Search results for "Euryhaline"

2017

Both effective population size and life history may influence the efficacy of purifying selection, but it remains unclear if the environment affects the accumulation of weakly deleterious nonsynonymous polymorphisms. We hypothesize that the reduced energetic cost of osmoregulation in brackish water habitat may cause relaxation of selective constraints at mitochondrial oxidative phosphorylation (OXPHOS) genes. To test this hypothesis, we analyzed 57 complete mitochondrial genomes of Pungitius pungitius collected from brackish and freshwater habitats. Based on inter- and intraspecific comparisons, we estimated that 84% and 68% of the nonsynonymous polymorphisms in the freshwater and brackish …

Acute and chronic response to a change in salinity of the euryhaline polychaete Pygospio elegans (Claparède)

2019

Abstract Estuaries are thought to be very harsh environments because their physico-chemical parameters, such as salinity, temperature and oxygen, can fluctuate substantially. The distribution of species living in an estuary is largely determined by how well they can cope with such fluctuations. The spionid polychaete Pygospio elegans is common in boreal estuarine habitats that show strong salinity fluctuations, living in habitats ranging from fully marine salinities to brackish environments with salinities as low as 5. In this study we investigated the abilities of P. elegans to cope with an acute as well as a long-term change in salinity. Specimens originating from a salinity of about 15 w…

Euryhaline Brachionus strains (Rotifera) from tropical habitats: morphology and allozyme patterns

2006

The euryhaline rotifer Brachionus is a complex of sibling species. Although many investigations have been carried out in the past, the relationships among the Spanish species, the tropical SS strains and the clusters previously described, remained unknown. In this study, allozyme data for five populations from the tropics and two from Spanish lagoons — one of them B. ibericus and the other B. rotundiformis — were combined with data from the previous studies. Cluster analysis based on genetic distance allowed the 74 strains to be divided into two major groups. One group was associated with B. plicatilis-like strains, and the other group was associated with B. rotundiformis and B. ibericus. T…