Understanding marine ecosystems

 

Trait-based approaches to marine ecology and biogeochemistry

 
 
Emergent community structure in a global model with no distinction between autotrophs and heterotrophs.

Emergent community structure in a global model with no distinction between autotrophs and heterotrophs.

TROPHIC DIVERSITY IN MARINE ECOSYSTEMS

In terrestrial ecosystems, it is quite straightforward to tell the difference between a plant and an animal. This difference seems so clear as to be obvious, but in recent decades, marine scientists have begun to reveal that in the ocean such distinctions are not always appropriate. Among the microscopic but incredibly numerous plankton at the base of marine food-webs, the majority of species defy such strict classifications. These flexible organisms, known as mixotrophs, not only use energy from the sun to take up nutrients and grow, but at the same time they can also kill and eat other plankton. At present we know that mixotrophy is probably the default lifestyle for most single -celled plankton, and we know that they often dominate marine communities. As yet however, we do not have a concrete understanding of how environmental factors may shape the balance between different sources of nutrition in these communities, and how such changes might affect the ecological role of mixotrophs and their potential effects on the global cycling of climatically important elements, including carbon.


Unfortunately, no one can be told what the matrix is. You have to see it for yourself.

Unfortunately, no one can be told what the matrix is. You have to see it for yourself.

A MATRIX Metacommunity model

This project aims to identify the key drivers of plankton community assembly, using a new eco-evolutionary model that is unique in combining oceanic dispersal, competition and the adaptive generation of new phenotypes. If we define the ‘metacommunity’ as the globally interconnected set of local plankton communities, this can be represented in a two-dimensional matrix relating to phenotype and spatial location. This allows the model to be very rapidly evaluated in Matlab.


Suppression of picoplankton biomass by harsh conditions in the Arctic. Warming will likely drive a poleward expansion of these tiny cells.

Suppression of picoplankton biomass by harsh conditions in the Arctic. Warming will likely drive a poleward expansion of these tiny cells.

PELAGIC MICROBIAL ECOSYSTEMS AND ORGANIC CYCLING IN THE CHANGING ARCTIC

Through a comprehensive multi-location and multi-seasonal cruise programme, we will address major knowledge gaps in the links between Arctic microbial ecosystem structure and function. This will allow us to quantify impacts of Arctic seasonality on the structure and functioning of microbial ecosystems in relation to OM cycling, allowing us to track major changes in autotrophic and heterotrophic production. Combining observation and modelling, we will analyse the underlying mechanisms that impact microbial dynamics and subsequent OM cycling on seasonal scales. Data-model synthesis will enable us to resolve and constrain processes that remain either unresolved or are assumed constant in contemporary model, allowing improved future projections of the Arctic in global climate models.