Nitrate in Fresh Waters

2021 ◽  
pp. 185-208
Author(s):  
Daniel F. Gomez Isaza ◽  
Essie M. Rodgers
Keyword(s):  
Life ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 606
Author(s):  
Daria Sanna ◽  
Ilenia Azzena ◽  
Fabio Scarpa ◽  
Piero Cossu ◽  
Angela Pira ◽  
...  

In the fresh waters of Sardinia (Italy), the non-indigenous crayfish species Procambarus clarkii has been reported from 2005, but, starting from 2019, there have been several reports of a new non-indigenous crayfish in southern and central areas of this Mediterranean island, and its morphology suggests that this species may be the marbled crayfish Procambarus virginalis. Forty-seven individuals of this putative species were analyzed, using the mitochondrial gene Cytochrome c Oxidase subunit I as molecular marker to identify this crayfish and investigate the level of genetic variability within the recently established population. Phylogenetic and phylogeographic analyses were carried out on a dataset including sequences from the Sardinian individuals and from all congenerics available in GenBank. Results showed that the new Sardinian crayfish belong to the species P. virginalis. All the sequences belonging to P. virginalis from European countries are identical, with only few exceptions found among Sardinian individuals. In conclusion, this paper highlights the occurrence of a new further alien species in the Sardinian fresh waters, which are already characterized by the high presence of non-indigenous species.


1992 ◽  
Vol 55 (12) ◽  
pp. 1009-1015 ◽  
Author(s):  
RONDA M. DILLON ◽  
THAKOR R. PATEL

Listeria is an environmental contaminant which has been isolated from marine and fresh waters, as well as various seafoods. Furthermore, Listeria, including Listeria monocytogenes, has been isolated from processed seafood products such as smoked fish, cooked and frozen seafoods, marinated fish, surimi products, etc. The pathogen, L. monocytogenes, does have a certain degree of heat resistance. It was found to survive in internally infected shrimp after boiled for up to 5 min. However, the commercial pasteurization process for crab meat was found to be sufficient to inactivate Listeria. The current recovery methodology for L. monocytogenes from seafoods is the Food and Drug Administration Listeria protocol.


1985 ◽  
Vol 101 (3) ◽  
pp. 150-156 ◽  
Author(s):  
P. S. Maitland ◽  
R. H. Britton

Science ◽  
1938 ◽  
Vol 87 (2248) ◽  
pp. 87-88
Author(s):  
Gordon Gunter
Keyword(s):  

1968 ◽  
Vol 48 (2) ◽  
pp. 339-358
Author(s):  
D. W. SUTCLIFFE ◽  
J. SHAW

1. A quantitative study of sodium influx and loss was made on populations of Gammarus duebeni obtained from four freshwater localities in Ireland. 2. Characteristic features of sodium regulation in animals from the four localities were as follows, (a) The sodium influx increases gradually with increasing external sodium concentrations, but a maximum (saturation) level is abruptly reached at an external concentration of 1-2 mM/l. and the transporting system is half saturated at about 0.5 mM/l. sodium, (b) Over the range of sodium concentrations found in fresh waters a low rate of sodium uptake is sufficient to balance sodium losses at concentrations down to between 0.5 and 0.25 mM/l. At lower concentrations the influx is increased and the loss rate is reduced. (c) Calculations suggest that hypotonic urine containing approximately 40 mM/l sodium is produced at external concentrations ranging from fresh water to 40 % sea water. At external concentrations below 0.25 mM/l. sodium the urine concentration is probably reduced to well below 40 mM/l. sodium. 3. A detailed comparison is made of sodium regulation at external concentrations ranging between 0.07 and 1 mM/l. sodium in G. duebeni from fresh water in Ireland and from fresh water and brackish water in Britain. It is suggested that G. duebeni in Ireland constitutes a distinct physiological race adapted for living in fresh waters with relatively low sodium concentrations.


2018 ◽  
Vol 141 (3) ◽  
pp. 281-305 ◽  
Author(s):  
Sujay S. Kaushal ◽  
Arthur J. Gold ◽  
Susana Bernal ◽  
Tammy A. Newcomer Johnson ◽  
Kelly Addy ◽  
...  
Keyword(s):  

1932 ◽  
Vol 7 (1) ◽  
pp. 127-137
Author(s):  
HAZEL M. KING

A study of the occurrence of silica in the waters of Passamaquoddy bay region has shown very little difference in amount from top to bottom in localities where the turning over of water was very marked, but where the water movement was not so pronounced the values varied considerably with depth. The silica content of the water decreased during the summer months. Fresh waters tributary to the bay had a higher silica content than that of the waters of the bay itself.


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