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Lettuce (Lactuca sativa L.) and African catfish (Clarias gariepinus) were preferred to grow in aquaponics due to their high and fast productivity growth. However, limited research was conducted on the impact on different inorganic substrates‘ growth performance in aquaponics. In this study, lettuce‘s growth performance was determined in four different kinds of inorganic substrates in Nutrient Film Technique (NFT) aquaponics by measuring final weight, daily growth rate, stem diameter, plant and root lengths, leaf number per plant and shoot/root ratio. Polyester fiber, rock wool, zeolite, and gravel were used as inorganic substrate materials. A constant flow rate of 0.3 L/min was maintained using with a submersible pump motor. At the end of the study, the African catfish‘s feed conversion ratio was estimated to be 0.66, while the specific growth rate (SGR) was 2.3%. Total lettuce yields for polyester fiber, rock wool, zeolite and gravel were obtained as 5.072,22 kg/m2, 4.934,03 kg/m2, 6.067 kg/m2, and 5.382,64 kg/m2 respectively. There were statistically significant differences for daily growth rate between the inorganic substrates that the significantly highest values were recorded in the zeolite. The results revealed that initial plant length and shoot/root ratio were the significant factors on the growth performance for lettuce in aquaponic system tested. The best lettuce yield performance was observed in zeolite substrate but, economically available option was found as gravel for hydroponic troughs.

Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect effects of temperature were the main drivers of the spatial distribution in the toxins produced by the cyanobacterial community, the toxin concentrations and toxin quota. Generalized linear models showed that a Toxin Diversity Index (TDI) increased with latitude, while it decreased with water stability. Increases in TDI were explained through a significant increase in toxin variants such as MC-YR, anatoxin and cylindrospermopsin, accompanied by a decreasing presence of MC-LR. While global warming continues, the direct and indirect effects of increased lake temperatures will drive changes in the distribution of cyanobacterial toxins in Europe, potentially promoting selection of a few highly toxic species or strains. © 2018 by the authors. Licensee MDPI, Basel, Switzerland., The authors acknowledge COST Action ES 1105 “CYANOCOST—Cyanobacterial blooms and toxins in water resources: Occurrence impacts and management” and COST Action ES 1201 “NETLAKE—Networking Lake Observatories in Europe” for contributing to this study through networking and knowledge sharing with European experts in the field. Evanthia Mantzouki was supported by a grant from the Swiss State Secretariat for Education, Research and Innovation (SERI) to Bas Ibelings and by supplementary funding from the University of Geneva. We thank Clare Ahnlund, Ena Suarez and Irene Gallego for helping out with the Swiss survey. We thank Wendy Beekman and Els J. Faassen for the nutrient and toxin analysis.

This study aimed to determine the physicochemical characteristics of the water quality and trophic state of Akgöl Lagoon located in the eastern Mediterranean. Cluster analysis clearly revealed the spatial heterogeneity classifying sampling stations as saline and freshwater/brackish water sites. A multivariate analysis of variance followed by principal component analysis supported that salinity was major factor affecting physicochemical water quality variations in the lagoon. As salinity was mainly governed by freshwater inflows depending on agricultural irrigation, it can be proposed that water quality was significantly influenced from freshwater use by human activities. The parameters used as predictors (total nitrogen, total phosphorus, chlorophyll a and Secchi disk transparency) yielded different trophic states for the lagoon. However, as chlorophyll is a better predictor than the other indices, it was concluded that the Akgöl Lagoon is at mesotrophic status.

WOS: 000302596800006, Metal concentrations were determined in water, sediment, and freshwater fish samples (Squalus cephalus, Barbus esocinus, and Barbus xanthopterus) collected from Karakaya Dam Lake, Turkey, to estimate the risk of human consumption and pollution. Metal concentrations differed between the species (p < 0.05) even as they were living in similar habitats. Metal analyses were performed by inductively coupled plasma optical emission spectroscopy (ICP-OES). Cd and Hg were not detected in water, sediment, and fish samples. Also, Mn, Ni, and Se were not determined in water. The accumulation order of the metals were found to be Fe > Zn = Cu in water and Fe > Zn > Mn > Ni > Cu in sediment. In general, the accumulation order of elements in the tissues all of the species sampled were found as Fe > Zn > Se > Mn > Cu > Ni > Cd in muscle, Zn > Fe > Mn > Se > Se > Cu > Ni > Cd in gills, Fe > Zn > Se > Mn > Cu > Ni > Cd in liver and gonad, and Zn > Fe > Cu > Mn > Se > Ni > Cd in kidney. It was concluded that the fish from the dam lake are not heavily burdened with metals, but they should be controlled periodically to avoid excessive intake of trace metals by humans, and to monitoring the pollution of aquatic environment., Ministry of Agriculture of Turkey; Elazig Aquaculture Research Institute [TAGEM/HAYSUD/2002/09/05/01], This research was supported by the Ministry of Agriculture of Turkey and Elazig Aquaculture Research Institute Directorate project (TAGEM/HAYSUD/2002/09/05/01).

Seasonal Variation of Water Quality in Coastal Area of Cip and Kalecik Dam Lakes (Elazig) In this study, on the coastal areas of Kalecik and Cip Dam Lake with similar size surface area, seasonal variation of water quality were evaluated in the two sampling points in April, June, October, December of 2011. The temperature, dissolved oxygen saturation, pH, conductivity, total hardness, total alkalinity, chemical oxygen demand, dissolved anions and cations (lithium, sodium, potassium, calcium, magnesium, ammonium, nitrite, nitrate, fluoride, chloride, bromide and sulfate ) and the total phosphorus amount were monitored. Kalecik Dam Lake was characterized as a medium hard waterly lake with lower pH and having low electrical conductivity and total solids amount, relatively low amounts of anions and cations were contained. Having higher pH, Cip Dam Lake was identified as a hard waterly lake which has high electrical conductivity and total solids amount as a result of dissolved anion and cation content. Each of the two reservoirs were determined as eutrophic lake at Class-II quality, due to the high total phosphorus content. Key words: Kalecik Dam Lake, Cip Dam Lake, water quality Ozet Bu calismada benzer buyuklukte yuzey alanlarina sahip Kalecik Baraj Golu ile Cip Baraj Golu’nun kiyi bolgelerinde 2011 yili; Nisan, Haziran, Ekim, Aralik aylarinda ikiser ornekleme noktasinda su kalitesinin mevsimsel degisimi degerlendirilmistir. Sicaklik, cozunmus oksijen ile doygunlugu, pH, elektriksel iletkenlik, toplam sertlik, toplam alkalinite, kimyasal oksijen ihtiyaci, cozunmus anyon ve katyonlar (lityum, sodyum, potasyum, kalsiyum, magnezyum, amonyum, nitrit, nitrat, florur, klorur, bromur ve sulfat) ile toplam fosfor miktarlari izlenmistir. Kalecik Baraj Golu daha dusuk pH degeri ile nispeten dusuk anyon ve katyon miktarlari sergileyen, dusuk elektriksel iletkenlik ve toplam kati madde icerigine sahip orta sert sulu bir gol olarak karakterize olmustur. Daha yuksek pH degerine sahip olan Cip Baraj Golu ise yuksek cozunmus anyon ve katyon iceriginin sonucu olarak yuksek elektriksel iletkenlik ve toplam kati madde icerigine sahip sert sulu bir gol olarak tanimlanmistir. Her iki baraj golunun de, yuksek toplam fosfor miktarlari nedeniyle Sinif-II kalitede otrofik gol oldugu belirlenmistir. Anahtar Kelimeler: Kalecik Baraj Golu, Cip Baraj Golu, Su kalite

This study aimed to explain the seasonal and vertical distribution of phytoplankton in the pelagic zone of a deep alkaline lake that is characterized by low phytoplankton abundance. Phytoplankton and water samples were collected seasonally from 9 points and 7 depths between the surface and 20 m from December 2004 to September 2005. Planktolyngbya contorta was the dominant or subdominant species in all seasons and depths. The dominance of Gomphonema species was observed in December, but they were subdominant in September. Cyclotella meneghiniana was dominant at 20 m and subdominant in the upper depths during March, June, and September. Melosira sp. and Meridion circulare were the dominant taxa of the surface phytoplankton in March and June, respectively. A nonparametric test showed the prevalence of cyanobacteria and green algae at a depth of 10 m. Principal component analysis showed the effect of temperature, pH, dissolved solids, nitrate, and silica on the abundance and distribution of phytoplankton. The generalized linear model revealed that high pH and high dissolved solids content seemed to affect the abundance of phytoplankton via limiting nutrient availability.

This study was conducted to determine the effects of zeolites on total ammonia nitrogen (TAN) removal during a 24-hour-sea bass transport. Five experimental treatments (0 (control), 10, 20, 30 and 40 g/l zeolite) with 3 replications were applied in 14 l plastic tanks. 90 sea bass (total weight 175.07 ± 0.49 g) were stocked in each tank. The zeolites were placed in mesh bags and renewed 8 and 16 hours (h) after the commencement of transfer. TAN contents of tank waters were measured after 8, 16 and 24 h. The results revealed that at the 8th h, 20, 30 and 40 g/l zeolite doses were significantly effective compared with the control. At the 16th and 24th h the lowest zeolite level (10 g/l) was also effective in TAN removal. In general highest TAN removal was achieved with 40 g/l treatment with efficiencies of 18.33%, 34.08% and 20.96% at the 8th, 16th and 24th h respectively. Overall, the results suggest that the use of zeolite in sea bass transportation could bring remarkable benefits and thereby increase fish transportation density and welfare.

This study aimed to check the effectiveness of water quality indices (WQIs) in the specific assessment of trout culture impacts on a stream water quality by selecting the parameters in various approaches. Water quality was monitored monthly for a period of 1 year in one reference point and four affected stream reaches in which discharges from intensive trout farms, and rural and agricultural activities were present. The objective WQI calculation using 24 parameters and the minimum WQI (WQI(min)) using dissolved oxygen, biochemical oxygen demand, total suspended solids, total phosphorus, ammonia nitrogen (NH4+-N), and total nitrogen as major indicators in trout farm effluents could not distinguish the aquaculture-impacted stream reaches. However, WQI(min) calculation with NH4+-N, total organic nitrogen (TON), soluble reactive phosphorus, and total organic phosphorus which were selected using the principal component analysis findings meaningfully classified the sampling points. Further reduction of parameters to NH4+-N and TON in WQI(min) calculation achieved a similar successful classification of the sampling points. This study showed that WQI(min) calculated using NIH4+-N and TON is a useful and easily applicable methodology in the assessment of the impacts of trout farm effluents on the stream water quality. (C) 2013 Elsevier Ltd. All rights reserved.