Murat Öztürk

MtDNA and Y-chromosome variation in Kurdish groups

In order to investigate the origins and relationships of Kurdish‐speaking groups, mtDNA HV1 sequences, eleven Y chromosome bi‐allelic markers, and 9 Y‐STR loci were analyzed among three Kurdish groups: Zazaki and Kurmanji speakers from Turkey, and Kurmanji speakers from Georgia. When compared with published data from other Kurdish groups and from European, Caucasian, and West and Central Asian groups, Kurdish groups are most similar genetically to other West Asian groups, and most distant from Central Asian groups, for both mtDNA and the Y‐chromosome. However, Kurdish groups show a closer relationship with European groups than with Caucasian groups based on mtDNA, but the opposite based on the Y‐chromosome, indicating some differences in their maternal and paternal histories. The genetic data indicate that the Georgian Kurdish group experienced a bottleneck effect during their migration to the Caucasus, and that they have not had detectable admixture with their geographic neighbours in Georgia. Our results also do not support the hypothesis of the origin of the Zazaki –speaking group being in northern Iran; genetically they are more similar to other Kurdish groups. Genetic analyses of recent events, such as the origins and migrations of Kurdish‐speaking groups, can therefore lead to new insights into such migrations.

Iron speciation in eutrophic and oligotrophic Mediterranean coastal waters; impact of phytoplankton and protozoan blooms on iron distribution

Speciation, distribution and temporal differences in iron chemistry are important for understanding the biological roles of iron in marine systems. This paper presents a study of iron species in different coastal systems of the northeastern Mediterranean and the observed consequences of enrichments of coastal water by major nutrients and iron. Iron species were detected by using a serial chromatographic column method in the eutrophic inner and middle, transient and oligotrophic outer section of Izmir Bay, western Turkey. In order to understand the impact of biological activity on the distribution of Fe species in coastal systems, phytoplankton densities and POC were also measured along with other relevant biological, physical and chemical variables in surface waters at different stations and seasons in Izmir Bay. A significant decrease in iron concentration was observed in the outer bay despite of a very high iron input particularly from the sediment in shallow waters of the inner and middle bay. Average colloidal iron (ColFe) was 14±7% of the total iron that could pass a filter (<0.4 μm) (TFFe) throughout the bay water, however, Chelex column-labile Fe (ClxLFe) was significantly higher (42±25% of TFFe) and reached up to 80% of TFFe, especially in the shallow inner and middle bay. A dramatic decrease in ClxLFe was observed during the phytoplankton bloom in early April in the inner and middle bay. Hydrophobic organically complexed iron (HpOFe) and ClxLFe increased with increasing protozoan activity and collapse of phytoplankton.

Iron speciation and biogeochemistry in different nearshore waters

Abstract Different environmental conditions in various nearshore waters dynamically determine the speciation of iron, its solubility, removal and hence bioavailability to phytoplankton. The iron speciation, the impact of phytoplankton blooms and the effects of organic matter on iron speciation and transformation were studied in four different coastal systems: the Trondheim Fjord, Norway, which is a coastal system that is open to a vast riverine impact; Hopevagen, Norway, a pristine coastal basin, which has negligible river and anthropogenic impact; Izmir Bay, Turkey, a Mediterranean embayment with heavily polluted eutrophic inner–middle section, and the oligotrophic outer section. In this paper, we compare iron speciation in these different coastal systems. While colloidal iron (ColFe) was the predominant species especially in the Trondheim Fjord and to some degree also in Hopavagen, Chelex labile iron (ClxLFe) and hydrophobic organic-iron complex (HpOFe) were predominate species in both the inner–middle and the outer section of Izmir Bay. The impact of phytoplankton blooms on the ClxLFe was significant especially in the Trondheim Fjord, in the inner–middle section of Izmir Bay and in Hopevagen.

The effects of enhanced phytoplankton production on iron speciation and removal in mesocosm experiments in a landlocked basin of Hopavagen, Norway

This study examined the concentration, transformation and removal of various operationally defined iron species, including one control and one experimental mesocosm bag (40 m3 each) in the landlocked basin of Hopavagen, Norway. The experimental mesocosm bag was spiked with nitrate, ammonia, phosphate and silicate as part of the MesoNor-97 project. During the mesocosm experiments concentrations of total filter-passing iron (TFFe<0.4 μm) decreased from about 30 to about 5 nmol l−1, while Chl a increased to 38 μg l−1 on day 9 in the nutrient-enriched mesocosms (bag 7). Colloidal iron (ColFe) and chelex-labile iron (ClxLFe) appeared have the greatest bioavailability and/or to be most susceptible to biologically mediated removal. In contrast, on day 9, anionic organic Fe complexes (AnOFe) was still present and hydrophobic–lyphophlic–non polar organic Fe complexes (HpOFe) increased considerably in the surface water of the enriched mesocosm. Sediment trap data show that the iron flux reached its highest level while primary production was at a maximum. A rather high level of atmospheric iron flux was calculated (33.6±16 μmol m−2 day−1) based on sediment trap data during the mesocosm experiment.