Metabolism and Gaseous Exchanges in Two Coastal Lagoons from Rio de Janeiro with Distinct Limnological Characteristics

Thomaz, Sidinei Magela; Enrich‐Prast, Alex; Gonçalves, José Francisco; Santos, Anderson Medeiros dos; Esteves, Francisco A.

doi:10.1590/s1516-89132001000400015

Cited by 15 publications

(9 citation statements)

References 5 publications

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“…Even though tropical lakes have been pointed out to act as important CO 2 sources to the atmosphere (Marotta et al, 2009), our findings demonstrate the importance of meteorological variables driving limnological conditions. Consequently, shifts in aquatic metabolism along the year are found, as has been recorded in other subtropical (Carmouze et al, 1991;Thomaz et al, 2001) and temperate lakes (Staehr et al, 2010).…”

Section: Discussionmentioning

confidence: 53%

Determining the high variability of pCO2 and pO2 in the littoral zone of a subtropical coastal lake

2014

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Abstract:The aquatic metabolism comprises production and mineralization of organic matter through biological processes, such as primary production and respiration that can be estimated by gases concentration in the water column. Aim: The study aimed to assess the temporal variability of pCO 2 and pO 2 in the littoral zone of a subtropical coastal lake. Our hypotheses are i) high variability in meteorological conditions, such as temperature and light, drive the high variability in pCO 2 and pO 2 , and ii) the lake is permanently heterotrophic due to the low phosphorus concentration. Methods: We estimated pCO 2 from pH-alkalinity method, and pO 2 from dissolved oxygen concentration and water temperature measured in free-water during 24 hours in the autumn, winter, spring and summer. Results: Our findings showed that limnological variables had low temporal variability, while the meteorological variables and pCO 2 presented a high coefficient of variation, which is representative of each climatic season. In autumn and winter, it was recorded that the lake was supersaturated in CO 2 relative to the atmosphere, while in spring and summer CO 2 concentration was below the concentration found in the atmosphere. Over 24 hours, pCO 2 also showed high variability, with autumn presenting higher concentration during the night when compared to daytime. Water temperature and chlorophyll a were negatively correlated with pCO 2 , while pO 2 was positively correlated with wind and light. Conclusion: Agreeing with our first hypothesis, pCO 2 showed an expressive temporal variation in a subtropical lake associated to the high variability in meteorological conditions. On the other hand, our second hypothesis was not confirmed, since Peri Lake exported CO 2 to the atmosphere in some periods and in others, CO 2 was removed from the atmosphere.Keywords: subtropical, temporal variation, aquatic metabolism, meteorological conditions, seasonality.Resumo: O metabolismo aquático envolve os processos de produção e mineralização da matéria orgânica através de processos biológicos, tais como produção primária e respiração, que podem ser estimados através da concentração de gases na coluna d'água. Objetivo: O objetivo do presente estudo foi determinar a variabilidade temporal da pCO 2 e da pO 2 na zona litorânea de uma lagoa costeira subtropical, tendo como hipótese que i) a alta variabilidade nas condições meteorológicas, tais como temperatura e luz, direcionam a elevada variabilidade na pCO 2 e pO 2 e que ii) o ambiente é permanentemente heterotrófico devido à baixa concentração de fósforo. Métodos: Nós estimamos a pCO 2 através do método pH-alcalinidade, e a pO 2 a partir da concentração de oxigênio dissolvido e temperatura da água, medidos em água livre, durante 24 horas, no outono, inverno, primavera e verão. Resultados: Nossos resultados mostraram que as variáveis limnológicas amostradas apresentaram baixa variabilidade temporal, porém as variáveis meteorológicas e a pCO 2 apresentaram elevado coeficiente de variação, refletindo a variação...

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Section: Discussionmentioning

confidence: 53%

Determining the high variability of pCO2 and pO2 in the littoral zone of a subtropical coastal lake

2014

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“…Additionally, high concentration of humic acids, originated from the decomposition of plants, leads to dark-colored water, inhibiting primary production (Thomaz et al, 2001).…”

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confidence: 99%

The influence of environmental variables on spatial and temporal phytoplankton dissimilarity in a large shallow subtropical lake (Lake Mangueira, southern Brazil)

et al. 2014

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Aim:The uneven distribution of organisms in aquatic ecosystems is generally attributed to environmental heterogeneity in both space and time, reflecting the occurrence of appropriate environmental conditions and the availability of resources to biological communities. The aim of this study was to understand how the dissimilarity of the phytoplankton community in a large subtropical shallow lake is related to environmental dissimilarities. Methods: Biotic and environmental data were gathered at 19 sites along the 90-km length of Lake Mangueira. Sampling was carried out quarterly during 2010 and 2011, totaling 152 sampling units. The relationship between phytoplankton dissimilarity and the dissimilarity of environmental variables was assessed by the BioEnv analysis. Major results: There is a significant relationship between phytoplankton dissimilarity and environmental dissimilarity. The model that best explained the dissimilarity of phytoplankton among the sampling units included pH, turbidity and nitrate. Conclusions: The dissimilarity of phytoplankton was related to the dissimilarity, which were directly associated to the variability of conditions and resources in space and time in Lake Mangueira.

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“…Indeed, the CO 2 decrease observed in more N- and P-enriched clear water microcosms was mainly related to the presence of periphyton biomass on the walls, which was absent in the humic water microcosms likely due to light attenuation to primary production in their dark waters (Thomaz et al, 2001). In humic waters, TSS increase might be related to the phytoplankton growth, as the p CO 2 decreased without any periphyton growth on the microcosm walls.…”

Section: Discussionmentioning

confidence: 99%

Experimental evidence of nitrogen control on pCO2 in phosphorus-enriched humic and clear coastal lagoon waters

2013

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Natural and human-induced controls on carbon dioxide (CO2) in tropical waters may be very dynamic (over time and among or within ecosystems) considering the potential role of warmer temperatures intensifying metabolic responses and playing a direct role on the balance between photosynthesis and respiration. The high magnitude of biological processes at low latitudes following eutrophication by nitrogen (N) and phosphorus (P) inputs into coastal lagoons waters may be a relevant component of the carbon cycle, showing controls on partial pressure of CO2 (pCO2) that are still poorly understood. Here we assessed the strength of N control on pCO2 in P-enriched humic and clear coastal lagoons waters, using four experimental treatments in microcosms: control (no additional nutrients) and three levels of N additions coupled to P enrichments. In humic coastal lagoons waters, a persistent CO2 supersaturation was reported in controls and all nutrient-enriched treatments, ranging from 24- to 4-fold the atmospheric equilibrium value. However, both humic and clear coastal lagoons waters only showed significant decreases in pCO2 in relation to the controlled microcosms in the two treatments with higher N addition levels. Additionally, clear coastal lagoons water microcosms showed a shift from CO2 sources to CO2 sinks, in relation to the atmosphere. Only in the two more N-enriched treatments did pCO2 substantially decrease, from 650 µatm in controls and less N-enriched treatments to 10 µatm in more N-enriched microcosms. Humic substrates and N inputs can modulate pCO2 even in P-enriched coastal lagoons waters, thereby being important drivers on CO2 outgassing from inland waters.

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Metabolism and Gaseous Exchanges in Two Coastal Lagoons from Rio de Janeiro with Distinct Limnological Characteristics

Abstract: ABSTRACT

Cited by 15 publications

References 5 publications

Determining the high variability of pCO2 and pO2 in the littoral zone of a subtropical coastal lake

Determining the high variability of pCO2 and pO2 in the littoral zone of a subtropical coastal lake

The influence of environmental variables on spatial and temporal phytoplankton dissimilarity in a large shallow subtropical lake (Lake Mangueira, southern Brazil)

Experimental evidence of nitrogen control on pCO2 in phosphorus-enriched humic and clear coastal lagoon waters

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