2 Master’s Projects (Marine Biology/Microbiology/Geochemistry)

“Growth and skeletal composition of the cold-water coral
Desmophyllum dianthus
under
in situ
aragonite undersaturated and saturated conditions”

Project 2:

“Differences in energetic constitution of the cold-water coral
Desmophyllum dianthus
due to growth under
in situ
aragonite undersaturated and saturated conditions
"
In the division
Biosciences
, section
Bentho-Pelagic Processes
we are looking for a Master student in
summer/fall 2019
, who will participate in a first expedition in
late spring 2019.
Project description
The Master projects are integrated in the AWI Strategy Fund project
DACCOR
(
D
eciphering the
A
ntarctic
C
old-water
C
oral
R
ecord), which aims to develop a proxy archive for the Southern hemisphere and especially for the Antarctic region using cold-water corals (CWC) to reconstruct temperature and pH in seawater. Within

DACCOR
we use a multidisciplinary approach to investigate the ecological, physiological and molecular regulations of biomineralization processes and to read geochemical signatures in CWC grown under laboratory (AWI) and field conditions (Patagonia and in the Antarctic peninsula).

Methods applied

• Staining of living corals with calcein at different replicated sites in aragonite-saturated (shallow) and undersaturated waters (deep).
• Tissue analyses of corals sampled

in situ
from different sites in aragonite-saturated (shallow) and undersaturated waters (deep).

• Skeletal analyses of sampled corals (linear extension rates, skeletal density, organic matrix, optional: elemental and isotopic composition).
• Biomass analyses of sampled corals (protein, lipid, fatty acid composition and C/N ratios).
• Dermination of the

in situ
water chemical conditions by continuous monitoring (with different logger systems deployed on a long-term mooring) and discrete water samples for i.e. dissolved inorganic carbon (DIC), total alkalinity (TA), pH.

Tasks

You will investigate
(1) the skeletal growth, composition, linear extension and calcification rates, and
(2) the energetic constitution and biomass composition (protein, lipid and fatty acid composition) of the cold-water coral (CWC)
Desmophyllum dianthus
from the Patagonian Comau Fjord (Chile) to reveal the skeletal and physiological baseline data for the above described approach.
Growth and metabolic rates of these scleractinians are believed to depend on seawater chemistry, particularly the saturation state of the mineral (aragonite) composing the skeleton, which is related to the pH and other chemical constituents.

The Comau Fjord near the Golfo de Ancud offers a unique setting to study calcification under aragonite-saturated waters near the surface and undersaturated waters at depth due to its highly stable stratification. The approach will reveal, how skeletal growth, composition and calcification rates depend on energetic constitution and biomass composition and change under different settings of aragonite saturation and due to natural variations of the saturation state as a result of seasonal changes in water column chemistry. The studies of you will be closely related and accompanied by several complementary research approaches simultaneously addressing questions on differences in metabolic rates (respiration) of the corals, as well as their molecular response to the different environmental settings.

Requirements

• Interest and previous knowledge in the subject and methods described
• University admission for Master thesis
• Current German scientific Diver (Forschungstaucher) or ESD licence
• Willingness to participate in expeditions to remote region in North Patagonia, Chile
• Team player and good communication skills
• Readiness to move to Bremerhaven for sample and data analyses, interpretation of results and thesis writing.

mehr...

zur Vakanz

Weitere Jobs von Awi