8604 research outputs found
Sort by
Elucidating the Role of Marine Benthic Carbon in a Changing World
Full text linkThe ocean plays a major role in controlling atmospheric carbon at decadal to millennial
timescales, with benthic carbon representing the only geologic‐scale storage of oceanic carbon. Despite its
importance, detailed benthic ocean observations are limited and representation of the benthic carbon cycle
in ocean and Earth system models (ESMs) is mostly empirical with little prognostic capacity, which
hinders our ability to properly understand the long‐term evolution of the carbon cycle and climate change‐
related feedbacks. The Benthic Ecosystem and Carbon Synthesis (BECS) working group, with the support
of the US Ocean Carbon & Biogeochemistry Program (OCB), identified key challenges limiting our
understanding of benthic systems, opportunities to act on these challenges, and pathways to increase the
representation of these systems in global modeling and observational efforts. We propose a set of
priorities to advance mechanistic understanding and better quantify the importance of the benthos: (a)
implementing a model intercomparison exercise with existing benthic models to support future model
development, (b) data synthesis to inform both model parameterizations and future observations, (c)
increased deployment of platforms and technologies in support of in situ benthic monitoring (e.g., from
benchtop to field mesocosm), and (d) global coordination of a benthic observing program (“GEOSed”) to
fill large regional data gaps and evaluate the mechanistic understanding of benthic processes acquired
throughout the previous steps. Addressing these priorities will help inform solutions to both global and
regional resource management and climate adaptation strategies
A climatological baseline for understanding patterns of seasonal lake dynamics across sub-Sahelian Africa
Full text linkLakes in sub-Sahelian Africa are facing growing ecological threats from climate change and human, yet most research has focused on a handful of well-known large lakes. This study analyses 137 lakes, many previously understudied, and identifies consistent seasonal co-variability patterns across meteorological variables, satellite-derived lake physical and biogeochemical variables, and morphological and anthropogenic characteristics. We identify four distinct clusters of lakes, shaped by the atmospheric variability and its synchrony with water temperature seasonality. Within each cluster, we observe three seasonal patterns of chlorophyll-a concentration tied to wet and dry seasons. These patterns align with regional climatic threats in Africa, such as shifts in rainfall seasonality, altered frequency of tropical cyclones and wildfires, thus positioning our study as a framework to assess lake vulnerability across the sub-Sahelian region
Chemical composition of the harvested subtidal kelp, Lessonia trabeculata, from a coastal location in central Chile
No full textKelp forests are important ecosystem engineers in temperate and sub-polar regions, providing ecosystem services valued at billions of dollars annually. In Chile, over 72,000 tons/yr of wet subtidal kelp (Lessonia trabeculata) are harvested annually for the alginate industry, yet its chemical variation remains poorly understood. In this study we examined the alginate content and nutritional profile (i.e., proximal analyses) across different kelp morphological structures (holdfasts and stipes) over 8 months in Las Cruces, Central Chile (33°SL). Each month, tissue from six sporophytes was pooled and averaged, resulting in eight independent samples (n = 8 months), with each sample analyzed in triplicate. Results revealed significant variability between kelp morphological structures and across seasons. Alginate and carbohydrate concentrations peaked in austral summer, with patterns of interannual variation identified. Protein and fiber contents were higher than those in other kelp species, peaking in spring and summer, while lipid concentration peaked in autumn but remained relatively stable year-round. All compounds were generally more abundant in holdfasts. These findings suggest a potential for extracting high-value compounds, such as proteins, from L. trabeculata beyond the current alginate focus. Interannual variations as well as corresponding trends between kelp composition and physico-chemical properties of surface seawater were also observed, highlighting the need for further research to understand and predict these patterns better. These findings could help pinpoint the best harvesting times for specific chemical profiles, boosting profitability while reducing environmental impact
Management regime influences the recovery of subtidal kelp forests following harvesting
No full text1. Physical disturbances, especially those that reduce or remove foundation species, have complex effects on ecosystem functioning. Evaluating resilience to predict these impacts requires long-term research over large temporal and spatial scales.
2. This study investigates the recovery of the subtidal kelp (Lessonia trabeculata) to simulated kelp harvesting in areas under different fisheries management regimes (Territorial Use Rights for Fisheries (TURF) vs. Open Access (OA) sites) along the Northern–Central Chilean coast.
3. The managed TURF sites demonstrated significantly faster recovery of adult kelp densities following harvesting, while OA sites exhibited consistently lower kelp densities and delayed recovery. However, the generality of this pattern varied across regions.
4. Morphological traits such as holdfast diameter were larger at TURF sites, where kelp exhibited larger size. Delayed size recovery was evidenced at OA sites.
5. Herbivore densities were higher in OA than in TURF sites, potentially contributing to differences in kelp density, size and recovery. These patterns highlight the interaction between herbivory and management efficacy.
6. Synthesis and applications. Our findings highlight the critical role of local fisheries management in enhancing kelp recovery after harvesting. The faster recovery of kelp at most TURF sites demonstrates how spatially explicit management can buffer ecological impacts of herbivore density and promote kelp recovery. To improve outcomes, managers should prioritize the implementation and enforcement of management plans in the TURF to promote herbivore control measures and invest in long-term monitoring programmes to support adaptive strategies that sustain kelp forest ecosystems and the valuable services they provide to coastal communities
Fine-scale behavioural responses to mixing fronts are linked to variation in geographic space use in a medium ranging seabird
Full text linkMarine predators forage in dynamic, heterogeneous environments, where resources are unevenly distributed. Consequently, predators often concentrate foraging activity in areas where oceanographic processes, such as tidal mixing fronts, enhance prey abundance and availability. Using GPS telemetry data from breeding Black-legged Kittiwakes (Rissa tridactyla) at two neighbouring North Sea colonies (Flamborough and Filey, NE England), foraging in areas characterised by welldefined seasonal mixing fronts, we investigated fine-scale behavioural responses of the birds to front-related covariates: distance to the nearest front, sea surface temperature (SST), and surface chlorophyll. We combined generalized hidden Markov models (gHMM) with spatial clustering of individual-level tracking data to classify the at-sea behaviour of Kittiwakes and identify distinct foraging areas. Three space-use clusters were identified at Flamborough and four at Filey, primarily differentiated by direction and distance travelled from the colony. The clearest response to front activity was
observed in Kittiwakes at Flamborough in space-use cluster 3, where birds were more likely to be classified as foraging/searching within 5 km of the nearest front. Across clusters, Kittiwakes were generally more likely to forage in cooler waters with lower chlorophyll concentrations. However, behavioural responses to the environmental covariates varied across space-use clusters and were sometimes non-linear. Overall, behavioural responses were context-dependent, shaped by local environmental conditions and the extent of overlap with tidal fronts. Our findings highlight how individual variation in space use can lead to divergent foraging strategies, especially when key oceanographic features occur in specific locations
Examining global trends of satellite-derived water quality variables in shallow lakes
Full text linkLakes are a vital resource for freshwater supply and key sentinels of climate change, and it is
projected that global warming will more persistently affect hydrology, nutrient cycling and
biodiversity. In this context, shallow lakes are considered particularly sensitive to a changing
environment and it is essential to acknowledge their water quality conditions and recent trends to
guide effective water resource management and mitigation strategies. The European Space
Agency Climate Change Initiative (ESA-CCI) offers globally consistent satellite observations of the
Lakes Essential Climate Variable (ECV) including satellite products such as chlorophyll-a (Chl-a),
turbidity and surface water temperature (LSWT) for over 2000 lakes during 1992–2020. From this
dataset, we extracted a subset of 347 lakes with mean depth ≤ 3 m distributed globally to
investigate a long-term timeseries (2002–2020) for Chl-a and turbidity. Theil-Sen trend analysis
showed that Chl-a did not change significantly in 33 % of lakes, significantly increased in 45 %
and decreased in 22 % of the lakes, while turbidity significantly increased in 60 % and decreased
in 17 % of lakes. Most lakes with increasing Chl-a and turbidity trends were located in lowland
areas, and had relatively large areas (surface area >50 km2
). Further analysis revealed that the
majority of lakes showed a concurrent increase in both Chl-a (48 %) and turbidity (50 %) with
LSWT, indicating the potential influence of climate warming on lake water quality. A structural
equations model-based analysis used for modelling the interactions between climatic, socioeco�nomic features and water conditions overall showed that Chl-a and turbidity had a concurrent
positive increase with population and gross regional product in most lakes. This finding suggests
that the impact of human population growth in lake catchments represents an important factor
driving pressures on the water quality of shallow lake
Insights Into Spatial Synchrony Enabled by Long-Term Data
No full textSpatial synchrony, the tendency for temporal fluctuations in an ecological variable to be positively associated in different locations, is a widespread and important phenomenon in ecology. Understanding of the nature and mechanisms of synchrony, and how synchrony is changing, has developed rapidly over the past 2 decades. Many recent developments have taken place through the study of long-term data sets. Here, we review and synthesise some important recent advances in spatial synchrony, with a focus on how long-term data have facilitated new understanding. Longer time series do not just facilitate better testing of existing ideas or more precise statistical results; more importantly, they also frequently make possible the expansion of conceptual paradigms. We discuss several such advances in our understanding of synchrony, how long-term data led to these advances, and how future studies can continue to improve the state of knowledg
On the generalization ability of probabilistic neural networks for hyperspectral remote sensing of absorption properties across optically complex waters
Full text linksensing observations. Yet, their generalization ability when applied to new water bodies, beyond those they
were trained on, is not well understood. We present a novel approach for assessing model generalization
across various scenarios, including interpolation within in situ observation datasets, extrapolation beyond
the training scope, and application to hyperspectral observations from the PRecursore IperSpettrale della
Missione Applicativa (PRISMA) satellite involving atmospheric correction. We evaluate five probabilistic neural
networks (PNNs), including novel architectures like recurrent neural networks, for their ability to estimate
absorption at 443 and 675 nm from hyperspectral reflectance. The median symmetric accuracy (MdSA) worsens
from ≥25% in interpolation scenarios to ≥50% in extrapolation scenarios, and reaches ≥80% when applied
to PRISMA satellite imagery. Across all scenarios, models produce uncertainty estimates exceeding 40%,
often reflecting systematic underconfidence. PNNs show better calibration during extrapolation, suggesting
an intrinsic awareness of retrieval constraints. To address this miscalibration, we introduce an uncertainty
recalibration method that only withholds 10% of the training dataset, but improves model calibration in 86%
of PRISMA evaluations with minimal accuracy trade-offs. Resulting well-calibrated uncertainty estimates enable
reliable uncertainty propagation for downstream applications. IOP retrieval uncertainty is predominantly
aleatoric (inherent to the observations). Therefore, increasing the number of measurements from the same
distribution or selecting a different neural network architecture trained on the same dataset does not enhance model accuracy. Our findings indicate that we have reached a predictability limit in retrieving IOPs using
purely data-driven approaches. We therefore advocate embedding physical principles of IOPs into model
architectures, creating physics-informed neural networks capable of surpassing current limitations
Seasonal vertical migration of large polar copepods reinterpreted as a dispersal mechanism throughout the water column
Full text linkSeasonal vertical migration of large lipid-rich copepods is often described as a mass descent of animals when primary production ceases, with important implications for mesopelagic food webs and global carbon sequestration. This view ignores the existence of surface-resident individuals, but here we show that non-migrants can form a substantial part of the populations of polar migrant species. In the Central Arctic Ocean, the biomass-dominant Calanus hyperboreus was evenly distributed throughout the water column from November 2019 to March 2020, with ~20% of subadults and adult females remaining in the upper 200 m and ~41% migrating to 1000–2000 m. These vertical positions aligned with differences in the copepods’ cholesterol content, which can enhance the tissue density at higher temperatures. Gonad development and the vertical distribution of their offspring indicate that both non-migrant and migrant females contribute to the population recruitment. We reinterpret copepod seasonal migration as a bet-hedging strategy that balances nutritional benefits near the surface with survival benefits at depth, and thereby contributes to the species’ resilience under climatic change
Spatial conflict in offshore wind farms: Challenges and solutions for the commercial fishing industry
Full text linkThe offshore wind (OW) energy industry is growing exponentially. Coastal seas provide a wealth of ecosystem
services and national regulators face the challenge of managing co-location and spatial conflict between multiple
marine industries. Due to its prominent position in the global OW energy market, we use the UK as a case study
through which to investigate interactions between the commercial fishing industry and OWFs. This study presents views from the fishing industry gathered through a structured survey and one-on-one interviews, and reveals the major issues and concerns facing fishermen in respect of current, and future developments. The
majority of fishermen surveyed feel their fishing grounds and livelihoods are threatened by OWFs, with social,
wellbeing and economic impacts felt across vessel sizes (5–50m in length) and fleet sectors (represented by 11
types of fishing gear). A small minority identified potential benefits, and most suggested potential solutions and opportunities for mitigation of impacts. We summarise the findings, outline conflicts and opportunities, and
converge these into policy recommendations with the aim of supporting increased collaboration and equity
between commercial fishermen and energy companies in future offshore leasing rounds, and provide insight and
best practice to other global nations developing offshore wind energ