Blood viscosity and optimal hematocrit in a deep-diving mammal, the northern elephant seal (Mirounga angustirostris)

Elephant seals offer a unique opportunity to examine rheological characteristics of blood because of the normally high hematocrits in this species. A comparison of blood viscosity of the elephant seal with that of a terrestrial mammal (rabbit; HCT = 35%) reveals a threefold increase in viscosity of elephant seal blood over that of rabbit blood due to the high hematocrit (HCT = 65%). While the increased hematocrit of elephant seal blood reflects increased oxygen storage capacity, blood oxygen transport may actually be reduced by the effects of increased blood viscosity on blood flow. Elephant seal plasma viscosity was also higher than that of rabbit plasma; this was associated with a higher concentration of plasma proteins. There were no apparent differences in the viscous properties of the red blood cells of the two species. The theoretically optimal hematocrit was determined in vitro for reconstituted blood from each species and compared with the observed in vivo hematocrit. It was found that the observed hematocrit of the elephant seal lies far to the right of the predicted hematocrit for optimal oxygen transport, while the rabbit hematocrit was identical with the predicted value. These results suggest that elephant seals have increased oxygen storage capacity at the expense of optimizing oxygen transport. The observed increase in hematocrit and viscosity may be of importance in considering the diving behavior and energetics of elephant seals.

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Diving behavior in relation to ambient water temperature in northern elephant seals

Canadian Journal of Zoology ◽

10.1139/z94-087 ◽

1994 ◽

Vol 72 (4) ◽

pp. 643-651 ◽

Cited By ~ 11

Author(s):

Hiroshi Hakoyama ◽

Burney J. Le Boeuf ◽

Yasuhiko Naito ◽

Wataru Sakamoto

Keyword(s):

Water Temperature ◽

Elephant Seal ◽

Diving Behavior ◽

Mirounga Angustirostris ◽

Ambient Water ◽

Northern Elephant Seal ◽

Elephant Seals ◽

Northern Elephant Seals ◽

Abrupt Changes ◽

Ambient Water Temperature

Our aim was to describe changes in ambient water temperature during the course of migration by northern elephant seals (Mirounga angustirostris) and to examine evidence for the seal using abrupt temperature gradients for locating prey. During migration in the post breeding season, the diving patterns of 10 adult females and 7 breeding-age males from Año Nuevo, California, were recorded with time–depth recorders in 1989–1991. Recorded sea surface temperatures declined from 11–13 °C to a low of 3–9 °C as the seals moved north and increased as they returned. Depth of diving was not closely linked to sharp thermal gradients. A thermocline was evident only at the beginning and end of the migration in less than 100 m of water, where less than 2% of diving takes place. There were sex differences in the temperature range at the depths where 75% of diving and foraging occurred, owing in part to habitat separation. The temperatures were lower and the range narrower for females (4.2–5.2 °C at 388–622 m) than for males (5.3–6.0 °C at 179–439 m). We conclude that the northern elephant seal habitat does not provide abrupt changes in temperature that might serve as important cues for locating prey.

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The extra burden of motherhood: reduced dive duration associated with pregnancy status in a deep-diving mammal, the northern elephant seal

Biology Letters ◽

10.1098/rsbl.2017.0722 ◽

2018 ◽

Vol 14 (2) ◽

pp. 20170722 ◽

Cited By ~ 8

Author(s):

Luis A. Hückstädt ◽

Rachel R. Holser ◽

Michael S. Tift ◽

Daniel P. Costa

Keyword(s):

Marine Mammals ◽

Elephant Seal ◽

Dive Duration ◽

Northern Elephant Seal ◽

Continuous Increase ◽

Elephant Seals ◽

Deep Diving ◽

Pregnancy Status ◽

The Cost ◽

Free Ranging

The cost of pregnancy is hard to study in marine mammals, particularly in species that undergo pregnancy while diving continuously at sea such as elephant seals (genus Mirounga ). We analysed the diving behaviour of confirmed pregnant and non-pregnant northern elephant seals ( M. angustirostris , n = 172) and showed that after an initial continuous increase in dive duration, dives of pregnant females become shorter after week 17. The reasons for this reduction in dive duration remain unknown, but we hypothesize that increased fetal demand for oxygen could be the cause. Our findings reveal an opportunity to explore the use of biologging data to investigate pregnancy status of free-ranging marine mammals and factors that could affect pregnancy success.

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Investigation of the Oxygen Exchange Property and Oxygen Storage Capacity of CexZr1−xO2 Nanocrystals

The Journal of Physical Chemistry C ◽

10.1021/jp808075t ◽

2009 ◽

Vol 113 (17) ◽

pp. 6921-6928 ◽

Cited By ~ 34

Author(s):

Jing Ouyang ◽

Huaming Yang

Keyword(s):

Storage Capacity ◽

Oxygen Storage Capacity ◽

Oxygen Exchange ◽

Oxygen Storage ◽

Exchange Property

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On-line Oxygen Storage Capacity Estimation of a Catalyst

10.4271/2003-01-1000 ◽

2003 ◽

Cited By ~ 13

Author(s):

Grant A. Ingram ◽

Gopichandra Surnilla

Keyword(s):

Storage Capacity ◽

Oxygen Storage Capacity ◽

Oxygen Storage ◽

Capacity Estimation ◽

On Line ◽

Line Oxygen

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Autothermal Reforming of Propane Over Ni Catalysts Supported on a Variety of Perovskites

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2007.093 ◽

2007 ◽

Vol 7 (11) ◽

pp. 4013-4016 ◽

Cited By ~ 5

Author(s):

SeungSoo Lim ◽

DongJu Moon ◽

JongHo Kim ◽

YoungChul Kim ◽

NamCook Park ◽

...

Keyword(s):

Thermal Stability ◽

Storage Capacity ◽

Flow Reactor ◽

Oxygen Storage Capacity ◽

Autothermal Reforming ◽

Oxygen Storage ◽

Hydrogen Yield ◽

Impregnation Method ◽

Ni Catalysts ◽

Atmospheric Flow

Autothermal reforming of propane for hydrogen over Ni catalysts supported on a variety of perovskites was performed in an atmospheric flow reactor. Perovskite is known for its higher thermal stability and oxygen storage capacity, but catalytic activity of itself is low. A sites of the ABO3 structured perovskites were occupied by La while B sites by one of Fe, Co, Ni, and Al by citrate method. The composition of the reactant mixture was H2O/C/O2 = 8.96/1.0/1.1. The changes in the states of the catalysts after reaction were analyzed by XRD, TPD, and TGA. Ni/LaAlO3 catalyst maintained the perovskite structure after reaction. It showed higher hydrogen yield and thermal stability compared to those of the catalysts with Fe, Co, or Ni in B sites. Catalysts prepared by deposition-precipitation (DP) method showed higher activity than those prepared by impregnation method, presumably due to the smaller sizes of the NiO crystal particles.

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Mn3O4 doped with highly dispersed Zr species: a new non-noble metal oxide with enhanced activity for three-way catalysis

New Journal of Chemistry ◽

10.1039/c6nj02272c ◽

2016 ◽

Vol 40 (12) ◽

pp. 10108-10115 ◽

Cited By ~ 9

Author(s):

Genyuan Zhao ◽

Jing Li ◽

Wenshuang Zhu ◽

Xueqin Ma ◽

Yonghua Guo ◽

...

Keyword(s):

Metal Oxide ◽

Manganese Oxide ◽

Noble Metal ◽

Storage Capacity ◽

Catalytic Properties ◽

Oxygen Storage Capacity ◽

Oxide Catalysts ◽

Oxygen Storage ◽

Highly Dispersed ◽

Three Way Catalysis

Herein, we demonstrate the influence of zirconium species on promoting the oxygen storage capacity and three-way catalytic properties of zirconium-manganese oxide catalysts.

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