海洋酸化效应对海水鱼类的综合影响评述

人类活动引起的大气CO2浓度的升高,除了使全球温度升高外,导致的另一个严重生态问题——海洋酸化(Ocean acidification,OA),受到社会各界包括科研界的高度重视,该领域的大部分研究结果都是在近十年才发表出来的,目前还有很多需要解决的问题。海洋酸化的研究涉及到很多学科的交叉包括化学、古生物学、生态学、生物地球化学等等。在生物学领域,海洋酸化主要围绕敏感物种,例如由碳酸钙形成贝壳或外骨骼的贝类,珊瑚礁群体等。鱼类作为海洋脊椎动物的代表生物类群,自身具有一定的酸碱平衡调节能力,但相关海洋酸化方向的研究并不是很多。尽管人们对于海洋酸化对鱼类的影响了解甚少,这并不说明海洋酸化对鱼类没有作用或者效应小,在相关研究逐步展开的同时,发现鱼类同样受到海洋酸化的危害,几乎涉及到鱼类整个生活史和几乎大部分生理过程,尤其是早期生活史的高度敏感。因此就目前国内外对此领域研究结果做综述,以期待业界同行能够对海水鱼类这个大的类群引起重视。

A review of comprehensive effect of ocean acidification on marine fishes

Increasing anthropogenic atmospheric CO2 is not only increasing global temperature but also rapidly acidifying seawater through the formation of carbonic acid.This results in another serious ecological problem: a process known as ’ocean acidification’.If the current trajectory of global emissions is maintained,atmospheric CO2 concentrations will exceed 500 μL/L by mid-century and could reach between 730 and 1020 μL/L at the end of the century.This would cause ocean pH to decline by 0.3—0.4 units compared with current-day levels(8.06),with a rate of change many times faster than at any time during the past 650000 years. Research of ocean acidification involves many fields,including chemistry,ecology,biogeochemistry,and so on.Ocean acidification is expected to influence marine ecosystems through its effects on marine calcifying organisms(which biomineralize calcium carbonate into hard parts such as shells and skeletons),such as shelled mollusks and coral reefs.Most papers on ocean acidification have been published in the past decade,and have highlighted effects on marine calcifiers from a range of marine ecosystems including deep-sea and tropical corals.There are still some problems that need to be resolved.These effects are not well understood at the community and ecosystem levels,especially for non-calcifying species such as marine fishes,although the consequences are likely to involve range shifts and population declines.A current focus in ocean acidification research is to understand the resilience that organisms possess to withstand such changes,and to extend these investigations beyond calcification,addressing impacts on other vulnerable physiological processes. In general,marine fishes appear to be relatively tolerant to mild increases in CO2 and decreases in pH;however,the research on ocean acidification effects has been very scarce.Although we know little about the impacts of ocean acidification on marine fish,it does not mean that ocean acidification will have little or no effect on them.In fact,there is increasing evidence from laboratory experiments that elevated levels of dissolved CO2 and reduced seawater pH can affect developmental,metabolic and behavioral processes of some marine species,including some non-calcifying species,with highly significant consequences for population replenishment and sustainability.In general,ocean acidification could affect marine fish at all ontogenetic stages and mostly physiological duration. Most benthic marine species have a planktonic larval phase that must transition to a benthic existence to join the adult population.This life-history transition is usually associated with high rates of mortality and can be a period of strong sensitivity to environmental factors.Thus,the highest sensitivity of marine fishes is in the early life history stages,during which serious adverse impacts on the whole wild fish populations can arise.This paper summarizes empirical evidence for the impacts of ocean acidification on marine fish,and we hope that special emphasis will be placed on this important area of research.