UHE, constatou\u00a0 que, ainda que em menores quantidades que as observadas em canais abertos, as diatom\u00e1ceas incrustantes s\u00e3o capazes de se desenvolver mesmo em locais onde n\u00e3o h\u00e1 incid\u00eancia luminosa.<\/p>

Em um experimento realizado por Larned\u00a0et al.<\/em>\u00a0(2011) com\u00a0D. geminata<\/em>, os autores observaram que as esp\u00e9cies, em concentra\u00e7\u00f5es reduzidas de luz e oxig\u00eanio, adotaram um metabolismo heterotr\u00f3fico. Qing\u00a0et al.<\/em>\u00a0(2003) e Tuchman\u00a0et al.<\/em>\u00a0(2006) relataram que sob condi\u00e7\u00f5es de luz limitada, muitas diatom\u00e1ceas poderiam entrar em um estado latente ou desencadear o desenvolvimento de um metabolismo heterotr\u00f3fico. Essas esp\u00e9cies de \u00e1gua doce, segundo Tuchman\u00a0et al.<\/em>\u00a0(2006), podem metabolizar eficientemente at\u00e9 mesmo na aus\u00eancia de luz, mas s\u00f3 usam estes mecanismos em condi\u00e7\u00f5es extremas.<\/p>

Refer\u00eancia<\/strong><\/p>

ANDREWARTHA, J.\u00a0 et al. Drag force and surface roughness measurements on freshwater biofouled surfaces.\u00a0Biofouling,\u00a0<\/strong>v. 26, n. 4, p. 487-496,\u00a0 2010. ISSN 0892-7014.\u00a0<\/p>

ANDREWARTHA, J.; SARGISON, J.; PERKINS, K. The effect of gomphonema and filamentous algae streamers on hydroelectric canal capacity and turbulent boundary layer structure. Australasian Fluid Mechanics Conference, 2007,\u00a0\u00a0 Citeseer. p.241-246.<\/p>

BOTHWELL, M.\u00a0 et al. Blooms of Didymosphenia geminata in rivers on Vancouver Island 1990 to present: a new invasive species. Journal of Phycology, 2009,\u00a0\u00a0 WILEY-BLACKWELL PUBLISHING, INC COMMERCE PLACE, 350 MAIN ST, MALDEN 02148\u00a0\u2026. p.33-33.<\/p>

CALLOW, M. E. A review of fouling in freshwaters.\u00a0Biofouling,\u00a0<\/strong>v. 7, n. 4, p. 313-327,\u00a0 1993. ISSN 0892-7014.\u00a0<\/p>

CLEVE, P. T.\u00a0Synopsis of the naviculoid diatoms<\/strong>.\u00a0\u00a0 PA Norstedt & s\u00f6ner, 1894.<\/p>

KAWECKA, B.; SANECKI, J. Didymosphenia geminata in running waters of southern Poland\u2013symptoms of change in water quality?\u00a0Hydrobiologia,\u00a0<\/strong>v. 495, n. 1-3, p. 193-201,\u00a0 2003. ISSN 0018-8158.\u00a0<\/p>

KILROY, C. A new alien diatom, Didymosphenia geminata (Lyngbye) Schmidt: its biology, distribution, effects and potential risks for New Zealand fresh waters.\u00a0NIWA, CHC2004-128, Christchurch, New Zealand<\/strong>,\u00a0 2004.\u00a0\u00a0<\/p>

KIRKWOOD, A. E.\u00a0 et al. Didymosphenia geminata in two Alberta headwater rivers: an emerging invasive species that challenges conventional views on algal bloom development.\u00a0Canadian Journal of Fisheries and Aquatic Sciences,\u00a0<\/strong>v. 64, n. 12, p. 1703-1709,\u00a0 2007. ISSN 0706-652X.\u00a0<\/p>

KOCIOLEK, J. P.\u00a0 et al. New Gomphonema (Bacillariophyta) species from Tasmania.\u00a0Phycologia,\u00a0<\/strong>v. 43, n. 4, p. 427-444,\u00a0 2004. ISSN 0031-8884.\u00a0<\/p>

LARNED, S. T.\u00a0 et al. Interactions between the mat\u2010forming alga Didymosphenia geminata and its hydrodynamic environment.\u00a0Limnology and Oceanography: Fluids and Environments,\u00a0<\/strong>v. 1, n. 1, p. 4-22,\u00a0 2011. ISSN 2157-3689.\u00a0<\/p>

PERKINS, K.; SARGISON, J.; HALLEGRAEFF, G. DIATOM FOULING PROBLEMS IN A TASMANIAN HYDRO CANAL, INCLUDING THE DESCRIPTION OF GOMPHONEMA TARRALEAHAE SP. NOV.\u00a0Diatom Research,\u00a0<\/strong>v. 24, n. 2, p. 377-391,\u00a0 2009. ISSN 0269-249X.\u00a0<\/p>

PERKINS, K. J.\u00a0 et al. Succession and physiological health of freshwater microalgal fouling in a Tasmanian hydropower canal.\u00a0Biofouling,\u00a0<\/strong>v. 26, n. 6, p. 637-644,\u00a0 2010. ISSN 0892-7014.\u00a0<\/p>

QING, Z.; GRADINGER, R.; QINGSONG, Z. Competition within the marine microalgae over the polar dark period in the Greenland Sea of high Arctic.\u00a0\u6d77\u6d0b\u5b66<\/strong>\u62a5 (<\/strong>\u4e2d\u6587\u7248)<\/strong>, n. 2, p. 233-242,\u00a0 2003.\u00a0\u00a0<\/p>

RAVIZZA, M.\u00a0Stalk forming fouling diatoms: a problem for the hydro-electricity industry<\/strong>. 2015.\u00a0\u00a0 University of Tasmania<\/p>

SASTRE, A. V.\u00a0 et al. First record of the invasive diatom Didymosphenia geminata (Lyngbye) Schmidt in a Patagonian Andean river of Argentina.\u00a0 2013. ISSN 2242-1300.\u00a0<\/p>

SEGURA, P.\u00a0A slimy invader blooms in the rivers of Patagonia<\/strong>: American Association for the Advancement of Science 2011.<\/p>

SPAULDING, S.; ELWELL, L. Increase in nuisance blooms and geographic expansion of the freshwater diatom Didymosphenia geminata: recommendations for response.\u00a0White Paper. USEPA Region,\u00a0<\/strong>v. 8,\u00a0 2007.\u00a0\u00a0<\/p>

THOMPSON, S. E.\u00a0 et al. THE ROLE OF NITRIC OXIDE IN DIATOM ADHESION IN RELATION TO SUBSTRATUM PROPERTIES 1.\u00a0Journal of phycology,\u00a0<\/strong>v. 44, n. 4, p. 967-976,\u00a0 2008. ISSN 0022-3646.\u00a0<\/p>

TUCHMAN, N. C.\u00a0 et al. Differential heterotrophic utilization of organic compounds by diatoms and bacteria under light and dark conditions. In: (Ed.).\u00a0Advances in Algal Biology: A Commemoration of the Work of Rex Lowe<\/strong>: Springer, 2006.\u00a0 p.167-177.\u00a0<\/p>

WETHERBEE, R.\u00a0 et al. Minireview\u2014the first kiss: establishment and control of initial adhesion by raphid diatoms.\u00a0Journal of Phycology,\u00a0<\/strong>v. 34, n. 1, p. 9-15,\u00a0 1998. ISSN 0022-3646.\u00a0<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"

Por Ra\u00edssa Leite Didymosphenia geminata: A\u00e7\u00e3o incrustante em usinas hidrel\u00e9tricas de energia. idymosphenia geminata, popularmente conhecida como didymo, \u00e9 uma diatom\u00e1cea caracter\u00edstica de \u00e1guas temperadas do hemisf\u00e9rio Norte (Cleve, 1894; Kociolek et al., 2004). Por\u00e9m, nos \u00faltimos anos a esp\u00e9cie passou a expandir sua distribui\u00e7\u00e3o em ritmo acelerado (Spaulding e Elwell, 2007). De acordo com […]<\/p>\n","protected":false},"author":5,"featured_media":5243,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jnews-multi-image_gallery":[],"jnews_single_post":[],"jnews_primary_category":[],"footnotes":""},"categories":[258],"tags":[],"class_list":["post-5238","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-divulgacao-cientifica"],"_links":{"self":[{"href":"https:\/\/gia.org.br\/portal\/wp-json\/wp\/v2\/posts\/5238","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gia.org.br\/portal\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/gia.org.br\/portal\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/gia.org.br\/portal\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/gia.org.br\/portal\/wp-json\/wp\/v2\/comments?post=5238"}],"version-history":[{"count":0,"href":"https:\/\/gia.org.br\/portal\/wp-json\/wp\/v2\/posts\/5238\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/gia.org.br\/portal\/wp-json\/wp\/v2\/media\/5243"}],"wp:attachment":[{"href":"https:\/\/gia.org.br\/portal\/wp-json\/wp\/v2\/media?parent=5238"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gia.org.br\/portal\/wp-json\/wp\/v2\/categories?post=5238"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gia.org.br\/portal\/wp-json\/wp\/v2\/tags?post=5238"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}