Marine Chemistry and Biogeochemistry

Master Projects

Trace elements /micronutrients  biogeochemistry

 

1-Studying iron uptake and growth rate of two different phytoplankton a) prokaryote (cyanobacteria) and b) eukaryote (Diatom)

Both cyanobacteria (blue-green algae) and diatoms are very important microbial organism for marine productivity, Nitrogen and Carbon cycles.

To study iron uptake of these microorganism may give crucial information for evolutionary mechanism of phytoplankton in marine systems.

Collaboration with Dept. of Biotechnology

In addition, we work together with biotechnological researchers to control genes, which are expected to be involved in a newly discovered iron uptake mechanisms. By comparing the growth rates and physiology of the mutants and the wild type under iron shortage we can draw important conclusion about the iron uptake mechanism.

Experiment : Phytoplankton cultures will be incubated with different iron forms and  their growth rate and uptake rate of iron  will be monitored.
Different forms of iron in water and in cell will be determined 

 

 

2- Improvement the analytical methods for iron and other trace element determination in seawater

 

a) Multi analytical approach for Iron determination in seawater
Iron is an essential micronutrient for microbial organisms (bacteria and phytoplankton) in oceans. Iron is a limiting nutrient in almost 40 % of the Ocean, especially in the Antarctic waters and most of the Southern Ocean. It is one of the key element which has important role for regulation of the atmospheric CO2 hence Climate of the Earth.
 

Determination of iron and its forms in seawater is a challenging task. The student will test various factors to improve the determination of the iron by using Sea-FAST pre-concentration instrument and High Resolution Inductively Coupled Plasma - Mass Spectrometry (HR-ICP-MS) and Flow Injection Analysis (FIA)


b)  Multi analytical approach for selected trace element (i.e. Mn, Co, Ni, Zn, Cu, Au, Cd, Pb, U and Ti )determination in seawater
Some trace elements (TE) are essential as micronutrients for microbial organisms (bacteria and phytoplankton) in oceans. They are crucial in many vital enzymatic reactions. Some other trace elements are toxic for marine organism. Due to climate change and human made impact, the mobility, solubility hence bioavailability and toxicity of TE may be changing dramatically. It is, therefore, important to develop  useful analytical techniques to monitor the changes in TE concentration in seawater and their roles in ecosystem.

Determination of iron and its forms in seawater is a challenging task. The student will test various factors to improve the determination of the iron by using Sea-FAST pre-concentration instrument and High Resolution Inductively Coupled Plasma - Mass Spectrometry (HR-ICP-MS) and Diffusive Gradient in Thin film (DGT) methods.

 

Ocean Acidification
Impact of CO2 seepage from subsea-bed CO2 storage sites on the biogeochemistry on the sediment-water  interface

 


3- Trace and rare earth elements (REE) at the sediment –water interface

This work  will be part of a NFR projects with international partners). The task is to follow the mobilization of the different trace elements (both toxic and bio-essential elements) mobility and distribution of the surface sediment. Multi analytical techniques will be used to determine the distribution and transformation of elements (i.e. Sea-fast pre-concentration technique, ICP-MS, sediment sequential extraction etc).

Experiment : Pressurized Titanium tank (Karl Erik TiTank) was developed specially to study the impact of CO2 leakage on the marine ecosystem, is a unique experimental vessel. KE-TiTank offers us a continuous monitoring of CO2 l impact on marine ecosystem under fully controlled seawater flow rate, various CO2 fluxes, and various pressures (1 - 30 atm) conditions. Samples will be taken the ongoing experiment under 30
Collaboration with SINTEF

 

4- Dissolved organic carbon (DOC) –determination and characterization

This project will be part of two projects (an EEA project and a NFR projects with international partners). The task is to follow the mobilization and characterization of the organic matter, their mobility and distribution at the sediment- water interface. Multi analytical techniques will be used to determine the distribution and transformation of DOC (i.e. Synapt G2-S Q-TOF, CDOM, FDOM).

Co-Supervisor : Alexandros Asimakopoulos alexandros.asimakopoulos@ntnu.no

 

 

5- Studying the effects of CaO (or Ca(OH)2 ) addition to seawater and its impact on marine microbial ecosystem :
 

The impact of CaO/ Ca(OH)2  addition on the calcifying phytoplankton Emiliania huxleyi, EHUX,  the most dominant  species of coccolithophore in the oceans.

Since CaO/ Ca(OH)2 will affect master variables of pH and alkalinity, this may also cause positive or negative impact on marine organism, their internal pH and may alter acid–base balance of some marine organism. To test this hypothesis we proposed  the following microcosm experiment.

Experiment : Addition of CaO (or Ca (OH)2) to microcosm culture with different pH and alkalinity. we an chose pH condition for pre-industrial, modern and future scenarios that is (pH:8.2-8.3;  7.9-8.0 and 7.7-7.8 respectively) pH and alkalinity of the seawater can be adjusted by using  either CO2 gas bubbling or mineral acid with combination of NaHCO3/Na2CO3.
sampling can be done by short and long term perspectives (minutes, hours and days). EHUX culture will be incubated under constant temperature and light, their growth rate and calc formation will be monitored

Analysis & Techniques:  pH, alkalinity will be measured by using potentiometric or optical methods.  pCO2, and DIC (HCO-3, CO-23, CO2) will be calculated by using CO2Sys and SeaCarb programs. Calcium carbonate formation of EHUX will be monitored by electron microscopy.

CaO, Ca(OH)2, CaCO3 and other Ca, Mg carbonate species will be followed by XRD after filtration. Relevant total and dissolved elements will be measured by SeFast connected HR-ICP-MS. Analysis of dissolved fraction   (< 0.2 µm):  Techniques : HR-ICP-MS

 

6- Studying Fate of CaO addition and the effects of CaO (or Ca(OH)2) to seawater and its impact on pH, alkalinity and dissolved inorganic carbon, DIC

Adding “quicklime” (calcium oxide, CaO) or "hydrated lime" (calcium hydroxide, Ca(OH)2 ) in the seawater can neutralized  H+ and increases alkalinity. That is why addition of CaO or Ca(OH)2 to seawater have been suggested as mitigation technique for Ocean Acidification and named as “Ocean liming” (OL) or “artificial ocean alkalinization” (AOA) (Kheshgi 1995, Paguey and Zeebe, 2013, Renforth et al., 2013, Renforth and Kruger, 2013). This technique may help to capture extra CO2 from atmosphere by Ocean. However, there is extremely limited knowledge  and a great uncertainty on OL and AOA, especially their possible impacts on marine biogeochemistry and ecosystem (Cripps  et al , 2013; Paguey and Zeebe, 2013; Feng et al, 2016)

Experiment : Addition of CaO (or Ca (OH)2) to seawater with different pH and alkalinity.
we can chose initial pH conditions (pre-industrial, modern and future scenarios that is (pH:8.2-8.3;  7.9-8.0 and 7.7-7.8 respectively).  pH and alkalinity of the seawater can be adjusted by using  either CO2 gas bubbling or addition of a mineral acid with combination of NaHCO3/Na2CO3.
Sampling can be done by short and long-term perspectives (minutes, hours and days)

Analysis & Techniques:  pH, alkalinity will be measured by using the potentiometric or optical methods.  pCO2, and DIC (HCO-3, CO-23, CO2) will be calculated by using CO2Sys and SeaCarb programs.

CaO, Ca(OH)2, CaCO3 and other Ca, Mg carbonate species will be followed by XRD after filtration. Relevant total and dissolved elements will be measured by SeFast connected HR-ICP-MS

 

CO2/ Carbon cycle :
Characterization of the organic carbon in seawater and surface sediments

 

Increasing CO2 in the atmosphere is one of the main global environmental problem. Both greenhouse effects and ocean acidification ere due to accumulation of CO2  in the atmosphere. It is critical to control CO2 increase in the atmosphere. Oceanic processes are important for removal of CO2 and control its level in the atmosphere by photosynthesis and eventually by exporting biologically fixed CO2  as forms of dissolved and particulate Organic  Carbon (DOC/POC) into deep water and  sediment.

it is important to follow the carbon export from surface water to the deep water and its fate. In this work we are going to collect DOC and POC  in water column and sediment (pore water) to characterize whether they are labile  or refractory  for microbial decomposition.
Multi analytical techniques will be used to determine the distribution and transformation of DOC and POC  (i.e. Synapt G2-S Q-TOF, , NMR, CDOM, FDOM).
Collaboration with Marine Biologist in Dept of Biology.

 

Co-Supervisor : Alexandros Asimakopoulos alexandros.asimakopoulos@ntnu.no

Co-Supervisor : Nebojsa Simic nebojsa.simic@ntnu.no

 

Reactive Oxygen Species  (ROS)

Role of plankton for H2O2  production in seawater

Hydrogen peroxide, H2O2 is one of the most  dominant ROS in surface water. It is very strong oxidizing molecules and increase in concentration of , H2O2 is important stressors  for biology, and have critical impact of  many vital chemical process in seawater.

We are testing the role of grazing activities  of different zooplankton  on the production of , H2O2 


 

CONTACTS:
 

For details Murat V. Ardelan,  

                  Office: D2-214                              Murat.v.ardelan@ntnu.no


 For CO2 related  topics contact  Ana Borrero ana.r.borrero@ntnu.no
 

For Iron / Trace metals, contact  Annie Vera Hunnestad, annie.v.hunnestad@ntnu.no


For  ROS  contact  Nicolas Sanchez,         nicolas.sanchez@ntnu.no


 

Current projects

 

Master Projects