Seaweed communities – Responses to invasion, climate change and nutrients

Speakers: Gaby Keeler-May, Isla Twigg, Ben Williams, and Nam Chand. This month we have a series of short talks from four Marine Science PhD students.

Gaby Keeler-May is assessing the impacts of the invasive kelp, Undaria pinnatifida, in the subtidal rocky reefs of southern New Zealand. Her focuses are to compare invasive and native seaweed contributions to the total biomass of kelp forest ecosystems, to evaluate the distribution and expansion of Undaria at sites of past and recent introductions, and to determine the impact of Undaria on native kelp abundance and its ability to resettle after large-scale removal.

Isla Twigg’s research revolves around the microbial communities of kelp forests. She is interested in how the productivity of different microbial communities changes with environmental conditions, and between species of macroalgae. This involves tracking seasonal patterns in environmental conditions and bacterial productivity, as well as experiments exposing these microbial communities to different types of stress. Nam Chand will discuss her research on the community habitat and ecophysiology of soft sediment red macroalgal communities in Otago Harbour, with a focus on the red endemic macroalgae Adamsiella chauvinii. Specifically the research investigates the algal habitat community and epifauna composition within A. chauvinii meadows. Moreover, it will also assess the nitrogen uptake by A. chauvinii and other dominant algae within its meadows.

Ben Williams’ will talk about the trends in kelp forest decline in New Zealand driven by climate change and anthropogenic stressors. He will also discuss the future for kelp forest reseeding and how this can be used to rebuild degraded fisheries.