ALBERT

Description: Aquaponics production of spearmint (Mentha spicata) was evaluated under commercial grow-out conditions of African catfish (Clarias gariepinus) in Northern Germany (Mecklenburg-Western Pomerania). Fish batch production under different stocking densities in an extensive aquacultural unit (EAU) and an intensive aquacultural unit (IAU) was connected to conventional plant cultivation on ebb-and-flood planting tables and compared to a liquid fertilizer control. The best growth parameters of M. spicata were found under the intensive stocking density of C. gariepinus (IAU), resulting in a plant leaf area of 10.9 ± 2.5 cm2, leaf length of 8.6 ± 1.6 cm, and a cut fresh biomass from aboveground of 31.8 ± 13.8 g/plant, compared to the EAU (5.6 ± 2.1 cm2; 5.4 ± 1.4 cm; 17.4 ± 4.7 g/plant) and the control (5.7 ± 2.2 cm2; 5.5 ± 1.4 cm; 11.2 ± 5.3 g/plant). The fresh biomass of the whole plants was not significantly different between the EAU (165.5 ± 71.7 g/plant) and the IAU (190.7 ± 105.6 g/plant), though the latter gained more weight. The initial fish number ratio between the EAU and the IAU of 1/4 increased the M. spicata leaf area by twofold in the IAU. Our results demonstrate that aquaponics (s.l.) production of M. spicata is possible under the direct use of effluent waters from intensive African catfish cultivation without the addition of any liquid fertilizer.

Description: Recycling of phosphorus (P) from feed input in aquaculture systems gains increasing importance, especially relating to sustainable agriculture and food production. In order to find possible areas of application of African catfish solid waste, the purpose of this study was to characterize the elemental and organic matter composition and P speciation in the aquaculture fish waste. Pyrolysis-field ionization mass spectrometry (Py-FIMS) was used to investigate the composition of organic matter and P K-edge X-ray absorption near edge structure (XANES) spectroscopy to describe the occurring P-containing compounds in African catfish solid waste from an intensive recirculation aquaculture system (RAS). The solid fish waste was mainly composed of sterols, free fatty acids and alkylaromatics, as it is common for digestive systems of animals. Ingredients such as the phytosterol beta-sitosterin confirm plant-based feed ingredients and some recalcitrance against digestion in the African catfish gut. The P in the solid fish waste was exclusively bound as calcium-phosphates. These calcium-phosphate minerals as major constituents of African catfish waste may have beneficial effects when applied to soils, suggesting the use of this waste as possible soil amendment in the future.

Description: Optimal crop production in aquaponics is influenced by water pH and potassium concentrations. The addition of potassium hydroxide (KOH) into the recirculating aquaculture system (RAS) may benefit aquaponics by increasing the water pH for better biofilter activity and supplementing K for better plant growth and quality. We investigated the growth, feed conversion, body composition and welfare indicators of juvenile African catfish (Clarias gariepinus) treated with four concentrations of K (K0 = 2, K200 = 218, K400 = 418, and K600 = 671 mg L−1). While growth, feed conversion and final body composition were unaffected, the feeding time and individual resting significantly increased with increasing K+. The swimming activity and agonistic behavior were reduced significantly under increased concentrations of K+. Leftover feed and the highest number of skin lesions were observed under K600. We suggest that K+ concentrations between 200 and 400 mg L−1 can improve the welfare status of juvenile African catfish. This enables the application of KOH in RAS to supply alkalinity to achieve optimum nitrification at minimum water exchange and improve the nutritional profile of the process water with benefits for the welfare status of African catfish and aquaponics plant production and quality.

Description: Traditionally, it had been assumed that meta-representational Theory of Mind (ToM) emerges around the age of 4 when children come to master standard false belief (FB) tasks. More recent research with various implicit measures, though, has documented much earlier competence and thus challenged the traditional picture. In interactive FB tasks, for instance, infants have been shown to track an interlocutor's false or true belief when interpreting her ambiguous communicative acts (Southgate et al . 2010 Dev. Sci. 13 , 907–912. ( doi:10.1111/j.1467-7687.2009.00946.x )). However, several replication attempts so far have produced mixed findings (e.g. Dörrenberg et al . 2018 Cogn. Dev. 46 , 12–30. ( doi:10.1016/j.cogdev.2018.01.001 ); Grosse Wiesmann et al. 2017 Dev. Sci. 20 , e12445. ( doi:10.1111/desc.12445 ); Király et al . 2018 Proc. Natl Acad. Sci. USA 115 , 11 477–11 482. ( doi:10.1073/pnas.1803505115 )). Therefore, we conducted a systematic replication study, across two laboratories, of an influential interactive FB task (the so-called ‘Sefo’ tasks by Southgate et al . 2010 Dev. Sci. 13 , 907–912. ( doi:10.1111/j.1467-7687.2009.00946.x )). First, we implemented close direct replications with the original age group (17-month-olds) and compared their performance to those of 3-year-olds. Second, we designed conceptual replications with modifications and improvements regarding pragmatic ambiguities for 2-year-olds. Third, we validated the task with explicit verbal test versions in older children and adults. Results revealed the following: the original results could not be replicated, and there was no evidence for FB understanding measured by the Sefo task in any age group except for adults. Comparisons to explicit FB tasks suggest that the Sefo task may not be a sensitive measure of FB understanding in children and even underestimate their ToM abilities. The findings add to the growing replication crisis in implicit ToM research and highlight the challenge of developing sensitive, reliable and valid measures of early implicit social cognition.

Description: The signals of the Arctic Amplification are manifold. Different climate developments like the increase in moisture and air temperature or the decrease of the snow cover can be observed. The Svalbard archipelago is one of the warmest areas in the Arctic. It lies at the end of the North Atlantic cyclone track which is the main source of energy for the Arctic. A warming-induced intensified hydrological cycle increases the frequency of cyclones in Svalbard and thereby the occurrence of extreme rain events, in particular in winter. Only a few publications investigated the changes of precipitation in accordance to the existing permafrost, which characterizes 40% of the archipelago. This study describes the development of (extreme) liquid precipitation in Spitsbergen and investigates the impact of extreme rain events in relation to the degradation of permafrost that already occurs due to the amplified warming. Therefore, meteorological data as well as topsoil temperature data of Ny-Ålesund (Spitsbergen) were analyzed for the period from 1999 to 2020. It confirms an actual increase of (extreme) liquid precipitation in general and in winter season. Further, an examination of distinct extreme events revealed a remarkable effect of extreme rainfall on topsoil temperature on a micro-level and indicates complex interactions of several environmental factors regarding the heat fluxes between the atmosphere and the ground. In particular rain-on-snow events have a noticeable impact on topsoil temperature and thereby influence the thermal state of the permafrost substantially.