Overview

Eutrophication and climate change are two most pressing environmental issues affecting 30-40% of freshwater lakes and reservoirs worldwide 1, 2, and reducing provision of water resource 3, biodiversity 4 and other services such as tourism and recreation 5, 6. Deterioration of inland waters typically arises from a combination of excess nutrient input and a breakdown in grazers’ trophic control, with profound implications for ecosystem structure and function 7. Lakes’ historical records show that changes in nutrient inputs can induce transitions between eutrophic and oligotrophic states and that regulation of nutrient loads can lead to a return to clear water conditions 8, 9. While a great deal of work has focused on these environmental transitions in the context of regime shifts 10, 11, by coupling the transitions with the evolutionary dynamics of keystone grazers12, drivers of community dynamics, we can gain robust insights into whether the grazer might persist and evolve through environmental shifts and contribute to the persistence, rather than breakdown, of aquatic ecosystem services under climate change.

The keystone grazers Daphnia spp offer the unique opportunity to ‘resurrect’ historical populations from lake sediment13, providing us with the ability to reconstruct the evolution of a key player in the grazing community through environmental transitions and to reveal the relative importance of plasticity and evolution in persistent community structure and ecosystem service.

This project has three objectives:

Objective 1: to reconstruct the evolutionary response of the keystone grazer Daphnia to past shifts from oligotrophic to eutrophic conditions and to document its persistence under realistic global change scenarios.

Objective 2: to uncover the molecular and metabolic processes underpinning evolutionary responses to eutrophication and climate change

Objective 3: to link fitness responses to the genetic and metabolic processes that ensure species persistence to global change.

Capitalizing on the well-defined role of Daphnia spp. in sustaining freshwater ecosystems 14, 15 and its unique life cycle that enables us to perform common garden experiments on ancestral (extinct) and modern populations, we will gain unprecedented insights into natural patterns of evolution and into how history of local adaptation can orchestrate a response to future climate change.

(A) Adult Daphnia (waterflea) and (B) dormant embryos decapsulated from the ephippium (white arrow), a kitin case that protects dpormant embryos from the environment.

Methodology

Objective 1: Using ‘resurrection ecology’ we will resurrect specimens of the keystone aquatic grazer Daphnia magna from lakes with known history of eutrophication and temperature changes. Extinct and modern populations will be used in common garden experiments to document fitness changes that occurred in response to past and that will occur under future environmental shifts.

Objective 2: Using multiomics approaches we will characterize the genome, transcriptome and metabolome of resurrected populations to disentangle the interplay between phenotypic plasticity and genetic adaptation in the response to global change.

Objective 3. Using advanced computational tools and biostatistic approaches we will perform a cutting-edge integrative analysis of multiomics and fitness data to uncover the genetic and metabolic elements driving adaptation to global change and ensuring species persistence.

Training and Skills

CENTA students complete 45 days training throughout their PhD including a 10 day placement. In the first year, students will be trained as a single cohort on environmental science, research methods and core skills. Throughout the PhD, training will progress from core skills sets to master classes specific to the student's projects and themes.

The supervisor team, collectively, has a long track record of graduate and postgraduate supervision. The DR will receive multisciplinary training by this supervisor team spanning from evolutionary biology, multiomics technologies, advanced computational and biostatistics skills. The DR will have access to the NERC Biomolecular Analysis Facility for Metabolomics and the Joint Centre for Environmental Omics, providing him/her with training in the most up to date ‘omics’ technologies. Moreover he/she will have access to one of the largest Daphnia facilities in England managed by a specialized technician who provides hands-on training for undergraduate and graduate students.

 

Timeline

Year 1: Resurrect Daphnia magna specimens from lake sediment (material available); establish isoclonal cultures; perform common garden experiments exposing resurrected lines to environmental conditions that mimic historical environmental shifts to uncover evolutionary mechanisms driving adaptation; perform common garden experiments mimicking realistic future global change scenarios to assess species persistence to future global change. Collect tissue for multiomics. Present preliminary data in a poster at the student conference in Birmingham. Complete data analysis of experimental work and prepare first thesis chapter for publication in year 2.

Year 2: Obtain genomic, transcriptomic and metabolomic data. Perform preliminary analysis for multiomics data to be deposited in public databases. Start analysing the multiomics data. Attend small workshop or conference presenting a talk.

Year 3: Perform integrative analysis of multiomics and fitness data to be published in one large or two smaller chapters in year 4. This integrative analysis will require advanced computational and biostatistic skills. Hence, it will be directly supervised by Prof JB and Dr SH. Present thesis work in an international conference.

Partners and collaboration (including CASE)

This project is a unique multidisciplinary partnership among several Schools at the University of Birmingham and integrating expertise in evolutionary biology and genomics (LO), functional genomics (JKC), metabolomics (MV), computation biology (JB) and computer science (SH). The project builds on an established partnership of the supervision team who has been recently awarded a NERC highlights grant to discover the molecular targets of natural selection and their contributions to the process of adaptation. Thanks to this partnership the student will have access to some of the most advanced multiomics facilities.

Further Details

For questions about the project contact:

Dr Luisa Orsini

School of Biosciences

University of Birmingham