000			03569nab a2200445 a 4500
003			AR-ReUNN
005			20260702003054.0
008			260630s2006 ag |||||||||||||||||spa
041	0		_aspa _aeng
100	1		_aBechara, José Alfredo _96469
700	1		_aVarela, Maria Elvira _9144700
700	1		_aBonetto, Argentino a. _977121
245	1	3	_aLa fauna bentónica de lagunas y cursos de agua del sistema Iberá - Corrientes, Argentina - / José A. Bechara, María Elvira Varela, Argentino A. Bonetto
264		1	_c2006
300			_a16 páginas
500			_aEjemplar disponible en estante de INICNE Contiene: Artículo duplicado, disponible en caja 33a no 1 de INICNE
520			_aBenthic fauna from lakes and streams of the Iberá system (Corrientes, Argentina) The taxonomic composition , diversity and abundance of bottom dwelling invertebrates are described for a series of lakes and streams located in an area peculiar for its extensive development of swamps. A preliminary classification of these waterbodies using invertebrates, is proposed. The lakes are surrounded and endroached upon by swampy vegetation forming 'embalsados' ('sudss') which can reduce substantially the open water surface. Submerged vegetation is also often abundant. The lakes are shallow (<3.5 m) and are characterized by highly organic sediments overlying a sandy basement and well oxygenated, acid waters (pH 4.2 to 7.0) of very low conductivity (22 to 49 µm/cm2) and high transparency. The most frequent and abundant taxa collected were Chironomidae, Oligochaeta and Mollusca, which together constituted between 50% and 90% of the macrofauna collected (organisms retained on 500 µm mesh size sieve). The macrofauna was more diverse on sediments in vegetated zones, and the abundance of Chironomidae but not other benthic groups was significantly higher (Wilcoxon test, p<0.05) than in the absence of vegetation. The meiobenthos (organisms retained on 150 µm mesh size sieve) was rich and abundant specially on sandy bottoms covered with little organic matter. Common meiobenthic organisms included nematodes, harpacticoid copepods and testacea protozoan. Samples were ordinated using a principal components analysis and cluster analysis technique. Along the first principal axis, samples follow a N-S geographic gradient, probably related to an increasing development of submerged macrphytes. In the absence of submerged vegetation, the bottom of the largest lakes studied are exposed to wind action, thus permitting the frequent resuspension of sediments and providing little opportunity for the development of a benthic fauna. The second and third axis separate samples which differ in the thickness of organic sediments presented on the sandy basement. The second axis also separates lakes from streams.
650		4	_aIbera _922437
650		4	_aArgentina _94258
650		4	_aWater Analysis _9147427
650		4	_aWater Currents _9147428
650		4	_aCorriente _971642
650		4	_aDistribución Geografica _97085
650		4	_aBenthos _9147135
650		4	_aEcología _94910
650		4	_aCorrientes _94086
650		4	_aLagunas _93932
650		4	_aStatistics _9147429
650		4	_aEstadisticas _97548
650		4	_aAnalisis de Agua _9118428
650		4	_aEcology _9117438
650		4	_aEsteros del Ibera _99237
650		4	_aBentos _9136293
650		4	_aLagoons _9121699
650		4	_aGeographical Distribution _9147031
773	0		_tEcosur _x0325-108X _gv. 16 n. 27 (1990) _w234603
942			_cART
035			_a(INICN)33961
001			234604
999			_c234604 _d234604
040			_aAR-ReUNN _bspa _cAR-ReUNN _eaacr2