The combined effect of pH and dissolved inorganic carbon concentrations on the physiology of plastidic ciliate Mesodinium rubrum and its cryptophyte prey.

Ocean acidification is caused by rising atmospheric partial pressure of CO (pCO) and involves a lowering of pH combined with increased concentrations of CO and dissolved in organic carbon in ocean waters. Many studies investigated the consequences of these combined changes on marine phytoplankton, yet only few attempted to separate the effects of decreased pH and increased pCO. Moreover, studies typically target photoautotrophic phytoplankton, while little is known of plastidic protists that depend on the ingestion of plastids from their prey.

Microfluidic Impedance Cytometry for Single-Cell Particulate Inorganic Carbon:Particulate Organic Carbon Measurements of Calcifying Algae.

Calcifying algae, like coccolithophores, greatly contribute to the oceanic carbon cycle and are therefore of particular interest for ocean carbon models. They play a key role in two processes that are important for the effective CO flux: The organic carbon pump (photosynthesis) and the inorganic carbon pump (calcification). The relative contribution of calcification and photosynthesis can be measured in algae by the amount of particulate inorganic carbon (PIC) and particulate organic carbon (POC).

Soil networks become more connected and take up more carbon as nature restoration progresses.

Soil organisms have an important role in aboveground community dynamics and ecosystem functioning in terrestrial ecosystems. However, most studies have considered soil biota as a black box or focussed on specific groups, whereas little is known about entire soil networks. Here we show that during the course of nature restoration on abandoned arable land a compositional shift in soil biota, preceded by tightening of the belowground networks, corresponds with enhanced efficiency of carbon uptake.

Elevated pCO2 causes a shift towards more toxic microcystin variants in nitrogen-limited Microcystis aeruginosa.

Elevated pCO2 may promote phytoplankton growth, and potentially alleviate carbon limitation during dense blooms. Under nitrogen-limited conditions, elevated pCO2 may furthermore alter the phytoplankton carbon-nitrogen (C:N) balance and thereby the synthesis of secondary metabolites, such as cyanobacterial toxins. A common group of these toxins are the microcystins, with variants that differ not only in C:N stoichiometry, but also in toxicity.

Community stoichiometry in a changing world: combined effects of warming and eutrophication on phytoplankton dynamics.

The current changes in our climate will likely have far-reaching consequences for aquatic ecosystems. These changes in the climate, however, do not act alone, and are often accompanied by additional stressors such as eutrophication. Both global warming and eutrophication have been shown to affect the timing and magnitude of phytoplankton blooms.

The good, the bad and the plenty: interactive effects of food quality and quantity on the growth of different Daphnia species.

Effects of food quality and quantity on consumers are neither independent nor interchangeable. Although consumer growth and reproduction show strong variation in relation to both food quality and quantity, the effects of food quality or food quantity have usually been studied in isolation. In two experiments, we studied the growth and reproduction in three filter-feeding freshwater zooplankton species, i.

Induced defenses in herbivores and plants differentially modulate a trophic cascade.

Inducible defenses are dynamic traits that modulate the strength of both plant-herbivore and herbivore-carnivore interactions. Surprisingly few studies have considered the relative contributions of induced plant and herbivore defenses to the overall balance of bottom-up and top-down control. Here we compare trophic cascade strengths using replicated two-level and three-level plankton communities in which we systematically varied the presence or absence of induced defenses at the plant and/or herbivore levels.