Natural events of anoxia and low respiration index in oligotrophic lakes of the Atlantic Tropical Forest

Marotta, Humberto; Fontes, Maria Luiza Schmitz; Petrucio, Maurício Mello

doi:10.5194/bg-9-2879-2012

Cited by 5 publications

(3 citation statements)

References 39 publications

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“…Terrestrial organic carbon subsiding CO 2 emissions through community respiration have been reported in other lakes around the world (Cole et al, 2006, 2007; Marotta et al, 2012). Consequently, the terrestrial dissolved organic carbon (tDOC) may account for up to 76% of pelagic bacterial demand (Cole et al, 2006).…”

Section: Discussionmentioning

confidence: 86%

Dynamics of Planktonic Prokaryotes and Dissolved Carbon in a Subtropical Coastal Lake

Fontes¹,

Tonetta²,

Dalpaz³

et al. 2013

Front. Microbiol.

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To understand the dynamics of planktonic prokaryotes in a subtropical lake and its relationship with carbon, we conducted water sampling through four 48-h periods in Peri Lake for 1 year. Planktonic prokaryotes were characterized by the abundance and biomass of heterotrophic bacteria (HB) and of cyanobacteria (coccoid and filamentous cells). During all samplings, we measured wind speed, water temperature (WT), pH, dissolved oxygen (DO), precipitation, dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), and carbon dioxide (CO2). DOC was higher in the summer (average = 465 μM – WT = 27°C) and lower in the winter (average = 235 μM – WT = 17°C), with no significant variability throughout the daily cycles. CO2 concentrations presented a different pattern, with a minimum in the warm waters of the summer period (8.31 μM) and a maximum in the spring (37.13 μM). Daily trends were observed for pH, DO, WT, and CO2. At an annual scale, both biological and physical-chemical controls were important regulators of CO2. HB abundance and biomass were higher in the winter sampling (5.60 × 109 cells L−1 and 20.83 μmol C L−1) and lower in the summer (1.87 × 109 cells L−1 and 3.95 μmol C L−1). Filamentous cyanobacteria (0.23 × 108–0.68 × 108 filaments L−1) produced up to 167.16 μmol C L−1 as biomass (during the warmer period), whereas coccoid cyanobacteria contributed only 0.38 μmol C L−1. Precipitation, temperature, and the biomass of HB were the main regulators of CO2 concentrations. Temperature had a negative effect on the concentration of CO2, which may be indirectly attributed to high heterotroph activity in the autumn and winter periods. DOC was positively correlated with the abundance of total cyanobacteria and negatively with HB. Thus, planktonic prokaryotes have played an important role in the dynamics of both dissolved inorganic and organic carbon in the lake.

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Section: Discussionmentioning

confidence: 86%

Dynamics of Planktonic Prokaryotes and Dissolved Carbon in a Subtropical Coastal Lake

Fontes¹,

Tonetta²,

Dalpaz³

et al. 2013

Front. Microbiol.

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“…Concentrations of CO 2 in the surface waters of Peri Lake may have increased due to a deepening of the mixed layer or from sediments via physical processes (such as wind and convection), without changing the rates of respiration in the water column (Marotta et al 2009b(Marotta et al , 2012b(Marotta et al , 2014. Thus, turbulence is important in regards to potentially increasing pCO 2 in surface waters and consequential fluxes to the atmosphere.…”

Section: Discussionmentioning

confidence: 97%

Linking summer conditions to CO2 undersaturation and CO2 influx in a subtropical coastal lake

2015

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In this study, we tested the hypothesis that pCO 2 and air-water CO 2 fluxes in the surface waters of a subtropical lake vary on two time scales (diel and seasonally) and that CO 2 concentrations would decrease during the day and in summer. We estimated the variability of pCO 2 and the air-water CO 2 flux from pH-alkalinity in four 48-h periods that were representative of each subtropical season. There was high variability in pCO 2 and the air-water gas flux over 48 h, but there was no clear pattern between day and night. CO 2 concentrations showed a strong positive correlation with heterotrophic bacterial biomass and a negative correlation with dissolved organic carbon concentrations and water temperature. The lake was predominantly diel and seasonally CO 2 supersaturated; the highest CO 2 efflux was observed in the spring and a CO 2 influx was observed in summer. Our hypothesis was confirmed; pCO 2 was lowest in summer and during the daytime in spring and summer due to physical and biological conditions that favoured photosynthetic activities. These findings suggest that temporal shifts in the microbial community and meteorological variables, which are indirectly related to temperature, may be important drivers of CO 2 concentrations in Peri Lake. In conclusion, pCO 2 and the air-water CO 2 flux vary temporally (diel and seasonally) in the littoral zone of this subtropical coastal lake, with shifts between CO 2 influx and efflux throughout the sampling periods.

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“…According to Marotta et al (2012), the natural lakes in the Atlantic Forest are especially sensitive to degradation. In Marola Lake, we detected important changes in physical, chemical and phytoplankton data.…”

Section: Discussionmentioning

confidence: 99%

The necessity of management in a lake of the Atlantic Forest biodiversity hotspot: nitrogen levels connected to a persistent bloom of Cylindrospermopsis raciborskii

2016

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Conservational studies of the threatened Atlantic Forest biome are frequently restricted to terrestrial ecosystems. We know little about the water bodies, specially considering that this biome covers the third largest system of lakes in Brazil. Some of these lakes are located inside the protected "Rio Doce State Park", but many others are found outside this reserve. Th ese external lakes are seldom studied, but understanding their response to human activities is essential for the conservation and the protection of the lakes inside the Park. We evaluated the eff ects of degradation in a lake outside the Park, which shows a constant bloom of the toxic invasive cyanobacteria Cylindrospermopsis raciborskii. Phytoplankton, climate and physico-chemical variables were assessed from 2011 to 2013 to evaluate which were the major determinants of the lake dynamics. Despite the seasonal changes, the lake was always eutrophic, and cyanobacteria, transparency and nutrients were the major indicators of water characteristics. Th e lake seems to be nitrogen-limited and cyanobacteria were negatively correlated with nitrogen levels, since the constantly dominant C. raciborskii is a superior competitor for N. We suggest that the monitoring of nitrogen levels is fundamental to establish management strategies to avoid harmful algae blooms in this Atlantic Forest lake.

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Natural events of anoxia and low respiration index in oligotrophic lakes of the Atlantic Tropical Forest

Cited by 5 publications

References 39 publications

Dynamics of Planktonic Prokaryotes and Dissolved Carbon in a Subtropical Coastal Lake

Dynamics of Planktonic Prokaryotes and Dissolved Carbon in a Subtropical Coastal Lake

Linking summer conditions to CO2 undersaturation and CO2 influx in a subtropical coastal lake

The necessity of management in a lake of the Atlantic Forest biodiversity hotspot: nitrogen levels connected to a persistent bloom of Cylindrospermopsis raciborskii

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