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We present a systematic examination of the volatile (Cl, F, Br, S) and trace element (Na, Mg, V, Mn, Fe, Sr, Y, Zr, Ba, REEs, Th, U) abundances in apatite from 29 samples from base to top of the Layered Series in the Skaergaard intrusion, East Greenland. Apatite occurs as an interstitial phase in the lower zones, but joins the liquidus assemblage late in the crystallisation history (c. 90% crystallised), defining the base of Upper Zone b. The apatite can be classified as fluorapatite with low Cl/F ratios (< 0.4), confirming previous result. The REE content of interstitial apatite decreases from the base up to the middle part of the intrusion, followed by an increase towards the base of Upper Zone b. When apatite becomes a primocryst (liquidus phase) it shows significant difference in composition, including elements such as REEs + Y, Cl, Sr, and Eu compared to interstitial apatite. Whilst Sr and Eu are enriched in primocryst, the other REEs + Y and Cl are depleted compared to interstitial grains. Whilst the REE composition of primocryst apatite can be explained by fractional crystallisation of the Skaergaard parental magma, the peculiar trend and enrichment of REEs in interstitial apatite can be reproduced using a simple mass balance model (i.e. a simple mass balance equilibrium model where the bulk concentration of an element is evenly distributed between all phases in the final cumulate rock according to the respective partitioning coefficients). In this regard, the difference in composition between interstitial and primocryst apatite is explained by different formation environments (i.e. crystallising (late) from trapped liquid vs. main magma). Compared to primocryst apatite, interstitial apatite in Skaergaard is more REE (and Cl) rich due to crystallisation and continued reaction with a highly fractionated trapped interstitial melt. During crystallisation and continued reaction with the interstitial melt and sub-liquidus equilibration, Sr and Eu partition into plagioclase, depleting interstitial apatite in Eu and Sr compared to primocryst apatite. The mass balance model demonstrates that the REE content of interstitial apatite can be attributed to partitioning competition within the present mineral assemblage during crystallisation of the interstitial melt and diffusive re-equilibration. In this regard, the proportion of trapped interstitial melt relative to the proportion of different primocryst minerals is crucial. It is shown that especially the modal abundance of clinopyroxene exerts strong control on the distribution of REE in interstitial apatite.

To characterize the polycyclic aromatic hydrocarbons (PAHs) in PM 2.5 (particles with an aerodynamic diameter ≤ 2.5 µm) in Delhi, the national capital of India and one of the most polluted megacities in the world, we conducted a comprehensive field campaign at six sampling sites in different areas during winter and summer. Both the PM 2.5 and PAH concentrations exhibited seasonal variations, with higher values during winter (356 ± 136 µg m −3 and 75.1 ± 50.2 ng m −3 for the PM 2.5 and PAHs, respectively) than summer (268 ± 94 µg m −3 and 10.4 ± 8.5 ng m −3 , respectively). Additionally, the maximum winter concentrations were found in the urban industrial-cum-residential area (430 ± 104 µg m −3 and 124.5 ± 70.7 ng m −3 for the PM 2.5 and PAHs, respectively). Among the PAHs, benzo[ ghi ]perylene displayed the highest ambient concentration (14.3 ± 7.4 ng m −3 during winter), followed by indeno[1,2,3- cd ]pyrene (13.1 ± 7.3 ng m −3 during winter), at the majority of the sampling sites. Additionally, based on the benzo[ a ]pyrene-equivalent concentrations at the six sites, we estimated the PAH-associated incremental lifetime cancer risk (ILCR) in the entire study area to be 423 per 1 million persons, which exceeds the World Health Organization (WHO) limit. Source apportionment performed with the Chemical Mass Balance Model version 8.2 (CMB8.2) revealed that emissions from vehicles, municipal waste burning and biomass burning contributed 62%, 15% and 11% to the total PAH mass, respectively. Our results indicate that PM 2.5 -bound PAHs in Delhi will continue to pose serious health risks without collective initiatives for pollution control from scientific, policy-making and regulatory bodies.

Glacier assessment and monitoring are crucial for understanding glacial hydrology and its response to climate change. A user-friendly glacier mass balance model was developed in this study, which requires basic meteorological inputs to generate glacier mass balance components, including, melt rate, accumulation rate, and evaporation, and subsequently generate daily glacier area. The model was calibrated and tested for 15 selected glaciers in the Mago basin of Arunachal Pradesh. An automatic calibration module was developed to automate the calibration process and generate the optimal set of parameters required for the simulation process. The model’s performance was satisfactory, with an average error percentage ranging from 1.01 to 6.32% during calibration and 4.66 to 7.34% during the validation period. The testing on the validation glaciers also produced favourable results, with average errors ranging from 1.98 to 9.06%. Consequently, the model proved to be reliable in simulating glacier areas for one test glacier each from Western and Central Himalaya also.

Ecosystem modeling is becoming increasingly important, as it reveals how energy flows and species interactions shape ecosystem stability, resilience, and the sustainability of fisheries. However, model‐based ecosystem studies are scarce for the Kaptai Lake (KL) of Bangladesh. Therefore, a mass‐balanced trophic model was built to illustrate the trophic structure and ecosystem features of KL. The model outputs indicated that the apex predator, Catfish (TL‐3.364), occupied the top trophic niches, while the overabundant (B: 3.264 t/km2) Clupeid (TL‐2.56) dominated the lower trophic level in the food web. The higher values of ecotrophic efficiency (> 0.5) for most of the groups indicate heavy fishing pressure. The ecosystem is Phytoplankton‐based, where two core food chains that make up the majority of the food web are the Detritus (35.12%) and primary production (64.88%). The mixed trophic impact plot revealed a substantial positive effect of Detritus and Phytoplankton on the majority of the fish groups. Clupeids displayed a negative effect on most of the fish groups, indicating a lack of major predators of this group. In the KL ecosystem, Catfish and Phytoplankton were the key predator and producer groups, respectively. The network analysis indicates that the KL is a developing ecosystem with moderate system maturity, as evidenced by total primary production and respiration ratio (2.034), total primary production and biomass ratio (71.764), and Finn Cycling Index (5.627%). The low connectance index (0.426) indicates that the food web is still linear rather than a web‐like structure and thereby vulnerable to external influences. Besides, the ever‐increasing trend of Clupeid and declination of large fish populations indicates that the KL ecosystem may encounter severe consequences in the future. Consequently, ecosystem‐based management interventions have been proposed that will help to restore food web integrity, recover vulnerable species and ensure long‐term sustainability of fisheries in this lake. Kaptai Lake is a developing ecosystem with a linear food web and thereby vulnerable to external influences. The apex predator, Catfish (TL‐3.364), occupied the top trophic niches, while the overabundant (B: 3.264 t/km2) Clupeid (TL‐2.56) dominated the lower trophic level in the food web. The higher values of ecotrophic efficiency for most of the groups indicate heavy fishing pressure.

Mark Duffy produced a complete set of grinding data on a pilot-scale tower mill. Here these data are analyzed in terms of grinding kinetics. The results show that the data can be fitted with a simple first-order breakage model, which is not normally observed in any grinding system, including other types of grinding machines such as tumbling ball mills and rod mills. The model has only two parameters, making it possible to determine the parameters using simple search methods. The results show that larger particles break faster than smaller particles, as is usually observed in all mills. Statistical analysis of the data showed that one of the parameters could be fixed for seven of the nine tests.

The external phosphorus (P) loading has been halved, but the P content in the water column and the area of anoxic bottoms in Baltic proper has increased during the last 30 years. This can be explained by a temporary internal source of dissolved inorganic phosphorus (DIP) that is turned on when the water above the bottom sediment becomes anoxic. A load-response model, explaining the evolution from 1980 to 2005, suggests that the average specific DIP flux from anoxic bottoms in the Baltic proper is about 2.3 g P m⁻² year⁻¹. This is commensurable with fluxes estimated in situ from anoxic bottoms in the open Baltic proper and from hydrographic data in the deep part of Bornholm Basin. Oxygenation of anoxic bottoms, natural or manmade, may quickly turn off the internal P source from anoxic bottoms. This new P-paradigm should have far-reaching implications for abatement of eutrophication in the Baltic proper.

Jiaozhou Bay, an urbanized coastal bay located in the southern part of Shandong Peninsula, China, has been deeply affected by anthropogenic activities. Here, the naturally occurring 222Rn isotope was used as a tracer to assess the submarine groundwater discharge (SGD) in this bay. The time series of 222Rn concentrations in nearshore seawater were monitored continuously over several tidal cycles at two fixed sites (Tuandao (TD) and Hongdao (HD)) during the dry season in spring and the wet season in autumn of 2016. 222Rn concentrations in seawater were negatively related to the water depth, indicating the influence of tidal pumping. A 222Rn mass balance model revealed that the mean SGD rates were 21.9 cm/d at TD and 17.8 cm/d at HD in the dry season, and were 19.5 cm/d at TD and 26.9 cm/d at HD in the wet season. These rates were about 8–14 times the discharge rates of the local rivers. Enhanced groundwater inputs occurred at HD in the wet season, likely due to the large tidal amplitudes and the rapid response to local precipitation. Large inputs of SGD may have important influences on nutrients levels and structure, as well as the water eutrophication occurring in coastal waters.

Great Salt Lake of Utah is among the largest and most ecologically important water bodies in North America. Since the late 1950s, the lake has been divided into two hydrologically distinct water bodies by a rock-fill railroad causeway. Flux through the causeway is driven by two forces: differential surface elevation and differential density between the north and south arms. The south arm features episodic vertical stratification due to the influx of deep, dense brine from the north arm. The source of this brine (a breach, two culverts, or subsurface flow) has been investigated over the past 50 years. Quantification of subsurface water flux through the causeway has been problematic due to the heterogeneous and slowly compacting nature of the causeway fill over time. Between 2008 and 2015, enhanced gauging of various surface inflows and outflows and density measurements made throughout the lake permitted detailed water volume calculations of both lake arms. Results show that during high precipitation years, density-driven, north-to-south flow through the causeway predominates due to freshening of water in the south arm. At other times, south-to-north head gradient driven flow and north-to-south density-driven flow are approximately equal. The model suggests subsurface flux through the causeway is one important driver of the ecologically important deep brine layer in the south arm of the lake over the past 20 years.

This paper presents the case for adopting ecosystem rebuilding as the goal of fisheries management. Movement toward this goal may represent the only hope for fisheries, as we know them, to exist 50 years in the future alongside essential services provided by marine ecosystems. First, I review archaeological, historical, and recent evidence that bears witness to a long, dismal record of overexploitation. Second, I examine the ecological effects of overfishing on aquatic ecosystems. Fish with life histories and spatial behavior inimical to harvesting are selectively removed, both within and among species. The loss of keystone species and the replacement of high-value, demersal resources with pelagic, rapid-turnover, low-value species shifts the nature of ecosystems, evidenced by accelerating local extinctions and a worldwide decline in trophic level. Disconcertingly, harvest limits that appear safe by single species evaluation can engender ecosystem changes that are hard to reverse. Driven by a progression of clever human harvest technologies, three ratchet-like processes have brought about episodes of depletion. \"Odum's ratchet\" is ecological in nature, comprising depletion and local extinction. \"Ludwig's ratchet,\" economic in nature, is a positive feedback loop between increased catching power and serial depletion, driven by the need to repay borrowed money. \"Pauly's ratchet\" is cognitive, shifting the baseline of what each generation regards as primal abundance and diversity. Third, a rebuilding policy goal is distinguished from that of sustaining current catches and biomass, since the baseline can refer to present misery. In this sense, present policies can inadvertently foreclose future options for the generation of food, wealth, and services from ocean resources. A policy to rebuild ecosystems can reverse this trend and maximize economic value in tomorrow's markets, where supply will vastly outstrip demand for high-quality fish products. Fourth, I outline a novel methodology, termed \"Back to the Future,\" that can implement a goal of ecosystem rebuilding. Models of past ecosystems are reconstructed using information about the presence and abundance of species from historical documents, archaeology, and local and traditional environmental knowledge (LEK and TEK). Economic evaluation compares past with present and alternative ecosystems. \"Back to the Future\" gives the TEK of aboriginal and indigenous peoples a valuable, direct function in resource management. Finally, I discuss two practical management measures, paralleling recent developments in terrestrial reconstruction ecology, the implementation of large no-take marine reserves, and the reintroduction of high-value species that were formerly endemic.

Projecting the global evolution of glaciers is crucial to quantify future sea-level rise and changes in glacier-fed rivers. Recent intercomparison efforts have shown that a large part of the uncertainties in the projected glacier evolution is driven by the glacier model itself and by the data used for initial conditions and calibration. Here, we quantify the effect that mass balance observations, one of the most crucial data sources used in glacier modelling, have on glacier projections. For this, we model the 21st century global glacier evolution under Coupled Model Intercomparison Phase 6 project (CMIP6) climate scenarios with the Global Glacier Evolution Model (GloGEM) calibrated to match glacier-specific mass balance observations, as opposed to relying on regional mass balance observations. We find that the differences in modelled 21st century glacier changes can be large at the scale of individual glaciers (up to several tens of percent), but tend to average out at regional to global scales (a few percent at most). Our study thus indicates that the added value of relying on glacier-specific observations is at the subregional and local scale, which will increasingly allow projecting the glacier-specific evolution and local impacts for every individual glacier on Earth. To increase the ensemble of models that project global glacier evolution under CMIP6 scenarios, simulations are also performed with the Open Global Glacier Model (OGGM). We project the 2015–2100 global glacier loss to vary between 25 ± 15 % (GloGEM) and 29 ± 14 % (OGGM) under SSP1-2.6 to 46 ± 26 % and 54 ± 29 % under SSP5-8.5 (ensemble median, with 95 % confidence interval; calibration with glacier-specific observations). Despite some differences at the regional scale and a slightly more pronounced sensitivity to changing climatic conditions, our results agree well with the recent projections by Rounce et al. (2023), thereby projecting, for any emission scenario, a higher 21st century mass loss than the current community estimate from the second phase of the Glacier Model Intercomparison Project (GlacierMIP2).