Helen S. Findlay

Plymouth Marine Laboratory

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Stephen Widdicombe

Plymouth Marine Laboratory

Jamie D. Shutler

University of Exeter

Peter E. Land

Plymouth Marine Laboratory

Vassilis Kitidis

Plymouth Marine Laboratory

Richard Sims

University of Exeter

John I. Spicer

University of Plymouth

Hannah Green

Plymouth Marine Laboratory

Jean-François Piollé

Ifremer

Piero Calosi

Université du Québec à Rimouski

J. Murray Roberts

University of Edinburgh

Cooperative Institutions

Plymouth Marine Laboratory

University of Colorado Boulder

Centre National de la Recherche Scientifique

University of Plymouth

University of California, San Diego

National Oceanography Centre

Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung

John Wiley & Sons (United States)

University of Chicago

University of Exeter

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The increasing importance of satellite observations to assess the ocean carbon sink and ocean acidification

Earth-Science Reviews (2024)

Jamie D. Shutler Nicolas Gruber Helen S. Findlay Peter E. Land Luke Gregor

The strong control that the emissions of carbon dioxide (CO2) have over Earth's climate identifies the need for accurate quantification of the emitted CO2 and its redistribution within the Earth system. The ocean annually absorbs more than a quarter of all CO2 emissions and this absorption is fundamentally altering the ocean chemistry. The ocean thus provides a fundamental component and powerful constraint within global carbon assessments used to guide policy action for reducing emissions. These carbon assessments rely heavily on satellite observations, but their inclusion is often invisible or opaque to policy. One reason is that satellite observations are rarely used exclusively, but often in conjunction with other types of observations, thereby complementing and expanding their usability yet losing their visibility. This exploitation of satellite observations led by the satellite and ocean carbon scientific communities is based on exciting developments in satellite science that have broadened the suite of environmental data that can now reliably be observed from space. However, the full potential of satellite observations to expand the scientific knowledge on critical processes such as the atmosphere-ocean exchange of CO2 and ocean acidification, including its impact on ocean health, remains largely unexplored. There is clear potential to begin using these observation-based approaches for directly guiding ocean management and conservation decisions, in particular in regions where in situ data collection is more difficult, and interest in them is growing within the environmental policy communities. We review these developments, identify new opportunities and scientific priorities, and identify that the formation of an international advisory group could accelerate policy relevant advancements within both the ocean carbon and satellite communities. Some barriers to understanding exist but these should not stop the exploitation and the full visibility of satellite observations to policy makers and users, so these observations can fulfil their full potential and recognition for supporting society.

Ocean Acidification

Ocean observations

Earth system science

10.1016/j.earscirev.2024.104682

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Assessing the living and dead proportions of cold-water coral colonies: implications for deep-water Marine Protected Area monitoring in a changing ocean

PeerJ (2017)

Johanne Vad Covadonga Orejas Juan Moreno-Navas Helen S. Findlay J. Murray Roberts

Coral growth patterns result from an interplay of coral biology and environmental conditions. In this study colony size and proportion of live and dead skeletons in the cold-water coral (CWC) Lophelia pertusa (Linnaeus, 1758) were measured using video footage from Remotely Operated Vehicle (ROV) transects conducted at the inshore Mingulay Reef Complex (MRC) and at the offshore PISCES site (Rockall Bank) in the NE Atlantic. The main goal of this paper was to explore the development of a simple method to quantify coral growth and its potential application as an assessment tool of the health of these remote habitats. Eighteen colonies were selected and whole colony and dead/living layer size were measured. Live to dead layer ratios for each colony were then determined and analysed. The age of each colony was estimated using previously published data. Our paper shows that: (1) two distinct morphotypes can be described: at the MRC, colonies displayed a 'cauliflower-shaped' morphotype whereas at the PISCES site, colonies presented a more flattened 'bush-shaped' morphotype; (2) living layer size was positively correlated with whole colony size; (3) live to dead layer ratio was negatively correlated to whole colony size; (4) live to dead layer ratio never exceeded 0.27. These results suggest that as a colony develops and its growth rate slows down, the proportion of living polyps in the colony decreases. Furthermore, at least 73% of L. pertusa colonies are composed of exposed dead coral skeleton, vulnerable to ocean acidification and the associated shallowing of the aragonite saturation horizon, with significant implications for future deep-sea reef framework integrity. The clear visual contrast between white/pale living and grey/dark dead portions of the colonies also gives a new way by which they can be visually monitored over time. The increased use of marine autonomous survey vehicles offers an important new platform from which such a surveying technique could be applied to monitor deep-water marine protected areas in the future.

10.7717/peerj.3705

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Citations (33)

Arctic in Rapid Transition: integrating spatial and temporal scales in the changing Arctic system: toward future research priorities

Nathalie Morata Sanna Majaneva Helen S. Findlay Michael Fritz M. Kedra

Nathalie Morata (LEMAR/CNRS, University of Western Brittany, France) Sanna Majaneva (University of Helsinki, Finland) Helen Findlay (Plymouth Marine Laboratory, United Kingdom) Michael Fritz (Alfred-Wegner-Institute for Polar and Marine Research, Department of Periglacial Research, Germany) Monika Kedra (Institute of Oceanology, Polish Academy of Sciences, Poland) Anna Nikolopoulos (AquaBiota Water Research, Sweden) Matt ORegan (Department of Geological Sciences, Stockholm University, Sweden) Alexey Pavlov (Norwegian Polar Institute, Fram Centre, , Norway) Ilka Peeken (Alfred-Wegner-Institute for Polar and Marine Research, Germany) Makoto Sampei (Graduate School of Biosphere Science, Hiroshima University, Japan) Kristin Werner (Byrd Polar Research Center, United States) Carolyn Wegner (GEOMAR, Germany)

Norwegian

Marine research

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Environmental research

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Increasing Costs Due to Ocean Acidification Drives Phytoplankton to Be More Heavily Calcified: Optimal Growth Strategy of Coccolithophores

PLoS ONE (2010)

Takahiro Irie Kazuhiro Bessho Helen S. Findlay Piero Calosi

Ocean acidification is potentially one of the greatest threats to marine ecosystems and global carbon cycling. Amongst calcifying organisms, coccolithophores have received special attention because their calcite precipitation plays a significant role in alkalinity flux to the deep ocean (i.e., inorganic carbon pump). Currently, empirical effort is devoted to evaluating the plastic responses to acidification, but evolutionary considerations are missing from this approach. We thus constructed an optimality model to evaluate the evolutionary response of coccolithophorid life history, assuming that their exoskeleton (coccolith) serves to reduce the instantaneous mortality rates. Our model predicted that natural selection favors constructing more heavily calcified exoskeleton in response to increased acidification-driven costs. This counter-intuitive response occurs because the fitness benefit of choosing a better-defended, slower growth strategy in more acidic conditions, outweighs that of accelerating the cell cycle, as this occurs by producing less calcified exoskeleton. Contrary to the widely held belief, the evolutionarily optimized population can precipitate larger amounts of CaCO3 during the bloom in more acidified seawater, depending on parameter values. These findings suggest that ocean acidification may enhance the calcification rates of marine organisms as an adaptive response, possibly accompanied by higher carbon fixation ability. Our theory also provides a compelling explanation for the multispecific fossil time-series record from ∼200 years ago to present, in which mean coccolith size has increased along with rising atmospheric CO2 concentration.

Ocean Acidification

Iron fertilization

10.1371/journal.pone.0013436

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Citations (32)

Carbon dioxide and ocean acidification observations in UK waters. Synthesis report with a focus on 2010–2015

Clare Ostle Phillip Williamson Yuri Artioli Dorothée C. E. Bakker Silvana N.R. Birchenough

Key messages: 1.1 The process of ocean acidification is now relatively well-documented at the global scale as a long-term trend in the open ocean. However, short-term and spatial variability can be high. 1.2 New datasets made available since Charting Progress 2 make it possible to greatly improve the characterisation of CO2 and ocean acidification in UK waters. 3.1 Recent UK cruise data contribute to large gaps in national and global datasets. 3.2 The new UK measurements confirm that pH is highly variable, therefore it is important to measure consistently to determine any long term trends. 3.3 Over the past 30 years, North Sea pH has decreased at 0.0035±0.0014 pH units per year. 3.4 Upper ocean pH values are highest in spring, lowest in autumn. These changes reflect the seasonal cycles in photosynthesis, respiration (decomposition) and water mixing. 3.5 Carbonate saturation states are minimal in the winter, and lower in 7 more northerly, colder waters. This temperature-dependence could have implications for future warming of the seas. 3.6 Over the annual cycle, North-west European seas are net sinks of CO2. However, during late summer to autumn months, some coastal waters may be significant sources. 3.7 In seasonally-stratified waters, sea-floor organisms naturally experience lower pH and saturation states; they may therefore be more vulnerable to threshold changes. 3.8 Large pH changes (0.5 - 1.0 units) can occur in the top 1 cm of sediment; however, such effects are not well-documented. 3.9 A coupled forecast model estimates the decrease in pH trend within the North Sea to be -0.0036±0.00034 pH units per year, under a high greenhouse gas emissions scenario (RCP 8.5). 3.10 Seasonal estimates from the forecast model demonstrate areas of the North Sea that are particularly vulnerable to aragonite undersaturation.

Ocean Acidification

Sink (geography)

Annual cycle

Carbon sink

10.13140/rg.2.1.4819.4164

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Citations (17)

Overwintering individuals of the Arctic krill Thysanoessa inermis appear tolerant to short-term exposure to low pH conditions

Polar Biology (2017)

Theresa A. Venello Piero Calosi Lucy M. Turner Helen S. Findlay

Ocean Acidification

Fjord

Overwintering

10.1007/s00300-017-2194-0

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Citations (4)

Comment on essd-2022-129

Peter E. Land Helen S. Findlay Jamie D. Shutler Jean-François Piollé Richard Sims

Abstract. In recent years, large datasets of in situ marine carbonate system parameters (partial pressure of CO₂ (pCO₂), total alkalinity, dissolved inorganic carbon and pH) have been collated, quality-controlled and made publicly available. These carbonate system datasets have highly variable data density in both space and time, especially in the case of pCO₂, which is routinely measured at high frequency using underway measuring systems. This variation in data density can create biases when the data are used, for example, for algorithm assessment, favouring datasets or regions with high data density. A common way to overcome data density issues is to bin the data into cells of equal latitude and longitude extent. This leads to bins with spatial areas that are latitude- and projection-dependent (e.g.Â become smaller and more elongated as the poles are approached). Additionally, as bin boundaries are defined without reference to the spatial distribution of the data or to geographical features, data clusters may be divided sub-optimally (e.g.Â a bin covering a region with a strong gradient). To overcome these problems and to provide a tool for matching surface in situ data with satellite, model and climatological data, which often have very different spatiotemporal scales both from the in situ data and from each other, a methodology has been created to group in situ data into âregions of interestâ: spatiotemporal cylinders consisting of circles on the Earth's surface extending over a period of time. These regions of interest are optimally adjusted to contain as many in situ measurements as possible. All surface in situ measurements of the same parameter contained in a region of interest are collated, including estimated uncertainties and regional summary statistics. The same grouping is applied to each of the non-in situ datasets in turn, producing a dataset of coincident matchups that are consistent in space and time. About 35Â million in situ data points were matched with data from five satellite sources and five model and reanalysis datasets to produce a global matchup dataset of carbonate system data, consisting of â¼286â000Â regions of interest spanning 54 years from 1957 to 2020. Each region of interest is 100âkm in diameter and 10âd in duration. An example application, the reparameterisation of a global total alkalinity algorithm, is presented. This matchup dataset can be updated as and when in situ and other datasets are updated, and similar datasets at finer spatiotemporal scale can be constructed, for example, to enable regional studies. The matchup dataset provides users with a large multi-parameter carbonate system dataset containing data from different sources, in one consistent, collated and standardised format suitable for modelâdata intercomparisons and model evaluations. The OceanSODA-MDB data can be downloaded from https://doi.org/10.12770/0dc16d62-05f6-4bbe-9dc4-6d47825a5931 (Land and PiollÃ©, 2022).

10.5194/essd-2022-129-rc1

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Comment on bg-2021-166

Richard Sims Michael Bedington Ute Schuster Andrew Watson Vassilis Kitidis

Abstract. Surface ocean CO₂ measurements are used to compute the oceanic air–sea CO₂ flux. The CO₂ flux component from rivers and estuaries is uncertain. Estuarine and coastal water carbon dioxide (CO₂) observations are relatively few compared to observations in the open ocean. The contribution of these regions to the global air–sea CO₂ flux remains uncertain due to systematic under-sampling. Existing high-quality CO₂ instrumentation predominantly utilise showerhead and percolating style equilibrators optimised for open ocean observations. The intervals between measurements made with such instrumentation make it difficult to resolve the fine-scale spatial variability of surface water CO₂ at timescales relevant to the high frequency variability in estuarine and coastal environments. Here we present a novel dataset with unprecedented frequency and spatial resolution transects made at the Western Channel Observatory in the south west of the UK from June to September 2016, using a fast response seawater CO₂ system. Novel observations were made along the estuarine–coastal continuum at different stages of the tide and reveal distinct spatial patterns in the surface water CO₂ fugacity (fCO₂) at different stages of the tidal cycle. Changes in salinity and fCO₂ were closely correlated at all stages of the tidal cycle and suggest that the mixing of oceanic and riverine end members determines the variations in fCO₂. The observations demonstrate the complex dynamics determining spatial and temporal patterns of salinity and fCO₂ in the region. Spatial variations in observed surface salinity were used to validate the output of a regional high resolution hydrodynamic model. The model enables a novel estimate of the air–sea CO₂ flux in the estuarine–coastal zone. Air–sea CO₂ flux variability in the estuarine–coastal boundary region is dominated by the state of the tide because of strong CO₂ outgassing from the river plume. The observations and model output demonstrate that undersampling the complex tidal and mixing processes characteristic of estuarine and coastal environment bias quantification of air-sea CO₂ fluxes in coastal waters. The results provide a mechanism to support critical national and regional policy implementation by reducing uncertainty in carbon budgets.

10.5194/bg-2021-166-rc2

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Ocean acidification and climate change

Climate Change (2021)

Helen S. Findlay Carol Turley

Oceans have the capacity to absorb large amounts of carbon dioxide (CO2) because CO2 dissolves and reacts in seawater to form bicarbonate (HCO3−) and protons (H+). About a quarter to a third of the CO2 emitted into the atmosphere from the burning of fossil fuels, cement manufacturing, and land use changes has been absorbed by the oceans. Over thousands of years, the changes in pH have been buffered by bases, such as carbonate ions (CO32−). However, the rate at which CO2 is currently being absorbed into the oceans is too rapid to be buffered sufficiently to prevent substantial changes in ocean pH and CO32−. As a consequence, the relative seawater concentrations of CO2, HCO3–, CO32−, and pH have been altered. Since preindustrial times, the ocean pH has decreased by a global average of 0.1. It is estimated that unmitigated CO2 emissions will cause ocean pH to decrease by as much as 0.4 by 2100 and 0.77 by 2300. These will be the most rapid and greatest changes in ocean carbonate chemistry experienced by marine organisms over the past tens of millions of years. Laboratory experiments, field observations of natural CO2-rich seawater "hot spots," and studies of previous ocean acidification in Earth's history indicate that these changes are a threat to the survival of many marine organisms but particularly organisms that use CaCO3 to produce shells, tests, and skeletons. The only way of reducing the impacts of ocean acidification on a global scale is through urgent and substantial reductions in anthropogenic CO2 emissions. Ocean acidification is a key argument for united global societal action in ongoing climate change negotiations.

Ocean Acidification

Bicarbonate

Ocean chemistry

10.1016/b978-0-12-821575-3.00013-x

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Citations (30)

Effects of elevated CO<sub>2</sub> and temperature on phytoplankton community biomass, species composition and photosynthesis during an experimentally induced autumn bloom in the western English Channel

Biogeosciences (2018)

Matthew Keys Gavin H. Tilstone Helen S. Findlay Claire E. Widdicombe Tracy Lawson

Abstract. The combined effects of elevated pCO2 and temperature were investigated during an experimentally induced autumn phytoplankton bloom in vitro sampled from the western English Channel (WEC). A full factorial 36-day microcosm experiment was conducted under year 2100 predicted temperature (+4.5 ∘C) and pCO2 levels (800 µatm). Over the experimental period total phytoplankton biomass was significantly influenced by elevated pCO2. At the end of the experiment, biomass increased 6.5-fold under elevated pCO2 and 4.6-fold under elevated temperature relative to the ambient control. By contrast, the combined influence of elevated pCO2 and temperature had little effect on biomass relative to the control. Throughout the experiment in all treatments and in the control, the phytoplankton community structure shifted from dinoflagellates to nanophytoplankton . At the end of the experiment, under elevated pCO2 nanophytoplankton contributed 90 % of community biomass and was dominated by Phaeocystis spp. Under elevated temperature, nanophytoplankton comprised 85 % of the community biomass and was dominated by smaller nanoflagellates. In the control, larger nanoflagellates dominated whilst the smallest nanophytoplankton contribution was observed under combined elevated pCO2 and temperature (∼ 40 %). Under elevated pCO2, temperature and in the control there was a significant decrease in dinoflagellate biomass. Under the combined effects of elevated pCO2 and temperature, dinoflagellate biomass increased and was dominated by the harmful algal bloom (HAB) species, Prorocentrum cordatum. At the end of the experiment, chlorophyll a (Chl a) normalised maximum photosynthetic rates (PmB) increased > 6-fold under elevated pCO2 and > 3-fold under elevated temperature while no effect on PmB was observed when pCO2 and temperature were elevated simultaneously. The results suggest that future increases in temperature and pCO2 simultaneously do not appear to influence coastal phytoplankton productivity but significantly influence community composition during autumn in the WEC.

Dinoflagellate

Microcosm

Bloom

pCO2

10.5194/bg-15-3203-2018

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Citations (22)