Comparison of heterotrophic bacterial production rates in early spring in the turbid estuaries of the Scheldt and the Elbe

Goosen, Nico; Rijswijk, Pieter van; Brockmann, U. H.

doi:10.1007/bf00008569

Cited by 44 publications

(13 citation statements)

References 26 publications

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“…Due to a reduction of light availability in the port, and an increase of suspended particulate matter, primary production is inhibited in this region (Goosen et al, 1995;Wolfstein and Kies, 1999), and the fresh phytoplankton biomass brought in by the Elbe water is an optimal source for remineralization by heterotrophic bacteria (Kerner, 2000). Enhanced remineralization and decreasing phytoplankton activity leads to increased O 2 consumption and a decrease of O 2 production, respectively, leading to the observed minimal O 2 concentrations in the deep Hamburg port region (Schöl et al, 2014).…”

Section: Discussion N 2 O Source Regions In the Estuarymentioning

confidence: 99%

High Resolution Measurements of Nitrous Oxide (N2O) in the Elbe Estuary

et al. 2017

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Nitrous oxide (N 2 O) is one of the most important greenhouse gases and a major sink for stratospheric ozone. Estuaries are sites of intense biological production and N 2 O emissions. We aimed to identify hot spots of N 2 O production and potential pathways contributing to N 2 O concentrations in the surface water of the tidal Elbe estuary. During two research cruises in April and June 2015, surface water N 2 O concentrations were measured along the salinity gradient of the Elbe estuary by using a laser-based on-line analyzer coupled to an equilibrator. Based on these high-resolution N 2 O profiles, N 2 O saturations, and fluxes across the surface water/atmosphere interface were calculated. Additional measurements of DIN concentrations, oxygen concentration, and salinity were performed. Highest N 2 O concentrations were determined in the Hamburg port region reaching maximum values of 32.3 nM in April 2015 and 52.2 nM in June 2015. These results identify the Hamburg port region as a significant hot spot of N 2 O production, where linear correlations of AOU-N 2 O xs indicate nitrification as an important contributor to N 2 O production in the freshwater part. However, in the region with lowest oxygen saturation, sediment denitrification obviously affected water column N 2 O saturation. The average N 2 O saturation over the entire estuary was 201% (SD: ±94%), with an average estuarine N 2 O flux density of 48 µmol m −2 d −1 and an overall emission of 0.18 Gg N 2 O y −1 . In comparison to previous studies, our data indicate that N 2 O production pathways over the whole estuarine freshwater part have changed from predominant denitrification in the 1980s toward significant production from nitrification in the present estuary. Despite a significant reduction in N 2 O saturation compared to the 1980s, N 2 O concentrations nowadays remain on a high level, comparable to the mid-90s, although a steady decrease of DIN inputs occurred over the last decades. Hence, the Elbe estuary still remains an important source of N 2 O to the atmosphere.

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Section: Discussion N 2 O Source Regions In the Estuarymentioning

confidence: 99%

High Resolution Measurements of Nitrous Oxide (N2O) in the Elbe Estuary

et al. 2017

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“…(3) and (4), Y decreases toward a minimum value. In the model, freshwater phytoplankton and bacterioplankton in the river are subject to salt stress when freshwater mixes with saltwater; and the freshwater microbial populations die in this zone (Flameling and Kromkamp, 1994;Goosen et al, 1995). In the model, the salinity also limits the seaward distribution of saline water plankton, invertebrates (e.g.…”

Section: Article In Pressmentioning

confidence: 99%

An ecohydrology model of the Guadiana Estuary (South Portugal)

Wolanski

Chı́charo

et al. 2006

Estuarine, Coastal and Shelf Science

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A 1-D ecohydrology model is proposed that integrates physical, chemical and biological processes in the Guadiana Estuary during low flow conditions and that predicts the ecosystem health as determined by the following variables: river discharge, nutrients, suspended particulate matter, phytoplankton, zooplankton, bivalves, zooplanktivorous fish and carnivorous/omnivorous fish. Low flow conditions prevail now that the Alqueva dam has been constructed. The ecological sub-model is based on the non-linear LotkaeVolterra equation. The model is successful in capturing the observations of along-river changes in these variables. It suggests that both bottom-up and top-down ecological processes control the Guadiana Estuary ecosystem health. A number of sensitivity tests show that the model is robust and can be used to predict e within likely error bounds provided by the sensitivity tests e the consequences on the estuary ecosystem health of human activities throughout the river catchment, such as the irrigation farming downstream of the Alqueva dam, reclamation of the salt marshes by urban developments, and flow regulation by the Alqueva dam. The model suggests that the estuarine ecosystem health requires transient river floods and is compromised by flow regulation by the Alqueva dam. Remedial measures are thus necessary.

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“…showed a highly significant (p < 0.0001, r2 = 0.56 to 0.74) correlation in the lower estuary, Stns l to 5. Goosen et al (1995) showed in the Schelde estuary that Bacterial growth rates bacterial production changed substantially during a tidal cycle and thus as a function of changing salinity.…”

Section: Salinity (Psu)mentioning

confidence: 99%

“…Billen et al (1988) predicted intensive bacterial growth, by modelling microbial processes, and Soetaert & Herman (1995b) showed a very high degree of heterotrophy in the Schelde estuary. By in situ measurements Goosen et al (1995) showed that in spring, bacteria! production rates in the S c h e l d~ P S~I Iary are among the highest reported for temperate estuaries.…”

Section: Introductionmentioning

confidence: 99%

Regulation of annual variation in heterotrophic bacterial production in the Schelde estuary (SW Netherlands)

Goosen¹,

Rijswijk²,

Kromkamp³

et al. 1997

Aquat. Microb. Ecol.

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Heterotrophic bacter~oplankton production (3H-thymidine incorporation rate) and abundance in the surface water of the Schelde estuary (The Netherlands) were studied during an annual cycle in 1991 along the salinity gradient ( 0 8 to 33 psu) Bacterial production and numbers increased from the lower to the uppel estuary This spatial varlabil~ty of bacterial production was positively coilelated wlth concentrations of dissolved and particulate organic carbon and negatively correlated with the oxygen concentration O n a n annual scale the ratio gloss bacterial production net primary production was larger than 1 in the whole estuary a n d ~ncreased from the lower to the upper estual y This lndicates that bacteria processed more carbon than was put into the system by phytoplankton primary production A comparable situation is found in other estuanes and s h o~v s the high degree ot heterotrophy of these systems Despite the high degree of heterotrophy, temporal variation in bacterial production In the lower Schelde estuary was charactensed by a sprlng and summer bloom and was correlated wlth phytoplankton prlmary production This apparent contradiction IS explained by r a p~d uptake of labile algal exudates by bacteria and a subsequent inciease of bacter~al production rate durlng and after the phytoplankton bloom This idea is corroborated by the absence of a n increase in d~ssolved organic carbon d u n n g phytoplankton blooms in the lower estuary Due to a n excess of allochthonous organic carbon and nutlients in the upper estuary tempelature was the most important factor in explaining the variability of bacterial production in this region K E Y WORDS. Hetei-otrophic bacterial production . Organic carbon . Primary product~on . Estuary

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Comparison of heterotrophic bacterial production rates in early spring in the turbid estuaries of the Scheldt and the Elbe

Cited by 44 publications

References 26 publications

High Resolution Measurements of Nitrous Oxide (N2O) in the Elbe Estuary

High Resolution Measurements of Nitrous Oxide (N2O) in the Elbe Estuary

An ecohydrology model of the Guadiana Estuary (South Portugal)

Regulation of annual variation in heterotrophic bacterial production in the Schelde estuary (SW Netherlands)

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