Seasonal variation in denitrification and dissolved nitrogen fluxes in intertidal sediments of the Tagus estuary, Portugal

Cabrita, Maria Teresa; Brotas, Vanda

doi:10.3354/meps202051

Cited by 118 publications

(83 citation statements)

References 52 publications

(61 reference statements)

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“…In general this is expected since denitrification in marine sediments is a temperature dependent process (Rysgaard et al 2004). On the other hand, our finding is in contrast with other studies from temperate estuaries and coastal systems, where lower denitrification rates were observed in summer during limiting NO 3 -and O 2 conditions Cabrita and Brotas 2000;Sundbäck et al 2000). At B1, H2 and H4, however, O 2 was never limiting and NO 3 -for denitrifiers was mainly generated through nitrification.…”

Section: Discussioncontrasting

confidence: 99%

Seasonal oxygen, nitrogen and phosphorus benthic cycling along an impacted Baltic Sea estuary: regulation and spatial patterns

et al. 2014

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The regulatory roles of temperature, eutrophication and oxygen availability on benthic nitrogen (N) cycling and the stoichiometry of regenerated nitrogen and phosphorus (P) were explored along a Baltic Sea estuary affected by treated sewage discharge. Rates of sediment denitrification, anammox, dissimilatory nitrate reduction to ammonium (DNRA), nutrient exchange, oxygen (O 2 ) uptake and penetration were measured seasonally. Sediments not affected by the nutrient plume released by the sewage treatment plant (STP) showed a strong seasonality in rates of O 2 uptake and coupled nitrification-denitrification, with anammox never accounting for more than 20 % of the total dinitrogen (N 2 ) production. N cycling in sediments close to the STP was highly dependent on oxygen availability, which masked temperaturerelated effects. These sediments switched from low N loss and high ammonium (NH 4 ? ) efflux under hypoxic conditions in the fall, to a major N loss system in the winter when the sediment surface was oxidized. In the fall DNRA outcompeted denitrification as the main nitrate (NO 3 -) reduction pathway, resulting in N recycling and potential spreading of eutrophication. A comparison with historical records of nutrient discharge and denitrification indicated that the total N loss in the estuary has been tightly coupled to the total amount of nutrient discharge from the STP. Changes in dissolved inorganic nitrogen (DIN) released from the STP agreed well with variations in sedimentary N 2 removal. This indicates that denitrification and anammox efficiently counterbalance N loading in the estuary across the range of historical and present-day anthropogenic nutrient discharge. Overall low N/P ratios of the regenerated nutrient fluxes impose strong N limitation for the pelagic system and generate a high potential for nuisance cyanobacterial blooms.

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Section: Discussioncontrasting

confidence: 99%

Seasonal oxygen, nitrogen and phosphorus benthic cycling along an impacted Baltic Sea estuary: regulation and spatial patterns

et al. 2014

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“…An increase in temperature for instance can directly result in an increase in the rate of denitrification, but, can also increase the nitrification rate which then additionally enhances the supply of nitrate (Seitzinger, 1988). A seasonal variation in denitrification can be observed frequently and is reported for Baltic Sea sediments (Tuominen et al, 1998;Sundbäck et al, 2000;Hietanen and Kuparinen 2008) as well as for other regions (Nowicki et al, 1997;Cabrita and Brotas, 2000;Dong et al, 2000). For the Gulf of Finland, Hietanen and Kuparinen (2008) found a seasonal cycle with higher rates during autumn and early winter, whereas Tuominen et al (1998) measured the highest rates in late summer and early autumn.…”

Section: Factors Controlling the Rate Of Denitrification In Baltic Sementioning

confidence: 98%

Denitrification in sediments as a major nitrogen sink in the Baltic Sea: an extrapolation using sediment characteristics

et al. 2010

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Abstract.Rates of denitrification in sediments were measured with the isotope pairing technique at different sites in the southern and central Baltic Sea. The rates varied between 0.5 µmol N m −2 h −1 in sands and 28.7 µmol N m −2 h −1 in muddy sediments and showed a good correlation to the organic carbon contents of the surface sediments. N-removal rates via sedimentary denitrification were estimated for the entire Baltic Sea calculating sediment specific denitrification rates and interpolating them to the whole Baltic Sea area. Another approach was carried out by using the relationship between the organic carbon content and the rate of denitrification. The N-removal by denitrification in sediments varied between 426-652 kt N a −1 , which is around 48-73% of the external N inputs delivered via rivers, coastal point sources, and atmospheric deposition. Moreover, an expansion of the anoxic bottom areas was considered under the assumption of a rising oxycline from 100 to 80 m water depth. This leads to an increase of the area with anoxic conditions and an overall decrease in sedimentary denitrification by 14%. Overall, we show here that this type of data extrapolation is a powerful tool to estimate the nitrogen losses for a whole coastal sea and may be applicable to other coastal regions and enclosed seas.

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“…Using the standing stock of Uvigerina phlegeri, G. turgida, and Valvulineria bradyana in the Tagus prodelta (32), and their cell-specific denitrification rate, foraminiferal denitrification rates range between 72 and 240 μmol nitrogen m −2 ·d −1 . Denitrification measured there in July-October, which corresponds to the period when the above-mentioned species were enumerated (32), is 480-960 μmol nitrogen m −2 ·d −1 (33). The foraminifers might thus contribute 8-50% of the measured denitrification activity.…”

Section: Nitrate-storing Foraminifers: Implications For the Marine Nimentioning

confidence: 99%

Widespread occurrence of nitrate storage and denitrification among Foraminifera andGromiida

Piña-Ochoa

Høgslund

Geslin

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

254

259

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Benthic foraminifers inhabit a wide range of aquatic environments including open marine, brackish, and freshwater environments. Here we show that several different and diverse foraminiferal groups (miliolids, rotaliids, textulariids) and Gromia , another taxon also belonging to Rhizaria, accumulate and respire nitrates through denitrification. The widespread occurrence among distantly related organisms suggests an ancient origin of the trait. The diverse metabolic capacity of these organisms, which enables them to respire with oxygen and nitrate and to sustain respiratory activity even when electron acceptors are absent from the environment, may be one of the reasons for their successful colonization of diverse marine sediment environments. The contribution of eukaryotes to the removal of fixed nitrogen by respiration may equal the importance of bacterial denitrification in ocean sediments.

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Seasonal variation in denitrification and dissolved nitrogen fluxes in intertidal sediments of the Tagus estuary, Portugal

Cited by 118 publications

References 52 publications

Seasonal oxygen, nitrogen and phosphorus benthic cycling along an impacted Baltic Sea estuary: regulation and spatial patterns

Seasonal oxygen, nitrogen and phosphorus benthic cycling along an impacted Baltic Sea estuary: regulation and spatial patterns

Denitrification in sediments as a major nitrogen sink in the Baltic Sea: an extrapolation using sediment characteristics

Widespread occurrence of nitrate storage and denitrification among Foraminifera andGromiida

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