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Amarasinghe, Punsara; Vijverberg, J.

doi:10.1023/a:1022985908451

Cited by 16 publications

(4 citation statements)

References 14 publications

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“…The Peri Lake features, such as its position along shorelines, its exposure to local wind, and its relative shallowness, prevented water column stratification, as was observed by Hennemann and Petrucio (2011) in Peri Lake, as well as in other environments (Amarasinghe and Vijverberg, 2002;Wondie et al, 2007;Montero et al, 2011).…”

Section: Vertical Variationmentioning

confidence: 93%

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Planktonic production and respiration in a subtropical lake dominated by Cyanobacteria

2015

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Planktonic primary production and respiration rates were estimated in a subtropical coastal lake dominated by Cyanobacteria in order to investigate the temporal and vertical variation in this lake and to evaluate its relationships with limnological variables and phytoplankton. Light and dark bottles were incubated at four different depths in the central part of the lake and were performed bimonthly from June/2009 to December/2010. No significant difference was evident among depths in relation to phytoplankton, limnological variables and metabolic rates. However, the highest production rates were recorded at the surface, and decreased towards the bottom, coupled with phytoplanktonic photosynthetic capacity. Wind induced mixing in Peri Lake played an important role in nutrient and phytoplankton redistribution, characterizing this lake as polymictic. According to density and biovolume, the phytoplankton community was dominated by filamentous Cyanobacteria, especially Cylindrospermopsis raciborskii (Woloszynska) Seenayya and Subba-Raju. This study has shown that both water temperature and nutrient availability drive phytoplankton growth and consequently the temporal variation in metabolic rates, where respiration is higher than primary production.Keywords: subtropical coastal lake, primary production, respiration, phytoplankton, Cylindrospermopsis raciborskii.Produção e respiração planctônicas em uma lagoa subtropical dominada por cianobactérias ResumoAs taxas de produção primária e respiração planctônicas foram estimadas em um lago costeiro subtropical dominado por cianobactérias, com o objetivo de investigar a variação temporal e vertical nesta lagoa e avaliar suas relações com as variáveis limnológicas e os grupos fitoplanctônicos. Garrafas claras e escuras foram incubadas em quatro diferentes profundidades na parte central da lagoa e foram realizadas bimensalmente de junho/2009 a dezembro/2010. Nenhuma diferença significativa foi encontrada entre as profundidades amostradas, em relação ao fitoplâncton, variáveis limnológicas e taxas metabólicas. No entanto, as maiores taxas de produção foram registradas na superfície, diminuindo com o aumento da profundidade, juntamente com a capacidade fotossintética do fitoplâncton. A ação do vento na lagoa do Peri promoveu a homogeneidade de nutrientes e do fitoplâncton na coluna d'água, caracterizando-o como polimítico. De acordo com a densidade e biovolume, a comunidade fitoplanctônica foi dominada por cianobactérias filamentosas, especialmente Cylindrospermopsis raciborskii (Woloszynska) Seenayya and Subba-Raju. Este estudo demonstrou que a temperatura da água combinada com a disponibilidade de nutrientes influencia a comunidade fitoplanctônica, determinando a variação temporal das taxas metabólicas, onde a respiração é maior que a produção primária.Palavras-chave: lagoa costeira subtropical, produção primária, respiração, fitoplâncton, Cylindrospermopsis raciborskii.

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Section: Vertical Variationmentioning

confidence: 93%

“…Previous studies reveal that high temperature and light availability, in the tropics, favors high planktonic primary production and respiration, which promotes the fastest nutrient cycling, and maintains metabolic rates constant along the time (Berman et al, 1995;Amarasinghe and Vijverberg, 2002).…”

Section: Introductionmentioning

confidence: 99%

Planktonic production and respiration in a subtropical lake dominated by Cyanobacteria

2015

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“…Primary production can be much higher in tropical lakes due to the direct effect of the temperature, under nutrient saturation (Lewis, 1996), reaching values 2 to 3 times higher than in temperate lakes (Lewis, 1996;Amarasinghe and Vijverberg, 2002). The complex dynamics of the mixed layer and the higher metabolic rates in tropical lakes speed up the return of nutrients to the euphotic zone (Lewis, 1996).…”

Section: Introductionmentioning

confidence: 99%

Primary productivity of the phytoplankton in a tropical Brazilian shallow lake: experiments in the lake and in mesocosms

Feresin¹,

Arcifa²,

Silva³

et al. 2010

Acta

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Aim: To evaluate the primary productivity of the phytoplankton in the Lake Monte Alegre, southeastern Brazil, and the factors that influence its fluctuations, experiments were carried out in the lake and in mesocosm; Methods: Primary productivity rates were measured using the 14 C technique, in experiments carried out monthly in the lake, during one year, and in two mesocosm experiments, one in the winter and another in the summer. Other factors also analyzed were temperature, dissolved oxygen, pH, electrical conductivity, chlorophyll-a, alkalinity, nutrients, and nitrogen limitation. Hypotheses on the influence of grazing and excretion by zooplankton and fish on phytoplankton properties were tested in two mesocosm experiments; Results: Higher PP in the water column of the lake occurred in the transition periods, when thermal stratification is unstable, and lower PP in the cool season (frequent mixing) and in mid-summer (more stable stratification). The limiting factor in the cool season seems to be mainly temperature and in mid-summer lower light intensities, due to higher rainfall and overcast, N limitation and physical disturbances caused by storms. PP was not influenced by the zooplankton in the experiment I, despite the effect of grazing on other phytoplankton properties. The excretion by the phytoplanktivorous fish (adults of Tilapia rendalli) enhanced PP in the experiment II, outweighing grazing on the phytoplankton; Conclusions: We suppose that the preponderant factors which affected primary productivity in the lake were physical and chemical ones, biotic factors having a secondary role. The thermal behavior of the lake, which is warm discontinuous polymictic, governs nutrient losses and releases, influencing PP in addition to other factors related to seasons.Keywords: primary productivity, assimilation rates, chlorophyll-a, thermal behavior, bottom-up and top-down control.Resumo: Objetivo: Para avaliar a produtividade primária do fitoplâncton e os fatores que influenciam suas flutuações foram feitos experimentos no Lago Monte Alegre e em mesocosmos; Métodos: Foram feitos experimentos mensais de produtividade primária (PP), usando o método do 14 C, no lago, durante um ano, e em dois experimentos em mesocosmos, um no inverno e outro no verão. Outros fatores medidos foram temperatura, oxigênio dissolvido, pH, condutividade elétrica, clorofila-a, alcalinidade, nutrientes e limitação de nitrogênio. Foram testadas hipóteses sobre a influência do consumo e excreção do zooplâncton e peixes sobre o fitoplâncton em dois experimentos realizados em mesocosmos; Resultados: Maior PP na coluna de água do lago ocorreu nos períodos de transição, quando a estratificação é instável, e menor PP na estação fria (circulação freqüente) e no meio do verão (estratificação mais estável). O fator limitante na estação fria parece ser principalmente a temperatura e no meio do verão as intensidades luminosas mais baixas, devido a maior pluviosidade e tempo nublado, limitação de nitrogênio e perturbações físicas causadas po...

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“…Biomass of animal organisms was estimated by measuring the organisms under the microscope and applying published length-weight relationships from the literature to dry weight or fresh weight (Smock, 1980;Culver et al, 1985;Amarasinghe et al, 2008). To convert dry weight to fresh weight we multiplied microfauna dry weight by 10 and macrofauna dry weight by 5 (Winberg, 1971).…”

Section: Discussionmentioning

confidence: 99%

Availability of animal food organisms and their utilization by cyprinids in Sri Lankan hill-stream pools

Vijverberg¹,

Land²,

Vreeke³

et al. 2019

Sri Lanka J. Aquat.

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The food and feeding of cyprinid fishes in three stream pools in South West Sri Lanka, was investigated from 29 June 1984 to 25 February 1986. S.W. Sri Lanka was chosen as a study site because the rainforest and its fish fauna are here severely threatened. Feeding ecology was studied by gut contents analysis. The availability of prey organisms in the environment was quantified and food utilization in each pool was estimated by comparing diet compositions of the fish species with the food availability. Seven cyprinid species represented more than 98% of the fish numbers caught. These were Pethia cumingii (PC), Puntius dorsalis (PD), Dawkinsia singhala (DS), Pethia nigrofasciata (PN), Systomus pleurotaenia (SP), Devario malabaricus (DM) and Rasbora daniconius (RD). Three of these species: the two surface feeders DM and RD and the generalist SP fed > 33 % (biovolume) on terrestrial arthropods. Since we were not able to quantify the availability of terrestrial arthropods-mainly ants falling from the trees into the stream-these three species were not included in part of the analysis. Chironomid larvae were most abundant and, on basis of biovolume, the most important animal food items of the remaining four cyprinid species (PC, PD, DS, PN). PD and PN strongly positively selected chironomid larvae, but DS and PC only weakly negatively. Although coleopterans and ephemeropterans were after chironomid larvae the most abundant food items in the environment the former were often negatively selected and ephemeropterans positively, so that the latter were generally after chironomid larvae the most frequently eaten food items.

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Cited by 16 publications

References 14 publications

Planktonic production and respiration in a subtropical lake dominated by Cyanobacteria

Planktonic production and respiration in a subtropical lake dominated by Cyanobacteria

Primary productivity of the phytoplankton in a tropical Brazilian shallow lake: experiments in the lake and in mesocosms

Availability of animal food organisms and their utilization by cyprinids in Sri Lankan hill-stream pools

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