Biomass of Eichhornia crassipes, (Mart) Solms. In the Chacororé–Sinhá Mariana, lake System Pantanal of Mato Grosso, Brazil Biomassa de Eichhornia crassipes, (Mart) Solms. no Sistema de Baías Chacororé–Sinhá Mariana, Pantanal of Mato Grosso, Brasil Biomassa de Eichhornia crassipes, (Mart) Solms. en el sitema de lagos Chacororé–Sinhá Mariana, Pantanal of Mato Grosso, Brasil

The Pantanal constitutes the biggest floodplain of the world, forming a mosaic of different habitats, sustaining rich aquatic and terrestrial biota. This mosaic of habitats of the Pantanal is well represented in the Barão de Melgaço region by the Chacororé-Sinhá Mariana Lake System, this system of parental lakes of Cuiabá river are recognized by their aquatic productivity and scenically beauty. The aquatic macrophyte are very abundant organisms being considered the most productive community in the aquatic system, with great capacity of accumulate biomass and nutrients. The samples were collected into three stations representing the Chacororé-Sinhá Mariana lakes and the transition between them. This study had as purpose to evaluate the spatial and temporal dynamic of biomass in E. crassipes in the stands of this specie in Chacororé-Sinhá Mariana “baía” system. The results shown that both lakes shown bigger biomass during flood, and that in transition sample area were verified the bigger biomass of studied areas. This research supports another studies realized in the Pantanal about the importance of the “flood pulse” in the temporal variation of the biomass and shown that the variation of the biomass of E. crassipes in the lakes evidence the spatial heterogeneity which exists between those lakes. In this way the aquatic macrophyte can indicate the impacts resulting of the hydrological changes in this system of lakes.


Introduction
E. crassipes has been cited like a specie with high values of biomass, 8.6 to 24t. ha -1 (Poi de Neiff, 1994), comparison of the biomass of E. crassipes with another species of aquatic macrophytes in the medium Paraná being that this specie shown more than ten times bigger than another species. To Pott and Pott (2000) this specie reaches 200t.ha. year, Da Silva (1990) found 1480g.DW.m 2 in the Pantanal of Mato Grosso.
Limnological studies realized in the water bodies belonging to river-plain systems of flooding has shown a serial of changes arising from the seasonal variation of the water level, like changes in the water transparency, in the pH, electrical conductivity, in the suspended material, in the nutrient concentration and in the biotic community. (Hamilton & Lewis Jr, 1990;Da Silva, 1990;Da Silva & Esteves, 1995;Junk & Da Silva 1995;Da Silva & Figueiredo, 1999;Schessi, 1999, Abdo & Da Silva, 2004, Nunes et al., 2006, Nunes & Da Silva (2009. Before from the seasonal changes caused by the water level variation, aquatic environment into the flooding plain shown spacial limnological variation, because of the macrophyte cover, wind, genesis, drainage standard, diversity of terrestrial environment surrounding the area, between another factor already seen by Nogueira (1989); Panoso (1993); , Da Silva and Figueiredo (1999), Ramachandra et al. (2002), Nunes et al. (2017), Santos et al. (2017) between another.
This study had as objective to analyses the spacial and temporal variation of biomass of E. crassipes into three sample points in the Chacororé-Sinhá Mariana Baía System.

Methodology
To the fields samples were selected three points in the Chacororé-Sinhá Mariana "baía" system, being the first one (point 1) in the Chacororé "baía" located in the 21k 0615537 and 8196165 UTM to 158above sea level. The points 2 and 3 are localized in the Sinhá Mariana "baía" being the point 2 situated in the confluence of this one with the Mutum river, is  Development, v. 10, n. 2, e141029293, 2021 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v10i2.9293 3 To evaluate the biomass, the samples were collected through the "Harvest" method, with squares with 0.25m 2 which were throw randomly in the stands of E. crassipes in which squares were collected all parts of the plants (blade, petiole, rhizome, root, stolon and detritus) till the hands reach (flood season) or till the soil (dry season). In the laboratory was cleaned with current water. Those were packaged into paper bags and carried to heater (Heraeus instruments) under 60ºC degrees and dehydrated till constant weight, when their structures were weighted into analytical scale (Sartorius laboratory), with two houses of precision. After weighted, it was processed the calculation to obtain values of biomass.
The Physical-Chemical variables of water were measured in field, under macrophyte cover, are described in Nunes and Da Silva (2005), Nunes et al. (2020) and Abdo et al (2012).
The data of pluvial precipitation, sunstroke, relative air humidity and evapotranspiration to the period of September of 2000 to August of 2002, were obtained in the Agroclimatic Station Padre Ricardo Remetter from Mato Grosso Federal University located in the Santo Antonio do Leverger town (Lat. 15º 51'S; Long. 56º 04'W; to 140m.a.s.l.) and are described in Nunes and Da Silva (2005).
To statistical analysis of the data were used the program SPSS (Statistical Package for Social Science) ANOVA, Levene, Wilcoxon-Nemenyi-McDonald-Thompson texts. To calculate the biomass supplies total were used the values already calculated to biomass (gDWm 2 ) and multiplicated by the length and width of each stand of E. crassipes, these values were measured during sample collects.

Study área
The research was developed in the Chacororé-Sinhá Mariana Baía System, in the Santo Antônio de Leverger and According to Pinto-Silva (1980) e Nunes et al (2012 the Chacororé lake show turbid water, is a lake with a semicircular shape, situated to 125.20m above sea level and with the following morphometric characteristics: maximum width, 10.18Km, maximum wide, 9.88Km, medium wide, 6.00Km, maximum depth, 4.00m, medium depth, 2.75m, volume, 178.6 x 10 6 m 3 , area, 64.92Km 2 . The Sinhá Mariana "baía" had black water, is formed by an enlargement of the Mutum river with one became linked during all year, and apart from which drain in the Cuiabá River. Was described by Pinto-Silva (1980), like a lake with elongate shape, with the following morphometries characteristics: maximum width, 8.75Km, maximum wide, 2.67Km, medium wide, 1.29Km, maximum depth, 4.75m, medium depth, 3.58m, volume, 40.40 x 10 6 m 3 , area 11.25Km 2 .

Results
The biggest biomass values of E. crassipes were obtained during flood season, following the hydrological cycle,  In Chacororé there was an increase of the biomass of blade and petiole in the high water period, the root shown the bigger biomass in the dry period probably because during this phase the plant is near of the sediment. The rhizome, stolon and detritus almost not showed variation in the biomass between hydrological periods. The structures of E. crassipes which most contributes to the increase of the biomass during high water period were: petiole with 2835.44gDW.m -2 (38.15 %), the blade with 1334.99gDW.m -2 (22.60%) and the root with 1199.97gDW.m -2 that although not showed bigger biomass during flood, showed anyway high biomass values (21.94%) (Figure 3).
In Sinhá Mariana/Mutum, had also an increase of biomass during flood period for petiole (1670.71gDW.m -2 ), blade (786.27gDW.m -2 ). The root and detritus has obtained bigger biomass during dry period respectively, 2149.07gDW.m -2 and 640.72gDW.m -2 due the high rate of decomposition on this period and to the fact of E. crassipes be fixed on the sediment from where passed to obtain nutrients. Rizome and stolon not showed variation for the hydrological period. The structure which were responsible by the increase of the biomass were: root with 2075.12gDW.m -2 (37.23%), petiole with 1670.61gDW.m -2 (31.70 %) and blade with 786.27gDW.m -2 (13.75%) ( Figure 6).
In Sinhá Mariana/Chacororé there was an increase of biomass during flood period for blade and petiole. The root had the inverse way being that the bigger biomass was obtained during dry period, rhizome, stolon and detritus not shown variation. The increase of the biomass during flood period were: petiole with 3254,21gDW.m -2 (44.91%), blade with 1239.60gDW.m -2 (18.08%) and root with 1223.52gDW.m -2 (17.44%). On all samples points the petiole, blade and root shown increase in the biomass in the flood varying only on intensity ( Figure 6). for this stay more elevated in dry period than Chacororé that show only (1547.17gDW.m -2 ) ( Figure 3). If considered the stock of biomass Chacororé possess a very bigger biomass, because all the stands of E. crassipes had a very bigger area on this lake, (Table I) mainly during flood. The biomass stock in Chacororé was for dry of 107.24KgDW for the stand where it was realized the collects (Table I)

Discussion
There was hydric deficiency during flood of the 2001 year not being this considered elevated for this region, because Soriano (1996)  Tarifa (1986) observed in The Pantanal humidity not less than 62% in dry till the 84% during flood those values are very near of the observed on this study, for the same period. The relative air humidity not follow diminish of the temperature which happens after April, this probable due evapotranspiration on those areas.
According Alfonsi and Camargo (1984) the northern region of Pantanal is more warm than south region, the most could month with temperature over 21ºC and the warmest over 27ºC, second Thornhwaite, classification The Pantanal is situated on a megatermic region, the values of evapotranspiration overcome 1.140mm.
On environments when the Flood Pulse is predictable and with long duration, the organisms adapted bringing benefits for their population. Many species reproduce during this period being their seeds overspread by water and fishes (Da Silva 1990;Da Silva & Esteves 1993, Nunes da Cunha & Junk 1996 those adaptations move in direction of efficient use of the resources on the ATTZ-aquatic/terrestrial transition zone, where alternate chronologically aquatic and terrestrial environment, establishing differences into the river-plain system including habitats permanent wetted, permanent lotic (main channel), permanent lentic and wetland (ATTZ).
Da Silva and Esteves (1993)  Sinhá Mariana/Mutum behave like Chacororé and like observed by Da Silva and Esteves (1993) although not in the same sequence root, petiole and blade were responsible by the increase of the biomass.
On all sample points petiole, blade and root shown increase on the biomass during flood being that only the order of increase of each one vary the same was observed by Da Silva and Esteves (1993) for the same specie on two lakes of the.
The increase of the biomass on flood for this specie is related to the increase of the free area for the development of this plant which grow as much by clonal reproduction as much sexual reproduction, increasing the occupied area through horizontal grow, expanding also biomass by unit of area through the development of petioles and blades bigger that is to say vertical grow, follow Da Silva and Esteves (1993) the growing of the cited structures of E. crassipes show the vertical grow of the plant, than it is possible to take a base to say that the bigger rate of vertical growing on the studied area occurs on flood, the grow of rhizome and stolon although in small proportion also indicates the horizontal grow observed on field during flood.
Sinhá Mariana/Chacororé showed the biggest biomass due to be situated on a point of confluence of Chacororé and Sinhá Mariana lakes, from where the water during dry drains to Cuiabá River (during rising water and flood the flux direction of water is inverse) this fact permits that this point receive nutrient as much from Chacororé as much from Sinhá Mariana.
The increase of biomass during flood is related also with the keep of the specie in the system, which reduces their biomass during dry, this behavior was observed by Silva (2002), for the E. crassipes specie. Before that the concentration of nutrients on the studied environment was bigger during the flood like cleared by Nunes and Da Silva (2005).
On the Chacororé-Sinhá Mariana lake system the biggest part of the aquatic macrophyte biomass are exported for the Cuiabá river by the "corixos" that connect this system of lakes to the river, this is easily verified during receding phase when big floating blocks (islands) of different size follow to river direction, carrying part of the biomass accumulated during flood, insects, fishes and birds, this fact also was observed by Da Silva and Esteves (1993), on the Porto de Fora lake in The Pantanal.
The increase of root biomass is due that on Sinhá Mariana the amount of ions dissolved in the water is small than in Chacororé the increase of the root area favor the caption of nutrient, the total biomass accumulated in dry on Sinhá Mariana/Mutum was 1185.43gDW.m -2 and during flood was 1392.74gDW.m -2 being on this way the small biomass accumulated during flood due the stands of E. crassipes being very small on this sample point.
Another fact which contribute for the high concentration of E. crassipes was the grow of ions present in the water during flood mainly in Chacororé and Sinhá Mariana/Chacororé also of geological origins, mainly on Chacororé, as much the decomposition of the terrestrial species now submerged, before still the organic matter carrying of the drainage area for the lake system, add to this fact the high temperature, oxygen concentration and humidity, because it were submerged what helps in a decisive way for decomposition and nutrient liberation (Penha et al., 1998;Villar et al., 2001;Asaeda et al., 2001),carried from riverine wood surrounding the lake system must to contributing to the increase of ion concentration and energy into the system (Guo & Sims 1999).
Studying an oxbow lake Camargo & Esteves (1996), observed that the main factors which control the increase of biomass and nutrient concentration in E. azurea were the flood pulse and the increase of ion into the water.
According Da Silva and Esteves (1993) the growing of E. crassipes during flood can be related to the elevated temperature and small thermal amplitude observed in months which precede the flood, Singh and Sahai (1979) also impute the biomass increase of E. crassipes to the rainy days and to the India, Sabatini (1985), also observed the increase of biomass of  On this way it was verified that the flood pulse develops a very important influence on the increase of biomass of E.
crassipes on the Chacororé-Sinhá Mariana lake system, allied still to the high temperature observed on field and the nutrient on water. Another important factor is that the system of lakes export nutrients for another regions of the Pantanal thorough the "corixos" which links the lake system to the rivers of the region.
Chacororé was the sample point which show biggest stock of biomass of the studied areas, Sinhá Mariana/Mutum show the small stock of biomass for the specie and Sinhá Mariana/Chacororé showed intermediary values.

Conclusion
It was possible to sad that Chacororé pass of less productive during dry to be by far the most productive during flood.
This factor certainty is linked with the bigger concentration of dissolved nutrients into the water of this lake.
Occurs still the death and reduction of the area of these plants with the arrive of receding phase and consequently diminish of the water volume in the lake system, the export of biomass is a factor to be considered.
In synthesis it was verified in this research that the flood pulse carries a direct and indirect influence on the physical and chemical variables and that these go up with the increase of the water column or diminish arising of the same.
In general, the Chacororé Lake showed the biggest values of biomass, Sinhá Mariana/Chacororé (transition zone) showed intermediary values and Sinhá Mariana/Mutum the small values.