Specialized adaptations allow vent-endemic crabs (Xenograpsus testudinatus) to thrive under extreme environmental hypercapnia

Garett J.P. Allen, Pou Long Kuan, Yung Che Tseng, Pung Pung Hwang, Alex R. Quijada-Rodriguez, Dirk Weihrauch*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


Shallow hydrothermal vent environments are typically very warm and acidic due to the mixing of ambient seawater with volcanic gasses (> 92% CO2) released through the seafloor making them potential ‘natural laboratories’ to study long-term adaptations to extreme hypercapnic conditions. Xenograpsus testudinatus, the shallow hydrothermal vent crab, is the sole metazoan inhabitant endemic to vents surrounding Kueishantao Island, Taiwan, where it inhabits waters that are generally pH 6.50 with maximum acidities reported as pH 5.50. This study assessed the acid–base regulatory capacity and the compensatory response of X. testudinatus to investigate its remarkable physiological adaptations. Hemolymph parameters (pH, [HCO3], PCO2, [NH4+], and major ion compositions) and the whole animal’s rates of oxygen consumption and ammonia excretion were measured throughout a 14-day acclimation to pH 6.5 and 5.5. Data revealed that vent crabs are exceptionally strong acid–base regulators capable of maintaining homeostatic pH against extreme hypercapnia (pH 5.50, 24.6 kPa PCO2) via HCO3/Cl exchange, retention and utilization of extracellular ammonia. Intact crabs as well as their isolated perfused gills maintained PCO2tensions below environmental levels suggesting the gills can excrete CO2 against a hemolymph-directed PCO2 gradient. These specialized physiological mechanisms may be amongst the adaptations required by vent-endemic animals surviving in extreme conditions.

Original languageEnglish
Article number11720
JournalScientific reports
Issue number1
Publication statusPublished - 2020 Dec 1
Externally publishedYes

ASJC Scopus subject areas

  • General


Dive into the research topics of 'Specialized adaptations allow vent-endemic crabs (Xenograpsus testudinatus) to thrive under extreme environmental hypercapnia'. Together they form a unique fingerprint.

Cite this