Assessment of Macrophyte Biological Index for Rivers, and evaluation of physicochemical parameters in the Sakarya River Basin of Turkey

In this study, the Macrophyte Biological Index for Rivers (IBMR) method and physicochemical measurements were used to assess the trophic status of the Sakarya River Basin in Turkey. The most abundant macrophytes were Phragmites australis, Thypa latifolia, Juncus sp., and Paspalum distichum. The IBMR values varied between 6.00 and 13.00 in spring, and between 6.714 and 14.40 in the fall season. The sampling stations, which are under the influence of agricultural runoffs, domestic effluents, and industrial discharges, had hypoxia accompanied by eutrophic and/or hypertrophic conditions at least in one season. The individual trophy levels of the sampling sites in the basin have been assessed as mesotrophic to eutrophic. However, considering the average IBMR value of all stations, the general trophy level of the basin was close to eutrophic. The results indicate that the physicochemical parameters are affected by various effluents discharged to the basin as observed during field studies, and the obtained data would be useful to apply conservation measures.

Assessment of Heavy Metal Concentrations and Public Health Risk in Fish Species of Sakarya River, Turkey

In this study, heavy metal concentrations including cadmium, lead, zinc, copper and arsenic concentrations were determined in five fish species (Capoeta sieboldii, Capoeta tinca, Scardinius erythrophthalmus, Squalius pursakensis and Barbus escherichii) obtained from the Sakarya River. The metal concentrations of fish supplied in four different seasons (winter, spring, summer and autumn) were determined by using atomic absorption spectrophotometry. Although the metal concentrations showed seasonal variations in some fish species and also varied with respect to particular fish species, the concentrations of these metals were found to be within the permissible limits. In addition, it was concluded that the concentration of metal contamination in the evaluated fish species would not pose a risk for human consuming fish species obtained from Sakarya River by considering estimated daily intake (EDI), target hazard quotient (THQ), hazard index (HI), and target cancer risk (TCR) values.

Mapping of Quaternary river terrace landforms with Unmanned Aerial Vehicle (UAV): A case study in the Sakarya River, NW Turkey

<p>River systems are areas that respond most rapidly to regional and / or local tectonic movements, with global climate changes and general basement fluctuations that occurred during the Quaternary period. The most important geomorphological units where these events can be observed are terrace systems, which are the result of deposition and erosion processes. In fluvial geomorphology research on terrace systems, modern technological innovations are used as well as conventional field methods. Especially low-cost Unmanned Aerial Vehicles (UAV) and modern photogrammetry methods are preferred because they both provide detailed and precise identification of terraces and high resolution topography outputs in spatial and temporal terms.<br>This study aims to put a comprehensive mapping of the terrace systems observed in an area of 1.27 km² around Gemiciköy (Bilecik Province), which is located in the middle part of the Sakarya River valley, the largest river in Northwest Anatolia. Accordingly, we used the Structure from Motion (SfM) method which is based on photogrammetric principles and UAV. During the study, 582 images taken from a height of 100 m and having 80% overlap in line with the flight plans by using the DJI Mavic Mini UAV model were evaluated in Agisoft Metashape Professional software. With the use of image processing algorithms, the dense point cloud was first obtained, and then the orthomosaic and digital surface model with 3.29 cm resolution was produced. Two terrace levels (+10 m and +19 m) detected with digital surface modeling, and these were verified by stratigraphic and sedimentological observations made in the field.<br>As a result, low-cost UAV technologies are quite useful in terms of providing more detailed monitoring, mapping and analysis of river environments, together with the production of sensitive and high resolution topography data required in modern fluvial geomorphology research.</p>

Description of two new Cymbella (Bacillariophyta) species from Sakarbaşı spring, Turkey

The descriptions of the new species Cymbella balkii sp. nov. and C. yerlii sp. nov. were given in this study. The species were found in a karstic limnocrene spring which is one of the most important sources of Sakarya River. Cymbella balkii sp. nov. is very similar to C. pervarians, C. simonsenii, C. percymbiformis, C. perparva, C. alpestris and C. vulgata. Among them, C. pervarians is the most similar taxon however, the former has higher stigmata number and larger valve than the latter. Cymbella yerlii sp. nov. is very similar to C. parva, C. perparva and C. parviformis are similar taxa. Among them, C. parva is the most similar taxon in all related ones with similar outline. However, length/width ratio is higher in C. yerlii than the other taxa.

VULNERABILITY OF A RIVER DELTA COAST TO THE IMPACTS OF CLIMATE CHANGE

The main drivers of coastal morphology evolution related to climate change are wave characteristics, storm frequency/intensity and watershed runoff. Estuaries and deltaic plains, strongly affected by the sea-level change, are highly vulnerable to future climate change impacts. Karasu Beach, located in the southwestern Black Sea, Turkey, is impacted by the Sakarya River plume. River discharge and energetic wind and wave climate are among the major physical processes that control the sediment transport pattern along the shoreline. Due to the decrease of sediment runoff to the coast related to the construction reservoirs and a harbor, significant erosion occurred, with a 7.5 m/year retreat of the coastal line. The erosion problem threatens the coastal area as well as the deep spot.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/DfYQlbOXEh8

Lake morphometry underlies physical and chemical parameters affecting the distribution of phytoplankton functional groups in lakes of the Sakarya River Basin (Turkey)

To test the effects of lake morphometry (lake size and depth) on water quality parameters which affect the phytoplankton functional groups (FG) distribution, phytoplankton and some environmental parameters were sampled in November 2017 and May 2018 at the two or three monitoring stations in nine Lakes of Sakarya River Basin (Turkey). Lake size and depth affected phytoplankton FG distribution in both large-sized and small-sized lakes by affecting light availability which was mainly driven by the mixing events during the studied period. Al- though PO4 -P and alkalinity were the other main environmental constraints influencing phytoplankton distribution, they were not directly affected by lake morphometry. Codon Lo was mainly found in small-sized and shallow lakes, whereas coda B, C, D, J, R, and T, which do not have active buoyancy regulation and adapt to high Zmix/Zeu con- ditions, occurred with high relative biovolume in large-sized water bodies.

Alburnus nasreddini, a synonym of A. escherichii (Teleostei: Leuciscidae)

Alburnus nasreddini described from Lake Eber in Central Anatolia is a junior synonym of A. escherichii, a widespread species in adjacent Sakarya River drainage. We found no morphological characters to distinguish Alburnus nasreddini from A. escherichii and both are poorly distinguished on a molecular level also.