Saturated constructed wetlands for the remediation of cylindrospermopsin and microcystin-LR: Plants, microbes, and biodegradation pathways.

Harmful cyanobacterial blooms will be more intense and frequent in the future, contaminating surface waters with cyanotoxins and posing a threat to communities heavily reliant on surface water usage for crop irrigation. Constructed wetlands (CWs) are proposed to ensure safe crop irrigation, but more research is needed before implementation. The present study operated 28 mesocosms in continuous mode mimicking horizontal sub-surface flow CWs.

Do weathered microplastics impact the planktonic community? A mesocosm approach in the Baltic Sea.

Microplastics (MPs) are ubiquitous pollutants of increasing concern in aquatic systems. However, little is still known about the impacts of weathered MPs on plankton at the community level after long-term exposure. In this study, we investigated the effects of weathered MPs on the structure and dynamics of a Baltic Sea planktonic community during ca.

Glacial meltwater and seasonality influence community composition of diazotrophs in Arctic coastal and open waters.

The Arctic Ocean is particularly affected by climate change with unknown consequences for primary productivity. Diazotrophs-prokaryotes capable of converting atmospheric nitrogen to ammonia-have been detected in the often nitrogen-limited Arctic Ocean but distribution and community composition dynamics are largely unknown. We performed amplicon sequencing of the diazotroph marker gene nifH from glacial rivers, coastal, and open ocean regions and identified regionally distinct Arctic communities.

How Microbial Food Web Interactions Shape the Arctic Ocean Bacterial Community Revealed by Size Fractionation Experiments.

In the Arctic, seasonal changes are substantial, and as a result, the marine bacterial community composition and functions differ greatly between the dark winter and light-intensive summer. While light availability is, overall, the external driver of the seasonal changes, several internal biological interactions structure the bacterial community during shorter timescales. These include specific phytoplankton-bacteria associations, viral infections and other top-down controls.

Effects of oil spill response technologies on marine microorganisms in the high Arctic.

We studied how exposure to oil spill response technologies affect marine microorganisms during Arctic winter and spring. Microorganisms were exposed to chemically dispersed oil (DISP), in situ burnt oil (ISB), and natural attenuated oil (NATT) in mesocosms from February to May. We subsampled the mesocosms and studied the effects of oil in laboratory incubations as changes in biomass of the major functional groups: bacteria, heterotrophic-nanoflagellates, dinoflagellates, ciliates, pico- and nanophytoplankton, and diatoms over two 14-day periods.

Bacterial community composition responds to changes in copepod abundance and alters ecosystem function in an Arctic mesocosm study.

Combining a minimum food web model with Arctic microbial community dynamics, we have suggested that top-down control by copepods can affect the food web down to bacterial consumption of organic carbon. Pursuing this hypothesis further, we used the minimum model to design and analyse a mesocosm experiment, studying the effect of high (+Z) and low (-Z) copepod density on resource allocation, along an organic-C addition gradient. In the Arctic, both effects are plausible due to changes in advection patterns (affecting copepods) and meltwater inputs (affecting carbon).

Spatiotemporal Dynamics of Ammonia-Oxidizing Thaumarchaeota in Distinct Arctic Water Masses.

One of the most abundant archaeal groups on Earth is the Thaumarchaeota. They are recognized as major contributors to marine ammonia oxidation, a crucial step in the biogeochemical cycling of nitrogen. Their universal success is attributed to a high genomic flexibility and niche adaptability.

Heterogeneous distribution of plankton within the mixed layer and its implications for bloom formation in tropical seas.

Intensive sampling at the coastal waters of the central Red Sea during a period of thermal stratification, prior to the main seasonal bloom during winter, showed that vertical patches of prokaryotes and microplankton developed and persisted for several days within the apparently density uniform upper layer. These vertical structures were most likely the result of in situ growth and mortality (e.g.