The bivalve Laternula elliptica: physiological and molecular response to changing coastal Antarctic environments

• Main Author: Husmann, Gunnar
• Other Authors: Melzner, Frank, Rosenstiel, Philip
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: 2013
• Subjects: thesis; ddc:570; Antarctic Peninsula; bivalve; transcriptome; hemocytes; oxidative stress; Antarctic; The Antarctic; King George Island; Potter Cove; 25 de Mayo; isla 25 de Mayo; Antarc*; Isla 25 de Mayo
• Online Access: https://nbn-resolving.org/urn:nbn:de:gbv:8-diss-115100; https://macau.uni-kiel.de/receive/diss_mods_00011510; https://macau.uni-kiel.de/servlets/MCRFileNodeServlet/dissertation_derivate_00004744/Dissertation_Gunnar_Husmann.pdf

Increasing temperatures and glacier-disintegration at the Western Antarctic Peninsula (WAP) are presently altering environmental conditions in shallow coastal areas. Rising water temperatures, enhanced ice scouring impacts as well as increasing input of inorganic sediments from melt water runoff are anticipated to particularly affect slow growing sessile benthic filter feeders like the Antarctic soft shell clam Laternula elliptica, a long-lived species which is a major component of the nearshore benthic infauna. In order to address the question of how populations will be affected by current and future changes of the nearshore environment, this thesis set out to investigate a suite of whole organismic, biochemical, cellular and molecular responses of L. elliptica under effects of increased turbidity, ice scouring and food restriction particularly focusing on age-specific sensitivities. Behaviour, metabolism, cellular accumulation of metals as well as oxidative stress markers were investigated in young and old individuals from two field-stations of the Potter Cove (King George Island/Isla 25 de Mayo, WAP), which are characterized by different scales of turbidity or ice scouring. Comparison of age-related responses pointed out younger individuals coped better with high turbidity, as seen on their stable respiration rates and were able to selectively survive effects of ice scouring, as indicated by their higher reburrowing activity and higher survival rates after injury, compared to older individuals. Also cellular products of oxidative stress (lipofuscin) and most metals investigated were found to be age-related and accumulate over lifetime whereas higher sedimentation or physiological stress due to ice scouring could not consistently be related to these markers (lipofuscin, protein carbonyls, metals). Tissue trace metal content rather seems to originate from the water column or food source than from sedimentation per se. The comparison of animals from both field stations suggest that inorganic turbidity and ...