The Subtropical Zhujiang (Pearl River) Estuary: Nutrient, Trace Species and Their Relationship to Photosynthesis

Zhang, J.; Yu, Zhigang; Wang, J.T.; Ren, Jianqiang; Chen, H.T.; Xiong, Hui; Li, Dong; Xu, Wei

doi:10.1006/ecss.1999.0500

Cited by 126 publications

(81 citation statements)

References 18 publications

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“…Observed N/P ratios (total dissolved inorganic nitrogen to phosphate) in the upper reaches of the Pearl River Estuary ranged from 470-510 in January 2005 to 300-470 in March 2006, and70-230 in August 2005, showing a significant seasonal variability with higher N/P ratios in the dry winter. This N/P ratio declined seaward (not shown), reaching ∼80-100 in the vicinity of the Humen in both winter and summer, similar to what was previously documented (Cai et al, 2004;Dai et al, 2006;Zhang et al, 1999). Silicate ranged between 50 and 150 µmol L −1 , which is comparable with historical data (Cai et al, 2004;Dai et al, 2006;Lin et al, 1985;Zhang et al, 1999).…”

Section: Spatial-temporal Distribution Of Inorganic Nutrientssupporting

confidence: 88%

“…The highly variable endmember concentrations were apparently influenced by the seasonal variation of river discharge, which had profound effects on the supply of organics and nutrients as well as the water mixing of the estuary. The maximum NO (Cai et al, 2004;Yin et al, 2001;Zhang et al, 1999). Observed N/P ratios (total dissolved inorganic nitrogen to phosphate) in the upper reaches of the Pearl River Estuary ranged from 470-510 in January 2005 to 300-470 in March 2006, and70-230 in August 2005, showing a significant seasonal variability with higher N/P ratios in the dry winter.…”

Section: Spatial-temporal Distribution Of Inorganic Nutrientsmentioning

confidence: 98%

“…As a consequence, many environmental issues have emerged, such as ammonium contamination and hypoxia Zhai et al, 2005), which at the same time offer an opportunity to examine nitrogen transformation in human-perturbed estuaries. Unfortunately, available data on the spatial and temporal variations of dissolved inorganic nitrogen are still limited in the open literature though research devoted to this region has grown recently in response Wong and Cheung (2000) b Cheung et al (2000) c PRWRC/PRRCC (1991) d Cheng (2001) to progressively worsening environmental conditions (Cai et al, 2004;Yin, 2002;Yin et al, 2001;Zhang et al, 1999). Moreover, most of the previous studies have focused on the Lingdingyang Estuary (one of the three sub-estuary complexes) leaving information on nutrient biogeochemistry in the other two sub-estuaries unavailable.…”

Section: Introductionmentioning

confidence: 99%

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Nitrification and inorganic nitrogen distribution in a large perturbed river/estuarine system: the Pearl River Estuary, China

Dai

Wang²,

Guo³

et al. 2008

Biogeosciences

222

176

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Abstract. We investigated the spatial distribution and seasonal variation of dissolved inorganic nitrogen in a large perturbed estuary, the Pearl River Estuary, based on three cruises conducted in winter (January 2005), summer (August 2005) and spring (March 2006). On-site incubation was also carried out for determining ammonium and nitrite oxidation rates (nitrification rates). We observed a year-round pattern of dramatic decrease in NH , accompanied by extremely high concentrations of ammonia (up to >800 µmol L −1 ) and nitrate (up to >300 µmol L −1 ). In summer, the upper estuary showed higher nitrification rates (ammonia oxidation rate ∼1.5-33.1 µmol N L −1 d −1 , nitrite oxidation rate ∼0.6-32.0 µmol N L −1 d −1 ) with lower concentrations of ammonia (<350 µmol L −1 ) and nitrate (<120 µmol L −1 ). The Most Probable Number test showed relatively lower nitrifier abundance in summer at most sampling stations, indicating a greater specific nitrification rate per cell in the warm season. Temperature appeared to control nitrification rates to a large degree in different seasons. Spatial variability of nitrification rates appeared to be controlled by a combination of many other factors such as nutrient concentrations, nitrifier abundance and dissolved oxygen (DO) concentrations. In addition to aerobic respiration, nitrification contributed significantly to the consumption of DO and production of free CO 2 at upper estuary. Nitrification-induced consumption accounted for up to approximately one third of the total waCorrespondence to: M. Dai (mdai@xmu.edu.cn) ter column community DO consumption in the upper estuary during the surveyed periods, boosting environmental stress on this large estuarine ecosystem.

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Section: Spatial-temporal Distribution Of Inorganic Nutrientssupporting

confidence: 88%

Section: Spatial-temporal Distribution Of Inorganic Nutrientsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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Nitrification and inorganic nitrogen distribution in a large perturbed river/estuarine system: the Pearl River Estuary, China

Dai

Wang²,

Guo³

et al. 2008

Biogeosciences

222

176

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“…With reference to our proposed models, if seasonal changes in riverine loading do not change its P-limited status, then mixing is the main factor that triggers the change in limitation status. The Pearl River Estuary tends toward N limitation in the dry season and P limitation in the wet season (Yin 2002;Yin et al 2004), but its riverine endmember shows P limitation based on its high [N] : [P] ratios in both wet and dry seasons (Zhang et al 1999;Chen et al 2008). This result implies that seasonal changes in the limiting nutrient in estuaries, such as the Pearl River Estuary, may simply be a result of changes in salinity distribution.…”

Section: Discussionmentioning

confidence: 99%

Shifts in limiting nutrients in an estuary caused by mixing and biological activity

Lui

Chen

2011

Limnology & Oceanography

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Simple general equations are used to show that when riverine water mixes with seawater, the N : P ratio is a nonlinear function of salinity. Thus, a shift in the limiting-nutrient status at a particular salinity along a continuum is a mathematical certainty, albeit complicated by biological consumption and remineralization. The salinity where the shift occurs is a function of biological nutrient uptake ratio. Four general modes, each with a corresponding formula, are deduced here to explain the factors that govern changes in nutrient ratios vs. salinity. These formulas help to explain why changes in the seasonal nutrient limitation status in some estuaries are in some cases triggered by variations in nutrient loading, and in other cases by mixing.Limiting nutrients and nutrient budgets in aquatic systems are of wide interest because of their fundamental importance in understanding carbon fixation, coastal eutrophication, and waste management (Kelly 1998;Howarth and Marino 2006;Smith 2006). In estuaries, it is still difficult to conclude whether N or P of riverine loadings should be controlled to reduce the eutrophication and the resulting hypoxia in marine ecosystems (Howarth and Marino 2006;Conley et al. 2009). This difficulty may arise because of a general phenomenon that in rivers with relatively high dissolved inorganic nitrogen (DIN 5 [NO4 ]) molar ratios (DIN : SRP ratios), these ratios decrease as salinity increases (Fisher et al. 1992;Doering et al. 1995;Yin et al. 2004). A decrease in DIN : SRP ratios, to a certain extent, is generally consistent with the results of bioassays that there is a shift from P to N limitation (Doering et al. 1995;Yin et al. 2001;Smith 2006). Because surface seawater contains low nutrients, most previous studies have focused on changes in riverine nutrient loadings or additional sources of P in estuaries to explain the nonlinear decrease of N : P ratios across the salinity gradient (Fisher et al. 1992;Yin et al. 2004;Harrison et al. 2008).The switch from P-limited riverine water to N limitation with increasing salinity is expected, because surface seawater generally has a DIN : SRP ratio of # 3 (Fanning 1992), although in the Mediterranean Sea, DIN : SRP ratios may exceed the Redfield ratio of 16 in winter (Krom et al. 1991;Kress and Herut 2001). Previous studies have implied that a sudden shift in the limiting nutrient across estuaries is a salinity-related phenomenon (Caraco 1988;Doering et al. 1995), but whether this shift is mainly because of changing riverine loadings, increasing salinity stress, additional sources of phosphorus, or just simply through mixing remains unclear. The linear relationship between a conservative element and salinity during freshwater and seawater mixing is widely used to study biogeochemistry in estuaries and oceans. Although nutrient ratios also are widely used to determine the limiting nutrient in aquatic environments, changes in the nutrient ratio through freshwater and seawater mixing remain unstudied. Thus, whether the changes in nu...

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“…For the micro-algae many of the data relate to Fe-limited, or marginally Felimited, organisms. For the land plant leaves and for H. banksii there is no external evidence of Fe limitation, although there is evidence of Fe limitation of primary productivity in estuarine and coastal environments, and especially those with anthropogenic input of available nitrogen and phosphorus and of Fe-sequestering material (Suzuki et al 1995;Kawaguchi et al 1997;Zhang et al 1999; see also Wells 1999) or on calcareous substrata (Duarte et al 1995).…”

Section: Roles Of and Quantitative Requirement For Fe In The Phaeopmentioning

confidence: 99%

Iron and zinc content ofhormosira banksiiin New Zealand

Cooke

Hurd²,

Lord

et al. 2004

New Zealand Journal of Marine and Freshwater Research

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The Subtropical Zhujiang (Pearl River) Estuary: Nutrient, Trace Species and Their Relationship to Photosynthesis

Cited by 126 publications

References 18 publications

Nitrification and inorganic nitrogen distribution in a large perturbed river/estuarine system: the Pearl River Estuary, China

Nitrification and inorganic nitrogen distribution in a large perturbed river/estuarine system: the Pearl River Estuary, China

Shifts in limiting nutrients in an estuary caused by mixing and biological activity

Iron and zinc content ofhormosira banksiiin New Zealand

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