Over the past few years, marine life worldwide has suffered many mass mortality events, with a prominent recent UK example being the dead and distressed crabs that washed up around Teesside in Oct 2021. The exact causes of these mortality events are many and varied but there is an urgent need to develop tools that will allow us to distinguish between natural (e.g. harmful algal blooms) and anthropogenic (e.g. pollutant release by sediment displacement) causes.
To do this, environmental toxicology has traditionally relied on chemical analyses of waters, tissues and sediments to look for environmental toxins. These are powerful techniques but a drawback is that the effects of toxins may linger (for example, through bioaccumulation) long after the toxins themselves have dropped below any threshold of detection. Similarly, many mortality events result from the interaction of multiple smaller stressors, any one of which may look innocuous on its own. One way to complement chemical analyses is, therefore, to use increasingly cheap and rapid transcriptomic- and metabolomic- based approaches to look at the acute and chronic responses of indicator species. By looking directly at how indicator species are allocating their metabolic resources, we can deliver more subtle answers about the interrelationships that tie together marine species and human activity.
Objectives:
a. To describe the relationship between transcriptome and metabolome in at least two key brown seaweed indicator genera: the perennial wracks (Fucus spp.) and the annual kelps (Laminaria spp.). Work will focus on the Teesside coastline, which is prone to mortality events, but our CASE partnership with The Fishmongers’ Company will allow us quick and responsive access to other coastal regions around the UK.
b. To create digital models of macroalgal metabolism, which will incorporate their responses to xenobiotics (e.g. pollutants, heavy metals) to allow them to be used as baselines to help diagnose ongoing or past mortality events.
c. To develop and encourage the student as an independent researcher
Marine and coastal ecosystems are increasingly under economic pressure, so this studentship represents a clear opportunity for the UK to lead excellence in this area. More broadly, the proposal addresses two of NERC’s Priority Areas (‘Environmental Solutions‘ and ‘Resilient environment’). Results will be based around the mortality events that recur around Teesside but will inform the study of other mortality events worldwide.
Methodology
Marine mortality events of various sizes are relatively common in UK waters but are hard to predict and the earliest warnings of their onsets come from coastal end-users. For that reason, we have made this studentship a CASE partnership with The Fishmongers’ Company’s Fisheries Charitable Trust. Our CASE partner will allow us to monitor and track the onset of mortality events and arrange field access to affected areas. Meanwhile, the baseline collection of seaweed samples will be helped by our link with the North East Fishing Collective as end users, because their inshore fishing boats will allow us to harvest kelp samples along the north east coastline that would otherwise be inaccessible by shore sampling.
Our methodology will therefore involve:
1. Field sampling (CASE partner): In a series of field trips, we will collect keystone brown seaweed species (Fucus, Laminaria, Saccharina) during different seasons and from areas around the main UK fishing ports (Peterhead, Scrabster, Brixham, Newlyn, Shoreham, Grimsby). Importantly, we will also sample responsively and rapidly from areas in which mortality events are reported: this will be co-ordinated and arranged with and through our CASE partner, who monitor UK-wide mortalities.
2. Transcriptomic data collection (Supervisor 1): Work will begin using standard RNAseq technology to record the transcriptional signatures of seaweed indicator species, but a particular aim of our project will be to develop Oxford nanopore technology for field transcriptomic work. Lab stresses, including chronic low-level pollution, will complement field samples collected around mortality events.
3. Metabolomic data collection (Supervisor 2): The student will use a range of chemical analytical techniques (GC-MS, fractionation and NMR) to describe acute and chronic (eg cell walls) metabolite levels in seaweed indicator species.
4. Metabolic modelling (Supervisor 1): Bespoke metabolic models for field indicator species will be constructed using e.g. COPASI.
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