Hard-bottom habitats are among the most structurally complex ecosystems in temperate shelf seas. Identification of reef habitats is fundamental for biodiversity conservation and ecosystem-based marine spatial planning. We used high-resolution seabed mapping combined with field surveys, including benthic sampling, to identify previously undocumented reefs in the Polish part of the Baltic Sea. The newly detected habitat exhibited characteristic hard-substrate morphology and supported diverse benthic assemblages, indicating ecological relevance disproportionate to its spatial extent. The presence of characteristic reef-associated taxa, high biodiversity, and significant natural value of both macrozoobenthic and macroalgal communities were noted. The data presented here not only enrich the existing knowledge on marine habitats but also contribute to the development of more effective environmental conservation strategies for marine ecosystems under international protection. The findings will have direct implications for marine spatial planning and highlight the need to integrate updated habitat data into decision-making processes.
Mangrove wetlands are critical ecotones between terrestrial and marine environments, yet the spatial distribution and environmental origins of microbial communities in their groundwater–sediment systems remain poorly characterized. Microbial source tracking using the SourceTracker2 Bayesian algorithm was applied to 22 samples collected along a single mangrove wetland transect on Qi’ao Island, Pearl River estuary, China—comprising a freshwater well, supratidal and transition zones, seaward mangrove wetland piezometers, and two 60-cm sediment cores from a mangrove-vegetated and an adjacent unvegetated site. Shannon diversity of source profiles was narrowly constrained across the whole gradient (3.15 ± 0.26; coefficient of variation 8.4%) and did not differ significantly among sample groups (Kruskal–Wallis H = 7.38, p = 0.194), indicating strong diversity buffering. In contrast, source composition was strongly structured (PERMANOVA pseudo-F = 4.14, R2 = 0.56, p = 0.0001). Mangrove core sediments were dominated by sediment-associated (9.98%), rhizosphere (8.58%) and soil (6.69%) sources, whereas the adjacent non-mangrove core was dominated by freshwater sediment (17.52%) and marine sediment (9.29%) sources. Aggregating the 104 reference sources into eight ecological categories showed that vegetation- and soil-derived sources accounted for 29.5% of the mangrove core but only 20.1% of the non-mangrove core (p = 0.035), while freshwater sources showed the opposite pattern (15.3% versus 32.2%, p = 0.002). Wastewater- and host-associated sources together contributed 39.3% in mangrove wetland piezometers, identifying a pronounced anthropogenic imprint. Depth profiling revealed systematic vertical structuring in the mangrove core only, with marine and undifferentiated sediment sources decreasing with depth (β = −0.377 and −0.115% cm−1; R2 = 0.71 and 0.76; p = 0.034 and 0.025) and vegetation- and soil-derived sources increasing with depth (β = +0.375% cm−1, R2 = 0.75, p = 0.026); the non-mangrove core was vertically homogeneous. These results quantify the interplay of terrestrial, marine and anthropogenic microbial inputs in mangrove groundwater systems and provide a baseline for monitoring contaminant transport and ecosystem integrity in coastal aquifers. Because the design comprises a single transect sampled on one wet-season occasion with pseudo-replicated depth intervals, the findings should be treated as a spatially explicit baseline rather than a generalizable description of mangrove microbiomes.
Effective sludge dewatering remains a critical challenge in wastewater treatment due to the complex structure of extracellular polymeric substances that encapsulate bound water. This study investigated the synergistic effects of ultrasound combined with modified corn-core powder and sludge-based biochar on municipal sludge dewaterability. Orthogonal and single-factor experiments were designed to optimize conditioning parameters, and the underlying mechanisms were elucidated through comprehensive analyses of extracellular polymeric substance composition, three-dimensional excitation-emission matrix fluorescence spectroscopy, fluorescence regional integration, fractal dimension, particle-size distribution, and statistical correlation. The results demonstrated that optimal dewatering performance was achieved at an ultrasonic specific energy of 4000 kJ/kg dry solids for the modified corn-core powder and sludge-based biochar with ultrasound system, where net sludge solids yield increased by 124%, while specific resistance of filtration and moisture content decreased by 78% and 19%, respectively. Mechanistic analysis revealed that low-intensity ultrasound disrupted sludge flocs, released extracellular polymeric substance-bound organic matter, and promoted the shift of organic components from soluble extracellular polymeric substances to tightly bound extracellular polymeric substances, facilitated by the long-chain adsorption of modified corn-core powder and the skeleton-building effect of sludge-based biochar. Excessive ultrasound (specific energy > 8000 kJ/kg dry solids) caused particle fragmentation, increased system viscosity, and deteriorated dewaterability. Pearson correlation and principal component analysis confirmed that ultrasonic specific energy and organic components in soluble extracellular polymeric substances were the dominant factors governing dewatering performance. This study provides a promising strategy for reducing chemical conditioner consumption while enhancing sludge dewaterability through controlled ultrasound assistance.
Spatial investigation planning under data scarcity requires a clear separation of source evidence, pathway assumptions, and decision preferences. We evaluated conditional groundwater investigation priorities in Debrecen, Hungary, using published As and Pb topsoil screening rasters, a DRASTIC-inspired pathway proxy, and heuristic soil-retention scenarios. The reference depth scenario combined 14 stations of the Municipal Environmental Control System (KER) and 16 water-authority monitoring stations covering 1 September 2025–22 August 2026, with separate network scenarios used to examine sensitivity to the monitoring source. At 500 m spatial support, using a nominal 20% area quota within each decision rule, the screening-only and multiplicative selections differed across 11.8% of the study area for As and 9.5% for Pb. Depending on the weighting assigned to the decision rules, areas with a preference-weighted mean selection frequency of at least 0.80 covered 4.2–5.0% of the study area for As and 2.5–4.1% for Pb. Groundwater observations from the KER network showed persistent As exceedance at KER04, while Pb and Cd remained below their comparison thresholds at the locations and sampling occasions assessed within the study polygon. The results demonstrate that investigation priorities depend on the decision rule and the assumptions used to represent subsurface pathways.
The Saemangeum Reservoir is an artificial reservoir created following completion of a 33.9-km-long seawall in 2010, with seawater inflow regulated through two sluice gates. After construction of the seawall, reduced seawater exchange, increased freshwater residence time, and weakened tidal influence were associated with deteriorating water-quality conditions, including increases in chlorophyll-a and dissolved inorganic nutrients. Since then, land reclamation and road and port construction have continued, while sluice-gate operation and seawater-exchange conditions have also been adjusted. As a result, the hydraulic environment and water-quality characteristics have continued to change. We examined the spatial water-quality structure along the river–brackish lake continuum and its interannual and seasonal dynamics using long-term seasonal water-quality data collected from 2014 to 2025. Principal component analysis (PCA) of the water-quality variables showed that the first principal component (PC1) primarily reflected a salinity–nutrient/organic gradient that separated riverine from brackish-lake sites. Interannual and seasonal trajectories clustered largely by spatial position, with a common long-term shift toward higher salinity and lower total nitrogen (TN), total phosphorus (TP), and COD; trajectory-based groups were all eutrophic on mean Korean trophic state index (TSIKO) but differed in level and variability, showing that the expected spatial structure alone does not fully capture long-term and seasonal water-quality dynamics. Thus, monitoring and management in artificial brackish systems should track spatially distinct temporal trajectories rather than rely on long-term averages, applying year-round nutrient reduction where high trophic conditions persist and intensified seasonal/interannual monitoring where variability is large, while considering hydrological and hydraulic conditions and potential trade-offs associated with sluice-gate operation.
