Abstract Changes in breeding periodicity in vertebrates can highlight important trends in population demographics that have conservation implications. Following widespread conservation measures, some previously endangered species have shown population recoveries across their range, with green turtles (Chelonia mydas) being an exemplar of global species recovery. At sites in the Indo-Pacific, green turtle nesting numbers have increased fourfold in 30 years. As sea turtles are generally non-annual breeders, we used a total of 1399 measurements of the breeding interval for marked individuals to reveal that the relative proportion of individuals breeding with a 4-year versus a 3-year interval has increased over time: 28% in 1997–2012 versus 37% in 2013–2024. Furthermore, this percentage of 4- versus 3-year nesting intervals was linked to annual nest numbers (R2 = 0.23, F1,23 = 6.92, p = 0.01). This lengthening of the breeding (remigration) interval may reflect density dependence, restricting foraging success so that individuals need longer to build body condition for migration and breeding. These results provide the first evidence for long-term lengthening of breeding intervals in this taxon and might have important global conservation implications in terms of reduced per capita reproductive output, a finding that echoes recent observations with cetaceans.
Abstract Oil palm cultivation on peatlands causes severe environmental damage, yet its greenhouse gas (GHG) footprint and underlying biogeochemical drivers remain poorly quantified. This study assessed how nitrogen fertilizer application impacts soil respiration and CH4 emissions across spatio-temporal scales in a fertilization trial with three application rates: 0 (N0), 154.5 (N1) and 309 (N2) kg N ha−1 yr−1. Fluxes and environmental variables were monitored monthly over a year and daily for a month after two fertilizations. Measurements were taken close to palms (CP), where fertilizer was applied, and farther from palm (FP). Soil respiration (Mg CO2-C ha−1 yr−1) was high compared to the literature, with N0 and N2 (27.3 ± 2.8 and 28.5 ± 3.0) exceeding N1 (18.8 ± 2.5). Fertilization triggered short-lived respiration increases, without affecting annual rates. Treatment and spatial differences (FP > CP) aligned with soil temperature and soil N2O emission patterns, suggesting links to peat mineralization. CH4 emissions (kg CH4-C ha−1 yr−1) were greater in N0 (3.9±1.5) compared to N1 (0.7 ± 0.6) and N2 (1.0 ± 1.3), inversely mirroring soil nitrate distribution under unfertilized conditions. A transient fertilizer effect occurred, without affecting annual rates. Our findings highlight strong interactions between soil respiration, CH4 emissions and N cycling in drained tropical peatlands, warranting further investigation to constrain GHG process-based modelling.
AbstractSkin integrity is vital for fish survival, as injuries compromise the protective barrier and increase infection risk. This study introduces a simple and eco-friendly strategy to enhance skin wound healing in aquatic species using a PVA+borax hydrogel. The hydrogel, characterized by tunable cross-linking and biodegradability, was applied to zebrafish and tilapia via water immersion to evaluate its therapeutic efficacy. Full-thickness wounds were created in zebrafish via laser ablation for precise assessment of closure kinetics. Among tested conditions, the PVA+borax formulation significantly accelerated wound closure compared with individual components and untreated controls. Acute toxicity and behavioural analyses confirmed high biocompatibility and no developmental or neurological abnormalities up to higher concentration use (0.01–100 ppm). qRT-PCR analysis showed that treatment reduced injury-induced inflammatory and macrophage markers, suggesting modulation of inflammatory responses during wound healing. Concurrent changes in basement membrane-related genes indicate coordinated extracellular matrix remodelling, consistent with progression towards tissue repair and balanced regeneration. Both zebrafish and tilapia exhibited faster re-epithelialization and collagen deposition under hydrogel treatment. These findings suggest that PVA+borax hydrogel is a safe, cost-effective and promising platform for accelerating wound healing in aquatic models, with translational potential in both biomedical research and aquaculture health management.
AbstractOil palm cultivation on peatlands causes severe environmental damage, yet its greenhouse gas (GHG) footprint and underlying biogeochemical drivers remain poorly quantified. This study assessed how nitrogen fertilizer application impacts soil respiration and CH4 emissions across spatio-temporal scales in a fertilization trial with three application rates: 0 (N0), 154.5 (N1) and 309 (N2) kg N ha−1 yr−1. Fluxes and environmental variables were monitored monthly over a year and daily for a month after two fertilizations. Measurements were taken close to palms (CP), where fertilizer was applied, and farther from palm (FP). Soil respiration (Mg CO2-C ha−1 yr−1) was high compared to the literature, with N0 and N2 (27.3 ± 2.8 and 28.5 ± 3.0) exceeding N1 (18.8 ± 2.5). Fertilization triggered short-lived respiration increases, without affecting annual rates. Treatment and spatial differences (FP > CP) aligned with soil temperature and soil N2O emission patterns, suggesting links to peat mineralization. CH4 emissions (kg CH4-C ha−1 yr−1) were greater in N0 (3.9±1.5) compared to N1 (0.7 ± 0.6) and N2 (1.0 ± 1.3), inversely mirroring soil nitrate distribution under unfertilized conditions. A transient fertilizer effect occurred, without affecting annual rates. Our findings highlight strong interactions between soil respiration, CH4 emissions and N cycling in drained tropical peatlands, warranting further investigation to constrain GHG process-based modelling.
