Abstract
In this thesis, I study the impacts of climate change on marineplankton and their ecosystem functions from past to future. To do
this, I developed a trait-based plankton ecosystem model to
incorporate the symbiosis and spine traits of foraminifera, a
calcifying zooplankton group with the most complete microfossil
record. This model was embedded in the cGENIE Earth system model and
used to study the plankton ecosystem in the Last Glacial Maximum
(LGM, 21 ka), pre-industrial age, the next century, and the
Cretaceous-Paleogene boundary (66 Ma).
The model results show that plankton have diverse and plastic
responses to climate change. Symbiotic and spinose foraminifera have
stronger adaptive capacities to warming than non-symbiotic groups
from the LGM to the next century. The LGM plankton community exhibited
different size structure and stoichiometric ratio to enhance carbon
export. However, ocean circulation which determines
nutrient supply, is important as well. The stratified LGM ocean
had lower global carbon export than the modern, and the
stratifying modern ocean will see declining foraminifera biomass
in the future.
In the K-Pg simulation, I explored the aftermath of the
extraterrestrial impact and the impacts on marine plankton. The
extreme "impact winter" killed all plankton except
picoplankton. However, despite great biodiversity loss, the marine
productivity and vertical carbon fluxes rapidly recovered in 3 years
because of the abundant nutrients brought by active ocean
mixing.
My study of various climate events in geological history highlights
the role of plankton ecology and nutrient availability in
determining their responses to climate change. Plankton traits
including body size and symbiosis can alleviate the risk of global
warming but are also limited by large-scale circulation patterns and
nutrient availability. This underscores the significance of
mitigating ongoing warming and protecting marine
biodiversity, as the recovery of lost biodiversity would take
millions of years.
| Date of Award | 1 Oct 2024 |
|---|---|
| Original language | English |
| Awarding Institution |
|
| Supervisor | Fanny M Monteiro (Supervisor) & Daniela N Schmidt (Supervisor) |