RECENT CASE NOTES

<p><i>Notes</i>: H-sites and L-sites refer to high-tide-zone sites and low-tide-zone sites, respectively.</p><p>Results of <i>t</i>-test for effects of different stands on aboveground net primary production (ANPP), soil pH, total carbon (TC), organic and inorganic carbon (SOC and SIC, 0–100 cm), and SMBC.</p

Effects of Spartina alterniflora invasion on soil respiration in the Yangtze River estuary, China.

Many studies have found that plant invasion can enhance soil organic carbon (SOC) pools, by increasing net primary production (NPP) and/or decreased soil respiration. While most studies have focused on C input, little attention has been paid to plant invasion effects on soil respiration, especially in wetland ecosystems. Our study examined the effects of Spartina alterniflora invasion on soil respiration and C dynamics in the Yangtze River estuary. The estuary was originally occupied by two native plant species: Phragmites australis in the high tide zone and Scirpus mariqueter in the low tide zone. Mean soil respiration rates were 185.8 and 142.3 mg CO2 m(-2) h(-1) in S. alterniflora and P. australis stands in the high tide zone, and 159.7 and 112.0 mg CO2 m(-2) h(-1) in S. alterniflora and S. mariqueter stands in the low tide zone, respectively. Aboveground NPP (ANPP), SOC, and microbial biomass were also significantly higher in the S. alterniflora stands than in the two native plant stands. S. alterniflora invasion did not significantly change soil inorganic carbon or pH. Our results indicated that enhanced ANPP by S. alterniflora exceeded invasion-induced C loss through soil respiration. This suggests that S. alterniflora invasion into the Yangtze River estuary could strengthen the net C sink of wetlands in the context of global climate change

Pyrene-Based Fluorescent Porous Organic Polymers for Recognition and Detection of Pesticides

Eating vegetables with pesticide residues over a long period of time causes serious adverse effects on the human body, such as acute poisoning, chronic poisoning, and endocrine system interference. To achieve the goal of a healthy society, it is an urgent issue to find a simple and effective method to detect organic pesticides. In this work, two fluorescent porous organic polymers, LNU-45 and LNU-47 (abbreviation for Liaoning University), were prepared using π-conjugated dibromopyrene monomer and boronic acid compounds as building units through a Suzuki coupling reaction. Due to the large π-electron delocalization effect, the resulting polymers revealed enhanced fluorescence performance. Significantly, in sharp contrast with the planar π-conjugated polymer framework (LNU-47), the distorted conjugated structure (LNU-45) shows a higher specific surface area and provides a broad interface for analyte interaction, which is helpful to achieve rapid response and detection sensitivity. LNU-45 exhibits strong fluorescence emission at 469 nm after excitation at 365 nm in THF solution, providing strong evidence for its suitability as a luminescent chemosensor for organic pesticides. The fluorescence quenching coefficients of LNU-45 for trifluralin and dicloran were 5710 and 12,000 (LNU-47 sample by ca. 1.98 and 3.38 times), respectively. Therefore, LNU-45 serves as an effective “real-time” sensor for the detection of trifluralin and dicloran with high sensitivity and selectivity

Locations of sampling transects and sites in the Dongtan wetland of Chongming Island, the Yangtze River estuary, China.

<p>The study area was drawn using ArcGIS software, with remote sensing data set MOD09Q1of 2009 downloaded from NASA Earth Observatory without copyright restrictions.</p

Soil microbial biomass carbon in different plant stands.

<p>Seasonal variations in soil microbial biomass carbon (SMBC) content (0–20 cm deep) in the <i>S</i>. <i>alterniflora</i> (<i>Spartina</i>) and <i>P</i>. <i>australis</i> (<i>Phragmites</i>) stands in the H-sites, and <i>S</i>. <i>alterniflora</i> and <i>S</i>. <i>mariqueter</i> (<i>Scirpus</i>) stands in the L-sites. Bars represent mean ± SE (n = 9), asterisks indicate significant differences (<i>P</i> < 0.05) between means of different stands.</p

Temporal variations in soil temperature and moisture in different plant stands.

<p>Temporal variations in soil temperature (a, b) and moisture (c, d) at 0–5 cm depth in the <i>S</i>. <i>alterniflora</i> (<i>Spartina</i>) and <i>P</i>. <i>australis</i> (<i>Phragmites</i>) stands in the H-sites, <i>S</i>. <i>alterniflora</i> and <i>S</i>. <i>mariqueter</i> (<i>Scirpus</i>) stands in the L-sites. Bars represent mean ± SE (n = 9), asterisks indicate significant differences (<i>P</i> < 0.05) between means of different stands.</p

Temporal variations in soil respiration in different plant stands.

<p>Temporal variations in soil respiration under <i>S</i>. <i>alterniflora</i> (<i>Spartina</i>) and <i>P</i>. <i>australis</i> (<i>Phragmites</i>) stands in the H-sites, and <i>S</i>. <i>alterniflora</i> and <i>S</i>. <i>mariqueter</i> (<i>Scirpus</i>) stands in the L-sites. Bars represent mean ± SE (n = 9), asterisks indicate significant differences (<i>P</i> < 0.05) between means of different stands.</p