Fatty acid analysis reveals the trophic interactions among organisms in the Zhelin Bay Marine Ranch

The fatty acid composition in organisms can reflect the trophic level, feeding habits, and utilization of local resources. In the present study, the living resources of different functional areas (artificial reef area, shellfish area, macroalgae area) in the Zhelin Bay Marine Ranch were investigated, and fatty acid analysis was used to elucidate the trophic relations across the food web. The results showed that 22:6ω3 FA (docosahexaenoic acid, DHA), 20:5ω3 FA (eicosapentaenoic acid, EPA), 16:1ω7 FA, and 16:0 FA are fatty acid biomarkers that distinguish carnivorous, omnivorous, and herbivorous organisms. The ratios of DHA/EPA, polyunsaturated fatty acids/saturated fatty acids (PUFA/SFA), and sum of ω3 fatty acids/sum of ω6 fatty acids (Σω3/Σω6) can be used as an important basis to assess the trophic level and feeding habits of organisms. In the comparison of the food web structure of different functional areas, the DHA/EPA ratio of carnivorous organisms in the Artificial Reef area was higher than that in other functional areas due to the abundant living resources, indicating that the food web of the Artificial Reef area presents lower stability to cope with perturbations. Furthermore, MixSIAR was used to quantitatively estimate the diet composition of consumers in the Zhelin Bay Marine Ranch based on their fatty acids. The results of the present study are a valuable contribution to understanding the trophic relationships in the Zhelin Bay Marine Ranch and provide theoretical support for future planning and construction of marine ranches

Low Crosstalk Plastic Optical Fiber-Based Dual-Parameter SPR Sensor With Stepped Side-Polished Structure and Differentiated Au-Film Thickness

peer reviewedIn this article, a surface plasmon resonance (SPR) sensor based on a stepped side-polished plastic optical fiber (POF) is proposed and demonstrated for simultaneous measurement of refractive index (RI) and temperature. A differentiated Au-film thickness was deposited on the stepped polished region, which can enlarge the wavelength space for the SPR peaks of RI and temperature sensing channels and reduce their crosstalk. The polydimethylsiloxane (PDMS) film was fabricated on the polished region with a deeper polished depth and a thicker Au-film thickness for temperature sensing. The stepped polished structure can obtain a better resonance peak visibility for the temperature sensing. The experimental results show that the RI sensitivity of the sensor is 1759 nm/RIU in the RI range of 1.335-1.37 and the temperature sensitivity is -0.82 nm/°C in the temperature range of 20 °C-80 °C. The probe has the advantages of easy fabrication and simple structure, which has potential application prospect in the field of biochemical sensing

An MMF-HCF Reflective SPR Sensor for Simultaneous Measurement of Temperature and Relative Humidity

peer reviewedIn this article, a reflective surface plasmon resonance (SPR) sensor based on multimode fiber (MMF)-hollow core fiber (HCF) structure is proposed for simultaneous measurement of temperature and humidity. Along the HCF, two different films, i.e., polyvinyl alcohol (PVA) film and polydimethylsiloxane (PDMS) film are coated on the outer surface to generate two SPR resonances at different wavelengths and achieve the simultaneous measurement function. In order to get a better sensing performance, the length ratio of PVA film and PDMS film, and the PVA coating times are optimized. The experimental results show that the humidity sensitivity of the sensor is 0.6351 nm/% relative humidity (RH) in the RH range of 48%-84% RH, and the temperature sensitivity of the sensor is 1.791 nm/°C in the temperature measurement range of 25 °C-80 °C. The sensor has great potential applications in monitoring the environmental temperature and humidity changes

Density, Storage and Distribution of Carbon in Mangrove Ecosystem in Guangdong's Coastal Areas

Using the mangrove plants and sediment of the typical mangrove areas in Guangdong's coastal areas, P. R. China as the research object, the density, storage and spatial distribution of carbon are studied. The study method is the combination of the wild field analysis and laboratory testing method. The results show that the carbon density of the sediment will gradually decrease because of the increased depth, and has nothing to do with the difference of the area and tree species. The average carbon density of 50cm sediment is 0.007gC/g. The carbon density is obviously different in different components of different mangrove species in different regions. The total carbon storage in different regions is in the following order: Zhuhai＞Gaoqiao＞Shenzhen＞Shuidong Bay＞Guanghai Bay＞Raoping＞Daya Bay＞Chenghai. The carbon density and carbon storage are obviously higher in mangrove covered area than blank area. It shows that mangroves have very strong carbon sink function

Marine Organisms in a Rapidly Changing Ocean

Oceans are changing due to intensive human activities and worsening climate change [...

Research Advances on Marine Ecological Effect and Repairing Techniques of Coastal Mangrove Wetland

Coastal mangrove wetland is one of the areas whose global ecological environmental conditions have severely changed. Its ecosystem is vulnerable to damaged. The international community has paid attention to conservation and wisely use of mangrove wetland. This paper describes five parts of coastal mangrove wetland at home and abroad, including seawater’s purification effect of nitrogen and phosphorus, seawater’s adsorption of heavy metals, the functions of carbon sequestration and climate regulation, implant restoration techniques and the status of protection and management .And research trends of coastal mangrove wetland were proposed, in order to provide reference for the restoration and protection of China's coastal mangrove wetland

Habitat Enrichment Causes Changes in Fish Behavioural Characteristics: A Case Study of <i>Sparus latus</i>

To better understand the habitat preferences and behavioural ecology of Sparus latus, we performed an experiment using box-shaped reefs as habitat enrichment materials, allowing us to determine the behavioural strategies and drivers involved in the response to different enrichment structures. The results showed that the first contact time of S. latus was negatively correlated (Pearson’s correlation, p S. latus, and there was a significant difference in the average distribution rate between the control and treatment groups (Adonis, p R2 = 0.36) explained the distribution difference of S. latus better than the opening shape (Adonis, R2 = 0.12). In the absence of an enrichment structure, S. latus remained more active during the daytime, exhibiting poor clustering, while in the presence of an enrichment structure, S. latus exhibited clustered movement at night. The opening ratio was negatively correlated with the average interindividual distance (Spearman’s correlation, p p S. latus. The light intensity was negatively correlated with the average distance moved, and the average speed (Spearman’s correlation, p p S. latus. These results provide a research basis for analysing the pattern and process of fish proliferation induced by artificial reef habitats

Effects of Light Color on the Growth, Feeding, Digestion, and Antioxidant Enzymes of <i>Tripneustes gratilla</i> (Linnaeus, 1758)

To study the effects of light color on sea urchin (Tripneustes gratilla), blue light (B, λ450nm), yellow light (Y, λ585–590nm), red light (R, λ640nm), green light (G, λ510nm), white light (W, λ400–780nm), and darkness (H) groups were established in a recirculating seawater aquaculture system. Six different LED light color treatment groups with a photoperiod of 12 L:12 D were tested for 30 days to investigate the effects of different light colors on the feeding, growth, and enzyme activities of T. gratilla (142.45 ± 4.36 g). We found that using different LED light colors caused significantly different impacts on the feeding, growth, and enzyme activity of T. gratilla. Notably, the sea urchins in group B exhibited better growth, with a weight gain rate of 39.26%, while those in group R demonstrated poorer growth, with a weight gain rate of only 26%. The feeding status differed significantly (p p > 0.05). Conversely, the pepsin viability significantly increased (p p p T. gratilla in comparison with those in other light environments, whereas red light had an inhibitory effect. Furthermore, T. gratilla is a benthic organism that lives on shallow sandy sea beds. Thus, as short wavelengths of blue and green light are more widely distributed on the seafloor, and long wavelengths of red light are more severely attenuated on the seafloor, shorter wavelengths of light promote the growth of bait organisms of sea urchins, which provide better habitats for T. gratilla

Development Path of Marine Ranching in South China Sea Based on SWOT Analysis

As a modern fishery model to repair the marine ecosystem and realize the proliferation of fishery resources, marine ranching is an important link in promoting the green development of marine economy, promoting the transformation and upgrading of traditional fisheries and building a community of shared future for the sea. However, there are many factors restricting the high-quality development of modern marine ranching in the actual construction. Rational planning of marine ranching and giving full play to its ecological, social and economic benefits are crucial to the sustainable development of marine ranching. This paper summarizes the current situation of the construction, technical development and policy management of marine ranching in the South China Sea, and comprehensively analyzes the development of marine ranching in the South China Sea by using SWOT analysis method, explains the advantages, disadvantages, opportunities and challenges of marine ranching in the South China Sea, and puts forward the path for the development of marine ranching industry in the South China Sea based on the experience and development trend of marine ranching construction at home and abroad, It is expected to provide reference for the high-quality development of marine ranching in China

Strategy of Stock Enhancement Using EnhanceFish Model: A Case of Acanthopagrus latus Enhancement in Nanlang Water Area, Zhongshan City

In recent years, the fishery resources in China's coastal and inland waters have declined seriously, along with a significant decrease in the number of economic fish stocks in many natural waters. Enhancement and release are important measures to conserve fishery resources, protect biodiversity and replenish the fishery environment. Since the 1980s, enhancement and release have gradually become an important way to increase fishery resources in China. With the yearly increase in variety, quantity, and scale of enhancement and release, the problem with the low efficiency of enhancement and release has become increasingly prominent. Therefore, a scientific and reasonable variant of the enhancement and release technique is the key to ensure its successful role in resource proliferation, including prior scientific planning as well as an accurate evaluation post release. At present, there are many studies on release assessment methods. Ecopath model method and empirical assessment method are often used to carry out pre-release planning research. Ecopath model method determines the release quantity in the water area by calculating the ecological capacity of the release water area. However, this method, like the empirical assessment method has the disadvantage of an extensive assessment of the capacity limiting its accuracy in planning the release quantity. The commonly used methods for evaluating the effect of post-release include external tagging method and statistical evaluation method. The external tagging method causes certain damage to fish and has poor stability, making it unsuitable for large-scale enhancement and releasing. The statistical evaluation method needs regular follow-up post release, making it manpower-, resources- as well as cost-intensive. In order to formulate scientific enhancement and release strategies and improve the effect of breed enhancement and release, the EnhanceFish model was introduced in this study using Acanthopagrus latus as the research object, Nanlang water area as the research area, and considering the life cycle, growth rate, mortality, sexual maturity, heritability, recruitment, economic cost and effort as the study parameters. The enhancement and release model of A. latus in Nanlang water was constructed, and the optimal release size, ecological capacity, population structure, and economic benefits of A. latus were scientifically evaluated in order to provide scientific guidance for the rational and standardized formulation of enhancement and release strategies.In this study, the effects of spawning stock biomass, profit, and fishing effort on the ecological structure of A. latus were comprehensively considered, and an intuitive data model was constructed to determine the range of release quantity and fishing effort. The results showed that the natural recruitment amount increased with the increase in releasing quantity. When the release quantity was 2 million, the natural recruitment amount reached the progressive value of 1.6 million. Therefore, the number of A. latus released in Nanlang water area was 0-1.6 million. While evaluating the relationship between fishing effort and economic benefit before release, the profit was 1 000 CNY assuming the current fishing effort E=1. When the fishing effort was E 1, the profit decreased with the increase in fishing effort. When it was E > 2, the profit was 2 000 CNY, which has no research value. Therefore, the limit of fishing effort E is 0-2