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

Studies investigating gene flow in sessile or sedentary marine species typically draw conclusions about larval dispersal by investigating genetic structure of adults. Here, we generated microsatellite data from adults, recruits, settlers and planktonic larvae of the brown mussel, Perna perna, from the southeast coast of South Africa, and identified a consistent mismatch in genetic structure between

Conserving wild fisheries requires identifying and monitoring distinct populations, yet prevalent genetic approaches often do not integrate habitat data and may not fully delineate these structures. This issue is critical in sea/river‐type sockeye salmon (Oncorhynchus nerka), an ecotype whose specific spawning habitats better define distinct breeding populations. Despite possessing traits that confer

The impacts of climate change on Arctic marine systems are noticeable within the scientific “lifetime” of most researchers and the iconic image of a polar bear struggling to stay on top of a melting ice floe captures many of the dominant themes of Arctic marine ecosystem change. But has our focus on open‐ocean systems and parameters that are more easily modeled and sensed remotely neglected an element

Biomass estimates are crucial for modeling and understanding energy flow through ecosystems. Many modeling frameworks rely on published body weights of organisms to convert density estimates to biomass. However, published body weight data are limited to few taxa in a limited number of systems. Here we present mean individual weights for common benthic macroinvertebrates of the Laurentian Great Lakes

Coastal lagoons are important nutrient filters and carbon sinks but may release large amounts of methane (CH4) to the atmosphere. Here, we hypothesize that eutrophication and population density will turn coastal lagoons into stronger methane emitters. We report benthic fluxes from 187 sediment cores incubated from three of the largest European lagoons suffering persistent eutrophication. Methane fluxes

Marine microbes are strongly interrelated to trace metals in the ocean. How the availability of trace metals selects for prokaryotic taxa and the potential feedback of microbial processes on the trace metal distribution in the ocean remain poorly understood. We investigate here the potential reciprocal links between diverse prokaryotic taxa and iron (Fe), manganese (Mn), copper (Cu), and nickel (Ni)

Modeling and sensor innovations in the last decade have enabled routine and continuous estimation of daily gross primary productivity (GPP) for rivers. Here, we generate and evaluate within and across year variability for 59 US rivers for which we have compiled a 14‐yr time series of daily GPP estimates. River productivity varied widely across (median annual GPP 462 g C m−2 yr−1, range 19–3445 g C

Oxygen isotopes in stream water can serve as natural tracers of watershed dynamics. Freshwater pearl mussels provide δ18Owater estimates that overcome temporal and spatial limitations of instrumental records. The reliability of shell‐based δ18Owater reconstructions depends on understanding which shell layer biomineralizes closer to oxygen isotopic equilibrium with ambient water. To determine this,

The frequency of news reporting about scientific topics is positively related to public interest as well as to public support for science funding and public policy change. This correlation can also have positive impacts on individual scientific careers depending on the chosen subject area of research. Analysis of a public news database shows the frequency and trends in news reporting of several popular

Understanding the patterns of marine microbial diversity (Bacteria + Archaea) is essential, as variations in their alpha‐ and beta‐diversities can affect ecological processes. Investigations of microbial diversity from global oceanographic expeditions and basin‐wide transects show positive correlations between microbial diversity and either temperature or productivity, but these studies rarely captured

Bacteria and macroalgae share an inseparable relationship, jointly influencing coastal ecosystems. Within macroalgae habitats, Planctomycetota, a group of bacteria notoriously challenging to cultivate, often dominate. However, the mechanisms facilitating their persistence in this environment remain unclear. Here, we successfully isolated a novel Planctomycetota bacterium, Stieleria sp. HD01, from the

In recent years, blooms of the neurotoxic dinoflagellate Alexandrium catenella have been documented in Pacific Arctic waters, and the paralytic shellfish toxins (PSTs) that this species produces have been detected throughout the food web. These observations have raised significant concerns about the role that harmful algal blooms (HABs) will play in a rapidly changing Arctic. During a research cruise

River networks contribute disproportionately to the global carbon cycle. However, global estimates of carbon emissions from inland waters are based on perennial rivers, even though more than half of the world's river length is prone to drying. We quantified CO2 and CH4 emissions from flowing water and dry riverbeds across six European drying river networks (DRNs, 120 reaches) and three seasons and

Leaf litter dominates particulate organic carbon inputs to forest streams. Using data‐informed simulations, we explored how litter type (slow‐ vs. fast‐decomposing species), pulsed autumn litter inputs, groundwater‐mediated temperature regimes, and climate warming affect litter breakdown in a 3rd‐order stream network. We found that the time‐dependent interactions of these variables govern network‐scale

Microzooplankton grazing is an essential parameter to predict the fate of organic matter production in planktonic food webs. To identify predictors of grazing, we leveraged a 6‐yr time series of coastal plankton growth and grazing rates across contrasting environmental conditions. Phytoplankton size–structure and trophic transfer were seasonally consistent with small phytoplankton cell dominance and

Although understanding nutrient limitation of primary productivity in lakes is among the oldest research priorities in limnology, there have been few broad‐scale studies of the characteristics of phosphorus (P)‐, nitrogen (N)‐, and co‐limited lakes and their environmental context. By analyzing 3342 US lakes with concurrent P, N, and chlorophyll a (Chl a) samples, we showed that US lakes are predominantly

We investigated changes in physiology and mechanical properties of diatoms exposed to chemical cues released by copepods Pseudodiaptomus annandalei. Our results showed that the diatoms Phaeodactylum tricornutum, Cylindrotheca closterium, Thalassiosira weissflogii, and Amphora coffeaeformis exhibited elevated growth rates and a substantial 2‐ to 50‐fold increase in biogenic silica (BSi) content increase

The low‐molecular‐weight (LMW) reduced sulfur substances (RSS) composition of dissolved organic matter (DOM) was examined along the GEOTRACES US‐GP15 section in the Pacific Ocean. We demonstrate that LMW RSS constitutes a significant fraction of nonvolatile dissolved organic sulfur (DOS). While thiols such as glutathione were below our detection limit (300 pM), RSS containing two carbon (C) sulfur

The temporal structures of gross primary production (GPP) and ecosystem respiration (ER) vary across time scales in response to complex interactions among dynamic drivers (e.g., flow, light, temperature, organic matter supply). To explore emergent patterns of river metabolic variation, we applied frequency‐domain analysis to multiyear records of metabolism across 87 US rivers. We observed a dominant

To enhance our understanding of the carbon cycle in the Arctic Ocean, comprehensive observational data are crucial, including measurements from the underlying ice water. This study proposed a practical method for calibrating pCO2 sensor using measured dissolved inorganic carbon and total alkalinity. Our findings suggested the minimum number of bottle samples needed for calibration to ensure 1% accuracy

We introduce a new approach to observe the impact of vegetation on tidal flow retardation and retention at large spatial scales. Using radar interferometry and in situ water level gauge measurements during low tide, we find that vegetation in deltaic intertidal zones of the Wax Lake Delta, Louisiana, causes significant tidal distortion with both a delay (between 80 and 140 min) and amplitude reduction

Shallow‐water hydrothermal vents have gained growing attention for their intricate characteristics caused by various epipelagic factors. The shallow‐water hydrothermal system offshore Kueishan Island, Taiwan, situated in an earthquake‐prone area, has prompted our exploration into the relationship between hydrothermal and seismic activities. Our 2‐yr observation uncovered that the hydrothermal venting

Reliable high‐resolution, pre‐observational‐period sea‐ice datasets are rare but critical for contextualizing recent sea‐ice declines and future scenarios. We combine sedimentary ancient DNA of the sea‐ice dinoflagellate Polarella glacialis (Pgla‐sedaDNA) with selected highly branched isoprenoid (HBI) biomarkers alongside other indicators to reconstruct sub‐decadal sea‐ice changes in a marine archive

Although seagrasses are expected to thrive in future acidified oceans by overcoming low CO2 diffusion into plant tissues, the co‐occurrence of environmental stressors may affect their growth. Volcanic CO2 vents are often associated with toxic gases and metal‐rich fluids representing ideal sites to assess the effects of multiple stressors. We evaluated the response of Posidonia oceanica growing near

In this study, we explored the realized thermal sensitivities of various phytoplankton groups in natural seawater, a crucial aspect for understanding the dynamics of marine ecosystems under climate change. Utilizing a decadal pigment dataset (2002–2015) from China Seas and employing generalized additive mixed models coupled with maximum entropy modeling, we discerned thermal sensitivity differentiations

Streams are significant emitters of carbon dioxide (CO2) to the atmosphere that are influenced by diel CO2 dynamics. However, we know little about diel CO2 variability within streams, the diel dynamics of CO2 in the air above streams, and the consequences for emission calculations. We studied five pre‐alpine streams by equipping three sites per stream in close proximity (~ 1 km apart) with automatic

Terrestrial groundwater travels through subterranean estuaries before reaching the sea. Groundwater‐derived nutrients drive coastal water quality, primary production, and eutrophication. We determined how dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP), and dissolved organic nitrogen (DON) are transformed within subterranean estuaries and estimated submarine groundwater discharge

Giant kelp (Macrocystis pyrifera) forests are common along the California coast. Attached on the rocky bottom at depths of approximately 5–25 m, the kelp, when mature, spans the water column and develops dense, buoyant canopies that interact with waves and currents. We present two novel results based on observations of surface gravity waves in a kelp forest in Point Loma, California. First, we report

Biodiversity generally increases productivity in ecosystems; however, this is mediated by the specific functional traits that come with biodiversity loss or gain and how these traits interact with environmental conditions. Most biodiversity studies evaluate the effects of species richness alone, despite our increasing understanding that intraspecific diversity can have equally strong impacts. Here

The PEG (Plankton Ecology Group) model predicts differences in phenology between eutrophic and oligotrophic lakes regarding the occurrence, timing and magnitude of annual chlorophyll maxima and minima. While these predictions have been tested between lakes, hardly any tests exist using long‐term data. We test these predictions using chlorophyll time‐series (1980–2019) from Lake Constance in which trophic

The (sub)tropical western North Pacific is potentially an area of intense nitrogen (N2) fixation in the global ocean, despite limited understanding of the flux and controlling factors. We conducted high‐resolution observations from 2016 to 2021 in this region and used machine learning algorithms to simulate N2 fixation flux. Models estimated an N2 fixation flux from 5.72 to 6.45 Tg N yr−1, with strong

Microbial biodiversity is fundamental to maintain ecosystem functioning in seasonally variable ecosystems. However, it remains unclear how alterations in water availability caused by episodic drying compromise the ability of stream microbes to maintain multiple functions simultaneously (e.g., primary production and carbon cycling). Using data from 32 streams, we investigated how the phenology of annual

Recent rapid changes in climate and environmental conditions have significantly impacted coastal ecosystem functioning. However, the complex interplay between global and local effects makes it challenging to pinpoint the primary drivers. In a multi‐ecosystem study, we analyzed pluri‐decadal trends of bivalve‐δ13C as recorder of global environmental changes. These trends were correlated with large‐scale

The implementation of deep learning algorithms has brought new perspectives to plankton ecology. Emerging as an alternative approach to established methods, deep learning offers objective schemes to investigate plankton organisms in diverse environments. We provide an overview of deep‐learning‐based methods including detection and classification of phytoplankton and zooplankton images, foraging and

As cross‐shelf gradients of most properties are typically much steeper than those in the alongshore direction, transport across isobaths tends to be inhibited, particularly at oceanic fronts where cross‐shelf gradients are markedly pronounced. Consequently, variations in cross‐shelf gradients may exert a significant influence on offshore transport; however, this influence is not yet well understood

In 2015, the Indian Ocean exhibits an exceptionally weakened CO2 uptake, highlighting strong interannual variability of ocean carbon sink. By utilizing multiple ocean CO2 partial pressure (pCO2) data and a state‐of‐the‐art ocean biogeochemical model, we show that the 2015 ocean CO2 anomaly is characterized by a basin‐wide amplification of ocean pCO2, differing from ocean pCO2 responses to other Indian

The impact of climate warming on coastal benthic fauna is already observed, but forecasting their long‐term fate remains challenging. This study uses δ18Oshell data of specimens of five bivalve species collected at six locations and results from kilometer‐scale atmosphere–ocean climate model for the time intervals of 1987–2017 and 2070–2100, to estimate changes in bivalve growth phenology. All species

Polyphosphate (polyP) is important to phytoplankton ecology, but a unified view of its variability and roles in ecosystem‐scale phosphorus (P) cycling is lacking. We study polyP in the world's largest freshwater ecosystem, the Laurentian Great Lakes, covering pelagic to nearshore areas across a wide nutrient gradient. We show that polyP (average 10.99 ± 3.90 nmol L−1) constitutes 3.8–30.2% (average

Scientific Significance Statement Aquaculture is a global industry that enriches the surrounding aquatic environment in nutrients, namely carbon, nitrogen, and phosphorus. Because these inputs are spatially and temporally defined, cage culture farms act as perturbation experiments for understanding the ecological impacts of nutrient enrichment on aquatic ecosystems. Individual farms form an existing

Understanding the fate of permafrost‐derived dissolved organic matter (DOM) is critical for unraveling its role in carbon cycling. However, it remains unclear whether the high lability of permafrost‐derived DOM can be attributed to intrinsic chemical properties or elevated carbon concentrations. We investigated the dynamics of permafrost DOM from the Qinghai–Tibetan Plateau using both biodegradation

Water temperature responses to climate change may vary across Earth's estuaries. To understand how climate change influences estuarine surface water temperature, we need global, long‐term records of estuarine temperature. Here, we generated surface water temperature data over 1060 estuaries globally using Landsat 5, 7, and 8 from 1985 to 2022 and compared water warming rates with local air temperature

Understanding species phenology and temporal co‐occurrence across trophic levels is essential to assess anthropogenic impacts on ecological interactions. We analyzed 15 yr of monitoring data to identify trends and drivers of timing and magnitude of bloom‐forming phytoplankton and diverse zooplankton taxa in the central Baltic Sea. We show that the timings of phytoplankton blooms advance, whereas crustacean