Bacteria and phytoplankton production rates in eight river stretches of the middle Rio Doce hidrographic basin (southeast Brazil)

Petrucio, Maurício Mello; Barbosa, Francisco A. R.; Thomaz, Sidinei Magela

doi:10.1590/s1516-89132005000300019

Cited by 8 publications

(4 citation statements)

References 17 publications

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“…However, they are in the same magnitude that those measured by Petrucio et al (2005) and Petrucio and Barbosa (2004) in rivers and lakes, respectively, in the middle Rio Doce basin and by Erikson, Vammen, Zelaya, and Bell (1999) in the tropical Lake Xolotla´n (Nicaragua).…”

Section: Article In Presssupporting

confidence: 65%

Bacterioplankton and phytoplankton production in seven lakes in the Middle Rio Doce basin, south-east Brazil

Petrucio

Furtado

2006

Limnologica

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The purpose of this study was to measure the phytoplankton production (PP) and bacterial production (BP) simultaneously in seven lakes in the middle Rio Doce basin (southeast Brazil) during the dry and the rainy seasons. Limnological monitoring was conducted from 1999 to 2001 as well as both PP (radioactive carbon fixation) and BP ( 3 H-Leucine incorporation) in four specific depths (100%, 10%, 1% of incident radiation, and aphotic zone). Furthermore, trophic state of the lakes was analyzed, considering the index proposed by Salas and Martino (1991) and Carlson (1977). In general, some parameters increased during the rainy season such as pH, conductivity, chlorophyll and total nitrogen. In the period of 1999/2000, the rain caused PP reduction in the lakes, excepting Carioca and Á guas Claras Lake, but in the years 2000/2001, the lakes did not show a similar pattern. In contrast, the rainy season of both years caused an expressive bacterioplankton production enhancing. Using Salas and Martino index, we observed that some lakes were affected by the seasonal runoff, therefore the typologie of these lakes changed from oligotrophic to mesotrophic conditions, otherwise considering the Carlson index all lakes were classified as eutrophic in both dry and rainy seasons. Indeed, Salas and Martino index demonstrated to be more appropriate to determine the trophic status of the lakes. Finally, our data indicate that until now, in spite of the lakes location, protected and unprotected area, the lakes still maintain their natural characteristics.

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Section: Article In Presssupporting

confidence: 65%

Bacterioplankton and phytoplankton production in seven lakes in the Middle Rio Doce basin, south-east Brazil

Petrucio

Furtado

2006

Limnologica

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“…The total solid substances which enter in the Pitimbu-Jiqui system, from the draining of adjacent lands and antropic activities (Oliveira, 1994;Guimarães-Segundo, 2002) can be important in aiding bacterial growth. In points with low phytoplanktonic biomass, as is the case of this system, the dissolved organic carbon of non-algal origin becomes the biggest power plant for bacteria (del Giorgio and Gasol, 1995;Petrucio et al, 2005). Since correlations between the chlorophyll a and bacterial variables were not found, the importance of the arrival of the organic allochthonous and autochthonous substancesfrom ressuspension and dealing with a low level environment -explained the elevated number and the high bacterial biomass.…”

Section: Discussionmentioning

confidence: 87%

Seasonal and spatial distribution of Bacterioplankton in a fluvial-lagunar system of a tropical region: density, biomass, cellular volume and morphologic variation

Araújo

Godinho

2008

Braz. arch. biol. technol.

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The temporal and spatial fluctuations of Bacterioplankton in a fluvial-lagunar system of a tropical region (Pitimbu River and Jiqui Lake, RN) (R=0.55; p=0.02) and vibrio (R=0.53; p=0.03). Significant spatial differences of biomass (Mann Whitney: p=0.01) and cellular volume of the morphotypes (Mann Whitney: p=0.003) were found between the sampling sites. The strong positive correlations of the water temperature and oxygen with bacterioplankton showed a probable high bacterial activity in this system.

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“…As the investigated streams lack substantial instream GPP as well as riparian trees and shrubs providing coarse particulate organic matter and leaf litter, groundwater DOC may be an important carbon source fuelling this high CR (Primavesi et al. , 2002; Petrucio, Barbosa & Thomaz, 2005).…”

Section: Discussionmentioning

confidence: 99%

Impacts of agricultural land use on ecosystem structure and whole‐stream metabolism of tropical Cerrado streams

2009

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1. The tropical Cerrado savannah, the second-largest South American biome, is undergoing the most rapid land-use change in South America, including a wholesale shift from native vegetation to pasture and cropland. However, the consequences of this development for aquatic ecosystem functioning remain unclear. In this study, we investigated how agriculture affects chemical, physical and biological characteristics of headwater streams in the Brazilian Cerrado, and how these changes relate to an important ecosystem function, i.e. ecosystem metabolism. 2. Three paired samplings of pristine and agricultural streams were conducted considering the most abundant morphotypes of Cerrado streams. Nutrient concentrations, stream morphometry and hydrodynamics, sediment transport, as well as benthic microbial biomass (BMB), and its chlorophyll a (Chl-a) content were measured. In parallel, wholestream gross primary production (GPP) and community respiration (CR) were estimated using a diel open-channel dissolved O 2 change technique. 3. Agricultural streams had consistently higher nutrient concentrations, less variability in channel morphology, smaller channel cross-sectional areas, smaller transient storage zones, higher current velocities and higher boundary shear stresses than pristine streams. At base flow, agricultural streams exhibited a midstream band of shifting sediments, while pristine streams had stable sediments. Both agricultural and pristine streams were dominated by thick microbial mats. Due to differences in hydrodynamics and sediment stability, these microbial mats covered the entire stream bed in pristine streams, but were restricted to the stream margins in agricultural streams. 4. As a result, BMB of agricultural streams was diminished by a factor of 7.5 compared to pristine streams. Interestingly, CR of agricultural streams was diminished only by a factor of 2.0, because higher BMB-specific respiration efficiencies, potentially due to increased nutrient availability, compensated for lower BMB due to physical stress. Similarly, the 3.3-fold elevated GPP in agricultural compared to pristine streams was only to a minor degree due to increased benthic Chl-a, but mainly a result of 2.4-fold higher Chl-a-specific primary production efficiencies, potentially due to increased nutrient availability. 5. In conclusion, agriculture impacted the studied Cerrado streams through two antagonistic mechanisms: physical stress resulted in decreased BMB and whole-stream CR by preventing BMB accrual in the central streambed, but higher nutrient availability led to increased primary production and respiration efficiencies in marginal zones, as well as higher whole-stream GPP. Finally, measures of whole-stream metabolism were useful Correspondence: Bjö rn Gü cker,

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Bacteria and phytoplankton production rates in eight river stretches of the middle Rio Doce hidrographic basin (southeast Brazil)

Cited by 8 publications

References 17 publications

Bacterioplankton and phytoplankton production in seven lakes in the Middle Rio Doce basin, south-east Brazil

Bacterioplankton and phytoplankton production in seven lakes in the Middle Rio Doce basin, south-east Brazil

Seasonal and spatial distribution of Bacterioplankton in a fluvial-lagunar system of a tropical region: density, biomass, cellular volume and morphologic variation

Impacts of agricultural land use on ecosystem structure and whole‐stream metabolism of tropical Cerrado streams

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