Toxic effects of nano-TiO_(2)in bivalves——A synthesis of meta-analysis and bibliometric analysis

Since the beginning of the 21 st century,the increasing production and application of nano-TiO_(2)in consumer products have inevitably led to its release into aquatic systems and therefore caused the exposure of aquatic organisms,resulting in growing environmental concerns.However,the safety of nano-TiO_(2)in aquatic environments has not been systematically assessed,especially in coastal and estuary waters where a large number of filterfeeding animals live.Bivalves are considered around the world to be a unique target group for nanoparticle toxicity,and numerous studies have been conducted to test the toxic effects of nano-TiO_(2)on bivalves.The aim of this review was to systematically summarize and analyze published data concerning the toxicological effects of nano-TiO_(2)in bivalves.In particular,the toxicity of nano-TiO_(2)to the antioxidant system and cell physiology was subjected to meta-analysis to reveal the mechanism of the toxicological effects of nano-TiO_(2)and the factors affecting its toxicological effects.To reveal the cooperation,hot keywords and cocitations in this field,bibliometric analysis was conducted,and the results showed that the toxicological molecular mechanisms of nano-TiO_(2)and the combined effects of nano-TiO_(2)and other environmental factors are two major hot spots.Finally,some perspectives and insights were provided in this review for future research on nano-TiO_(2)toxicology in bivalves.

Impacts of ocean acidification under multiple stressors on typical organisms and ecological processes

The oceans are taking up over one million tons of fossil CO_(2) per hour,resulting in increased/ρCO_(2) and declining pH,leading to ocean acidification(OA).At the same time,accumulation of CO_(2) and other greenhouse gases is causing ocean warming,which enhances stratification with thinned upper mixed layers,exposing planktonic organisms to increasing levels of daytime integrated UV radiation.Ocean warming also reduces dissolved oxygen in seawater,resulting in ocean deoxygenation.All these ocean global changes are impacting marine ecosystems and effects are well documented for each individual driver(pH,oxygen,temperature,UV).However,combined effects are still poorly understood,strongly limiting our ability to project impacts at regional or local levels.Different regions are often exposed(and often adapted)to contrastingly different physical and chemical environmental conditions and organisms,and ecosystems from different parts of the world will be exposed to unique combinations of stressors in the future.Understanding the modulating role of adaptation,species niche and stressors’interaction is key.This review,being a non-exhaustively explored one.aims to provide an overview on understandings of ecophysiological effects of OA and its combination with covarying drivers,mainly warming,deoxygenation and solar UV radiation.We propose a testable hypothetical model as well as future research perspectives.