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Dr Linn Hoffmann, Senior Lecturer

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Marine botany
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Email: linn.hoffmann@otago.ac.nz
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Phone: +64 3 479 7583 

Research interests

My work focuses on the effect of different environmental stressors for marine phytoplankton physiology and ecology. I am thereby mainly interested in the effect of climate change related stressors such as ocean acidification and ocean warming and the effect of trace metals e.g. from volcanic eruptions on marine phytoplankton and the implications for higher trophic levels of the food chain. I also work on biomechanical properties of diatom frustules and how they are affected by environmental conditions.

Dr Hoffmann is director of the Ocean Acidification Research Theme

Dr Hoffmann is also a member of the Coastal People: Southern Skies collaboration that connects communities with world-leading, cross-discipline research to rebuild coastal ecosystems.
Coastal People: Southern Skies

Current research

Some of the research projects that I am currently involved in include:

What is the effect of trace metal release from volcanic eruptions for marine phytoplankton species distribution and productivity?

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NASA  satellite image of Puyehue eruption in 2011 in Chile.

How does ocean acidification affect trace metal bioavailability and what are the implications thereof for marine phytoplankton?

linn_profile_labwork

How is phytoplankton species distribution in the Southern Ocean affected by climate change?

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SEHACK-secchi plankton study.

Does bioaccumulation of iron by seabirds enhance productivity around sub-Antarctic Islands?

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Photo credit: O Shatova.

Potential masters' or PhD research projects

  • Effect of ocean acidification on energy transfer in the marine food chain
  • Is diatom frustule stability affected by ocean acidification?
  • How does ocean acidification affect natural phytoplankton communities in the Southern Ocean?
  • Comparison of Fjordland phytoplankton communities New Zealand versus Chile
  • Volcanic eruptions and their effect on phytoplankton community structures

The University of Otago offers PhD scholarships to candidates with excellent academic records (irrespective of nationality). Please feel free to contact me if you are interested my research and would like to do your PhD in New Zealand. More information can be found on the Scholarships page.

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Postgraduate students

  • Nadjejda Espinel (PhD): Changes in larval settlement and metamorphosis in marine invertebrates in response to reduced seawater pH
  • Hannah Heynderickx (PhD): The effects of ocean acidification on phytoplankton‐bacteria interactions in Southern Ocean waters
  • Morgan Meyers (PhD): How does ocean acidification affect copepod grazing in subAntarctic waters?
  • Madeleine Post (MSc)
  • “Amirreza Zarekarizi (PhD): Effect of cultivation condition on the production of fucoxanthin by microalgae

Previous students

  • Ro Allen (PhD): Effect of ocean acidification and warming on natural Southern Ocean phytoplankton communities
  • Kelsey Donahue
  • Chittipat Nitithamyong
  • Francie Rudminat (PhD): Dinitrogen fixation in the South Pacific – Effect of ocean acidification on marine diazotrophs

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Teaching

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  • BTNY 203 Marine and Freshwater Botany (coordinator)
  • BTNY 301 Plant Ecology (co-coordinator)
  • BTNY 465 Plant and Environment
  • BIOL 123 Plants: How They Shape the World
  • OCEN 322 Biological Oceanography
  • ECOL 111 Ecology and Conservation of Diversity
  • ECOL212 Ecological Applications
  • ECOL211 Ecology of Communities and Ecosystems

Science Communication interview

Scott Bagley, one of Science Communication's students undertook an interview with Linn in 2015.
Science Communication student Scott Bagley interviews Dr Linn Hoffmann

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Publications

Espinel-Velasco, N., Tobias-Hünefeldt, S. P., Karelitz, S. E., Hoffmann, L. J., Morales, S. E., & Lamare, M. D. (2021). Reduced seawater pH alters marine biofilms with impacts for marine polychaete larval settlement. Marine Environmental Research. Advance online publication. doi: 10.1016/j.marenvres.2021.105291

Harvey, B. P., Allen, R., Agostini, S., Hoffmann, L. J., Kon, K., Summerfield, T. C., … Hall-Spencer, J. M. (2021). Feedback mechanisms stabilise degraded turf algal systems at a CO2 seep site. Communications Biology, 4(1), 219. doi: 10.1038/s42003-021-01712-2

Christensen, T. J. E., Zitoun, R., Hoffmann, L. J., Dillon, W. D. N., Dillingham, P. W., & McGraw, C. M. (2021). Redefining Ksp for calcite and aragonite with lower uncertainty in artificial seawater. Proceedings of the 14th Annual New Zealand Ocean Acidification Conference: Ocean Acidification in a Decade of Ocean Science. (pp. 24). Retrieved from http://nzoac.nz/conferences

Cowley, G. T., McGraw, C. M., & Hoffmann, L. J. (2021). Environmental science in civic society and policy: Outreach for a better world today. Proceedings of the 14th Annual New Zealand Ocean Acidification Conference: Ocean Acidification in a Decade of Ocean Science. (pp. 25). Retrieved from http://nzoac.nz/conferences

Zitoun, R., Connell, S. D., Cornwall, C. E., Currie, K. I., Fabricius, K., Hoffmann, L. J., Lamare, M. D., Murdoch, J. H., … Sander, S. G., … Smith, A. M. (2020). A unique temperate rocky coastal hydrothermal vent system (Whakaari-White Island, Bay of Plenty, New Zealand): Constraints for ocean acidification studies. Marine & Freshwater Research, 71(3), 321-344. doi: 10.1071/mf19167

Journal - Research Article

Espinel-Velasco, N., Tobias-Hünefeldt, S. P., Karelitz, S. E., Hoffmann, L. J., Morales, S. E., & Lamare, M. D. (2021). Reduced seawater pH alters marine biofilms with impacts for marine polychaete larval settlement. Marine Environmental Research. Advance online publication. doi: 10.1016/j.marenvres.2021.105291

Harvey, B. P., Allen, R., Agostini, S., Hoffmann, L. J., Kon, K., Summerfield, T. C., … Hall-Spencer, J. M. (2021). Feedback mechanisms stabilise degraded turf algal systems at a CO2 seep site. Communications Biology, 4(1), 219. doi: 10.1038/s42003-021-01712-2

Zitoun, R., Connell, S. D., Cornwall, C. E., Currie, K. I., Fabricius, K., Hoffmann, L. J., Lamare, M. D., Murdoch, J. H., … Sander, S. G., … Smith, A. M. (2020). A unique temperate rocky coastal hydrothermal vent system (Whakaari-White Island, Bay of Plenty, New Zealand): Constraints for ocean acidification studies. Marine & Freshwater Research, 71(3), 321-344. doi: 10.1071/mf19167

Allen, R., Hoffmann, L. J., Law, C. S., & Summerfield, T. C. (2020). Subtle bacterioplankton community responses to elevated CO2 and warming in the oligotrophic South Pacific Gyre. Environmental Microbiology Reports, 12(4), 377-386. doi: 10.1111/1758-2229.12844

Gutiérrez-Rodriguez, A., Safi, K., Fernández, D., Forcén-Vázquez, A., Gourvil, P., Hoffmann, L., … Nodder, S. D. (2020). Decoupling between phytoplankton growth and microzooplankton grazing enhances productivity in Subantarctic waters on Campbell Plateau, southeast of New Zealand. Journal of Geophysical Research: Oceans, 125(2), e2019JC015550. doi: 10.1029/2019JC015550

Hopwood, M. J., Santana-González, C., Gallego-Urrea, J., Sanchez, N., Achterberg, E. P., Ardelan, M. V., … Hoffmann, L., … Turner, D. (2020). Fe(II) stability in coastal seawater during experiments in Patagonia, Svalbard, and Gran Canaria. Biogeosciences, 17(5), 1327-1342. doi: 10.5194/bg-17-1327-2020

Allen, R., Hoffmann, L. J., Larcombe, M. J., Louisson, Z., & Summerfield, T. C. (2020). Homogeneous environmental selection dominates microbial community assembly in the oligotrophic South Pacific Gyre. Molecular Ecology. Advance online publication. doi: 10.1111/mec.15651

Hoffmann, L., Eggers, S. L., Allhusen, E., Katlein, C., & Peeken, I. (2020). Interactions between the ice algae Fragillariopsis cylindrus and microplastics in sea ice. Environment International, 139, 105697. doi: 10.1016/j.envint.2020.105697

Allen, R., Summerfield, T. C., Currie, K., Dillingham, P. W., & Hoffmann, L. J. (2020). Distinct processes structure bacterioplankton and protist communities across an oceanic front. Aquatic Microbial Ecology, 85, 19-34. doi: 10.3354/ame01938

Donahue, K., Klaas, C., Dillingham, P. W., & Hoffmann, L. J. (2019). Combined effects of ocean acidification and increased light intensity on natural phytoplankton communities from two Southern Ocean water masses. Journal of Plankton Research, 41(1), 30-45. doi: 10.1093/plankt/fby048

Zarekarizi, A., Hoffmann, L., & Burritt, D. (2019). Approaches for the sustainable production of fucoxanthin, a xanthophyll with potential health benefits. Journal of Applied Phycology, 31, 281-299. doi: 10.1007/s10811-018-1558-3

Espinel-Velasco, N., Hoffmann, L., Agüera, A., Byrne, M., Dupont, S., Uthicke, S., … Lamare, M. (2018). Effects of ocean acidification on the settlement and metamorphosis of marine invertebrate and fish larvae: A review. Marine Ecology Progress Series, 606, 237-257. doi: 10.3354/meps12754

Shatova, O. A., Wing, S. R., Hoffmann, L. J., Wing, L. C., & Gault-Ringold, M. (2017). Phytoplankton community structure is influenced by seabird guano enrichment in the Southern Ocean. Estuarine, Coastal & Shelf Science, 191, 125-135. doi: 10.1016/j.ecss.2017.04.021

Faucher, G., Hoffmann, L., Bach, L. T., Bottini, C., Erba, E., & Riebesell, U. (2017). Impact of trace metal concentrations on coccolithophore growth and morphology: Laboratory simulations of Cretaceous stress. Biogeosciences, 14(14), 3603-3613. doi: 10.5194/bg-14-3603-2017

Conway, T. M., Hoffmann, L. J., Breitbarth, E., Strzepek, R. F., & Wolff, E. W. (2016). The growth response of two diatom species to atmospheric dust from the Last Glacial Maximum. PLoS ONE, 11(7), e0158553. doi: 10.1371/journal.pone.0158553

Shatova, O., Wing, S. R., Gault-Ringold, M., Wing, L., & Hoffmann, L. J. (2016). Seabird guano enhances phytoplankton production in the Southern Ocean. Journal of Experimental Marine Biology & Ecology, 483, 74-87. doi: 10.1016/j.jembe.2016.07.004

Hoffmann, L. J., Breitbarth, E., McGraw, C. M., Law, C. S., Currie, K. I., & Hunter, K. A. (2013). A trace-metal clean, pH-controlled incubator system for ocean acidification incubation studies. Limnology & Oceanography: Methods, 11, 53-61. doi: 10.4319/lom.2013.11.53

Tatters, A. O., Roleda, M. Y., Schnetzer, A., Fu, F., Hurd, C. L., Boyd, P. W., … Hoffmann, L. J., & Hutchins, D. A. (2013). Short- and long-term conditioning of a temperate marine diatom community to acidification and warming. Philosophical Transactions of the Royal Society B, 368(1627), 20120437. doi: 10.1098/rstb.2012.0437

Olgun, N., Duggen, S., Langmann, B., Hort, M., Waythomas, C. F., Hoffmann, L., & Croot, P. (2013). Geochemical evidence of oceanic iron fertilization by the Kasatochi volcanic eruption in 2008 and the potential impacts on Pacific sockeye salmon. Marine Ecology Progress Series, 488, 81-88. doi: 10.3354/meps10403

Hoffmann, L. J., Breitbarth, E., Boyd, P. W., & Hunter, K. A. (2012). Influence of ocean warming and acidification on trace metal biogeochemistry. Marine Ecology Progress Series, 470, 191-205. doi: 10.3354/meps10082

Law, C. S., Breitbarth, E., Hoffmann, L. J., McGraw, C. M., Langlois, R. J., LaRoche, J., … Safi, K. A. (2012). No stimulation of nitrogen fixation by non-filamentous diazotrophs under elevated CO2 in the South Pacific. Global Change Biology, 18(10), 3004-3014. doi: 10.1111/j.1365-2486.2012.02777.x

Hoffmann, L. J., Breitbarth, E., Ardelan, M. V., Duggen, S., Olgun, N., ..., & Wängberg, S.-Å. (2012). Influence of trace metal release from volcanic ash on growth of Thalassiosira pseudonana and Emiliania huxleyi. Marine Chemistry, 132–133, 28-33. doi: 10.1016/j.marchem.2012.02.003

Smetacek, V., Klaas, C., Strass, V. H., Assmy, P., Montresor, M., Cisewski, B., … Hoffmann, L. J., … Wolf-Gladrow, D. (2012). Deep carbon export from a Southern Ocean iron-fertilized diatom bloom. Nature, 487, 313-319. doi: 10.1038/nature11229

Wilken, S., Hoffmann, B., Hersch, N., Kirchgessner, N., Dieluweit, S., Rubner, W., Hoffmann, L. J., … Peeken, I. (2011). Diatom frustules show increased mechanical strength and altered valve morphology under iron limitation. Limnology & Oceanography, 56(4), 1399-1410. doi: 10.4319/lo.2011.56.4.1399

Duggen, S., Olgun, N., Croot, P., Hoffmann, L., Dietzel, H., Delmelle, P., & Teschner, C. (2010). The role of airborne volcanic ash for the surface ocean biogeochemical iron-cycle: A review. Biogeosciences, 7(3), 827-844.

Breitbarth, E., Achterberg, E. P., Ardelan, M. V., Baker, A. R., Bucciarelli, E., Chever, F., … Hoffmann, L., Hunter, K. A., … Ye, Y. (2010). Iron biogeochemistry across marine systems: Progress from the past decade. Biogeosciences, 7(3), 1075-1097.

Breitbarth, E., Gelting, J., Walve, J., Hoffmann, L. J., Turner, D. R., Hassellöv, M., & Ingri, J. (2009). Dissolved iron (II) in the Baltic Sea surface water and implications for cyanobacterial bloom development. Biogeosciences, 6, 2397-2420.

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Conference Contribution - Published proceedings: Abstract

Christensen, T. J. E., Zitoun, R., Hoffmann, L. J., Dillon, W. D. N., Dillingham, P. W., & McGraw, C. M. (2021). Redefining Ksp for calcite and aragonite with lower uncertainty in artificial seawater. Proceedings of the 14th Annual New Zealand Ocean Acidification Conference: Ocean Acidification in a Decade of Ocean Science. (pp. 24). Retrieved from http://nzoac.nz/conferences

Cowley, G. T., McGraw, C. M., & Hoffmann, L. J. (2021). Environmental science in civic society and policy: Outreach for a better world today. Proceedings of the 14th Annual New Zealand Ocean Acidification Conference: Ocean Acidification in a Decade of Ocean Science. (pp. 25). Retrieved from http://nzoac.nz/conferences

Faucher, G., Wuttig, K., Bettoni, C., Erba, E., Koch, F., Trimborn, S., … Hoffmann, L. (2020). Influence of volcanic ash on growth and morphology of coccolithophore algae. Proceedings of the Ocean Sciences Meetings (OSM). CT41A-05. Retrieved from https://agu.confex.com/agu/osm20/meetingapp.cgi

Meyers, M., Décima, M., Currie, K. I., Hoffmann, L., & Wing, S. (2020). Salp distribution in coastal, subtropical, and subantarctic waters off the Southeast coast of New Zealand: Linking hydrology with ecosystem function. Proceedings of the Ocean Sciences Meetings (OSM). ME24E-0140. Retrieved from https://agu.confex.com/agu/osm20/meetingapp.cgi

Allen, R., Summerfield, T. C., Harvey, B., Agostini, S., & Hoffmann, L. J. (2019). Biofilm succession in an acidified ocean: Mechanistic insights from a volcanic CO2 seep study. Proceedings of the 12th New Zealand Ocean Acidification Workshop. (pp. 12). Retrieved from http://nzoac.nz

Meyers, M., McGraw, C., Décima, M., & Hoffmann, L. (2019). Design and employment of a new portable CO2 system for ocean acidification experiments. Proceedings of the 12th New Zealand Ocean Acidification Workshop. (pp. 50). Retrieved from http://nzoac.nz

Meyers, M., Décima, M., Law, C., Deppeler, S., Saint-Macary, A., Gall, M., … Wing, S., & Hoffmann, L. (2019). Grazing of calanoid copepod Temora turbinata on natural prey communities during the CARIM Mesocosm 4 experiment. Proceedings of the 12th New Zealand Ocean Acidification Workshop. (pp. 39). Retrieved from http://nzoac.nz

Allen, R., Rudminat, F., Law, C., Hoffmann, L., & Summerfield, T. (2018). Bacterioplankton resistance to acidification and warming in the oligotrophic ocean. Proceedings of the 11th New Zealand Ocean Acidification Workshop. (pp. 7). Retrieved from http://nzoac.nz

Espinel, N., Dupont, S., Uthicke, S., Byrne, M., Agüera, A., Hoffmann, L., & Lamare, M. (2018). The potential effects of ocean acidification on the settlement and metamorphosis of marine larvae: A review and with reference to CARIM experiments. Proceedings of the 11th New Zealand Ocean Acidification Workshop. (pp. 15). Retrieved from http://nzoac.nz

Meyers, M., Décima, M., Luan, Q., Hoffmann, L., & Wing, S. (2018). Copepod grazing and selectivity on natural prey communities during a high-temperature, low-pH mesocosm experiment. Proceedings of the 11th New Zealand Ocean Acidification Workshop. (pp. 19). Retrieved from http://nzoac.nz

Allen, R., Hoffmann, L., & Summerfield, T. (2017). The ecological and evolutionary importance of genetic diversity in phytoplankton responses to ocean acidification. Proceedings of the 10th New Zealand Ocean Acidification Workshop. (pp. 11). Retrieved from http://www.otago.ac.nz/oceanacidification/news/index.html

Law, C., Barr, N., Northcote, L., Gutierrez-Rodriguez, A., Decima, M., Marriner, A., … Fang, Z., Deans, F., Allen, R., Hoffmann, L., Baltar, F., & Gall, M. (2017). How will coastal plankton respond to increasing CO2? Preliminary results from the first two CAIRM mesocosm experiments. Proceedings of the 10th New Zealand Ocean Acidification Workshop. (pp. 20). Retrieved from http://www.otago.ac.nz/oceanacidification/news/index.html

Hoffmann, L., & Donahue, K. (2017). Phytoplankton community composition response to ocean acidification and increased light intensities. Proceedings of the 10th New Zealand Ocean Acidification Workshop. (pp. 17). Retrieved from http://www.otago.ac.nz/oceanacidification/news/index.html

Rudminat, F., Law, C., Hoffmann, L., & Summerfield, T. (2017). Bacterioplankton community response to elevated CO2 and/or temperature in the South Pacific. Proceedings of the 10th New Zealand Ocean Acidification Workshop. (pp. 26). Retrieved from http://www.otago.ac.nz/oceanacidification/news/index.html

Hoffmann, L. J., & Kearney, E. (2016). Effect of ocean acidification on diatom frustule stability. Proceedings of the 4th International Symposium on the Ocean in a High-CO2 World. Retrieved from http://www.highco2-iv.org/

Shatova, O., Wing, S., Hoffmann, L., Jack, L., & Gault-Ringold, M. (2015). Seabird guano enhances phytoplankton production in the Southern Ocean. Geophysical Research Abstracts, 17, EGU2015-166. [Abstract]

Law, C. S., Breitbarth, E., Hoffmann, L., McGraw, C., Langlois, R. R., LaRoche, J., … Safi, K. (2013). Are all nitrogen fixers ocean acidification "winners"? Proceedings of the 6th New Zealand Ocean Acidification Workshop. (pp. 33). Retrieved from http://www.otago.ac.nz/oceanacidification/news/

McGraw, C. M., Breitbarth, E., Hoffmann, L., & Hunter, K. A. (2012). Trace-metal clean automated culture system for ocean acidification experiments. Proceedings of the Ocean Sciences Meeting. (pp. 307-308). Retrieved from http://www.sgmeet.com/osm2012/

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