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Two geochemistry seminars: 1. Trace-element cycling in rivers 2. The role that iron plays in carbon sequestration by phytoplankton

Otago Geology postgraduate students Ben Perrett and Markus Dengg will share their research.

Kaikōrero (speaker): Ben Perrett

University of Otago Title: Climatic and tectonic controls on the trace element chemistry of rivers in the South Island of New Zealand Abstract:

Trace-elements are essential for many of the processes that control Earth’s global carbon and climate cycles. However, many aspects of trace-element cycling are poorly constrained, in particular those that control the trace-element composition of rivers and their flux into the ocean.

To clarify the environmental factors that control the release of trace elements into rivers, we employed source apportionment and statistical modelling for catchments in the South Island. Results emphasise how climatic and tectonic factors control the ratio of chemical and physical weathering and provide new constraints on the dissolved trace-element chemistry of rivers.

Kaikōrero (speaker): Markus Dengg

University of Otago Title: Micronutrient limitation of phytoplankton growth in Lakes of the Taupō Volcanic Zone Abstract:

Global concentrations of carbon dioxide (CO2) are rising due to anthropogenic activity, leading to warming of the global climate. Carbon sequestration by phytoplankton is one of the most important carbon sinks, counteracting rising CO2 levels. At the same time, rising temperatures lead to increasing occurrence of toxic algae blooms.

Results of this study show for the first time that the micronutrient iron plays an important role in freshwater phytoplankton bloom formation and has the potential to act as a controlling agent, increasing CO2 sequestration in freshwater lakes while limiting the occurrence of toxic algae blooms.

At Level 2 the talks will take place in the Benson common room with up to 18 seats available for in-person attendees. Please do come if you can – an in-person audience is always appreciated!

Zoom details

You will also be able to join remotely via Zoom at the following link:

https://otago.zoom.us/j/9687781320?pwd=dHZDSEtEOEJSeGx4MTM3RjJhQ3FSdz09

Date Wednesday, 13 October 2021
Time 1:00pm - 2:00pm
Audience Parents,Undergraduate students,Postgraduate students,Staff,Alumni
Event Category Sciences
Event Type Seminar
CampusDunedin
DepartmentGeology
LocationBenson Common Room (Gn9), Geology Building, University of Otago, Dunedin
CostFree
Contact Name Geology Office
Contact Emailgeology@otago.ac.nz

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