The Sakarya River basin is one of the largest basins in Turkey, and encompasses the Kocaeli, Düzce, Sakarya, Bursa, Bilecik, Bolu, Kütahya, Eskişehir, Ankara, Afyon, and Konya provinces. In this study, the water quality status of the basin was investigated using 18 diatom indices, calculated in Omnidia software. For this purpose, a total of 46 stations were surveyed in the rivers and streams of the basin in May 2018. As a result, 41 of 195 diatom taxa were found to be the most frequent (>10% share in assemblage). According to Detrented Correspondence Analysis (DCA), three subgroups were described as the spring section, Ankara and Polatlı section, and lowland section. The river basin quality was evaluated as moderate or lower quality status, while only a few sites had good status. The diatom index scores showed that the Descy’s Index (DES), Pampean Diatom Index (IDP), Artois-Picardie Diatom Index (IDAP), and Specific Pollution Sensitivity Index (IPS) appear best suited to water quality assessment in this area, showing the largest number of significantly important correlation with environmental variables.

The current article describes Navicula vanseeasp. nov., a new species of diatom from Lake Van, a highly alkaline lake in Eastern Anatolia (Türkiye). The description is based on light and scanning electron microscopy performed on two monoclonal cultures. The complete nuclear rRNA clusters and plastid genomes have been sequenced for these two strains and the complete mitogenome for one of them. The plastome of both strains shows the probable loss of a functional ycf35 gene. They also exhibit two IB4 group I introns in their rrl, each encoding for a putative LAGLIDADG homing endonuclease, with the first L1917 IB4 intron reported amongst diatoms. The Maximum Likelihood phylogeny inferred from a concatenated alignment of 18S, rbcL and psbC distinguishes N. vanseea sp. nov. from the morphologically similar species Navicula cincta and Navicula microdigitoradiata.

In this study, we describe Halamphora vantushpaensissp. nov., a newly identified diatom species found in the highly alkaline Lake Van in Eastern Turkey (Türkiye). This new species is characterized morphologically by light and scanning electron microscopy, performed on both wild and cultivated samples. Two monoclonal cultures were submitted to a genome-skimming approach, giving access to the complete sequence of their nuclear rRNA cluster of genes, mitochondrial and plastid genomes. Both strains were highly similar from the genomic point of view, with few mutations noted, although in organellar genomes some of them concerned protein coding genes and were non-silent. Also, the group II intron in the mitochondrial cox1 gene was found to display a relatively high number of polymorphisms. The plastome also distinguishes itself from other Halamphora spp. by the extension of its inverted repeat at the expense of the two single copy regions of the genome. Maximum likelihood molecular phylogeny inferred from a concatenated three genes dataset (18S, psbC and rbcL) positions this species within the K clade, which is known to contain hypersaline to freshwater species.

In this article we describe Nitzschia anatoliensis Górecka, Gastineau & Solak sp. nov., an example of a diatom species inhabiting extreme habitats. The new species has been isolated and successfully grown from the highly alkaline Van Lake in East Turkey. The description is based on morphology (light and scanning electron microscopy), the sequencing of its organellar genomes and several molecular phylogenies. This species could easily be overlooked because of its extreme similarity to Nitzschia aurariae but molecular phylogenies indicate that they are only distantly related. Furthermore, molecular data suggest that N. anatoliensis may occur in several alkaline lakes of Asia Minor and Siberia, but was previously misidentified as Nitzschia communis. It also revealed the very close genetic proximity between N. anatoliensis and the endosymbiont of the dinotom Kryptoperidinium foliaceum, providing additional clues on what might have been the original species of diatoms to enter symbiosis.

Cultures in Mediterranean climate zones (MCZs) around the world have long been reliant on groundwater and springs as freshwater sources. While their ecology and cultural sustainability are recognized as critically important, inter-relationships between springs and culture in MCZs have received less attention. Here we augmented a global literature review with case studies in MCZ cultural landscapes to examine the diversity and intensity of cultural and socio-economic relationships on spring ecohydrogeology. MCZs are often oriented on western and southern coasts in tectonically active landscapes which control aquifer structure, the prevalence of westerly winds, and aridity, and generally expose associated habitats and cultures to harsh afternoon sunlight. Cultural appreciation and appropriation of springs ranges widely, from their use as subsistence water supplies to their roles in profound traditions such as Greco-Roman nymphalea as well as Asian and Abrahamic spiritual cleansing and baptism. The abandonment of traditional ways of life, such as rural livestock production, for urban ones has shifted impacts on aquifers from local to regional groundwater exploitation. The commoditization of water resources for regional agricultural, industrial (e.g., mining, water bottling, geothermal resorts), and urban uses is placing ever-increasing unsustainable demands on aquifers and spring ecosystems. When the regional economic value of springs approaches or exceeds local cultural values, these irreplaceable aquatic ecosystems are often degraded, over-looked, and lost. Sustainable stewardship of springs and the aquifers that support them is a poorly recognized but central conservation challenge for modern Mediterranean societies as they face impending impacts of global climate change. Solutions to this crisis require education, societal dialogue, and improved policy and implementation.

We sequenced the chloroplast genome of Poterioochromonas malhamensis (Pringsheim) R.A.Andersen strain SZCZR2049, which originates from Van Lake in Turkey. This genome is 133,923 bp long, and like those currently available for six phototrophic chrysophytes, it displays a long, gene-rich inverted repeat and a very short single-copy region. Compared to its chrysophyte counterparts, the P. malhamensis inverted repeat differs noticeably in gene content and the whole genome is missing 11 protein-coding genes. The maximum likelihood phylogeny inferred from concatenated protein-coding genes positioned P. malhamensis among the chrysophytes sensu lato as sister to the clade containing the Synurales (Synurophyceae) and Chromulinales (Chrysophyceae).