期刊名称：International Journal of Environment and Geoinformatics
电子版ISSN：2148-9173
出版年度：2015
卷号：2
期号：2
页码：16-26
DOI：10.30897/ijegeo.303538
语种：English
出版社：IJEGEO
摘要：Ocean Ambient Noise (OAN) results from both anthropogenic and natural sources. Varied noise sources aredominant in low (LFB: 10 to 500 Hz), medium (MFB: 500 Hz to 25 kHz) and high (HFB:>25 kHz) frequencybands. Mostly, LFB is dominated by anthropogenic sources. MFB that cannot spread over long ranges of soundsources contribute to the OAN. Ocean is an exceptionally noisy place.Ocean acidification (OAc) from rising Carbon dioxide (CO2) levels will result in decreased sound absorptionand therefore, amplified levels of OAN. Carbon dioxide spewed into the atmosphere by burned fossil-fuelwhich dissolves in the seawater causes more acidic condition in oceans which has strong connection betweenchemical oceanography and sound propagation. As the ocean becomes more acidic, sound absorption at LFBdecreases and acidic oceans would result in significant decreases in ocean sound absorption.In the recent years, the acoustic environment of oceans has reacted to transformations in both natural andanthropogenic impacts. Greenhouse gases concentrations, especially CO2, rises in atmosphere due to industrialrevolution. CO2 dissolved in the seawaters deposited in two major forms (carbonate and bicarbonate), whichboth lead to decrease pH of surface waters. Over the last 400 million years, pH of oceans has been stablearound 8.2 globally. Latest investigations suggest that global pH is around 8.1 globally and various generaloceanic circulation models (GOCM) calculate that, emissions could reduce ocean pH by a degree between 0.4units (according to moderate approach) and 0.7 units (according to an aggressive one) by the end of thiscentury.This article discusses the CO2 considerations both in the atmosphere and hydrosphere which are directly relatedwith seawater pH and oceans noise levels.
