Marine pollution bulletin最新文献

The Baltic Sea highly susceptible to the proliferation of Phytoplankton blooms. Present work examines the long-term trend and spatio-temporal variability of satellite derived chlorophyll concentration (Chl a) in the Baltic Sea during the period 2004-2021. Furthermore, the influence of water quality and meteorological parameters on Baltic Sea primary productivity has been analyzed using robust Generalized Additive Models (GAM) and Granger Causality statistical test. Statistically significant increasing trend in chlorophyll a concentration is observed in the Baltic Sea at the 95 % confidence interval. GAM model reveals that the most significant controlling factor is sea surface temperature (p < 0.0001), followed by nitrate and phosphate. Both GAM and Granger Causality tests confirm that water quality parameters are the major drivers in limiting the growth of Phytoplankton blooms in the Baltic Sea. Summer bloom shows in-phase relationship with Sea surface temperature and out of phase relationship with the phosphate nutrient.

The drifting speed and trajectory of fish aggregation devices (FADs) influence tuna aggregation behavior. Based on expertise, fishermen modify FAD structures to slow down drifting speed, but few studies quantify material and structure effects on this speed. To address this, 14 different types of FAD models were tested under 5 different current velocities in a flume tank and compared drifting using pairwise Wilcoxon tests. Results indicate that 1) FAD models covered with netting exhibited higher drifting speeds than the others. 2) It is feasible that replacing the netting bundle with the cotton rope of the same diameter for constructing submerged structure effectively slows down the drifting speeds of FADs. 3) Additionally, FAD models with a floating structure aspect ratio close to 1 exhibited slower drifting speeds compared to other designs when the submerged structure is the same.

Blue carbon cycling in mangrove ecosystems is proving to be more complex than previously thought. The objective of this study was the application of structural equation modelling (SEM) to capture such complex and varying data types and provide a holistic understanding of mangrove blue carbon cycling using data from the Indian Sundarban as a test case. We found that SEM was effective at integrating multiple data types and characterizing the processes and variables that regulate the nature and magnitude of CO₂ fluxes within a mangrove ecosystem, including atmosphere-hydrosphere, atmosphere-pedosphere, and net ecosystem exchange. Overall, this study finds that atmospheric, water, and soil temperatures were the main and common drivers of CO₂ effluxes towards the atmosphere from the entire ecosystem, waterbodies, and soils of mangrove ecosystems, respectively. We conclude that SEM is useful for combining data from different sources, gaining an overarching view of the complex biogeochemical cycling of the blue carbon ecosystems.

With global warming, extreme weather frequently occurs, yet the consequences remain unexplored. A total of 156 heat waves and their characteristics were detected on the basis of a temperature dataset from 1954 to 2022 in Jiaozhou Bay (JZB). The increment is 0.62 times decade^-1 for the number of heat waves, 6.65 days decade^-1 for the sum of participating heat wave days and 0.66 days for the duration of each heat wave. The intensity of heat waves showed regular fluctuations with progressively shorter periods. Based on the dataset of 12 stations in JZB from 2003 to 2022, the zooplankton abundance was significantly greater during heat waves, which was strongly attributed to the greater abundance of copepods and gelatinous zooplankton during heat waves. However, the responses of plankton to heat waves were seasonally heterogeneous. Our study provides new insight into and a scientific basis for understanding the effects of heat waves on offshore plankton ecosystems.

Sharks, are highly vulnerable to fishing pressures, a key factor in their global population decline. Chemical pollution, however, especially metal and metalloid contamination, poses significant additional risks. Of around 520 shark species, about 170 are threatened, including the Sphyrna genus (hammerheads). This review examines contamination in these sharks and its ecological and human health implications. A scientometric review indicates limited research, mainly on juveniles and only mercury contamination, with scarce data on other metals, life stages, and consumption thresholds. The findings also indicate a certain amount of Colonial Science concerning ecotoxicological Sphyrna spp. assessments. The expected link between ecotoxicological risks and Sphyrna spp. threat status remains inconclusive due to insufficient data. Notably, larger hammerhead species do not always exhibit higher contamination levels, suggesting that local environmental factors may influence contamination more than biological characteristics. More research is required to understand how environmental pressures impact shark vulnerability and inform conservation strategies.

This research evaluated the emission characteristics of old ships during typical operations, under varying cruising speeds, and during lock transit, using a shaft power meter and PEMS. The research revealed that upstream and downstream low-load voyages accounted for 67.9 % and 65.4 % of the total voyage, respectively. The average emission factors of CO, NO_X and CO₂ were highest under lock transit with 17.13±0.51 g/kWh, 16.2±0.62 g/kWh and 1075.37±5.72 g/kWh, respectively, while SO₂ was highest under manoeuvring with 0.46 ± 0.001 g/kWh. Emissions are closely correlated with engine speed, with the largest emissions at cruising, and emissions at departure and docking significantly concentrated in the 10-15 % and 5-10 % loads. This research emphasizes the importance of considering low-load operating conditions in engine test cycles and provides data support for maritime decarbonization and emission reduction strategies. Future research should continue to explore the emission characteristics of old ships.

This study extensively investigated the abundance of microplastics in Thiruvottiyur coastal area of Chennai, India, before and after Cyclone Michaung. The results demonstrated a significant correlation between microplastic distribution and aftermath rainfall. The concentration of microplastics in sediments increased from 150 ± 48 particles kg^-1 to 186 ± 21 particles kg^-1 after the cyclone. In seawater, the concentration rose from 1.28 particles L^-1 to 3.65 particles L^-1, respectively. Heavy metals such as Al, Mg, Zn, Cr, Pb, Cu, Cd, Co, and As were detected on the surface of microplastics, demonstrating their vectorization potential for co-contaminants. After exposure, these microplastics induced oxidative stress in Artemia franciscana with increased superoxide dismutase (SOD), catalase, and reactive oxygen species (ROS). Fluctuations in weather conditions lead to heterogeneous changes in microplastic distribution, revealing the seasonal dynamics of microplastics. This study will provide background information to devise strategies for mitigating microplastic pollution in the marine environment.

Sea turtles can host a wide range of parasitic taxa, some of which may lead to severe diseases, weakening and endangering their health. Assessing free-ranging sea turtles' responses to these potential pathogens using biomarkers can provide valuable insights into the cellular and molecular impacts of parasites. This information can serve as a crucial tool for conservation efforts. During rehabilitation, hematological, genotoxic and innate immune parameters were evaluated in 70 free-ranging sea turtles rescued along the Southern Adriatic coast (Eastern Mediterranean Sea) from 2021 to 2023, 24 of which were found to have parasitic infections. Hapalotrema mistroides, Sulcascaris sulcata and Neospirorchis sp. were identified by coprological and molecular techniques. Some significant differences for biomarkers were associated with these parasites. These findings highlight the importance of considering the infection status of free-ranging sea turtles when evaluating biomarker results, as major pathogens like parasites can influence certain parameters.

Global warming poses a significant threat to coral reefs. It has been assumed that mesophotic coral ecosystems (MCEs, 30 to 150 m depths) may serve as refugia from ocean warming. This study examined the acclimation capacity and thermal tolerance of two shallow coral species, Porites cylindrica and Turbinaria reniformis, transplanted to mesophotic depths (40 m) for 12 months. Fragments from 5 and 40 m were exposed to control (28 °C), moderate (30 °C), and high (32 °C) temperatures over 14 days. MCE-acclimated fragments showed higher thermal thresholds and survival rates, delayed onset of bleaching, and less decline in photosynthesis efficiency (Fv/Fm) compared to shallow fragments. Both species maintained high thermal tolerance despite prolonged exposure to cooler temperatures of mesophotic depth. These findings suggest that low light intensity in MCEs can act as a modulator of bleaching, supporting the potential of these ecosystems as refugia for shallow corals in a rapidly changing world.