scholarly journals Karyological and gonadal sex of eels(Anguilla anguilla) from the German Bight and the lower River Elbe

1980 ◽  
Vol 34 (2) ◽  
pp. 159-164 ◽  
Author(s):  
T. Passakas ◽  
F. -W. Tesch

2017 ◽  
Vol 17 (18) ◽  
pp. 10997-11023 ◽  
Author(s):  
André Seyler ◽  
Folkard Wittrock ◽  
Lisa Kattner ◽  
Barbara Mathieu-Üffing ◽  
Enno Peters ◽  
...  

Abstract. A 3-year time series of ground-based multi-axis differential optical absorption spectroscopy (MAX-DOAS) measurements of NO2 and SO2 on the island Neuwerk has been analyzed for contributions from shipping emissions. The island is located in the German Bight, close to the main shipping lane (at a distance of 6–7 km) into the river Elbe towards the harbor of Hamburg. Measurements of individual ship plumes as well as of background pollution are possible from this location. A simple approach using the column amounts of the oxygen molecule dimer or collision complex, O4, for the determination of the horizontal light path length has been applied to retrieve path-averaged volume mixing ratios. An excellent agreement between mixing ratios determined from NO2 retrievals in the UV and visible parts of the spectrum has been found, showing the validity of the approach. Obtained mixing ratios of NO2 and SO2 are compared to co-located in situ measurements showing good correlation on average but also a systematic underestimation by the MAX-DOAS O4 scaling approach. Comparing data before and after the introduction of stricter fuel sulfur content limits (from 1 to 0.1 %) on 1 January 2015 in the North Sea Emission Control Area (ECA), a significant reduction in SO2 levels is observed. For situations with wind from the open North Sea, where ships are the only local source of air pollution, the average mixing ratio of SO2 decreased by a factor of 8, while for NO2 in the whole time series from 2013 to 2016, no significant change in emissions was observed. More than 2000 individual ship emission plumes have been identified in the data and analyzed for the emission ratio of SO2 to NO2, yielding an average ratio of 0.3 for the years 2013/2014 and decreasing significantly, presumably due to lower fuel sulfur content, in 2015/2016. By sorting measurements according to the prevailing wind direction and selecting two angular reference sectors representative for wind from the open North Sea and coast excluding data with mixed air mass origin, relative contributions of ships and land-based sources to air pollution levels in the German Bight have been estimated to be around 40 % : 60 % for NO2 as well as SO2 in 2013/2014, dropping to 14 % : 86 % for SO2 in 2015/2016.



2017 ◽  
Author(s):  
André Seyler ◽  
Folkard Wittrock ◽  
Lisa Kattner ◽  
Barbara Mathieu-Üffing ◽  
Enno Peters ◽  
...  

Abstract. A three-year time series of ground-based MAX-DOAS measurements of NO2 and SO2 on the island Neuwerk has been analyzed for contributions from shipping emissions. The island is located in the German Bight, close to the main shipping lane into the river Elbe towards the harbor of Hamburg. Measurements of individual ship plumes as well as of background pollution are possible from this location, which is a few kilometers from the shipping lane. A simple approach using the column amounts of the oxygen molecule dimer or collision complex, O4, for the determination of the horizontal light path length has been applied to retrieve path-averaged volume mixing ratios. An excellent agreement between mixing ratios retrieved from NO2 retrievals in the UV and visible parts of the spectrum has been found, showing the validity of the approach. Obtained mixing ratios of NO2 and SO2 are compared to co-located in-situ measurements showing good correlation on average with good agreement for well-mixed background pollution but systematic underestimation of plume concentrations by the MAX-DOAS O4 approach. Comparing data before and after the introduction of stricter fuel sulfur content limits (from 1 % to 0.1 %) on 1 January 2015 in the North Sea emission control area (ECA), a signifcant reduction in SO2 levels has been observed. For situations with wind from the open North Sea, where ships are the only local source of air pollution, the average mixing ratio of SO2 decreased by a factor of eight, while for NO2 in the whole time series from 2013 till 2016 no signifcant change in emissions has been observed. More than 2000 individual ship emission plumes have been identifed in the data and analyzed for the emission ratio of SO2 to NO2, yielding an average ratio of 0.3 for the years 2013/2014, decreasing signifcantly presumably due to lower fuel sulfur content in 2015/2016. By sorting measurements according to the prevailing wind direction and selecting two angular reference sectors representative for wind from open North Sea and coast excluding data with mixed air mass origin, relative contributions of ships and land-based sources to air pollution levels in the German Bight have been estimated to be around 40 % : 60% for NO2 as well as SO2 in 2013/2014, dropping to 14 % : 86 % for SO2 in 2015/2016.







2016 ◽  
Vol 86 (1-2) ◽  
pp. 36-47 ◽  
Author(s):  
Imen Dridi ◽  
Nidhal Soualeh ◽  
Torsten Bohn ◽  
Rachid Soulimani ◽  
Jaouad Bouayed

Abstract.This study examined whether perinatal exposure to polluted eels (Anguilla anguilla L.) induces changes in the locomotor activity of offspring mice across lifespan (post-natal days (PNDs) 47 – 329), using the open field and the home cage activity tests. Dams were exposed during gestation and lactation, through diets enriched in eels naturally contaminated with pollutants including PCBs. Analysis of the eel muscle focused on the six non-dioxin-like (NDL) indicator PCBs (Σ6 NDL-PCBs: 28, 52, 101, 138, 153 and 180). Four groups of dams (n = 10 per group) received either a standard diet without eels or eels (0.8 mg/kg/day) containing 85, 216, or 400 ng/kg/day of ϵ6 NDL-PCBs. The open field test showed that early-life exposure to polluted eels increased locomotion in female offspring of exposed dams but not in males, compared to controls. This hyperlocomotion appeared later in life, at PNDs 195 and 329 (up to 32 % increase, p < 0.05). In addition, overactivity was observed in the home cage test at PND 305: exposed offspring females showed a faster overall locomotion speed (3.6 – 4.2 cm/s) than controls (2.9 cm/s, p <0.05); again, males remained unaffected. Covered distances in the home cage test were only elevated significantly in offspring females exposed to highest PCB concentrations (3411 ± 590 cm vs. 1377 ± 114 cm, p < 0.001). These results suggest that early-life exposure to polluted eels containing dietary contaminants including PCBs caused late, persistent and gender-dependent neurobehavioral hyperactive effects in offspring mice. Furthermore, female hyperactivity was associated with a significant inhibition of acetylcholinesterase activity in the hippocampus and the prefrontal cortex.



2019 ◽  
Vol 625 ◽  
pp. 41-52 ◽  
Author(s):  
D Martínez-Alarcón ◽  
R Saborowski ◽  
E Melis ◽  
W Hagen


2018 ◽  
Vol 52 (4) ◽  
pp. 279-288 ◽  
Author(s):  
F. Bakaria ◽  
S. Belhaoues ◽  
N. Djebbari ◽  
M. Tahri ◽  
I. Ladjama ◽  
...  

Abstract The aim of the study was to examine metazoans parasite communities of European eels (Anguilla anguilla) in freshwater (Tonga Lake) and brackish water (El Mellah lagoon) in the northeast of Algeria. Six parasite taxa were collected: one monogenean, Pseudodactylogyrus sp.; two crustaceans, Ergasilus sp. and Argulus foliaceus; two nematodes, Cucullanus sp. and Anguillicola crassus; one cestode, Bothriocephalus claviceps. Th e most prevalent parasite taxa in freshwater were Pseudodactylogyrus sp., A. crassus and Bothriocephalus claviceps; whereas in the brackish water, eels were infected mainly with A. crassus. Th e characteristics of the parasite component community structure revealed low parasite species diversity and high dominance values in eels from the two localities. Both communities were dominated by a single parasite species: Tonga eels by the monogenean Pseudodactylogyrus sp. and El Mellah lagoon eels by the nematode A. crassus, verified by high Berger-Parker dominance values of 0.76 and 0.87 respectively.



Sign in / Sign up

Export Citation Format

Share Document