[MARMAM] New review paper: How man-made interference might cause gas bubble emboli in deep diving whales

Andreas Fahlman andreas.fahlman at tamucc.edu
Tue Jan 28 21:59:08 PST 2014

We are pleased to announce the publication of a short review that 
summarizes our current ideas how sonar may interfere with diving in 

This article is an open access publication, which means that it is 
freely accessible to any reader anywhere in the world. We encourage you 
to share the article link with any colleagues who may be interested in 
this work.

Title: * How man-made interference might cause gas bubble emboli in deep 
diving whales*
*Authors: **Andreas Fahlman, Peter L Tyack, Patrick James Miller, and 
Petter H Kvadsheim
**Journal: **Frontiers in Physiology**

*Abstract**: *

Recent cetacean mass strandings in close temporal and spatial 
association with sonar activity has raised the concern that 
anthropogenic sound may harm breath-hold diving marine mammals. Necropsy 
results of the stranded whales have shown evidence of bubbles in the 
tissues, similar to those in human divers suffering from decompression 
sickness (DCS). It has been proposed that changes in behavior or 
physiological responses during diving could increase tissue and blood 
N_2 levels, thereby increasing DCS risk. Dive data recorded from sperm, 
killer, long-finned pilot, Blainville's beaked and Cuvier's beaked 
whales before and during exposure to low- (1-2 kHz) and mid- (2-7 kHz) 
frequency active sonar were used to estimate the changes in blood and 
tissue N_2 tension (P_N2 ). Our objectives were to determine if 
differences in 1) dive behavior or 2) physiological responses to sonar 
are plausible risk factors for bubble formation. The theoretical 
estimates indicate that all species may experience high N_2 levels. 
However, unexpectedly, deep diving generally result in higher end-dive 
P_N2 as compared with shallow diving. In this focused review we focus on 
three possible explanations: 1) We revisit an old hypothesis that CO_2 , 
because of its much higher diffusivity, forms bubble precursors that 
continue to grow in N_2 supersaturated tissues. Such a mechanism would 
be less dependent on the alveolar collapse depth but affected by 
elevated levels of CO_2 following a burst of activity during sonar 
exposure. 2)_During deep dives, a greater duration of time might be 
spent at depths where gas exchange continues as compared with shallow 
dives. The resulting elevated levels of N_2 in deep diving whales might 
also make them more susceptible to anthropogenic disturbances. 3) 
Extended duration of dives even at depths beyond where the alveoli 
collapse could result in slow continuous accumulation of N_2 in the 
adipose tissues that eventually becomes a liability.**

*Citation:* Fahlman A, Tyack PL, Miller PJO and Kvadsheim PH (2014) How 
man-made interference might cause gas bubble emboli in deep diving 
whales./Front. Physiol/.*5*:13. doi: 10.3389/fphys.2014.00013

Andreas Fahlman
Department of Life Sciences
Texas A&M- Corpus Christi
6300 Ocean Dr Unit 5892
Corpus Christi, TX 78412
Ph. +1-361-825-3489
Fax +1-361-825-2025
mail: andreas.fahlman at tamucc.edu
web: http://www.comparative-physiology.tamucc.edu/

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