Aquaponics provides an alternative opportunity for the combined production of fish and plants. Most of the essential nutrients required for optimal plant growth can be supplied from the fish feed, except for K and Fe. These nutrients are usually inadequate in fish feed. In this study, red tilapia and rocket plants were co-cultivated in an aquaponics system along with the extra addition of K and Fe. Fish growth, morpho-anatomical characteristics, and K and Fe loading on fish gills were studied. Plant growth parameters were also determined. The addition of Fe and K slightly improved the produced fresh biomass of rocket per unit area and had no impact on tilapia growth and survival. No severe histological alterations in fish gills, liver, and midgut were detected. EDX analysis showed that the addition of K led to the enrichment of this specific ion in fish gills, but no effects of this accumulation were found on other aspects of fish growth and survival.

Light use efficiency (LUE) models are widely used to estimate gross primary productivity (GPP) because they provide strong accuracy while maintaining low complexity. The aim of this study is (a) to evaluate the performance of a LUE model (sCASE) and (b) to compare the performance of several alternative water scalars. The analyses are done using GPP measurements from thirteen eddy covariance sites across Europe, corresponding to different forest types. Daily GPP estimates produced by sCASE were highly accurate for most sites (average R² = 0.750 and average RMSE = 2.317 g C m⁻² d⁻¹), matching the performance of other widely used LUE models in the literature. All three scalars were essential for maintaining model accuracy, although their relative importance varied among sites. The developmental scalar, which is not incorporated in most productivity models, was particularly important for accurately estimating GPP in deciduous species. Among the ten water scalars tested, those based on simple water balance calculations performed best in water-limited sites, whereas the VPD-based scalar performed better in sites without water limitation. The EF (evaporative fraction) scalar showed high accuracy at some sites across both water status categories but very low accuracy at others. For large-scale applications, water scalars based on MODIS indices offer the advantage of global coverage, which can outweigh their lower accuracy relative to other scalars.

Monitoring vegetation phenology is crucial for understanding how plants respond to climate change and how the latter affects the role of vegetated ecosystems in biosphere cycles. It has been reported that the growing season has been extended, leading to an increase in global terrestrial productivity, but not much attention has been given to how different climatic variables affect specific tree species’ phenology. This study focuses on the main phenological events (SOS, Start Of Season; EOS, End Of Season; and LOS, Length Of Season) of two deciduous species (Fagus sylvatica L. and Castanea sativa Mill.) and the effects of temperature and precipitation on them. The analysis concerns a 23-year period (2000–2022) of various sites across southern Europe. The dates for each phenological event are estimated based on NDVI timeseries from MODIS satellite sensor. Both species show an elongation of their growing season, with SOS occurring 2.09 and 1.63 days/decade earlier and EOS 2.97 and 3.03 days/decade later for Fagus sylvatica and Castanea sativa, respectively, with this trend appearing more intense at lower altitudes. Temperature seems to be the major driver for these changes for both species, with higher temperatures before each phenological event leading to earlier SOS and delayed EOS. The effects of precipitation are less homogenous, showing different trends between sites and species.