Climate change is reshaping freshwater ecosystems worldwide, yet the extent to which its effects differ across trophic levels remains poorly understood. Despite growing evidence of community restructuring, few studies have jointly examined how multiple trophic levels respond to climate forcing within a functional and network‐based framework. Herein, we assessed how fish and zooplankton communities respond to contemporary and p...

Human activities such as agriculture and urban development are linked to water quality degradation. Canada represents a large and heterogeneous landscape of freshwater lakes, where variations in climate, geography and geology interact with land cover alteration to influence water quality differently across regions. In this study, we investigated the influence of water quality and land use on bacterial communities across 12 eco...

The development of cyanobacteria blooms is of increasing concern in many lakes worldwide, and as a result, modeling their predictors is vital for understanding where and why they occur. In this study, we developed and analyzed a 640‐lake data set that spans Canada and 12 ecozones to identify the drivers of cyanobacteria biomass and of several key toxin‐ and bloom‐forming genera ( Microcystis , Aphanizomenon , and Dolichospermu...

Lakes are undergoing striking physicochemical changes globally, including co‐occurring increases in dissolved organic carbon and nutrient concentrations, water color, and surface temperature. Although several experimental studies of lake browning and warming have been conducted over the last decade, knowledge remains limited as to the structural and functional responses of multitrophic plankton communities, especially under en...

Aim While it is now well accepted that human activities are having pronounced effects on natural ecosystems, regional variation in the rate and magnitude of various human impacts is unclear. Moreover, the effects of land use change on natural aquatic communities have only relatively recently begun to be explored. Our goal was to understand how and where assemblages of a central food web component of freshwater lakes have chang...

Canada is home to more lakes than any other nation, but there is a fragmented and limited understanding of the ecological status of these water bodies. Zooplankton are excellent bioindicators of lake health, given their central food web position. To date, many studies have investigated the effect of individual stressors on zooplankton communities, mediated through changes in water quality (e.g., macronutrients, temperature, or...

Agricultural pollution with fertilizers and pesticides is a common disturbance to freshwater biodiversity. Bacterioplankton communities are at the base of aquatic food webs, but their responses to these potentially interacting stressors are rarely explored. To test the extent of resistance and resilience in bacterioplankton communities faced with agricultural stressors, we exposed freshwater mesocosms to single and combined gr...

Aim We examined variation in crustacean zooplankton composition and diversity across Canada, the most lake‐rich country in the world. In addition to α ‐diversity patterns, we explore mechanisms behind β ‐diversity spatial variation, using taxonomic and functional metrics. Our goal was to explore geographical gradients and related mechanisms shaping zooplankton distribution across different spatial scales. Location Canada. Taxo...

Aquatic ecologists face challenges in identifying the general rules of the functioning of ecosystems. A common framework, including freshwater, marine, benthic, and pelagic ecologists, is needed to bridge communication gaps and foster knowledge sharing. This framework should transcend local specificities and taxonomy in order to provide a common ground and shareable tools to address common scientific challenges. Here, we advoc...

Theory predicts that population genetic structure and metacommunity structure are linked by the common processes of drift and migration, but how population genetic structure and metacommunity structure are related in nature is still unknown. Deeper understanding of the processes influencing both genetic and community diversity is vital for better predicting how environmental change will impact biodiversity patterns. We examine...

The relative importance of top‐down vs. bottom‐up control of phytoplankton biomass in aquatic ecosystems has been long debated and studied. However, few studies have considered the relative importance of top‐down vs. bottom‐up control on phytoplankton vertical distributions and characteristics of deep chlorophyll maxima (DCMs), and fewer still have investigated the importance of these drivers for multiple phytoplankton groups....

Mixotrophy is increasingly recognized as an important trophic pathway among phytoplankton, yet its underlying drivers remain largely unknown and unexplored. Here, we present a study utilizing 69 lake samplings in boreal Quebec, Canada, identifying variables driving the success of phytoplankton that have a capacity for mixotrophy and pointing to the underlying mechanisms. We found that the success of mixotrophs (% of total biom...

Summary Northern lakes are ice‐covered for a large part of the year, yet our understanding of microbial diversity and activity during winter lags behind that of the ice‐free period. In this study, we investigated under‐ice diversity and metabolism of Verrucomicrobia in seasonally ice‐covered lakes in temperate and boreal regions of Quebec, Canada using 16S rRNA sequencing, metagenomics and metatranscriptomics. Verrucomicrobia,...

The vertical distribution of chlorophyll in stratified lakes and reservoirs frequently exhibits a maximum peak deep in the water column, referred to as the deep chlorophyll maximum (DCM). DCMs are ecologically important hot spots of primary production and nutrient cycling, and their location can determine vertical habitat gradients for primary consumers. Consequently, the drivers of DCM structure regulate many characteristics...

Aim Understanding the magnitude and drivers of freshwater diversity over the last 150 years provides essential insights for developing scenarios of future change. Here, we quantify and identify drivers of spatial and temporal beta diversity in diatom assemblages between historical and modern times. Location United States of America. Major Taxa Studied Diatoms. Tim Period pre‐AD 1850 and c. 2007. Methods Using sedimentary genus...

Recent experimental evidence suggests that changes in the partial pressure of CO 2 ( pCO 2 ), in concert with nutrient fertilisation, may result in increased primary production and shifted phytoplankton community composition that favours species lacking adaptations to low CO 2 environments. It is not clear whether these results apply in ambient freshwaters, which are already often supersaturated in CO 2 , and where phytoplankt...

The use of functional traits to characterize community composition has been proposed as a more effective way to link community structure to ecosystem functioning. Organismal morphology, body stoichiometry, and physiology can be readily linked to large‐scale ecosystem processes through functional traits that inform on interspecific and species‐environment interactions; yet such effect traits are still poorly included in trait‐b...

This data compilation synthesizes 8609 individual observations and ranges of 13 traits from 201 freshwater and 191 marine crustacean taxa belonging to either Copepoda or Cladocera, two important zooplankton groups across all major aquatic habitats. Most data were gathered from the literature, with the balance being provided by zooplankton ecologists. With the aim of more fully assessing zooplankton effects on elemental process...