Dr Linn Hoffmann, Senior Lecturer

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 Hoffman is also director of the Ocean Acidification Research Theme

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?

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?

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

SEHACK-secchi plankton study.

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

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

• Ro Allen (PhD): Effect of ocean acidification and warming on natural Southern Ocean phytoplankton communities
• Nadjejda Espinel (PhD): Changes in larval settlement and metamorphosis in marine invertebrates in response to reduced seawater pH
• Morgan Meyers (PhD): How does ocean acidification affect copepod grazing in subAntarctic waters?

Previous students

• 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

• 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

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 Hoffman

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Selected publications

Faucher, G., L. Hoffmann, L. T. Bach, C. Bottini, E. Erba, U. Riebesell. 2017. Impact of trace metal concentration on coccolithophore growth and morphology: laboratory simulations of Cretaceous stress. Biogeosciences 14(14): 3603-3613.

Conway, T. M., L. J. Hoffmann, E. Breitbarth, R. F. Strzepek, E. W. Wolff. 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., S. R. Wing, M. Gault-Ringold, L. Wing and L. J. Hoffmann. 2016. Seabird guano enhances phytoplankton production in the Southern Ocean, Journal of Experimental Marine Biology and Ecology.483: 74-87.

Olgun, N., Duggen, S., Langmann, B., Hort, M., Waythomas, C. F., Hoffmann, L. J. and 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 . pp. 81-88. DOI 10.3354/meps10403.

Tatters, A. O., Roleda, M. Y., Schnetzer, A., Fu, F., Hurd, C. L., Boyd, P. W., Caron, D. A., Lie, A. A. Y., Hoffmann, L. J. and 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: Biological Sciences, 368 (1627). p. 20120437. DOI 10.1098/rstb.2012.0437.

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

Smetacek, V., Klaas, C., Strass, V. H., Assmy, P., Montresor, M., Cisewski, B., Savoye, N., Webb, A., d’Ovidio, F., Arrieta, J. M., Bathmann, U., Bellerby, R., Berg, G. M., Croot, P., Gonzalez, S., Henjes, J., Herndl, G. J., Hoffmann, L. J., Leach, H., Losch, M., Mills, M. M., Neill, C., Peeken, I., Röttgers, R., Sachs, O., Sauter, E., Schmidt, M. M., Schwarz, J., Terbrüggen, A. and Wolf-Gladrow, D. (2012) Deep carbon export from a Southern Ocean iron-fertilized diatom bloom Nature, 487 (7407). pp. 313-319. DOI 10.1038/nature11229.

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

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

Law, C. S., Breitbarth, E., Hoffmann, L. J., McGraw, C. M., Langlois, R., LaRoche, J., Marriner, A. and 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). pp. 3004-3014. DOI 10.1111/j.1365-2486.2012.02777.x.

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

Breitbarth, E., Achterberg, E. P., Ardelan, M. V., Baker, A. R., Bucciarelli, E., Chever, F., Croot, P., Duggen, S., Gledhill, M., Hassellöv, M., Hassler, C., Hoffmann, L. J., Hunter, K. A., Hutchins, D. A., Ingri, J., Jickells, T., Lohan, M. C., Nielsdóttir, M. C., Sarthou, G., Schoemann, V., Trapp, J. M., Turner, D. R. and Ye, Y. (2010) Iron biogeochemistry across marine systems - progress from the past decade Biogeosciences (BG), 7 (3). pp. 1075-1097. DOI 10.5194/bg-7-1075-2010.

Duggen, S., Olgun, N., Croot, P., Hoffmann, L. J., Dietze, H., Delmelle, P. and Teschner, C. (2010) The role of airborne volcanic ash for the surface ocean biogeochemical iron-cycle: a review Biogeosciences (BG), 7 (3). pp. 827-844. DOI 10.5194/bg-7-827-2010.

Breitbarth, E., Gelting, J., Walve, J., Hoffmann, L. J., Turner, D. R., Hassellöv, M. and Ingri, J. (2009) Dissolved iron (II) in the Baltic Sea surface water and implications for cyanobacterial bloom development Biogeosciences, 6 (11). pp. 2397-2420. DOI 10.5194/bg-6-2397-2009.

Hoffmann, L., Peeken, I. and Lochte, K. (2008) Iron, silicate, and light co-limitation of three Southern Ocean diatom species Polar Biology, 31 (9). pp. 1067-1080.

Hoffmann, L., Peeken, I. and Lochte, K. (2007) Effects of iron on the elemental stoichiometry during EIFEX and in the diatoms Fragilariopsis kerguelensis and Chaetoceros dichaeta Biogeosciences, 4 . pp. 569-579. DOI 10.5194/bg-4-569-2007.

Duggen, S., Croot, P., Schacht, U. and Hoffmann, L. (2007) Subduction zone volcanic ash can fertilize the surface ocean and stimulate phytoplankton growth: Evidence from biogeochemical experiments and satellite data Geophysical Research Letters, 34 (1). DOI 10.1029/2006GL027522.

Hoffmann, L., Peeken, I., Lochte, K., Assmy, P. and Veldhuis, M. (2006) Different reactions of Southern Ocean phytoplankton size classes to iron fertilization. Limnology and Oceanography, 51 (3). pp. 1217-1229. DOI 10.4319/lo.2006.51.3.1217.

Engel, A., Zondervan, I., Aerts, K., Beaufort, L., Benthien, A., Chou, L., Delille, B., Gattuso, J. P., Harley, J., Heemann, C., Hoffmann, L., Jacquet, S., Nejstgaard, J., Pizay, M. D., Rochelle-Newall, E., Schneider, U., Terbrüggen, A. and Riebesell, U. (2005) Testing the direct effect of CO2 concentration on a bloom of the coccolithophorid Emiliania huxleyi in mesocosm experiments Limnology and Oceanography, 50 . pp. 493-504. DOI 10.4319/lo.2005.50.2.0493.