Diatom quantification and their distribution with salinity brines in coastal sediments of Terra Nova Bay (Antarctica)

► In this study we count diatoms with specific oligonucleotide primers using real-time PCR. ► Salinity brines associated with diatoms were observed in sediments by scanning electron microscopy and X-ray dispersive microanalyses. ► Determination of cations and anions in water-washed sediments confirmed the presence of salinity brines. ► Salinity variation, rather than nutrients, was the most important environmental factor influencing F. curta distribution. ► Salinity below 50 allows a higher biodiversity with more benthic diatom species in sediments.