I am a biological oceanographer with a focus on marine phytoplankton eco-physiology. My work mainly focusses on the response of phytoplankton communities to multiple environmental and climate change related stressors such as light, macronutrient concentration, temperature, ocean acidification, ocean warming, trace metal bioavailability, and microplastics and the implications for higher trophic levels of the food chain. In my research, I work collaboratively with scientists from multiple disciplines such as chemistry, palaeoceanography, geology, geochemistry, biochemistry, and ecology.
Associate Professor 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:
Impacts of the Hunga Tonga - Hunga Ha'apai eruption on the marine ecosystem
What is the impact of marine heatwaves on the abundance of the parasitic dinoflagellate Syndiniales?
How is phytoplankton species distribution in the Southern Ocean affected by climate change?
SEHACK-secchi plankton study.
How is coccolithophore morphology affected by trace metal availability?
Image credit: G Faucher.
Potential MSc or PhD research projects
Effect of climate change on energy transfer in the marine food chain
Effect of climate change on macroalgae reproduction
Effect of marine heatwaves on phytoplankton successional cycles
Effect of marine heatwaves on phytoplankton community structures
Volcanic eruptions and their impact 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.
Postgraduate students
Zoe Battershill (PhD): Seaweed as food for human consumption
Alex Charlton (PhD): Edible seaweed as future foods: the impact of season, environment and lifecycle on raw seaweeds
Sajini Dissanayake (PhD): The effect of ocean warming and ocean acidification on mixotrophic plankton and Syndiniales
Jordan Sparrow (MSc): Phytoplankton variability in the Otago Harbour and adjacent shelf
Yuhan Zhou (MSc): Marine viruses in New Zealand waters
Previous students
Ro Allen (PhD): Effect of ocean acidification and warming on natural Southern Ocean phytoplankton communities
Kelsey Donahue
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?
Chittipat Nitithamyong
Madeleine Post (MSc)
Francie Rudminat (PhD): Dinitrogen fixation in the South Pacific – Effect of ocean acidification on marine diazotrophs
Amirreza Zarekarizi (PhD): Effect of cultivation condition on the production of fucoxanthin by microalgae
Olgun, N., Tari, U., Balci, N., Altunkaynak, S., Gürarslan, I., Yakan, S. D., … Hoffmann, L. (2023). Lithological controls on lake water biogeochemistry in maritime Antarctica. Science of the Total Environment. Advance online publication. doi: 10.1016/j.scitotenv.2023.168562
Journal - Research Article
Aflenzer, H., Hoffmann, L., Holmes, T., Wuttig, K., Genovese, C., & Bowie, A. R. (2023). Effect of dissolved iron (II) and temperature on growth of the Southern Ocean phytoplankton species Fragilariopsis cylindrus and Phaeocystis antarctica. Polar Biology, 46, 1163-1173. doi: 10.1007/s00300-023-03191-z
Journal - Research Article
Zarekarizi, A., Hoffmann, L., & Burritt, D. J. (2023). The potential of manipulating light in the commercial production of carotenoids from algae. Algal Research, 71, 103047. doi: 10.1016/j.algal.2023.103047
Journal - Research Article
Meyers, M., Décima, M., Law, C. S., Gall, M., Barr, N., Miller, M. R., … Sabadel, A., Wing, S., & Hoffmann, L. (2022). No evidence of altered relationship between diet and consumer fatty acid composition in a natural plankton community under combined climate drivers. Journal of Experimental Marine Biology & Ecology, 551, 151734. doi: 10.1016/j.jembe.2022.151734
Journal - Research Article
Zitoun, R., Achterberg, E. P., Browning, T. J., Hoffmann, L. J., Krisch, S., Sander, S. G., & Koschinsky, A. (2021). The complex provenance of Cu-binding ligands in the South-East Atlantic. Marine Chemistry, 237, 104047. doi: 10.1016/j.marchem.2021.104047
Journal - Research Article
Allen, R. J., Summerfield, T. C., Harvey, B. P., Agostini, S., Rastrick, S. P. S., Hall-Spencer, J. M., & Hoffmann, L. J. (2021). Species turnover underpins the effect of elevated CO2 on biofilm communities through early succession. Climate Change Ecology, 2, 100017. doi: 10.1016/j.ecochg.2021.100017
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, 167, 105291. doi: 10.1016/j.marenvres.2021.105291
Journal - Research Article
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
Journal - Research Article
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
Conference Contribution - Published proceedings: Abstract
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
Conference Contribution - Published proceedings: Abstract
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, 29, 4680-4691. doi: 10.1111/mec.15651
Journal - Research Article
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
Journal - Research Article
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
Journal - Research Article
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
Journal - Research Article
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
Journal - Research Article
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
Journal - Research Article
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
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 Meeting (OSM). CT41A-05. Retrieved from https://agu.confex.com/agu/osm20/meetingapp.cgi
Conference Contribution - Published proceedings: Abstract
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 Meeting (OSM). ME24E-0140. Retrieved from https://agu.confex.com/agu/osm20/meetingapp.cgi
Conference Contribution - Published proceedings: Abstract
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
Journal - Research Article
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
Journal - Research Article
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
Conference Contribution - Published proceedings: Abstract
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
Conference Contribution - Published proceedings: Abstract
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
Conference Contribution - Published proceedings: Abstract
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
Journal - Research Article
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
Conference Contribution - Published proceedings: Abstract
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
Conference Contribution - Published proceedings: Abstract
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
Conference Contribution - Published proceedings: Abstract
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
Journal - Research Article
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
Journal - Research Article
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
Conference Contribution - Published proceedings: Abstract
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
Conference Contribution - Published proceedings: Abstract
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
Conference Contribution - Published proceedings: Abstract
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
Conference Contribution - Published proceedings: Abstract
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
Journal - Research Article
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
Journal - Research Article
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/
Conference Contribution - Published proceedings: Abstract
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]
Conference Contribution - Published proceedings: Abstract
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
Journal - Research Article
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
Journal - Research Article
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
Journal - Research Article
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/
Conference Contribution - Published proceedings: Abstract
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
Journal - Research Article
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
Journal - Research Article
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
Journal - Research Article
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
Journal - Research Article
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/
Conference Contribution - Published proceedings: Abstract
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
Journal - Research Article
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.
Journal - Research Article
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.
Journal - Research Article
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.
Journal - Research Article
