Evaluation of the ecological status of shallow-water coral reefs in China using a novel method and identification of environmental factors for coral decline.

Coral reefs worldwide have faced extensive damage due to natural catastrophes and anthropogenic disturbances.The decline can cause their widespread collapse and an inability to recover from natural disturbances, highlighting the urgent need for their protection. This study conducted an extensive ecological condition assessment of seven coral reef regions in China's offshore. Our findings revealed the presence of 204 species of scleractinian corals belonging to 16 families. Massive corals were the predominant reef-building corals in all regions. The degradation of coral reef ecosystems was apparent in the present compared to historical reef conditions. The ecosystem suffered varying degrees of damage in surveyed regions according to a novel assessment approach, impling more effective measures should be taken to mitigate the local pressures. Our research establishes a baseline for understanding the status of coral reefs that can be used in future and provides a crucial foundation to designate protective zones for their conservation.

The identification of fish eggs of two species, the ovate sole Solea ovata and black porgy Acanthopagrus schlegelii.

Fish eggs of the ovate sole Solea ovata and black porgy Acanthopagrus schlegelii were identified through DNA barcoding of cytochrome c oxidase subunit I (COX1). Visual taxonomic features were achieved, and photographs of the eggs of both species at different developmental stages were reported for the first time. In addition, the dissolution of oil globules caused by ethanol as egg fixatives was observed. This result showed the importance of using formalin as egg fixatives in the case of morphometric analysis and the necessity of combining molecular and visual taxonomic method for morphological study.

Radioactive status of seawater and its assessment in the northeast South China Sea and the Luzon Strait and its adjacent areas from 2011 to 2014.

To understand the impact of the Fukushima nuclear accident (FNA), 137Cs, 134Cs, 90Sr, and gross beta were analyzed in the northeast South China Sea (NSCS), the Luzon Strait (LS) and its adjacent areas. 137Cs, 90Sr, and gross beta values in the NSCS were similar to those prior to the FNA. 90Sr and 137Cs in the LS and its adjacent areas were consistent with those in the NSCS. The high 137Cs-peak values occurred at depth of 150 m whereas the high 90Sr-peak values occurred at depth of 0.5 m. The 137Cs and gross beta mean values in Cruise I were higher than those in Cruise II whereas the 90Sr mean value was just the reverse. 134Cs in all seawater were below the minimum detectable activity. The past and present data since the 1970s suggested 137Cs and 90Sr in the study areas still originated from global fallout and the FNA influence were negligible.

Bacterial Communities in the Rhizospheres of Three Mangrove Tree Species from Beilun Estuary, China.

The bacterial communities played important roles in the high productivity mangrove ecosystem. In this study, we investigated the vertical distributions of rhizosphere bacteria from three mangrove species (Bruguiera gymnorrhiza, Kandelia candel and Aegiceras corniculatum) in Beilun Estuary, China using high throughput DNA pyrosequencing of the 16S rRNA gene. Phylogenetic analysis showed that bacterial communities from mangrove rhizosphere sediments were dominated by Proteobacteria (mostly Deltaproteobacteria and Gammaproteobacteria), followed by Chloroflexi, Bacteroidetes, Planctomycetes and Acidobacteria. However, the ANOVA analysis on Shannon and Chao1 indices indicated that bacterial communities among sediments of the three mangrove species varied more strongly than the sampling depths. In addition, the PCA result demonstrated that the bacterial communities could be separated into three groups according to the mangrove species. Moreover, the dominated orders Rhodospirillales, GCA004 and envOPS12 were significantly different among sediments of the three mangrove species. The results of this study provided valuable information about the distribution feature of rhizosphere bacteria from Chinese mangrove plants and shed insights into biogeochemical transformations driven by bacteria in rhizosphere sediments.

Landscape ecological security assessment based on projection pursuit in Pearl River Delta.

Regional landscape ecological security is an important issue for ecological security, and has a great influence on national security and social sustainable development. The Pearl River Delta (PRD) in southern China has experienced rapid economic development and intensive human activities in recent years. This study, based on landscape analysis, provides a method to discover the alteration of character among different landscape types and to understand the landscape ecological security status. Based on remotely sensed products of the Landsat 5 TM images in 1990 and the Landsat 7 ETM+ images in 2005, landscape classification maps of nine cities in the PRD were compiled by implementing Remote Sensing and Geographic Information System technology. Several indices, including aggregation, crush index, landscape shape index, Shannon's diversity index, landscape fragile index, and landscape security adjacent index, were applied to analyze spatial-temporal characteristics of landscape patterns in the PRD. A landscape ecological security index based on these outcomes was calculated by projection pursuit using genetic algorithm. The landscape ecological security of nine cities in the PRD was thus evaluated. The main results of this research are listed as follows: (1) from 1990 to 2005, the aggregation index, crush index, landscape shape index, and Shannon's diversity index of nine cities changed little in the PRD, while the landscape fragile index and landscape security adjacent index changed obviously. The landscape fragile index of nine cities showed a decreasing trend; however, the landscape security adjacent index has been increasing; (2) from 1990 to 2005, landscape ecology of the cities of Zhuhai and Huizhou maintained a good security situation. However, there was a relatively low value of ecological security in the cities of Dongguan and Foshan. Except for Foshan and Guangzhou, whose landscape ecological security situation were slightly improved, the cities had reduced values in landscape ecological security, with the most decreased number 0.52 in Zhaoqing. Results of this study offer important information for regional eco-construction and natural resource exploitation.