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Fresh submarine groundwater discharge (fresh SGD), the efflux of terrestrial groundwater directly into the ocean, is a ubiquitous pathway for nutrient-rich freshwater to coastal ecosystems, altering their hydrography, hydrochemistry, and primary productivity. Yet only little is known about the effects of fresh SGD on the fitness of higher trophic levels such as teleost fish. Otolith analysis revealed that somatic growth rates were significantly higher and settlement to reef habitat took place significantly earlier in juvenile gray demoiselle Chrysiptera glauca exposed to fresh SGD as compared to strictly marine conditions. Contrary to expectations, feeding conditions were comparable in both habitats. We propose that physiologically beneficial environmental conditions brought about by the submarine influx of cold acidic freshwater enabled juvenile fish to exhibit elevated growth rates, thereby increasing their survival potential. This effect would directly link changes in groundwater on land to variations in marine primary and secondary consumer biomass at the coast.

A yeast strain with a point mutation in the nuclear gene for the core subunit of mitochondrial RNA polymerase was used to isolate new extragenic suppressors. Spontaneously occurring phenotypical revertants were analysed by crosses with the wild-type and tetrad dissection. One of the new nuclear suppressor mutants was characterized by temperature-sensitive growth on non-fermentable carbon sources. This mutant was transformed with a genomic yeast library. Two independent types of DNA clones were isolated which both complemented the temperature-sensitive defect. Subcloning and DNA sequencing identified two novel yeast genes which code for proteins with the characteristic features of transcription factors. Both factors exhibit highly structured protein domains consisting of runs and clusters of asparagine and glutamine residues. One of the proteins contains in addition zinc-finger domains of the C2H2-type. Therefore the genes are proposed to be named AZF1 (asparagine-rich zinc-finger protein) and PGD1 (polyglutamine domain protein). Gene disruption of both reading frames has no detectable influence on the vegetative growth on complete glucose or glycerol media, indicating that the genes may act as high copy number suppressors of the mutant defect. Additional transformation experiments showed that AZF1 is also an efficient suppressor for the original defect in the core subunit of mitochondrial RNA polymerase.