REMineralisation of organic carbon by marine bActerIoplanktoN (REMAIN) - reducing the known unknown

Lead Research Organisation: University of East Anglia
Department Name: Environmental Sciences

Abstract

The balance between the uptake of CO2 during phytoplankton photosynthesis and the production of CO2 during bacterial, zooplankton and phytoplankton respiration influences how much carbon can be stored in the ocean and hence how much remains in the atmosphere to affect climate. Yet, despite its crucial role, our knowledge of the respiration of component plankton groups such as bacteria, is severely limited because we do not have a method which can differentiate the respiration of one group from that of the rest of the community. We resort to measuring the respiration of a subsample which contains only cells which have passed through a filter. Just as we take in oxygen when we breathe, plankton take in oxygen when they respire and so the standard way to measure respiration is as the decrease in oxygen in the water. Unfortunately the low rates of respiration mean that measurements of oxygen have to be made over many hours and the disruption of the plankton foodweb by the filtration can lead to major errors.

The recent development of a much more sensitive method (reduction of the tetrazolium salt INT) which can produce results in minutes and does not involve disruption of the plankton foodweb, is a major step forward and has revealed previously unknown variability. Unexpectedly, the results also suggest that the proportion of respiration attributable to the bacterial size class is consistently low, even in communities where bacteria are the most numerous plankton. This has profound implications for our understanding of the amount of CO2 produced by different plankton groups, and poses two new questions - which size class contributes most to plankton respiration if not the bacterial size class, and what influences the variability in respiration if not the type of plankton present.

Marine scientists including ourselves have excitedly started to use the new INT technique, but it has not been thoroughly tested for all plankton communities. In fact, recent data suggest that the method can sometimes underestimate respiration because not all plankton can take up INT and sometimes overestimate respiration because compounds not associated with respiration can affect the INT. Thus while this method could potentially enable a critical improvement in our understanding and thus prediction of CO2 cycling in the ocean, these new intriguing results cannot be confirmed until a comprehensive test of the method has been completed. This is what we will do.

We have brought together an international team of experts to undertake an innovative combination of laboratory and field work, taking advantage of a unique sampling opportunity - the Atlantic Meridional Transect - which allows the study of five different plankton ecosystems in the Atlantic Ocean. We will first develop a novel fluorescent method of tracking the uptake of INT into a representative range of plankton to quantify how different cells take it up. Then we will measure the INT reduction of both seawater samples and laboratory cultures to which have been added chemical inhibitors of plankton respiration and increasing concentrations of naturally occurring organic compounds, to determine to what extent these organic compounds lead to an overestimate of respiration. These results will be used to improve and validate the INT method. Finally we will participate in the research cruise to determine plankton respiration in size classes of the plankton community alongside identification of the plankton in these size classes and the concentration of organic compounds.

The main deliverable of the project - apportionment of plankton respiration to plankton size classes - is of benefit to marine scientists who aim to predict how a changing climate will affect plankton production of CO2, policy makers interested in how much carbon can be stored in the ocean, and potentially commercial companies interested in the development of the fluorescent probe for medical or water quality applications.

Planned Impact

Here we describe the non-academic communities who will benefit from the results of REMAIN and how they will benefit. In the Pathways to Impact section we detail the activities we will undertake in REMAIN in order to achieve this impact.

Policy makers

The lack of a validated dataset of bacterioplankton respiration restricts our ability to predict how a changing climate (increasing temperature, changing inorganic and organic nutrient concentrations) will affect the capacity of the ocean to mediate climate. This proposal aims to deliver lasting impact by providing increased understanding of the factors influencing the magnitude and variability of respiration attributable to the cells identified within size classes of the plankton community and thus carbon flow through the microbial foodweb now and in a future climate.

Our research will therefore benefit policy forming bodies such as National and International Governmental Environment and Climate Change Departments (e.g. UK Governmental bodies including DBEI and DEFRA and their international equivalents) and non-governmental organisations (NGOs), such as SCOR (Scientific Committee on Ocean Research), WCRP (World Climate Research Programme), IOC/UNESCO (Intergovernmental Oceanographic Commission / United Nations Educational, Scientific and Cultural Organization) and Future Earth with a particular interest in global carbon cycling and prediction of environmental change.

Governmental departments and regulatory agencies such as Cefas (Centre for Environment, Fisheries and Aquaculture Science), which assess the status of coastal marine ecosystems in the context of the Marine Strategy Framework Directive (MSFD) will benefit from REMAIN, as one of the key needs for implementing MSFD is better understanding of the functioning of marine ecosystems.

Global Carbon Budget modellers including those at the Tyndall Centre for Climate Change Research (http://www.tyndall.ac.uk/) who contribute to the IPCC assessments, will benefit from an improved understanding of the contribution of bacterioplankton to the production of CO2, and how this may be different in different ocean regions irrespective of the phytoplankton biomass or productivity.

Commercial companies

Commercial companies, particularly those involved in the use of bacterial enzymes, water quality and the functioning of antibiotics may benefit from REMAIN. Our development and testing of a new fluorescent probe to visualise intra-cellular aerobic respiratory activity may lead to a new method to differentiate active and dormant bacteria relevant to a range of physiological, medical and water quality applications.

General Public

REMAIN will be of interest to the general public, especially those who use the marine environment for sport and leisure, but also those who visit aquaria and museums or have a particular interest in the marine ecosystem or the microscopic structure of cells. Marine ecology is also of interest to school children, educators and the science media as a visual tangible example to use in learning and teaching the fundamentals of how the natural world works. The public will benefit from our research in terms of increased interest, enthusiasm and understanding of the marine environment, particularly of the importance of the smallest organisms in the sea.

Researcher development

REMAIN will be of benefit to the Researcher Co-I and PDRAs employed on the project, and the under- and postgraduate students whom the PI and Co-Is teach. The Researcher Co-I and PDRAs will benefit from extending their international scientific network and skillset, and broadening their understanding and training in flexibility and problem solving during fieldwork, thereby developing both their scientific and transferable skills. Under- and postgraduate students will benefit in terms of connecting with current research on marine plankton activity.

Publications

10 25 50
 
Description Fluorometric Tetrazolium Salt/Formazan Assays for Histochemistry and Biomedical Applications
Amount £17,521 (GBP)
Funding ID NE/S015493/1 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 01/2019 
End 06/2019
 
Description New Dual Colour fluorometric assays for drug discovery and plankton respiration E21-9694363929
Amount £10,000 (GBP)
Organisation Royal Society of Chemistry 
Sector Charity/Non Profit
Country United Kingdom
Start 02/2022 
End 01/2023
 
Description UEA / Faculty of Science Open Competition studentship
Amount £80,000 (GBP)
Organisation University of East Anglia 
Sector Academic/University
Country United Kingdom
Start 08/2021 
End 08/2024
 
Title In situ dissolved oxygen concentration during AMT28 
Description Concentrations of in situ dissolved oxygen measured during the AMT28 research cruise in 2018 deposited with BODC 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
Impact The data was used by SOCCUM US Biogeochemical Argo programme to calibrate the oxygen censors on their Argo floats 
 
Description Training in culture techniques for SAR 11 
Organisation University of East Anglia
Country United Kingdom 
Sector Academic/University 
PI Contribution One member of the research team trained a colleague in culture techniques for the fastidious but ubiquitous marine bacterium SAR 11. The research team member learned these techniques within REMAIN in collaboration with project partner Prof Giovannoni. The colleague is funded on a Leverhulme Grant RPG-2020-413. DMSOP, a missing link in the global sulfur cycle.
Collaborator Contribution The colleague is writing a publication based on the experiments using SAR 11, and the research team member will be a co-author of this publication.
Impact The collaboration is expected to lead to a publication which will be reported via Research Fish in due course.
Start Year 2022
 
Description Chair of debate at Norwich Science Festival on Climate change 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Chaired a panel debate organised by postgraduate environmental science students at the Norwich Science Festival. Attended by an audience of about 40 and streamed to an audience of about 30. Four students gave a short presentation on their topic of expertise and then the audience could ask questions of myself and the panel. Lots of engagement, school chlidren asking about sea ice melt and others about sewage pollution, climate change, oceanography and carbon cycling. A poll of views before and afterwards showed some change in perspectives.
Year(s) Of Engagement Activity 2021
 
Description Chair session at international conference + oral presentation on Respiration and dissolved oxygen cycling 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact Chaired session at Ocean Sciences Meeting 2022 - virtual - on marine oxygen cycling. Gave oral presentation overview of the REMAIN project. Questions and discussion. Future collaborations / comparisons of data discussed.
Year(s) Of Engagement Activity 2022
URL https://www.aslo.org/osm2022/
 
Description Global Science Opera - One Ocean 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Schools
Results and Impact Contributed to a music / drama activity along with school children from music and drama departments at schools all over the world on the theme of ONE OCEAN organised by the Global Science Opera in Norway
2 minute piece to camera in the middle of a 1 hour+ performance
Year(s) Of Engagement Activity 2018
URL http://globalscienceopera.com/productions/one-ocean-2018/
 
Description Introduction to Oceanography course 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Members of the general public (mostly divers, sailors and kayakers) including A level students and postgraduate students attended a 2 day Introduction to Oceanography course in March 2019 including 12 hours of lectures and 3 hours of practical demonstrations.
Year(s) Of Engagement Activity 2019
 
Description Norwich Science Festival exhibit 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Exhibit at Norwich Science Festival. A few thousand attendees per day. Estimate up to 100 interacted with exhibit. making plankton from Playdoh, chromatography with phytoplankton pigments, microscopy identify the phytoplankton. Public lecture over lunch break. Four staff members and 2 volunteer helpers manned the exhibit for 8 hours.
Year(s) Of Engagement Activity 2019
URL https://norwichsciencefestival.co.uk/about/norwich-science-festival-2019/
 
Description Presentation at virtual conference - ASLO June 2021 - Size fractionated respiration along the Atlantic Meridional Transect 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact Oral presentation at academic conference - ASLO (Association of the Sciences for Limnology and Oceanography) - highlighting and discussing the outputs of the grant to acadamic colleagues and students. Discussions about collaboration and requests for internships.
Year(s) Of Engagement Activity 2021
URL https://www.aslo.org/2021-virtual-meeting/
 
Description Public lecture at UEA 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact One hour public lecture at UEA on marine microbes. Advertised as part of Norwich Science Festival. https://norwichsciencefestival.co.uk/events/marine-microbes/
Streamed live and posted on YouTube.
Year(s) Of Engagement Activity 2019
URL https://www.youtube.com/watch?v=YzPZNIb8_a8
 
Description Sype a scientist - North Ridge Middle School Texas USA - presentation and discussion with class of school children 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Schools
Results and Impact Presentation on plankton photosynthesis and respiration via Zoom to a class of school children at North Ridge Middle School in Texas, USA followed by questions from the school children. Lots of engagement. Teacher and IT assistant very interested and complimentary afterwards. Schoolchildren sent thankyou cards. Teacher reported enthusiasm for further biology lessons. School tweeted photos and thanks.
Year(s) Of Engagement Activity 2021