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I recently finished my PhD at the Institute for Marine and Antarctic studies (IMAS) in Australia, where I studied the role of zooplankton in carbon export in the Southern Ocean. I just started a postdoc position with NIWA Wellington in New Zealand as zooplankton ecologist. I'm interested in ecology, biogeochemistry, climate change and science communication. Follow me on twitter (@svenja_halfter) for more updates.
November 2021 - June 2022
University of Tasmania
- Research Assistant
August 2017 - October 2017
- Field assistant
- Volunteering for the CETUS project, working as a marine mammal observer on cargo vessels, executing transects between Portugal mainland and Canary islands, Cabo Verde, Africa and Acores
The Southern Ocean plays a central role in the Earth System by connecting the Earth’s ocean basins, and it is a crucial link between the deep ocean, surface ocean and atmosphere. Hence, the ongoing changes in the Southern Ocean impact global climate, rates of sea level rise, biogeochemical cycles and ecological systems. Yet, understanding of the ca...
In the Southern Ocean, several zooplankton taxonomic groups, euphausiids, copepods, salps and pteropods, are notable because of their biomass and abundance and their roles in maintaining food webs and ecosystem structure and function, including the provision of globally important ecosystem services. These groups are consumers of microbes, primary a...
The subantarctic Southern Ocean plays an important role in the physical uptake and sequestration of carbon dioxide due to the formation and subduction of water masses. However, while extensively studied in other parts of the world's ocean, the zooplankton-mediated biological carbon pump has received less attention. Current knowledge gaps extend acr...
Zooplankton carcasses are an important, yet understudied, pathway of the biological gravitational pump. To understand their contribution to the downward carbon flux in the subantarctic, carcasses of the copepod Neocalanus tonsus were analyzed for carbon content, microbial remineralization rates, and sinking velocities. In addition, the sensitivity...
Southern Ocean ecosystems offer numerous benefits to human society and the global environment, and maintaining them requires well-informed and effective ecosystem-based management. Up to date and accurate information is needed on the status of species, communities, habitats and ecosystems and the impacts of fisheries, tourism and climate change. Th...
The Southern Ocean supports ecosystem services that are important on a global scale. Climate change and human activities (tourism, fishing, and research) will affect both the demand for, and the provision of, these services into the future. Here we synthesize recent assessments of the current status and expected future climate-driven changes in Sou...
Marine ecosystems regulate atmospheric carbon dioxide levels by transporting and storing photosynthetically fixed carbon in the ocean’s interior. In particular, the subantarctic and polar frontal zone of the Southern Ocean is a significant region for physically-driven carbon uptake due to mode water formation, although it is under-studied concernin...
Pressure in academia and science is rapidly increasing and early career researchers (ECRs) have a lot to gain from being involved in research initiatives such as large international projects. But just how inclusive are they? Here we discuss experiences of ECRs directly involved in the Marine Ecosystem Assessment for the Southern Ocean (MEASO), an A...
The “Biological Carbon Pump” helps to decrease atmospheric carbon dioxide levels and consequently, counteracts anthropogenic climate change. However, the contribution of zooplankton to the carbon downward flux is still understudied in the subantarctic zone. This PhD project investigates the following questions: (1) How does zooplankton species comp...
A new amphipod species and genus, Chevreuxiopsis franki, found in a pelagic sediment trap southwest of Tasmania is described. The new species can be recognized by its unique antenna 2, which consists of a narrow peduncle, and a 4-articulate flagellum, which has a massively developed, article 1, large, posteriorly drawn out articles 2 and 3, and an...
Mesozooplankton affect the marine carbon cycle in different ways: (1) they produce fast-sinking faecal pellets by feeding on phytoplankton. (2) At certain times of the year, non-consumptive mortality leads to a significant flux of carcasses to the deep sea. (3) Diel vertical migration (DVM) by some zooplankton groups leads to an active transport of...
Background to my PhD project, including significance and proposed research methods
Seasonal changes in environmental conditions in Arctic and subarctic waters, such as light or temperature, impact the timing of life cycle events of species. Interannual variation in plankton development can lead to a mismatch with higher trophic levels and have consequences for the entire food web. In this study, the spatial and temporal variabili...
I caught copepods before the spring bloom in the Southern ocean and measured length and sinking speed of their bodies. Both were only weakly correlated, so I had the idea to measure the body density in relation to body length to find out why. Does anyone have an idea how to measure body density of copepods?
The ocean’s biological pump is one of the main pathways of biogenic carbon into the oceans interior. Zooplankton play a key role in the biological pump via particle transformations by grazing activities or building blocks for heterogeneous particles (e.g. faecal pellets, mucous nets or carcasses), and hence have a strong influence on the magnitude and efficiency of carbon export. This post-graduate research fellowship will explore how selected zooplankton taxa contribute to the passive and active carbon flux to determine the total export flux out of the epipelagic subantarctic Southern Ocean. Due to significant mode water formation, this region is naturally an important area for carbon sequestration in the ocean's interior. The project focuses on the following topics: 1. Linking the community composition of subantarctic zooplankton in sediment traps from a long-term time series from the Southern Ocean Time-Series (SOTS) site (47˚S) to environmental conditions and carbon flux. 2. Analyse the contribution of carcass production by different zooplankton taxa, i.e. copepods and pelagic tunicates, to the downward carbon flux of the subantarctic zone. 3. Explore new ways of measuring epi- and mesopelagic respiration of zooplankton.