While climate change affects the phytoplankton biodiversity at both local and global scales, predicting phytoplankton community responses to warming is impaired by their polyphyletic complexity. High mountain lakes are highly vulnerable systems, partly due to their limited biodiversity, and forecasting their ecological trajectories is a key challenge for scientists and conservation managers. We evaluated

The daily cycle of solar radiation has a profound influence in structuring the physiology of microbes in the euphotic zone and subsequently setting the degree of coupling across trophic levels within ocean ecosystems. There has been an upsurge of interest in the biological role of the diel cycle and the ability to probe it using molecular approaches (i.e., “omics”), which now allow us to pinpoint the

Worldwide river deltas are impacted by human activities and climatic change, but it has been challenging to quantify their contributions due to nonlinear natural processes and a lack of long‐term geomorphological data. Time‐series bathymetric data were collected at submarine Hengsha Shoal in the Yangtze Delta during 11 repeat surveys over 60 yr. Our results show that the minimum riverine sediment supply

Understanding the impacts of multiple environmental stressors on phytoplankton biomass is crucial for predicting marine ecosystem responses under global climate change. This study employed a sequential modeling framework integrating principal component analysis, generalized additive models, and artificial neural networks to improve predictions of phytoplankton chlorophyll a concentrations in the Taiwan

Litter decomposition is usually modeled with the negative exponential model, which assumes constant proportional mass loss. We assessed this assumption and its interpretive consequences using 145 stream litter mass loss time series and process‐based simulations. Relatively simple (two to three parameters) models allowing time‐varying decay rates produced more accurate predictions and were generally

Freshwater systems are important sources of atmospheric methane (CH4). However, estimated emissions are associated with high uncertainties due to limited knowledge about the temporal variability in emissions and their associated controls, such as air–water gas transfer velocity. Here, we determined the gas transfer velocity of CH4 based on a novel measurement setup that combines simultaneous eddy covariance

Cold thermal refuges may mitigate detrimental effects of future climate warming; yet, pond ecosystems have been largely omitted from thermal refuge research despite being globally numerous and providing critical ecosystem services. We create a formal definition for pond thermal refuge quality, then operationalize this definition by measuring the thermal characteristics and environmental attributes

Ultraviolet radiation (UV) is the most energetic waveband of incident solar radiation and has wide‐ranging effects in the aquatic environment. Our analysis of an 18‐year record of underwater irradiance and related limnological variables in sub‐alpine, ultra‐oligotrophic Lake Tahoe revealed orders of magnitude changes in UV transparency associated with interannual climate perturbations. The large‐scale

Subterranean estuaries (i.e., seawater‐fresh groundwater mixing zones at coastal aquifers) are highly reactive boundaries between continental groundwater and coastal surface seawater. Because particulate organic matter is retained in shallow sediments, internal microbial transformations rely on dissolved organic matter (DOM) supply and bioavailability. Here, we investigated DOM carbon content and optical

Cobalt is a central component of cobalamins, which are nutrients essential for various metabolic processes in marine organisms. Dissolved cobalt in seawater is mostly bound to organic ligands, and the prevailing assumption to date is that these ligands are cobalamin‐related compounds, yet the identity and impact of these ligands on cobalt bioavailability remain unknown. In this study, we examined cobalt

Rivers transport ~200 Tg of particulate organic carbon (POC) to the global ocean annually, of which 30% is known to be buried in continental‐shelf sediments. The fate of the remaining “missing” terrestrial POC (POCterr) remains uncertain, with proposed explanations including rapid remineralization or transport to the remote deep ocean. Here, based on δ13C and 234Th tracers, we show that the vertical

Aquatic heatwaves are increasing in frequency, intensity, and duration worldwide. While increases in mean water temperatures are linked to enhanced phytoplankton biomass, it is unclear how heatwaves alter phytoplankton dynamics in lakes at an ecosystem scale. We investigated changes in surface chlorophyll during 29 summer heatwaves between 2008 and 2019 in 3 north temperate lakes. These lakes vary

Understanding the spatial ecology of migratory species is uniquely challenging using conventional approaches. In fisheries such as for Pacific salmon, genetic stock identification (GSI) and isotope‐based methods have emerged as strategies for reconstructing spatial ecology but are limited by the spatial resolution of genetic differentiation and isotopic heterogeneity. We show that integrating these

The major marine nitrogen‐fixing cyanobacterium, Crocosphaera watsonii, is restricted to warm tropical and subtropical oceans, while the underlying mechanisms remain unclear. C. watsonii fixes nitrogen (oxygen‐sensitive) and carbon (oxygen‐evolving) during night and day, respectively. By diel analyses of physiological rates and transcriptome at its optimal (28°C) and a lower temperature (23°C), we

The Cofán communities rely on the Cofán Bermejo Ecological Reserve for their survival and cultural practices. Due to the rugged and inaccessible topography of the reserve in the Northern Ecuadorian Amazon region, limited biomonitoring and ecological characterization studies of the ecosystem health have been conducted. We investigated the community composition and functional structure of benthic macroinvertebrates

Anthropogenic pressures like ocean warming, acidification, rising N : P ratios, and marine heatwaves (MHWs) are affecting eukaryotic plankton diversity, though their combined impacts are rarely studied. To address this, we conducted a mesocosm experiment on a North Sea plankton community, testing the influence of a MHW under ambient and future environmental conditions. Using 18S rRNA amplicon sequencing

Brachiopods have been employed for environmental and climatic reconstructions in the near and geological past. Traditionally, one datapoint is obtained per shell, providing time‐averaged bulk signals. However, brachiopods also have the potential to provide time‐resolved information on (sub)annual timescales, but this has been understudied due to difficulties in accounting for brachiopod shell growth

This study examines suspended sediment transport affected by flocculation settling in a highly stratified tidal estuary. In situ observation recorded two estuarine front passages during strong‐ebb and flood‐slack tides, respectively. The strong‐ebb front enhanced turbulence, increasing sediment concentrations (~ 5 ppm), macrofloc size (~ 300 μm) and settling efficiency. The surface plume combined with

Rivers produce and decompose large amounts of carbon globally due, in part, to high rates of gross primary production (GPP) and ecosystem respiration (ER), collectively known as ecosystem metabolism. Water temperature is a major driver of ecosystem metabolism, and in‐stream temperatures are increasing globally, including extreme temperature events called heatwaves. This study used published estimates

Lake ice cover is declining globally with important implications for lake ecosystems. Ice loss studies often rely on small numbers of lakes with long‐term data. We analyzed variation and trends in ice cover phenology from 1213 lakes over 74 yr (1949–2022) in Minnesota (USA), during which ice cover duration declined at a rate of 2 d per decade (14 d total) and became more variable. Despite variation

The Kuroshio Current, a western boundary current in the North Pacific Ocean, is regarded as a hotspot of nitrogen fixation that drives marine primary productivity and biogeochemical cycles. However, this assumption is based on limited, spatiotemporally biased data. We curated nitrogen fixation data and applied a generalized additive model to revisit the distribution and total amount of nitrogen fixation

Macroalgae are important primary producers in the coastal ocean, and they release a large fraction of their net primary production as dissolved organic carbon (DOC). It is assumed that much of this DOC is recalcitrant and results in the sequestration of large amounts of carbon. We lack sufficient knowledge about the bioavailability of this material and the role of other sinks such as photooxidation

We resolve mangrove nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2) vertical exchange with the atmosphere and lateral exchange with the ocean. Our new observations in Brazil were combined with literature data to reassess the overall mangrove carbon sequestration potential. The pristine mangrove creek was a source of CO2 and CH4, and a sink for N2O. The CO2‐equivalent N2O uptake offset

Coastal waters play a pivotal role in the global carbon cycle, showing increased short‐term variability of dissolved oxygen saturation (DOsat) and partial pressure of greenhouse gases like carbon dioxide (pCO2), especially in underrepresented tropical eutrophic environments. Here, we conducted high‐frequency (1‐min interval) diel measurements of surface DOsat and pCO2 in Guanabara Bay, Brazil, a highly

The formation of initial bivalve shell is sensitive to ocean acidification, encoding the basis of shell formation and environmental information. Here, we demonstrated how the initial shell building processes were affected under various acidified conditions. With decreasing pH, larvae showed smaller shells and higher incidences of deformity. Shell elemental and isotopic profiles suggested that larvae

Adjustments in the metabolism of marine fish are associated with the complexity of resource availability, prey–predator relationships, and biotic and abiotic interactions in the natural environment. To investigate the relationship between metabolism and body mass, this study used a conventional method to estimate the oxygen consumption rate (reflecting the resting metabolic rate) in black porgy, Acanthopagrus

The Japanese turban snail Lunella coreensis is sensitive to ocean currents due to its short pelagic larval stage and moderate dispersal ability, making it an ideal model for studying genetic diversity shaped by paleoclimatic shifts. In this study, we analyzed the mitochondrial genes COI and 12S of museum samples collected from various coasts across Japan and identified 10 haplogroups divided into Pacific

Gas transfer velocity () controls gas fluxes between aquatic ecosystems and the atmosphere. In streams, is controlled by turbulence and, thus, local hydrology and geomorphology. Resultantly, variability in can be large and modeling from physical parameters can have large uncertainty. Here, we leverage a large dataset of estimates derived from tracer‐gas experiments in 22 US streams across a range of

River networks serve as conduits for dissolved organic matter (DOM) and carbon (DOC) from inland to coastal waters. Human activities and climate change are altering DOM sources, causing hydrological and biogeochemical shifts that impact DOC concentrations and changing the transport and transformation of DOM and DOC. Here, we synthesize current knowledge of changing DOM sources, DOC concentrations,

Although the productivity–biodiversity relationship (PBR) has been a hot topic, few studies have considered how anthropogenic pressures affect PBRs in marine microzooplankton. Here, we provide the first insights into PBRs in tintinnid assemblages using 18‐yr data from Jiaozhou Bay, a typical coastal bay in the Yellow Sea. We hypothesized and verified that PBRs vary across contrasting anthropogenic

Reproductive data are vital for fisheries and conservation management. For cephalopods, reproductive data are usually obtained by analyzing gonads, which only provide data on an individual at a given time and require whole deceased specimens. We developed a novel method for extracting reproductive hormones from along the growth axis of a chitinous structure which could thus provide lifetime reproductive

Oysters inhabit a variety of coastal and deep‐sea settings over a wide latitudinal range and have a role as ecosystem engineers. They also represent an important food source for humans since hunter‐gatherer times, which motivates interest in using oyster shells as environmental and life history archives. Still, oysters have often been disregarded in sclerochronology studies, although several methods

Biological nitrogen fixation is the conversion of dinitrogen (N2) gas into bioavailable nitrogen by microorganisms with consequences for primary production, ecosystem function, and global climate. Here we present a compiled dataset of 4793 nitrogen fixation (N2‐fixation) rates measured in the water column and benthos of inland and coastal systems via the acetylene reduction assay, 15N2 labeling, or

Phosphorus, an element essential to all life, is impacted by calcium carbonate (CaCO3) co‐precipitation and dissolution dynamics across aquatic ecosystems. Changes to climate, hydrology, and eutrophication, coupled with differences in terminology related to naming CaCO3‐producing ecosystems (i.e., chalk, carbonate, karst, travertine), point to the urgency and challenges in understanding this portion

The iconic Great Barrier Reef (GBR) experienced mass coral bleaching in early 2024. In the southern GBR, heat stress triggered severe and widespread bleaching to levels not previously recorded and impacted a diverse range of coral genera at One Tree Reef (OTR). Over 161 d, we tracked the health of 462 coral colonies from heatwave peak to autumn and winter cooling. In February and April, 66% and 80%

The cycling of calcium carbonate (CaCO3) plays a significant role in deep‐water carbon sequestration and affects the buffer capacity of the upper ocean for absorbing atmospheric CO2. This study investigates the role of dissolved calcium (Ca) and potential alkalinity (PA) as tracers for CaCO3 cycling in the Southern Ocean. The correlation between PA and Ca concentrations in subantarctic and polar waters

Amidst the ongoing climate crisis, the need for observation‐based prediction of environmental tipping points becomes increasingly urgent. Detecting loss of resilience within a system can provide early warnings for tipping points. This requires long, regularly spaced time‐series, characteristics that are rare among marine observational and proxy records. Due to their remarkable length and temporal resolution

In aquatic ecosystems facing climate change, higher temperatures often co‐occur with alterations in resource availability. The metabolic theory of ecology uses activation energy to assess the sensitivity of biological processes to temperature, but neglects how resource availability might modify temperature sensitivities. To understand the impacts of resource limitation on temperature sensitivities

Fragmentation of marine snow affects the downward flux of organic matter, and other aggregate‐associated compounds such as oil. Using phytoplankton aggregates, we demonstrate that marine snow with oil, termed marine oil snow, had a higher resistance to fragmentation compared to marine snow without oil when exposed to turbulence ex situ. At moderate shear levels, typical of the ocean mixed layer, 17%

Arctic phytoplankton spring blooms have increased in magnitude and extent over the past two decades, particularly in waters near the sea ice edge. We develop an idealized model of phytoplankton dynamics that takes into account the role of sea ice meltwater flux and its impact on surface mixed layer depth. Satellite observations feature a characteristic peak in phytoplankton concentration at around

Arctic regimes. Currently, warming accelerates the erosion of permafrost coasts and the associated discharge of sediment, carbon, and nutrients into the Arctic Ocean. However, the impacts of coastal erosion on planktonic food webs remain understudied. We aimed to (1) understand how coastal erosion impacts nearshore carbon, nutrient, and light regimes; (2) investigate the effects on primary production

Measurement of the mineral surface area (MSA) of sedimentary particles is a traditional approach for studying the transport and protection of organic carbon (OC) in marine systems. We investigated the application of MSA on the biological carbon pump in the deep ocean interior in the Ulleung Basin (UB), East/Japan Sea. This is the second study of sinking particle MSA, and the first in an ocean with

Aquatic organisms are natural data loggers and record chemical variations within hardened accretionary structures like shells and teeth. Chemical sclerochronology is the study of these chemical variations through time and how they are used to understand environmental change and the physiology and ecology of species. While sclerochronology research has largely focused on bivalves, teleost fish, and

Interest in winter limnology is growing rapidly, but progress is hindered by a shortage of standardized multivariate datasets on winter conditions. Addressing the winter data gap will enhance our understanding of winter ecosystem function and of lake response to environmental change. Here, we describe a dataset generated by a multi‐institutional winter sampling campaign across all five Laurentian Great

The accelerating rate of global climate change at higher elevations and latitudes is increasing the potential for extreme climatic events. Here, a knowledge gap exists in how the order of exposure to, and duration of droughts and heatwaves affect their cumulative impact on aquatic communities. We tested experimentally for the legacy effects of simultaneous vs. sequential exposures to drought and heatwave

Limnological understanding of the role snow plays in under‐ice thermal dynamics is mainly based on studies of clear‐water lakes. Very little is known about the role snow plays in the thermal dynamics of dystrophic lakes. We conducted a whole lake experiment on a small, 8 m deep dystrophic bog lake in northern Wisconsin, where we removed all snowfall over two consecutive winters. Due to weather variability

Despite global evidence of lake deoxygenation, its duration, timing, and impacts over decadal to centennial timescales remain uncertain. This study introduces a novel model approach using 150 yr of limnological and paleolimnological data to evaluate the anthropogenic impacts on deep oxygen in Lake Geneva. Results highlight an increase in oxygen consumption rates due to cultural eutrophication, initially

Oxygen‐stable isotope (δ18O) in otoliths has been useful to infer marine fish migrations. However, because otolith δ18O is affected by two parameters, temperature and δ18O of ambient water, its interpretation becomes challenging when neither of them is constant. Here, I describe a simple method using hydrodynamic models to visualize potential migration histories from high‐resolution otolith δ18O chronologies

Climate change alters the sources and age of carbon in Arctic food webs by fostering the release of older carbon from degrading permafrost. Radiocarbon (14C) traces carbon sources and age, but data before rapid warming are rare and limit assessments over time. We capitalized on 14C data collected ~ 40 years ago that used fish as natural samplers by resampling the same species today. Among resampled

To save saltmarshes and their valuable ecosystem services from sea level rise, it is crucial to understand their natural ability to gain elevation by sediment accretion. In that context, a widely accepted paradigm is that dense vegetation favors sediment accretion and hence saltmarsh resilience to sea level rise. Here, however, we reveal how dense vegetation can inhibit sediment accretion on saltmarsh

Excessive nutrient inputs have caused eutrophication of coastal ecosystems worldwide, triggering extensive algal blooms, oxygen‐depletion, and collapse of local fisheries. In the Baltic Sea, inputs of nitrogen (N) and phosphorus (P) have been significantly reduced since the 1980s, but the environmental state shows little to no signs of recovery. However, a simulation with continued high loads from

Light affects the cellular iron (Fe) requirement of phytoplankton because of its presence in major photosynthetic proteins. Thus, interactions between variable Fe concentrations and light intensities could restrict photosynthetic carbon fixation in the ocean. Here we show a narrowing of the optimal light range for growth of a marine cyanobacterium, Prochlorococcus strain NATL1A, a member of LLI ecotype