Effects of Artificial Light at Night on Fitness-Related Traits of Sea Urchin (Heliocidaris crassispina).

Limited data are available regarding the effects of elevated coastal artificial light at night (ALAN) on intertidal echinoderms. In this study, we investigated the behavioral, morphological, and physiological responses of the sea urchin (Heliocidaris crassispina) after continuous exposure to ALAN at light intensities of 0.1, 300, and 600 Lux for 6 weeks. Our findings revealed that ALAN at 300 Lux substantially reduced food consumption, Lantern weight, and gonadosomatic index (GSI). On the other hand, ALAN at 600 Lux notably prolonged the righting and covering response times and elevated the 5-HIAA/5-HT ratio, while concurrently decreasing food consumption, body weight, Lantern weight, GSI, and Pax6 gene expression. These results indicated that continuous exposure to ALAN could cause an adverse effect on fitness-related traits, including behavioral responses, growth, reproductive performance, and photoreception of sea urchins. The present study provides new insights on the impact of light pollution on echinoderms.

Negative Impacts of Biochars on Urease Activity: High pH, Heavy Metals, Polycyclic Aromatic Hydrocarbons, or Free Radicals?

Although biochars show promise for soil remediation, their negative impacts have not been systematically assessed. This study investigated the effects of corn cob biochars on urease-mediated urea hydrolysis and attempted to determine the mechanisms underlying those effects. The results showed that biochars inhibited urease activity (indicated by the NH4+ generation). Released heavy metals and polyaromatic hydrocarbons explained the 20% inhibition of urease activity in biochar supernatants (200 °C) but could not explain the 70% inhibition in particle systems (400 °C). The levels of protein carbonyl and nitrotyrosine, common oxidative damagers of urease, were high in particle systems but very low in biochar supernatants. The electron paramagnetic resonance signal intensity reached its highest level in the 400 °C biochar and decreased in the 500 °C biochar, possibly due to the decomposition of organic molecules. The observed inhibition of urease activity may be the result of oxidative reactions with free radicals on the biochar surface or oxidative reactions with reactive oxygen species promoted by free radicals. We suggest that these potential hazards be evaluated further to gauge the relevance of these findings to field conditions and to assist in the development of safe and sustainable application schemes for biochars.

The role of ash content on bisphenol A sorption to biochars derived from different agricultural wastes.

Inorganic minerals are important compositions in biochars, but their roles in biochar functions are investigated limitedly, which restricted our understanding on biochar applications. This study applied different biomasses to produce biochars. Their properties as well as sorption to bisphenol A (BPA) were studied, with a major focus on the role of inorganic compositions. Oxalates, carbonates, as well as KCl crystals were observed in the produced biochars depending on the feedstocks and temperatures. Oxalates and KCl formed at relatively low temperature (200-300 °C), while carbonates generally formed at pyrolysis temperature above 400 °C. The separated insoluble crystal particles and the dissolved salts have limited contribution to the apparent BPA sorption, but ash content removal altered BPA sorption. The potential impact of inorganic composition to BPA sorption should be resulted from biochar properties. Based on biochar characterization and sorption comparison before and after ash removal, we proposed that the formation of inorganic mineral compositions in biochar particles may have blocked the inner pores, which limited the significance of these sorption sites. As a result, the interactions of BPA and biochars were mostly determined by biochar surface functional groups. The acid treatment removed most of the inorganic compositions, and exposed more sorption sites, which consequently increased BPA sorption. Biochar sorption capacity may be further increased if the accessibility of the inner pores could be enhanced.