Phosphorus limitation in the northern South China Sea during late summer: Influence of the Pearl River

Xu, Jie; Yin, Kedong; He, Lei; Yuan, Xiangcheng; Ho, Alvin Yam Tat; Harrison, Paul J.

doi:10.1016/j.dsr.2008.05.007

Cited by 102 publications

(67 citation statements)

References 45 publications

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“…The nSCS has experienced some dramatic change during the last several decades, mainly caused by intensified anthropogenic activities. Recent studies indicated that the bioproductivity of nSCS might be limited by P in estuarine and coastal areas (71,72). Our data showed that the two shallowest sampling sites, A3 and E501, indeed had quite low sediment pore water PO 4 3Ϫ concentrations (Table 1).…”

Section: Discussionsupporting

confidence: 50%

Environment-Dependent Distribution of the Sediment nifH -Harboring Microbiota in the Northern South China Sea

Dang

Yang

et al. 2013

Appl Environ Microbiol

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fThe South China Sea (SCS), the largest marginal sea in the Western Pacific Ocean, is a huge oligotrophic water body with very limited influx of nitrogenous nutrients. This suggests that sediment microbial N 2 fixation plays an important role in the production of bioavailable nitrogen. To test the molecular underpinning of this hypothesis, the diversity, abundance, biogeographical distribution, and community structure of the sediment diazotrophic microbiota were investigated at 12 sampling sites, including estuarine, coastal, offshore, deep-sea, and methane hydrate reservoirs or their prospective areas by targeting nifH and some other functional biomarker genes. Diverse and novel nifH sequences were obtained, significantly extending the evolutionary complexity of extant nifH genes. Statistical analyses indicate that sediment in situ temperature is the most significant environmental factor influencing the abundance, community structure, and spatial distribution of the sediment nifH-harboring microbial assemblages in the northern SCS (nSCS). The significantly positive correlation of the sediment pore water NH 4 ؉ concentration with the nifH gene abundance suggests that the nSCS sediment nifH-harboring microbiota is active in N 2 fixation and NH 4 ؉ production. Several other environmental factors, including sediment pore water PO 4 3؊ concentration, sediment organic carbon, nitrogen and phosphorus levels, etc., are also important in influencing the community structure, spatial distribution, or abundance of the nifH-harboring microbial assemblages. We also confirmed that the nifH genes encoded by archaeal diazotrophs in the ANME-2c subgroup occur exclusively in the deep-sea methane seep areas, providing for the possibility to develop ANME-2c nifH genes as a diagnostic tool for deep-sea methane hydrate reservoir discovery.

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Section: Discussionsupporting

confidence: 50%

Environment-Dependent Distribution of the Sediment nifH -Harboring Microbiota in the Northern South China Sea

Dang

Yang

et al. 2013

Appl Environ Microbiol

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“…Moreover, the fact that the annual rates of DIN and DIN:P were higher in the shallow water area (<200 m) than in the deep water area (>200 m) (Table 1) suggested the influence of the anthropogenic activities on the ecosystems of the shallow or coastal waters. These results agree well with Xu et al (2008) who also showed that N input from the Pearl River has caused the nSCS to become P-limited. Phosphate decline may be ascribed to the implementation of phosphate detergent ban in the late 1990s, and phytoplankton great consumption.…”

Section: Increasing Trends and The Response Of The Ecosystemsupporting

confidence: 82%

“…It has previously been observed that the occurrence of low SSS often corresponded to abnormally high discharge of the Pearl River (Xie and Zhang, 2003;Xu et al, 2008). During the period of 1990 to 2000, the Pearl River runoff increased by 22.5% in comparison with the mean discharge for 1960-1999 (Lei et al, 2003).…”

Section: Decreasing Trends and The Response Of The Ecosystemmentioning

confidence: 99%

Long term changes in the ecosystem in the northern South China Sea during 1976–2004

et al. 2009

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Abstract. Physical and chemical oceanographic data were obtained by seasonal monitoring along a transect (Transect N) in the northern South China Sea (nSCS) during 1976-2004. Fluctuations of DIN (dissolved inorganic nitrogen), seawater temperature (SST and T av -average temperature of the water column), N:P ratio and salinity (S av and S 200 -salinity at the 200 m layer) exhibited an increasing trend, while those of T 200 , DO, P, Si, Si:N and SSS exhibited a decreasing trend. The annual rates of change in DIN, DO, T and S revealed pronounced changes, and the climate trend coefficients, which was defined as the correlation coefficient between the time series of an environmental parameter and the nature number (namely 1,2,3,. . . . . . n), were 0.38 to 0.89 and significant (p≤0.01 to 0.05). Our results also showed that the ecosystem has obviously been influenced by the positive trends of both SST and DIN, and negative trends of both DO and P. For example, before 1997, DIN concentrations in the upper layer were very low and N:P ratios were less than half of the Redfield ratio of 16, indicating potential N limitation. However after 1997, all Si:P ratios were >22 and the N av :P av was close to the Redfield ratio, indicating potential P limitation, and therefore N limitation has been reduced after 1997.

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“…5). The unique phosphonate uptake mechanism may indicate the genetic and ecophysiological adaptability of thaumarchaeota to P-limited conditions in marine environments, such as the nSCS (48,49). No significant correlation was found between the abundance of thaumarchaeol and any of the thaumarchaeotal amoA, hcd, or MGI 16S rRNA gene abundances in nSCS surface sediments (data not shown).…”

Section: Fig 4 Cca Ordination Plot For the First Two Dimensions (Cca1mentioning

confidence: 70%

“…The presence of this P-scavenging genetic inventory indicates the importance of inorganic-P acquisition for thaumarchaeotal ecophysiology. Recent studies have suggested that the nutrient regime of the nSCS ecosystem has been changing from N-limited to P-limited conditions, especially in its estuarine and coastal areas (48,49). The importance of P availability (including both PO 4 3Ϫ and OrgP) to the amoA-bearing thaumarchaeota po- tentially identifies a previously overlooked linkage of N, C, and P cycles in marine environments.…”

Section: Fig 4 Cca Ordination Plot For the First Two Dimensions (Cca1mentioning

confidence: 99%

Thaumarchaeotal Signature Gene Distribution in Sediments of the Northern South China Sea: an Indicator of the Metabolic Intersection of the Marine Carbon, Nitrogen, and Phosphorus Cycles?

Dang

Zhou

Yang

et al. 2013

Appl Environ Microbiol

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f Thaumarchaeota are abundant and active in marine waters, where they contribute to aerobic ammonia oxidation and light-independent carbon fixation. The ecological function of thaumarchaeota in marine sediments, however, has rarely been investigated, even though marine sediments constitute the majority of the Earth's surface. Thaumarchaeota in the upper layer of sediments may contribute significantly to the reservoir of nitrogen oxides in ocean waters and thus to productivity, including the assimilation of carbon. We tested this hypothesis in the northern South China Sea (nSCS), a section of a large oligotrophic marginal sea with limited influx of nutrients, including nitrogen, by investigating the diversity, abundance, community structure, and spatial distribution of thaumarchaeotal signatures in surface sediments. Quantitative real-time PCR using primers designed to detect 16S rRNA and amoA genes in sediment community DNA revealed a significantly higher abundance of pertinent thaumarchaeotal than betaproteobacterial genes. This finding correlates with high levels of hcd genes, a signature of thaumarchaeotal autotrophic carbon fixation. Thaumarchaeol, a signature lipid biomarker for thaumarchaeota, constituted the majority of archaeal lipids in marine sediments. Sediment temperature and organic P and silt contents were identified as key environmental factors shaping the community structure and distribution of the monitored thaumarchaeotal amoA genes. When the pore water PO 4 3؊ concentration was controlled for via partial-correlation analysis, thaumarchaeotal amoA gene abundance significantly correlated with the sediment pore water NO 2 ؊ concentration, suggesting that the amoA-bearing thaumarchaeota contribute to nitrite production. Statistical analyses also suggest that thaumarchaeotal metabolism could serve as a pivotal intersection of the carbon, nitrogen, and phosphorus cycles in marine sediments.

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Phosphorus limitation in the northern South China Sea during late summer: Influence of the Pearl River

Cited by 102 publications

References 45 publications

Environment-Dependent Distribution of the Sediment nifH -Harboring Microbiota in the Northern South China Sea

Environment-Dependent Distribution of the Sediment nifH -Harboring Microbiota in the Northern South China Sea

Long term changes in the ecosystem in the northern South China Sea during 1976–2004

Thaumarchaeotal Signature Gene Distribution in Sediments of the Northern South China Sea: an Indicator of the Metabolic Intersection of the Marine Carbon, Nitrogen, and Phosphorus Cycles?

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