The effects of hypoxia on zooplankton population estimates and migration in lakes

Many zooplankton species typically exhibit diel vertical migration (DVM), where zooplankton migrate from the hypolimnion to the epilimnion of lakes at night. Zooplankton exhibit this behavior to avoid visual predators and UV radiation by remaining in the bottom waters during the day and ascending to the surface waters to feed on phytoplankton at night. However, hypoxic conditions in the hypolimnion of lakes mayinterfere with DVM and force zooplankton to increase diel horizontal migration (DHM) to find predation refuge in littoral zones. Climate change and eutrophication are expected to increase the prevalence and severity of hypoxic conditions worldwide and thereby possibly alter zooplankton migration patterns. We hypothesize that hypoxia will force zooplankton to shift their migration patterns from predominantly DVM to DHM to avoid oxygen-depleted bottom waters. To test our hypothesis, we are conducting a standardized global sampling program to test whether pelagic, full water column estimates of zooplankton are greater at night versus the day under hypolimnetic hypoxic versus oxic conditions. Participants are aiming to sample at least one lake with an oxic hypolimnion and one lake with a hypoxic hypolimnion during the thermally-stratified period at midday and midnight. With our global dataset (currently expecting about 60 lakes in 22 countries), our goal is to improve our understanding of how global change may alter zooplankton migration behavior and patterns in lakes.info:eu-repo/semantics/publishedVersio

Slaughter weight rather than sex affects carcass cuts and tissue composition of Bisaro pigs

Carcass cuts and tissue composition were assessed in Bisaro pigs (n=64) from two sexes (31 gilts and 33 entire males) reared until three target slaughter body-weights (BW) means: 17 kg, 32 kg, and 79 kg. Dressing percentage and backfat thickness increased whereas carcass shrinkage decreased with increasing BW. Slaughter weight affected most of the carcass cut proportions, except shoulder and thoracic regions. Bone proportion decreased linearly with increasing slaughter BW, while intermuscular and subcutaneous adipose tissue depots increased concomitantly. Slaughter weight increased the subcutaneous adipose tissue proportion but this impaired intramuscular and intermuscular adipose tissues in the loin primal. The sex of the pigs minimally affected the carcass composition, as only the belly weight and the subcutaneous adipose tissue proportions were greater in gilts than in entire males. Light pigs regardless of sex are recommended to balance the trade-offs between carcass cuts and their non-edible compositional outcomes.Work included in the Portuguese PRODER research Project BISOPORC – Pork extensive production of Bísara breed, in two alternative systems: fattening on concentrate vs chesnut, Project PRODER SI I&DT Medida 4.1 “Cooperação para a Inovação”. The authors are grateful to Laboratory of Carcass and Meat Quality of Agriculture School of Polytechnic Institute of Bragança ‘Cantinho do Alfredo’. The authors are members of the MARCARNE network, funded by CYTED (ref. 116RT0503).info:eu-repo/semantics/publishedVersio

Assessment of Heavy Metal Pollution Levels in Sediment Samples of Lower Catchment Area of Kapulukaya Reservoir (Kızılırmak, Kırıkkale)

Bu çalışmada Mayıs 2013-Şubat 2014 tarihleri arasında Kızılırmak Nehri’nin Kırıkkale il sınırları içerisinde kalan kısmında belirlenen altı istasyondan alınan sediment örneklerinde ağır metal kirlilik düzeyleri incelenmiştir. Al, Fe, As, Cr, Ni, Pb, Zn, Cd, Hg elementlerinin konsantrasyonları ICP-OES cihazı kullanılarak belirlenmiştir. Sonuçlara göre, Fe tüm istasyonlarda en yüksek konsantrasyonda birikim gösteren element olurken Hg, S1 istasyonu hariç en düşük konsantrasyonda birikmiştir. Çalışmanın yapıldığı dönemde Kırıkkale iline ait atık su arıtma tesisi bulunmaması sebebiyle kanalizasyon atıkları doğrudan Kızılırmak Nehri’ne bırakılmaktaydı. Atık suyun Kızılırmak Nehri’ne boşaltıldığı nokta, çalışmanın gerçekleştirildiği istasyonlardan S3 ile S4 arasında yer almaktadır. Buna göre ilk üç istasyon (S1, S2, S3) ve son üç istasyon (S4, S5, S6) karşılaştırıldığında ortalama değerlerin Hg hariç arttığı belirlenmiştir. Mevsimsel olarak anlamlı farklılık sadece Zn elementi için ilkbahar ile sonbahar ve ilkbahar ile kış arasında tespit edilmiştir (p<0,05). Sediment kalite rehberinde belirtilen değerler kullanılarak ağır metal konsantrasyonları canlılık açısından değerlendirilmiştir. As, Ni element konsantrasyonlarının sedimentte sıklıkla yaşayan ve sedimentten beslenen organizmalar üzerinde zararlı etkilere yol açabilmesi muhtemel görülmüştür. Ayrıca Pb element konsantrasyonunun S4 istasyonunda canlılık açısından zararlı etkiler açığa çıkarabileceği tespit edilmiştir.In this study, heavy metal pollution levels were investigated in the sediment samples which taken from six different sites in the Kızılırmak River in Kırıkkale province, between May 2013 and February 2014. The concentrations of Al, Fe, As, Cr, Ni, Pb, Zn, Cd and Hg were determined by using ICP-OES. According to the results, Fe was the element showing the highest concentration in all stations, while Hg was the element with lowest concentration except S1 site. During the study, seweage effluents were left directly to Kızılırmak River due to the lack of waste water treatment plant belonging to Kırıkkale province. The point where waste water is discharged to Kızılırmak River is located between S3 and S4 sites where the study is carried out. Accordingly to the results, when the first three stations (S1, S2, S3) and the last three stations (S4, S5, S6) were compared, it was found that the average values increased except Hg. Seasonally significant difference was found only for Zn element between spring and autumn and spring and winter seasons (p <0.05). Heavy metal concentrations levels were evaluated for organisms using the values specified in the sediment quality guideline. The concentrations of As, Ni are likely to have harmful effects on sediment-dwelling organisms. In addition, it was determined that Pb element concentration could cause harmful effects on viability in S4 station

Effect of seasonal water temperature variation on the blood serums thyroid hormone levels of juvenile chub fishes (Squalius cappadocicus)

In this study, the seasonal change (varying with water temperature) of thyroid hormones [Total triiodothyronine (TT3) and Total thyroxine (TT4)] in the blood serums of juvenile chub fish (Squalius cappadocicus) has been investigated. The research has been conducted on the chub fish caught in Melendiz Stream (Aksaray) at different times (2010–April, June, July, and November; 2011–February and March). As a result of the hormonal analyses on blood serums, TT3 and TT4 levels have shown meaningful changes (p < 0.05) inversely proportional to the water temperature. It made us think that this change is due to adaptation decreased/increased metabolic (energy) activity provided by the fishes against temperature stress

Microplastics in a dam lake in Turkey: type, mesh size effect, and bacterial biofilm communities

Çırak, Tamer ( Aksaray, Yazar )The evaluation of microplastic (MP) pollution has been drawing attention for the last decades. MP pollution has been studied widely in marine environments, but limited data exists for freshwater ecosystems on potential source and transport of MPs. The type, shape, plastic components, and the color of the MPs were investigated using various-mesh-sizes (300 and 100 μm) nets in four sampling stations of Süreyyabey Dam Lake in Turkey. The growth of bacterial isolates on the MPs surface and surrounding water was also investigated. The type of the MPs and the interaction between the mesh size and the type of the MPs showed significant differences (p < 0.05). Fibers were found to be the most abundant particle type constituting 45% and 80% of the total MPs found in 330-μm and 100-μm mesh sizes, respectively. In total the observed MP abundance in the dam lake was 5.25 particles m−3, and 4.09 particles m−3 was observed for 100-μm and 330-μm mesh sizes, respectively. The color of the identified microplastics showed variations among microplastic types; however, the dominant color was transparent in each net. The main plastic components of the MPs are polyethylene terephthalate, polyvinyl chloride, polystyrene, polyethylene, and polypropylene. The microbial community mainly consists of potentially pathogenic strains such as Escherichia coli, Enterococcus faecalis, and Acinetobacter baumanii complex. The current study could contribute valuable background information both for MP pollution and for biofilm composition in a dam. However, the surface of the MPs and biofilm formation should be investigated urgently to understand the vector potential of MPs

A review of plastic pollution in aquatic ecosystems of Turkey

Turkey is one of the major plastic pollution sources in the Mediterranean and the Black Sea. This review summarizes present information, data, and legislation on plastic pollution in Turkish aquatic ecosystems. According to results derived from reviewed studies, both macro- and microplastic pollutions were documented in Turkish aquatic ecosystems. Most of the studies on plastic pollution in Turkish waters were performed in the marine environment while only four were conducted in freshwater environments. Spatially, the majority of these studies, which were on levels in the marine environment, were conducted on the northeastern Mediterranean coasts of Turkey, especially Iskenderun and Mersin Bays. Additional studies were carried out on either the ingestion/presence/impact of microplastics by/to aquatic organisms or the entanglement of marine organisms in plastics. There were also studies assessing the microplastic content of commercial salt, and another has reported microplastic presence in traditional stuffed mussels sold in Turkish streets. Some studies were conducted on microplastic presence and/or their removal in wastewater treatment plants in Mersin, Adana, Mugla, and Istanbul cities. Macro- and microliter loading from a few Turkish rivers to the sea was also estimated. All these investigations indicate that Turkish aquatic environments have significant plastic pollution problems, which were also underlined by the legislative studies. The need for further studies in this field still exists, especially in freshwater environments

Tracking the microplastic accumulation from past to present in the freshwater ecosystems: A case study in Susurluk Basin, Turkey

Microplastic pollution in aquatic ecosystems has become a global issue in recent years due to its presence everywhere around the world. Although several studies have explored the impact of the accumulation of those small particles in marine environments, comparisons of freshwater systems with marine environments are scarce. In the current study, due to the lack of long-term data on microplastic pollution, we used paleolimnological approaches to acquire the missing information regarding this hot topic. Two short cores were taken from Bursa province in Turkey, which is the center of industrial and agricultural production with many different sectors such as textile and manufacturing. The first core sample was taken from a relatively pristine environment, Lake Uluabat, and the second one was taken from a delta area where all the discharge coming from the basin flowed through to the Marmara Sea. The sediment core from the lake was dated back to the 1960's and the majority of the sample was dominated by fibers. Despite there being no uniform distribution pattern, the number of the microplastics showed decreasing trend after the lake became a Ramsar site. Due to the continuous mixing in the sampling area, there were obstacles via the dating of the Delta core. Nevertheless, the data showed that a high number and variety of microplastics have accumulated over the last decade in the province. This can be interpreted as microplastic pollution reaching the sea directly from the basin. These findings revealed that a plastic chronostratigraphy would give important temporal data regarding the microplastic accumulation in aquatic ecosystems

Size-selective microplastic uptake by freshwater organisms: Fish, mussel, and zooplankton

Microplastics, as an emergent pollutant, have garnered substantial attention within aquatic environments, yet a significant knowledge gap persists regarding the interplay of organism size and pollution impacts on microplastic uptake in freshwater ecosystems. The main aim of the current study is to assess the microplastic ingestion by aquatic organisms across diverse trophic levels. To achieve this objective, zooplankton, mussels (Anodonta anatina), and fish (Carassius gibelio) were collected from the highly polluted Susurluk River Basin in Türkiye. The size distribution encompassed 160.8 ± 56.9 μm for the prevailing zooplankton, 6.9 ± 2.2 cm for mussel, and 20.4 ± 3.1 cm for fish, respectively. While no microplastic ingestion was observed among zooplankton, the finding highlights the influence of body-size and pollution on microplastic ingestion. In contrast, A. anatina and C. gibelio contained 617 and 792 microplastic particles, respectively. Predominantly, fibers emerged as the most prevalent microplastic type across trophic levels (except zooplankton) followed by films. Notably, only fish exhibited fragments within their gastrointestinal tract. A substantial correlation emerged between microplastic abundance and mussel size and weight, but no such correlation manifested for fish. The study also revealed a positive link between microplastic count and turbidity (phosphate and high Chl a level), impacting mussel ingestion capacity due to the variability in the food availability and potential shifts in feeding preferences. Conversely, no distinct pattern emerged for fish concerning water quality parameters and ingested microplastics. Consequently, our study underscores diverse microplastic uptake patterns in freshwater ecosystems, with a predominant frequency of microplastics falling with the 0.3 mm–3.0 mm range, emphasizing the significance of size-selective uptake by organisms