- Topic:Freshwater ecosystems
Lake browning counteracts cyanobacteria responses to nutrients: Evidence from phytoplankton dynamics in large enclosure experiments and comprehensive observational data
This study combines experiments in large enclosures with a comprehensive time series and a field survey to assess the joint effects of storm-induced lake browning, nutrient enrichment and deep-mixing on phytoplankton.Browning decreases nutrient enrichment effects on phytoplankton, including shifts in the species composition from cyanobacteria and chlorophytes to mixotrophic cryptophytes.
Flow dynamics in rivers with riffle-pool morphology: a dataset from case studies and field experiments
Riffle-pool sequences provide vital ecological services to aquatic organisms and are considered fundamental habitats in fluvial ecosystems. Little is known about riffle-pool hydrodynamics. The study presents a dataset on turbulent flow structure in riffle-pool sequences of a natural river, the Tagliamento River in Italy.
The authors detected great concentrations of source hotspots on the northern regions associated to lentic ecosystems, main European rivers acting as ecological corridors for all freshwaters, and a mixed distribution of connectivity hotspots in southern and Mediterranean ecoregions.
Socio-economic or environmental benefits from pondscapes? Deriving stakeholder preferences using analytic hierarchy process and compositional data analysis
The authors studied the needs and knowledge of stakeholders who own, work, research, or benefit from pondscapes in 8 countries. Using the analytic hierarchy process, this study shows that in general stakeholders in the European and Turkish demo-sites prefer environmental benefits, while stakeholders in the Uruguayan demo-sites rank the economic benefits higher.
Global patterns and controls of nutrient immobilization on decomposing cellulose in riverine ecosystems
The research team used a standardized, low-nutrient organic matter substrate (cotton strips) to quantify nutrient immobilization at 100 paired stream and riparian sites representing 11 biomes worldwide. Immobilization rates varied by three orders of magnitude, were greater in rivers than riparian zones, and were strongly correlated to decomposition rates.
Variability is inherent to all natural ecosystems, yet the consequences of alterations to existing variability patterns in environmental factors expected under global change scenarios remain unclear. The authors identified sources of mismatches, challenges, and knowledge gaps to contribute to a research agenda on the effects of variability in aquatic systems. T
From minute to day: ecophysiological response of phytoplankton to fluctuating light exposure during vertical mixing
The authors performed a cross-timescale investigation of a suite of physiological processes governing phytoplankton growth under fluctuating light exposure during vertical mixing: Respiration was enhanced in the short periods of low light following higher photosynthesis at the lake surface, indicating a tight connection between photosynthesis, respiration and biosynthesis under fluctuating light.
Spatial and temporal dynamics of water isotopes in the riverine-marine mixing zone along the German Baltic Sea coast
The spatial and temporal variability of stable water isotopes were investigated in the Schlei and in the Baltic Sea boddens. The data improve the understanding of hydrological processes behind those dynamics. Further they will be a helpful contribution to multiple IGB projects, e.g. in context of migration studies of pike and analysis of biochemical processes in macrophytes
The authors studied, with an individual-based phytoplankton model, how toxins can evolve and how intraspecific variation of toxicity can be maintained in toxic phytoplankton blooms. They found that small-scale spatial heterogeneity generated by binary division of phytoplankton cells can explain the evolution of toxins as a public good and the coexistence of toxic and non-toxic genotypes.
The authors studied the dissolved organic matter (DOM) composition from streams, rivers, ponds and lakes within Berlin. They found DOM from lakes and ponds to differ greatly from that of streams and rivers in composition and temporal turnover. Urban land use, nutrient supply and point source pollution were the main drivers of DOM. This suggests including DOM composition in regular monitoring.