Dear All We are happy to share our new paper that details how differences in blood and tissue gas solubility of oxygen, carbon dioxide and nitrogen results in changes in mass-balance and ung volume during diving. The reference, url and abstract are below and anyone wanting a pdf copy of the article can send an email to: afahlman@whoi.edu <mailto:afahlman@whoi.edu> Thank you Andreas Reference: Fahlman, A., Sato, K., and Miller, P. (2020). Improving estimates of diving lung volume in air-breathing marine vertebrates. The Journal of Experimental Biology 223, jeb216846. DOI: 10.1242/jeb.216846 URL: https://jeb.biologists.org/content/223/12/jeb216846 <https://jeb.biologists.org/content/223/12/jeb216846> Abstract: The air volume in the respiratory system of marine tetrapods provides a store of O2 to fuel aerobic metabolism during dives; however, it canalso be a liability, as the associated N2 can increase the risk of decompression sickness. In order to more fully understand the physiological limitations of different air-breathing marine vertebrates, it is therefore important to be able to accurately estimate the air volume in the respiratory system during diving. One method that has been used to do so is to calculate the air volume from glide phases – periods of movement during which no thrust is produced by the animal – which many species conduct during ascent periods, when gases are expanding owing to decreasing hydrostatic pressure. This method assumes that there is conservation of mass in the respiratory system, with volume changes only driven by pressure. In this Commentary, we use previously published data to argue that both the respiratory quotient and differences in tissue and blood gas solubility potentially alter the mass balance in the respiratory system throughout a dive. Therefore, near the end of a dive, the measured volume of gas at a given pressure may be 12–50% less than from the start of the dive; the actual difference will depend on the length of the dive, the cardiac output, the pulmonary shunt and the metabolic rate. Novel methods and improved understanding of diving physiology will be required to verify the size of the effects described here and to more accurately estimate the volume of gas inhaled at the start of a dive.