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Dive into the research topics where Ding He is active.

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Featured researches published by Ding He.


Chemosphere | 2015

Occurrence and distribution of monomethylalkanes in the freshwater wetland ecosystem of the Florida Everglades

Ding He; Bernd R.T. Simoneit; Blanca Jara; Rudolf Jaffé

A series of mono-methylalkanes (MMAs) with carbon numbers from C10 to C23 and C29 were detected in freshwater wetlands of the Everglades. A decrease in concentration and molecular complexity was observed in the order from periphyton and floc, to surface soil and deeper soil horizons. These compounds were present in varying amounts up to 27 μg gdw(-1) in periphyton, 74 μg gdw(-1) in floc, 1.8 μg gdw(-1) in surface soil, <0.03 μg gdw(-1) in deeper soils (12-15 cm). A total of 46 MMAs, including three iso and three anteiso-alkanes, were identified. Compound specific carbon isotopes values were determined for some dominant MMAs, and suggest that they originate from microbial sources, including cyanobacteria. Potential decarboxylation from fatty acids could also potentially contribute to the MMAs detected. Early diagenetic degradation was suggested to affect the accumulation of MMAs in soils and further studies are needed to address their applications as biomarkers.


Environmental Chemistry | 2016

Compositions and isotopic differences of iso- and anteiso-alkanes in black mangroves (Avicennia germinans) across a salinity gradient in a subtropical estuary

Ding He; Bernd R.T. Simoneit; Blanca Jara; Rudolf Jaffé

Environmental context Mangroves dominate at the interface between land and sea, especially along tropical and subtropical coasts. To gain a better understanding of how mangroves respond to various environmental stress factors, we investigated the use of monomethylalkanes as potential chemical tracers for black mangroves. The application of these chemical tracers could elucidate how black mangroves respond to environmental stress such as sea level rise in mixed mangrove environments. Abstract A series of iso- and anteiso-monomethylalkanes (MMAs) with carbon numbers from C23 to C35 and C14 to C34 respectively were detected in Avicennia germinans. These compounds were present in varying amounts up to 54.1, 1.0 and 3.4µg g–1 dry weight in the leaves, bark and the crustose lichens attached to the bark of A. germinans respectively. These MMAs were not detected in the leaf waxes of Rhizophora mangle and Laguncularia racemosa, but were detected in significantly lower abundances (2–6% of that in A. germinans leaf wax) in the bark and lichen of R. mangle. Significant odd-carbon number distributions and even-carbon number distributions were observed for long chain (C ≥ 25) iso- (maximising at C31) and anteiso-MMAs (maximising at C32) respectively in A. germinans leaf wax. However, no obvious carbon number preferences were detected for bark and lichen. The long chain (LC) iso- and anteiso-MMAs in A. germinans leaf waxes were found to be enriched in 13C by 0.3–4.3 and 0.7–4.2 per mille (‰) compared to the n-alkanes with the same carbon numbers respectively across the salinity gradient of 19.7–32.0 practical salinity units (psu). In comparison, the LC iso- and anteiso-MMAs were found to be more depleted in D by 6.1–55.1 and 7.3–57.0 ‰ compared to the n-alkanes with same carbon numbers respectively. The results imply that A. germinans could be another important source of iso- and anteiso-alkanes in sediments and soils, and that these compounds could potentially be used as biomarkers for this species in mixed mangrove environments.


Scientific Reports | 2018

Environmental factors controlling the distributions of Botryococcus braunii (A, B and L) biomarkers in a subtropical freshwater wetland

Ding He; Bernd R.T. Simoneit; Rudolf Jaffé

Here we report the molecular biomarker co-occurrence of three different races of Botryococcus braunii (B. braunii) in the freshwater wetland ecosystem of the Florida Everglades, USA. Thespecific biomarkers include C32–C34 botryococcenes for race B, C27–C32n-alkadienes and n-alkatrienes for race A, and lycopadiene for race L. The n-alkadienes and n-alkatrienes were present up to 3.1 and 69.5 µg/g dry weight (dw), while lycopadiene was detected in lower amounts up to 3.0 and 1.5 µg/g dw in periphyton and floc samples, respectively. Nutrient concentrations (P and N) did not significantly correlate with the abundances of these compounds. In contrast, n-alkadienes and n-alkatrienes were present in wider diversity and higher abundance in the floc from slough (deeper water and longer hydroperiod) than ridge (shallower water and shorter hydroperiod) locations. n-Alkadienes, n-alkatrienes, and lycopadiene, showed lower δ13C values from −40.0 to −35.5‰, suggesting that the source organisms B. braunii at least partially utilize recycled CO2 (13C depleted) produced from OM respiration rather than atmospheric CO2 (13C enriched) as the major carbon sources.


Organic Geochemistry | 2014

Assessing Source Contributions to Particulate Organic Matter in a Subtropical Estuary: A biomarker approach

Ding He; Ralph N. Mead; Laura L. Belicka; Oliva Pisani; Rudolf Jaffé


Organic Geochemistry | 2016

Occurrence of unsaturated C25 highly branched isoprenoids (HBIs) in a freshwater wetland

Ding He; Bernd R.T. Simoneit; Yunping Xu; Rudolf Jaffé


Phytochemistry Letters | 2015

Gas chromatography mass spectrometry based profiling of alkyl coumarates and ferulates in two species of cattail (Typha domingensis P., and Typha latifolia L.)

Ding He; Bernd R. T. Simoneit; Blanca Jara; Rudolf Jaffé


Organic Geochemistry | 2017

Inverse relationship between salinity and 2H/1H fractionation in leaf wax n-alkanes from Florida mangroves

Ding He; S. Nemiah Ladd; Julian P. Sachs; Rudolf Jaffé


Aquatic Sciences | 2016

Compound specific δD and δ13C analyses as a tool for the assessment of hydrological change in a subtropical wetland

Ding He; William T. Anderson; Rudolf Jaffé


Journal of Geophysical Research | 2018

Sheet Flow Effects on Sediment Transport in a Degraded Ridge-and-Slough Wetland: Insights Using Molecular Markers

Peter Regier; Ding He; Colin J. Saunders; Blanca Jara; Chris Hansen; Susan Newman; Erik Tate-Boldt; Carlos Coronado-Molina; Rudolf Jaffé


Archive | 2016

He et al., 2016, Org Geochem, C25 HBI in fresh wetland

Ding He; Bernd R. T. Simoneit; Yunping Xu; Rudolf Jaffé

Collaboration


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Rudolf Jaffé

Florida International University

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Blanca Jara

Florida International University

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Bernd R. T. Simoneit

Florida International University

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Yunping Xu

Florida International University

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Carlos Coronado-Molina

South Florida Water Management District

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Chris Hansen

South Florida Water Management District

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Colin J. Saunders

South Florida Water Management District

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Erik Tate-Boldt

South Florida Water Management District

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