Vernet Lab

The Ecology of

Polar Phytoplankton

Dr. Maria Vernet
Integrative Oceanography Division
Room 2123, Sverdrup Hall
Phone: (858) 534-5322
Fax: (858) 822-0562
Email: mvernet@ucsd.edu

October 19, 2017 | Not Logged In (public login | local login)

§ Research Projects » Antarctic Fjords

Collaborative Research: Fjord Ecosystem Structure and Function on the West Antarctic Peninsula - Hotspots of Productivity and Biodiversity? (FjordEco) (1 April 2015 – Present) – Principal Investigator: Maria Vernet, University of California-San Diego Scripps Inst of Oceanography. Collaborators: Craig Smith (Lead PI), Mark Merrifield and Brian Powell, University of Hawaii, Manoa; Peter Winsor and Martin Truffer, University of Alaska, Fairbanks.
Funded by the National Science Foundation, Grant # PLR-1443705

Project link: https://www.instagram.com/fjordphyto/

OVERVIEW: Glacio-marine fjords along the Western Antarctic Peninsula (WAP) appear to be intense, potentially climate sensitive, hotspots of biological production and biodiversity, yet the structure and dynamics of these fjord ecosystems are very poorly understood. We propose an integrated field and modeling program to evaluate physical oceanographic processes, glacial inputs, plankton dynamics, and benthic community structure and function in Andvord Bay, a glacio-marine fjord along the sub-polar WAP. Andvord Bay is a potential productivity/biodiversity hotspot and is well suited for the study of fjord ecosystem drivers along the WAP; we expect the mechanisms elucidated in Andvord Bay to operate in Antarctic fjords generally. Our research will help to address three overarching questions of relevance to WAP fjord ecosystems: a) Is Andvord Bay a substantial hotspot of productivity and biodiversity? (b) If so, what physical, glaciological, biological and chemical processes interact to enhance this productivity and biodiversity? (c) How sensitive are these processes to changing glacial meltwater and sediment inputs?

We will conduct a 15-month field program to test mechanistic hypotheses concerning oceanographic and glaciological forcing, and phytoplankton and benthic community response. The field program will (1) utilize moorings (physical oceanographic, sediment traps, seafloor time-lapse camera), weather stations, and glacial and sea-ice time-lapse cameras to obtain an integrated view of fjord ecosystem processes over 15 months, and (2) conduct two process cruises using shipboard measurements, a towed Acrobat system, and AUV glider to intensively evaluate fjord ecosystem structure and function during spring/summer and fall seasons. We will then use a coupled physical/biological modeling approach (ROMS/NEMURO) to evaluate the drivers of biogeochemical cycles in the fjords and to explore their potential sensitivity to enhanced meltwater and sediment inputs. We expect our field and modeling studies to elucidate fundamental pelagic and benthic ecosystem structure and function in the WAP fjords, and to identify key physical-chemical-glaciological forcings in these rapidly warming ecosystems.

INTELLECTUAL MERIT: Fjords with tidewater glaciers (glacio-marine fjords) occur widely at temperate to polar latitudes, and extensively along the sub-polar WAP. Glacio-marine fjord ecosystems can be heavily modulated by glacial ice, meltwater and terrigenous sediments, causing ecosystem structure and function to differ from the open continental shelf and to be highly sensitive to climate warming. Arctic Fjord ecosystems have been extensively studied and are strongly influenced by meltwater processes, high turbidity, and burial disturbance, yielding "cold spots" of productivity and biodiversity. Climate warming and glacial retreat in the Arctic is predicted to reduce glacial disturbance of many Arctic fjords, enhancing fjord productivity and biodiversity. In contrast, fjord ecosystem structure and function remain very poorly studied along the WAP, and several lines of evidence suggest that WAP fjords are intense hotspots of pelagic and benthic productivity and biodiversity, providing critical habitat for keystone species including krill and their predators. The high productivity/biodiversity in WAP fjords could be facilitated by existing conditions of weak meltwater and terrigenous-sediment inputs, which appear likely to change with climate warming. We expect our studies to yield major new insights into the structure and dynamics of a WAP fjord ecosystem, highlighting contrasts with Arctic sub-polar fjords, and transforming our understanding of the ecological role fjords can play in the rapidly warming WAP coastal marine landscape.

BROADER IMPACTS: Our broader impacts will be in three areas. (1) Four graduate students and a postdoc will conduct research, and six undergraduate students will participate in Antarctic fieldwork and develop senior theses, within the project. Material from the project will be incorporated into undergraduate/ graduate courses at UH, SIO and UAF. (2) We will develop a new a graduate-level summer lecture/field course at Friday Harbor Labs, based in part on our field and modeling results, titled Fjord Ecosystems and Climate Change. (3) Public outreach will be mediated by: participation in our cruises by a National Geographic photographer with the goal of producing magazine articles, websites, radio broadcasts and other types of outreach on WAP fjord ecosystems and climate change; maintenance of project web sites and cruise blogs at UH; and presentations at both UH and SIO open houses.

International Collaboration with Argentina

Phytoplankton communities in Andvord Bay (Antarctica): Diversity, dynamics and sedimentation (Primeras investigaciones sobre la comunidad fitoplanctónica de Bahía Andvord (Antártida). Diversidad, dinámica y sedimentación). (1 March 2017- 28 February 2020) - Principal Investigator: Dr. Gaston Almandoz, Universidad de La Plata, Argentina.
Funded by Research Council in Science and Technology, Argentina (CONICET, Comision Nacional de Ciencia y Tecnologia)

SUMMARY: The main objective of this project is to characterize the phytoplankton community composition, structure and dynamics and its response to environmental factors related to meltwater in a western Antarctic Peninsula marine fjord sensitive to global change. In particular, this project aims to characterize the phytoplankton floristic composition with emphasis on diatoms and dinoflagellates. We will determine phytoplankton abundance and composition within Andvord Bay and in surrounding waters of the Gerlache Strait in relation to physico-chemical properties in the water column affected by meltwater. Finally, we aim to estimate the contribution of the different taxonomic groups to cell and carbon sedimentation throughout the year.