[Ecological characteristics and seasonal changes of macrozoobenthos in the waters of Miaodao Archipelago, China]. / åº™å²›ç¾¤å²›æµ·åŸŸå¤§åž‹åº•æ –åŠ¨ç‰©ç”Ÿæ€ç‰¹å¾åŠå­£èŠ‚å˜åŒ–.

To understand the macrozoobenthic community composition and spatial-temporal distribution characteristics of macrobenthos in the waters of Miaodao Archipelago, Yantai, Shandong and its response to habitat changes, we conducted surveys of macrobenthos and environmental elements in the waters of Miaodao Islands in May (spring), August (summer), and October (autumn) in 2022. Results showed that a total of 127 macrozoobenthic species were recorded, with Mollusca and Annelida (Polychaeta) as the dominant taxa, consisting of 47 and 45 species, respectively. The key dominant species included Sternaspis chinensis, Glycinde bonhourei, Moerella hilaris, and Amphioplus (Lymanella) japonicus. The average annual density and biomass of macrozoobenthos were 190 ind·m-2 and 28.69 g·m-2, respectively. There was no significant seasonal differences in density and biomass. The Shannon diversity index (H), evenness index (J), and richness index (D) averaged 3.10, 0.90, and 2.40, respectively. Cluster analysis results showed low similarity coefficients of community among the three seasons, suggesting a distinct distribution pattern. Factors such as bottom seawater temperature, chlorophyll a, nutrient, sediment grain size, and organic matter content could significantly influence the structure and diversity of macrozoobenthic community. Compared with historical research data, the Changdao National Wetland Nature Reserve and the implementation of enclosure aquaculture have led to notable changes in the dominant species of macrobenthos. Specifically, there was a noticeable decline in both density and H, and an increase in biomass and J. Additionally, body size of benthic fauna was transitioning from small to big.

[Impacts of Spartina alterniflora invasion on the benthic food web in the Yellow River Delta during autumn]. / äº’èŠ±ç±³è‰å ¥ä¾µå¯¹é»„æ²³ä¸‰è§’æ´²ç§‹å­£åº•æ –é£Ÿç‰©ç½‘çš„å½±å“.

Spartina alterniflora was introduced into the Yellow River Delta (YRD) in 1990 with the purpose of shore protection and siltation accretion. However, it spread rapidly and became a severe threat to the local coastal wetland ecosystem. To assess the impacts of S. alterniflora invasion on the benthic food web, we sampled the potential food sources of macrobenthos in November 2020, analyzed the trophic level and the benthic food web structure based on stable isotope technique. Results showed that the average δ13C values of macrobenthic food sources followed an order: sediment organic matter (SOM) > S. alterniflora > benthic microalgae > particulate organic matter (POM) > Suaeda salsa. The average δ15N values significantly differed among food sources, ranging from 1.24‰ to 9.03‰. The trophic levels of different macrobenthos ranged from 1.73 to 4.19, of which the bivalve species was the lowest one. S. alterniflora and the decayed debris were the most important food sources for macrobenthos, but without any impact on the trophic level structure of macro-benthos. In conclusion, Spartina alterniflora invasion distinctly changed the composition of food sources of macrobenthos through a "bottom-up" effect, which would probably impact the local food web structure in the YRD wetland.

[Novel transmission element of antibiotic resistance genes ISCR and its ecological risk].

Antibiotic resistance genes (ARGs) as emerging environmental pollutants have become the focus of attention of many disciplines. The transmission and dissemination of ARGs in various environmental media has great hazards to environment and poses serious threat to human health. ISCR (insertion sequence common regions) elements are newly discovered resistance genes transmission elements. Because of the special genetic structure, ISCR elements can move any adjacent DNA sequences by rolling-circle replication and homologous recombination, and have become the efficient transmission elements of ARGs among different DNA molecules or bacterial species. Around the world, 27 members of the ISCR family have been discovered up to now. A lot of circumstantial evidence has indicated that ISCR elements may be associated with the mobility and transmission of kinds of ARGs, especially multiple drug resistance genes (MDR). In this review, we described some aspects of ISCR elements, including the horizontal transfer of ARGs, structural characteristics of ISCRs, classification of ISCRs and their related ARGs, research methods of these elements, possible ecological risk of ISCRs and proposal of research directions, hoping to provide help for further related research in the future.

Highly efficient esterification of ferulic acid under microwave irradiation.

A highly efficient synthesis of alkyl ferulates under microwave irradiation is described. The time of these reactions ranged from 3 to 5 minutes, which was much shorter than the traditional synthetic methods, and the alkyl ferulates were obtained in higher yields.