Bacterial Growth Efficiency in the Tropical Estuarine and Coastal Waters of Goa, Southwest Coast of India

Ram, Anirudh; Nair, Shanta; Chandramohan, D.

doi:10.1007/s00248-002-3005-9

Cited by 46 publications

(47 citation statements)

References 31 publications

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“…The high variability in BP, BR, BCD and BGE, also observed in other tropical estuaries (GUENTHER et al, 2008;RAM et al, 2007), was already expected due to the high hydrodynamic complexity of this system (GUENTHER et al, 2015). Although the BP rates measured in Recife harbor were similar, on average, to other tropical and temperate estuaries (APPLE; DEL GIORGIO, 2007;NEWELL, 2012;GUENTHER et al, 2008;RAM et al, 2003), the BR rates were higher, leading to lower BGE (see Table 3). Bacterial respiration rates were more variable than BP rates and inversely correlated to BGE (see Table 2) which suggest that BGE variations are better explained by BR.…”

Section: Discussionmentioning

confidence: 57%

“…Temperatures at Recife harbor are high throughout the year (25-30 o C), which led to high bacterial production but even higher bacterial respiration rates. Indeed, previous studies performed in tropical estuarine waters showed lower BR rates (BR max =0.7 µM C h LEE et al, 2009;RAM et al, 2003). Nutrient availability also plays a major role in regulating bacterial carbon metabolism (ASMALA et al, 2014;BERGGREN et al, 2010;GASOL et al, 2009;KEMP, 2003).…”

Section: Discussionmentioning

confidence: 95%

“…Nevertheless, several studies showed a great spatial and temporal variability in BGE within and among systems, due to several abiotic and biotic factors like temperature, inorganic nutrients availability, dissolved organic matter (DOM) quality, light incidence and grazing pressure (APPLE; DEL GIORGIO, 2007;APPLE et al, 2006;ASMALA et al, 2014;BERGGREN et al, 2010;CORY et al, 2010;RAM et al, 2003). The need for simultaneous in situ estimates of bacterial production and respiration rates became thus imperative to accurately evaluate the bacterial carbon metabolism in the aquatic systems and understand its regulation.…”

Section: Introductionmentioning

confidence: 99%

“…The high and continuous input of allochthonous nutrients and organic material from the surrounding lands and the domestic sewage leads to high phytoplankton and bacterial growth (BARRERA-ALBA et al, 2008;GAULKE et al, 2010;VALENTIN, 2008b;MORTAZAVI et al;SCHUMANN et al, 2003;YUAN et al, 2010). However, most of estuarine BGE in situ estimates were performed in temperate zones, with few exceptions on the tropics (GUENTHER et al, 2008a;LEE et al, 2009;RAM et al, 2003;RAM et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

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High bacterial carbon demand and low growth efficiency at a tropical hypereutrophic estuary: importance of dissolved organic matter remineralization

et al. 2017

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et al.: High BCD and low BGE at a hypereutrophic estuary 382High bacterial carbon demand and low growth efficiency at a tropical hypereutrophic estuary: importance of dissolved organic matter remineralization Medidas simultâneas de produção (PB) e respiração bacterianas (RB) são indispensáveis para o entendimento da magnitude do ciclo do carbono nos níveis tróficos mais basais dos sistemas aquáticos, mas são ainda escassas nos trópicos. O presente estudo foi realizado em um estuário extremamente produtivo (Porto do Recife, 08°03'S; 34°52'W, NE do Brasil), onde a demanda bacteriana por carbono (DBC=PB+RB) e a eficiência de crescimento bacteriano (ECB=PB/DBC) foram determinadas para estimar o principal papel do bacterioplâncton: fonte ou captador de carbono orgânico. Apesar das altas taxas de PB (0.03-0.4 µMC h -1 ), as taxas extremas de RB (0.5-4.1 µMC h -1 ) levaram a baixa ECB (0.02-0.29), provavelmente devido às altas temperaturas (>25 o C) e forte limitação por nitrogênio inorgânico (razão N:P) A alta DBC e a baixa ECB indicam que o bacterioplâncton esteja atuando principalmente como remineralizador da matéria orgânica dissolvida, alimentando a produção primaria do sistema. Esses resultados contradizem o que seria esperado baseado em estudos conduzidos em estuários eutróficos temperados (onde geralmente ECB > 0.30) e apontam para a importância de se aumentar estimativas in situ de PB e RB em sistemas estuarinos tropicais a fim de se promover um melhor entendimento do papel desses sistemas na ciclagem de carbono global. Simultaneous measurements of bacterioplankton production (BP) and respiration (BR) are imperative to understand the magnitude of carbon cycle in the lower trophic levels of the aquatic systems, but are still scarce in the tropics. The present study was performed in a highly productive estuary (Recife harbor, 08°03'S; 34°52'W, NE Brazil) where bacterial carbon demand (BCD=BP+BR) and growth efficiency (BGE=BP/BCD) were evaluated in order to estimate the major role of bacterioplankton: source or sink of organic carbon. In spite of the high BP rates (0.03-0.4 µMC h -1 ), the extremely high BR rates (0.5-4.1 µMC h -1 ) led to low BGE (0.02-0.29), possibly due to the high temperatures (>25 o C) and strong inorganic nitrogen limitation (N:P ratios) The high BCD and low BGE indicate the major role of bacterioplankton as dissolved organic matter remineralizers, fueling the primary productivity of the system. These findings contradict what could be expected from studies in highly productive temperate estuaries (where BGE is usually > 0.30) and highlight the importance of increasing in situ BP and BR estimates in tropical estuarine systems in order to better understand the role of these systems in global carbon cycling. Resumo AbstRActDescritores: Bacterioplâncton, Produção bacteriana, Respiração bacteriana, Alça microbiana, DBC, ECB.

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Section: Discussionmentioning

confidence: 57%

Section: Discussionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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High bacterial carbon demand and low growth efficiency at a tropical hypereutrophic estuary: importance of dissolved organic matter remineralization

et al. 2017

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“…Multiple lines of evidence suggest that Mandovi-Zuari tropical system is net heterotrophic especially in the monsoon season where respiration exceeds gross primary production, which can only occur when external subsidies of organic C support estuarine metabolism [39]. This study area forms a part of the Northern Indian Ocean (southeastern Arabian Sea) is characterized by extreme wind forcing and seasonal monsoon winds which are an annual recurring phenomenon in these estuaries [29].…”

Section: Introductionmentioning

confidence: 99%

Bacterial Growth Efficiency in a Tropical Estuary: Seasonal Variability Subsidized by Allochthonous Carbon

2007

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Bacterial growth efficiency (BGE) is a key factor in understanding bacterial influence on carbon flow in aquatic ecosystems. We report intra annual variability in BGE, and bacteria mediated carbon flow in the tropical Mandovi and Zuari estuaries (southwest India) and the adjoining coastal waters (Arabian Sea). BGE ranged from 3 to 61% and showed clear temporal variability with significantly (ANOVA, p < 0.01) higher values in the estuaries (mean, 28 ± 14%) than coastal waters (mean 12 ± 6%). The greater variability of BGE in the estuaries than coastal waters suggest some systematic response to nutrient composition and the variability of dissolved organic matter pools, as BGE was governed by bacterial secondary production (BP). Monsoonal rains and its accompanied changes brought significant variability in BGE and bacterial productivity to primary productivity (BP/PP) ratio when compared to non-monsoon seasons in the estuaries and coastal waters. High BP/PP ratio (> 1) together with high carbon flux through bacteria (> 100% of primary productivity) in the estuarine and coastal waters suggests that bacterioplankton consumed dissolved organic carbon in excess of the amount produced in situ by phytoplankton of this region, which led to the mismatch between primary production of carbon and amount of carbon consumed by bacteria. Despite the two systems being subsidized by allochthonous inputs, the low BGE in the coastal waters may be due to the nature and time interval in the supply of allochthonous carbon.

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Size fractionated phytoplankton biomass and net metabolism along a tropical estuarine gradient

Soria-Píriz

García‐Robledo

Papaspyrou

et al. 2017

Limnology & Oceanography

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Size structure of phytoplankton determines to a large degree the trophic interactions in oceanic and coastal waters and eventually the destiny of its biomass. Although, tropical estuarine systems are some of the most productive systems worldwide compared to temperate systems, little is known about phytoplankton biomass size fractions, their contribution to net metabolism, or the ecological factors driving phytoplankton size distribution in tropical estuaries. Hence, we measured the size-fractionated biomass and net metabolism of the plankton community along a salinity and nutrient gradient in the Gulf of Nicoya estuary (Costa Rica), during the dry season. Respiration (23.6 mmol O 2 m 23 h 21 ) was highest at the estuary head, whereas maximum net primary production (23.1 mmol O 2 m 23 h 21 ) was observed in the middle of the estuary, coinciding with the chlorophyll a maximum (15.9 mg m 23 ). Thus, only the middle section of the estuary was net autotrophic (2.9 g C m 22 d 21 ), with the rest of the estuary being net heterotrophic. Regression analysis identified light availability, and not nutrients, as the principal factor limiting primary production in the estuary due to increased turbidity. The changes in net metabolism along the estuary were also reflected in the phytoplankton's size structure. Although micro-and picophytoplankton were the most productive fractions overall, in the middle section of the estuary nanophytoplankton dominated primary production, chlorophyll, and autotrophic biomass.

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Bacterial Growth Efficiency in the Tropical Estuarine and Coastal Waters of Goa, Southwest Coast of India

Cited by 46 publications

References 31 publications

High bacterial carbon demand and low growth efficiency at a tropical hypereutrophic estuary: importance of dissolved organic matter remineralization

High bacterial carbon demand and low growth efficiency at a tropical hypereutrophic estuary: importance of dissolved organic matter remineralization

Bacterial Growth Efficiency in a Tropical Estuary: Seasonal Variability Subsidized by Allochthonous Carbon

Size fractionated phytoplankton biomass and net metabolism along a tropical estuarine gradient

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