Blood oxygen transport and depletion in diving emperor penguins
Data files
Feb 22, 2024 version files 5.05 MB
Abstract
Oxygen store management underlies dive performance and is dependent on the slow heart rate and peripheral vasoconstriction of the dive response to control tissue blood flow and oxygen uptake. Prior research has revealed two major patterns of muscle myoglobin saturation profiles during dives of emperor penguins. In Type A dives, myoglobin desaturated rapidly, consistent with minimal muscle blood flow, and low tissue oxygen uptake. Type B dives, with fluctuating and slower declines in myoglobin saturation, were consistent with variable tissue blood flow patterns and tissue oxygen uptake during dives. We examined arterial and venous blood oxygen profiles to evaluate blood oxygen extraction and found two primary patterns of venous hemoglobin desaturation that complemented corresponding myoglobin saturation profiles. Type A dives had venous saturations that a) increased or plateaued for most of the dive and that only declined during the latter stages of ascent, b) often became arterialized (arterio-venous (a-v) shunting). In Type B dives, variable but progressive venous hemoglobin desaturation profiles were interrupted by inflections in the profile that were consistent with fluctuating tissue blood flows and oxygen uptake. End-of-dive saturations of arterial and Type A venous dives were not significantly different, but did differ from those of Type B venous dives. These findings provide further support that the dive response of emperor penguins is a spectrum of cardiac and vascular components (including a-v shunting) that are dependent on the nature and demands of a given dive and even of a given segment of a dive.
README: Blood oxygen transport and depletion in diving emperor penguins
https://doi.org/10.5061/dryad.qv9s4mwnp
Data were collected with backpack recorders on diving emperor penguins, and then downloaded to computers for processing. Research was conducted at a sea ice camp in McMurdo Sound, Antarctica in 2001-2008 (see this article and related citations for details of procedures, data collection, and prior analyses of data). There were two types of recorders: an oxygen recorder and a depth recorder. The recorders stored time (mm dd yyyy hh:mm:ss) and depth (meters), and time (mm dd yyyy hh:mm:ss) and the partial pressure of oxygen (PO2, mm Hg). These data allowed construction of oxygen and depth profiles versus time. A given bird had either an arterial or venous oxygen electrode (one electrode per bird). As explained in the paper, the PO2 was converted to hemoglobin saturation (%) with use of the emperor penguin O2-hemoglobin dissociation curve from Meir and Ponganis, 2009. In this paper, the profiles were sorted into three groups according to the type of hemoglobin saturation profile: arterial, Type A venous, and Type B venous. Criteria for Type A and Type B venous saturation profiles are described in the text.
Description of the data and file structure
There are two files.
- Saturation Profile Groups - ID & Dive Parameters.xlsx
- Dive depth & Hb saturation data.xlsx
There are two .xlsx files in the directory. The first file (Saturation Profile Groups - ID & Dive Parameters.xlsx) summarizes oxygen profile and dive characteristics for all dives in the study. The summary for each group (arterial, Type A venous, Type B venous) included Bird ID, Dive ID (the number assigned to a given dive), dive duration (minutes), maximum dive depth (meters), start time and end time (time is in hh:mm:ss).
The second file (Dive depth & Hb saturation data.xlsx) contains serial collections of time, blood partial pressure of oxygen (PO2 in mm Hg), hemoglobin saturation (%, calculated with the pH 7.5 oxygen-hemoglobin dissociation curve) and depth (meters) for each bird. Blood oxygen and depth data are on a single worksheet for each bird in that file. On each worksheet, the Bird ID and a brief summary of the data are given at the top of the page. Time, PO2 and hemoglobin saturation are listed in the first set of columns; time and depth are presented in the second set of columns. Time is either in date/time (M D YYYY h:mm:ss.000) or in time (in hh:mm:ss.000) depending upon the bird.
Methods
Data were collected with backpack recorders on diving emperor penguins in 2001-2008, and downloaded to computers for analysis.