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Predation mechanisms of Rapana venosa (Gastropoda: Muricidae) in different biotopes along the Black Sea coast
2016
Kosyan, Alisa
Mechanisms of feeding by the invasive gastropod Rapana venosa from different biotopes of 11 sites along the Black Sea coast are discussed. Two methods – edge-drilling and suffocation – are used, but the prevailing method in a particular biotope depends on the type of bivalve prey. Drill signs were present on almost all shells of Chamelea gallina, captured by rapa whelks in field conditions, while in a field experiment, only 11% of all empty Mytilus galloprovincialis had drilling signatures. The degree of radula abrasion was also dependent on the available bivalves: it was the highest in biotopes with C. gallina and juvenile mussels, and the lowest in biotopes with large mussels. Intermediate degrees of abrasion were observed in biotopes with mixed prey: C. gallina and Anadara kagoshimensis, C. gallina and mussels, or small and large mussels. Since we observed only initial signs of drilling, simultaneous application of boring and suffocation could take place.
Show more [+] Less [-]Can environmental DNA (eDNA) be used for detection and monitoring of introduced crab species in the Baltic Sea?
2016
Forsström, Tiia | Vasemägi, Anti
The need to detect and monitor introduced marine species has increased with the increasing number of marine invasions. To complement standard detection and monitoring techniques, new approaches using environmental DNA (eDNA) have recently been developed. However, most of the eDNA work has focused on vertebrate species in spatially limited freshwater habitats while benthic invertebrates in coastal environments have received much less attention. Here, we evaluated the suitability of the eDNA approach for detecting benthic, hard-shelled, crustacean mud crab species in a brackish water environment. We demonstrated for the first time that eDNA from an introduced mud crab Rhithropanopeus harrisii can be successfully amplified in aquarium water samples and detected in the brackish water environment. However, the detection rate was rather low. This suggests that in contrast to freshwater vertebrates, it may be more challenging to develop a highly sensitive eDNA method for detecting crustacean species in a marine environment.
Show more [+] Less [-]Analysis of polycyclic aromatic hydrocarbons (PAHs) in Lebanese surficial sediments: A focus on the regions of Tripoli, Jounieh, Dora, and Tyre
2016
Manneh, Rima | Abi Ghanem, Carine | Khalaf, Gaby | Najjar, Elie | El Khoury, Bilal | Iaaly, Amal | El Zakhem, Henri
This paper aims to identify the concentrations of PAHs in the sediments of four coastal zones in Lebanon and determine their possible sources and effects. For each region (Tripoli, Jounieh, Dora, and Tyre), sampling, lyophilization, Soxhlet extraction, rotary evaporation, and gas chromatography were performed on 11, 10, 7, and 11 samples, respectively. The total PAHs concentrations ranged from 1.22 to 731.93μg/kg dry weight. The lowest concentrations were found in Tyre and the highest in Dora and Jounieh. The level of PAHs was classified as low to moderate and their source was mainly pyrogenic.
Show more [+] Less [-]Development of a short-term chronic toxicity test with a tropical mysid
2016
Figuerêdo, Lívia Pitombeira de | Nilin, Jeamylle | Silva, Allyson Queiroz da | Loureiro, Susana | Costa-Lotufo, Letícia Veras
There is an increasing need to develop reliable methodologies for chronic toxicity testing using tropical species. The present work aimed at developing a suitable short-term chronic toxicity test with Mysidopsis juniae using zinc (Zn) and nickel (Ni) as model chemicals and growth (length and dry weight), survival, and egg production (number of females with eggs) as endpoints after seven days of exposure. Survival and growth of newborn M. juniae were affected by chronic exposure to zinc, while nickel affected only survival. For zinc, dry weight was the most sensitive endpoint with significant effects even at the lowest tested concentration (75μgZn·L−1), whereas for nickel, survival was the most sensitive parameter (LC20 of 26μgNi·L−1). Egg production was not affected. M. juniae short-term chronic testing is a sensitive approach to evaluating metal toxicity; further studies are necessary to assess chronic toxicity for others contaminants in the proposed assay.
Show more [+] Less [-]Effects of the urban environmental conditions on the physiology of lichen and moss
2016
Sujetovienė, Gintarė | Galinytė, Vilma
The lichen Evernia prunastri (L.) Ach. and the moss Ptilium crista-castrensis (Hedw.) DeNot were exposed in three different urban sites along with the different pollution loads in order to evaluate the environmental quality. Physiological changes after the exposition were assessed by evaluating the content of photosynthetic pigments, chlorophyll fluorescence, membrane lipid peroxidation and integrity of cell membranes. The differences in response of fluorescence, chlorophylls contents and injuries of cell membranes were observed between the two species and between the sites. E. prunastri showed a great capacity to sustain the photosynthesis processes in the urban environment, while this capacity was very low in the transplanted moss P. crista-castrensis. The levels of malondialdehyde (MDA) indicated a significantly higher oxidative stress in the transplants at urban and residential sites. The integrity of cell membranes in moss samples was also more damaged than in lichen.
Show more [+] Less [-]A model study of the effects of river discharges and winds on hypoxia in summer in the Pearl River Estuary
2016
Wei, Xing | Zhan, Haigang | Ni, Peitong | Cai, Shuqun
The deterioration of dissolved oxygen conditions in the Pearl River Estuary (PRE) in summer has recently attracted considerable-scientific and political-attention. This paper documents the development, calibration, and verification of a coupled three-dimensional hydrodynamic and water quality model for the PRE. A comparison of the model's performance against field observations indicated that the model is capable of reproducing key hydrodynamic and water quality characteristics of the estuary within an acceptable range of accuracy. Furthermore, a scenario analysis showed that the extent of the hypoxic zone responds differently to changes in the river discharge at different inlets. Moreover, the hypoxic zone also changes in response to variations in the southwest wind in summer; specifically, a larger hypoxic zone develops as southwest winds blow in a more southward direction. However, the hypoxic conditions are much more sensitive to changes in the wind speed than changes in the wind direction.
Show more [+] Less [-]Waste production and regional growth of marine activities an econometric model
2016
Bramati, Maria Caterina
Coastal regions are characterized by intense human activity and climatic pressures, often intensified by competing interests in the use of marine waters. To assess the effect of public spending on the regional economy, an econometric model is here proposed. Not only are the regional investment and the climatic risks included in the model, but also variables related to the anthropogenic pressure, such as population, economic activities and waste production. Feedback effects of economic and demographic expansion on the pollution of coastal areas are also considered. It is found that dangerous waste increases with growing shipping and transportation activities and with growing population density in non-touristic coastal areas. On the other hand, the amount of non-dangerous wastes increases with marine mining, defense and offshore energy production activities. However, lower waste production occurs in areas where aquaculture and touristic industry are more exploited, and accompanied by increasing regional investment in waste disposal.
Show more [+] Less [-]Marine litter as a vector for non-native species: What we need to know
2016
Rech, Sabine | Borrell, Yaisel | García Vázquez, Eva
Plastic debris and other floating materials endanger severely marine ecosystems. When they carry attached biota they can be a cause of biological invasions whose extent and intensity is not known yet. This article focuses on knowledge gaps and research priorities needed for, first, understanding and then preventing dispersal of alien invasive species attached to marine litter.
Show more [+] Less [-]One-century decline of mollusk diversity as consequence of accumulative anthropogenic disturbance in a tropical estuary (Cuban Archipelago)
2016
Armenteros, Maickel | Díaz-Asencio, Misael | Fernández-Garcés, Raúl | Hernández, Carlos Alonso | Helguera-Pedraza, Yusmila | Bolaños-Alvarez, Yoelvis | Agraz-Hernández, Claudia | Sanchez-Cabeza, Joan-Albert
In order to infer changes in sediments and mollusk assemblages for the last century, we used biogeochemical data from two 210Pb dated cores collected in Sagua La Grande estuary, Cuban Archipelago. We found evidences of cumulative anthropogenic disturbance during the last century, causing considerable depletion of mollusk assemblage diversity and enhancement of the dominance of deposit feeding species. The sequence of impacts assessed was i) eutrophication due to nutrient releases from urban settlements, ii) habitat alteration due to water channeling and damming, and iii) mercury pollution. These successive impacts caused a steady diversity depletion from ca. 70 mollusk species in 1900 to less than five in 2010. Only two species persisted in the estuary: Nuculana acuta and Finella dubia. Hurricanes did not impact the molluscan fauna in the long term. The effects of the anthropogenic impacts suggest that the resilience of this estuarine system is compromised.
Show more [+] Less [-]An in-depth survey of the oil spill literature since 1968: Long term trends and changes since Deepwater Horizon
2016
Murphy, David | Gemmell, Brad | Vaccari, Liana | Li, Cheng | Bacosa, Hernando | Evans, Meredith | Gemmell, Colbi | Harvey, Tracy | Jalali, Maryam | Niepa, Tagbo H.R.
In order to characterize the state of oil spill research and describe how the field has changed since its inception in the 1960s and since the Deepwater Horizon spill in 2010, we examined approximately 10% of oil spill literature (1255 of over 11,000 publications) published from 1968 to 2015. We find that, despite its episodic nature, oil spill research is a rapidly expanding field with a growth rate faster than that of science as a whole. There is a massive post-Deepwater Horizon shift of research attention to the Gulf of Mexico, from 2% of studies in 2004–2008 to 61% in 2014–2015, thus ranking Deepwater Horizon as the most studied oil spill. There is, however, a longstanding gap in research in that only 1% of studies deal with the effects of oil spills on human health. These results provide a better understanding of the current trends and gaps within the field.
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