D. G. Johns

D. G. Johns
Marine Biological Association of the UK | MBA

BSc, MPhil

About

98
Publications
26,154
Reads
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4,337
Citations
Introduction
Head of the Continuous Plankton Recorder Survey and member of the MBA Senior Management Team. Management of the Survey, operations, analysis programme, health and safety, Quality Assurance, data flow and production. 22+ years of plankton analysis experience, covering zooplankton and phytoplankton taxa from the North and South Atlantic, Mediterranean and Pacific. Experience in working with the media, both national and international, including live TV. Chair of NE Atlantic Marine Biological Analytical Quality Control Scheme. Experienced in managing a team of staff, in both a laboratory setting and scientific research. Senior management in the organisation, with ability to think pro-actively and strategically.
Additional affiliations
July 1997 - present
Marine Biological Association of the UK
Position
  • Head of Department

Publications

Publications (98)
Article
Full-text available
The Continuous Plankton Recorder survey has monitored plankton in the Northwest Atlantic at monthly intervals since 1962, with an interegnum between 1978 and 1990. In May 1999, large numbers of the Pacific diatom Neodenticula seminae were found in Continuous Plankton Recorder (CPR) samples in the Labrador Sea as the first record in the North Atlant...
Article
Full-text available
Differences in phenological responses to climate change among species can desynchronise ecological interactions and thereby threaten ecosystem function. To assess these threats, we must quantify the relative impact of climate change on species at different trophic levels. Here, we apply a Climate Sensitivity Profile approach to 10,003 terrestrial a...
Article
Full-text available
Studies of the nitrogen cycle in the ocean generally assume that the distribution of the marine diazotroph, Trichodesmium, is restricted to warm, tropical and sub-tropical oligotrophic waters. Here we show evidence that Trichodesmium are widely distributed in the North Atlantic. We report an approximately five-fold increase during the 1980s and 199...
Article
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Plastic production has increased exponentially since its use became widespread in the 1950s. This has led to increased concern as plastics have become prevalent in the oceanic environment, and evidence of their impacts on marine organisms and human health has been highlighted. Despite their prevalence, very few long-term (>40 years) records of the...
Article
Full-text available
Almost nothing is known about the historical abundance of the ocean sunfish. Yet as an ecologically and functionally important taxa, understanding changes in abundance may be a useful indicator of how our seas are responding to anthropogenic changes including overfishing and climate change. Within this context, sightings from a coastal bird observa...
Article
Full-text available
Plankton form the base of the marine food web and are sensitive indicators of environmental change. Plankton time series are therefore an essential part of monitoring progress towards global biodiversity goals, such as the Convention on Biological Diversity Aichi Targets, and for informing ecosystem-based policy, such as the EU Marine Strategy Fram...
Article
Full-text available
Niche conservatism is the hypothesis that a species' niche remains stable in space and time. This concept is central to understanding phenomena ranging from the role of climate change impacts on species biogeography to community dynamics. Marine zooplankton have been used as indicators of global change in the ocean, and niche conservatism is usuall...
Article
Full-text available
Ocean warming linked to anthropogenic climate change is impacting the ecology of marine species around the world. In 2010, the Gulf of Maine and Scotian Shelf regions of the Northwest Atlantic underwent an unprecedented regime shift. Forced by climate-driven changes in the Gulf Stream, warm slope waters entered the region and created a less favorab...
Preprint
Full-text available
Plankton form the base of the marine food web and are sensitive indicators of environmental change. Plankton time-series are therefore an essential part of monitoring progress towards global biodiversity goals, such as the Convention on Biological Diversity Aichi Targets, and for informing ecosystem-based policy, such as the EU Marine Strategy Fram...
Article
Full-text available
Macroecological relationships provide insights into rules that govern ecological systems. Bergmann's rule posits that members of the same clade are larger at colder temperatures. Whether temperature drives this relationship is debated because several other potential drivers covary with temperature. We conducted a near‐global comparative analysis on...
Article
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Copepods are among the most abundant marine metazoans and form a key link between marine primary producers, higher trophic levels, and carbon sequestration pathways. Climate change is projected to change surface ocean temperature by up to 4°C in the North Atlantic with many associated changes including slowing of the overturning circulation, areas...
Article
Indicators based on broad functional characteristics, which group plankton taxa into “lifeforms”, summarize changes across a high number of taxa in a way that reflects changes in community functioning and are used to inform policy assessments. Key questions remain, however, as to what extent plankton taxa within these lifeforms share responses to e...
Article
Full-text available
As primary producers, phytoplankton play a pivotal role in the marine environment and are central to many biogeochemical processes. Changes to phytoplankton community composition could have major consequences for wider ecosystem functioning and may occur in response to climate change. Here we describe multi-decadal variability in phytoplankton comm...
Article
Growth is a fundamental physiological process influencing the state and dynamics of fish stocks, yet the physical and biological conditions affecting individual weight and growth throughout ontogeny are poorly known and often unaccounted for in fisheries management. This is rather surprising given that changes in growth have strong direct effects o...
Article
The development of biodiversity indicators is an integral component of forming marine strategies under the European Marine Strategy Framework Directive (MSFD). A key stage in the development of biodiversity indicators is the selection of an appropriate temporal scale over which to assess change in indicator state. This presents a particular challen...
Article
Full-text available
Continental margins are disproportionally important for global primary production, fisheries and CO 2 uptake. However, across the Northeast Atlantic shelves, there has been an ongoing summertime decline of key biota-large diatoms, dinoflagellates and copepods-that traditionally fuel higher tropic levels such as fish, sea birds and marine mammals. H...
Article
Full-text available
Increasing direct human pressures on the marine environment, coupled with climate‐driven changes, is a concern to marine ecosystems globally. This requires the development and monitoring of ecosystem indicators for effective management and adaptation planning. Plankton lifeforms (broad functional groups) are sensitive indicators of marine environme...
Technical Report
Full-text available
The State of Nature report 2019 presents an overview of how wildlife is faring in the UK and its Overseas Territories and Crown Dependencies. Additionally, it assesses the pressures that are acting on nature, and the responses being made, collectively, to counter these pressures.
Article
Full-text available
Within atolls, deep water channels exert significant control over local hydrodynamic conditions; which are important drivers of planktonic distributions. To examine planktonic responses to oceanography, this study tested the effect of proximity and exposure to deep oceanic flushing through these channels on water properties and planktonic assemblag...
Article
Plankton are sensitive indicators of change and, at the base of marine food webs, they underpin important ecosystem services such as carbon sequestration and fisheries production. In the UK and the Northeast Atlantic region, change in plankton functional groups, or ‘lifeforms’, constructed based on biological traits, is the formally accepted policy...
Method
Full-text available
Supplementary information for Ostle, C., Thompson, R. C., Broughton, D., Gregory, L., Marianne, W., & Johns, D. G. (2019). The rise in ocean plastics evidenced from a 60-year time series. Nature Communications, (2019), 1–6. https://doi.org/10.1038/s41467-019-09506-1
Article
Plankton communities make useful ecosystem indicators, and taking a historical perspective on plankton community composition provides insights into large-scale environmental change. Much of our understanding of long temporal-scale change in plankton communities in the North Sea has been provided by the Continuous Plankton Recorder (CPR) survey, ope...
Article
Full-text available
Clear, accessible, objective metrics of species status are critical to communicate the state of biodiversity and to measure progress towards biodiversity targets. However, the population data underpinning current species status metrics is often highly skewed towards particular taxonomic groups such as birds, butterflies and mammals, primarily due t...
Article
The Marine Strategy Framework Directive (MSFD) uses an indicator-based approach for ecosystem assessment; indicators of the state of ecosystem components ('state indicators') are used to determine whether, or not, these ecosystem components are at ‘Good Environmental Status’ relative to prevailing oceanographic conditions. Here, it is illustrated t...
Article
Full-text available
Long-term changes in climate are affecting the abundance, distribution and phenology of species across all trophic levels. Short-term climate variability is also having a profound impact on species and trophic interactions. Crucially, species will experience long- and short-term variation simultaneously, and both are predicted to change, yet studie...
Chapter
The Continuous Plankton Recorder (CPR) Survey, operated by the Sir Alister Hardy Foundation for Ocean Science (SAHFOS), is the longest running, most geographically extensive marine survey in the world. Since its inception in 1931, the Survey has monitored near surface planktonic communities, including pelagic copepods, providing essential baseline...
Article
Taxonomic information provides a crucial understanding of the most basic component of biodiversity – which organisms are present in a region or ecosystem. Taxonomy, however, is a discipline in decline, at times perceived as ‘obsolete’ due to technical advances in science, and with fewer trained taxonomists and analysts emerging each year to replace...
Article
Full-text available
Although it seems obvious that with more data, the predictive capacity of ecological models should improve, a way to demonstrate this fundamental result has not been so obvious. In particular, when the standard models themselves are inadequate (von Bertalanffy, extended Ricker etc.) no additional data will improve performance. By using time series...
Technical Report
Full-text available
The multimetric approach is a methodological tool which can be used to study a range of systems, including GES assessment of marine waters. Three indicators (PH1, PH2 and PH3) are currently being developed in the frame of the OSPAR convention for the pelagic habitat component. The three PH indicators provide information on different and complementa...
Article
Full-text available
Atmospheric carbon dioxide levels are strongly controlled by the depth at which the organic matter that sinks out of the surface ocean is remineralized. This depth is generally estimated from particle flux profiles measured using sediment traps. Inherent in this analysis is a steady state assumption; that export from the surface does not significan...
Article
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Published online subject to final type-setting KEY HEADLINES • Climate change has facilitated the establishment and spread of certain marine non-native species (NNS) in the Northeast Atlantic (e.g., Pacific oyster Crassostrea gigas).
Article
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Abstract The North Atlantic Ocean contains diverse patterns of seasonal phytoplankton blooms with distinct internal dynamics. We analyzed blooms using remotely-sensed chlorophyll a concentration data and change point statistics. The first bloom of the year began during spring at low latitudes and later in summer at higher latitudes. In regions wher...
Conference Paper
The black-legged kittiwake (Rissa tridactyla) is one of the UK's most abundant seabirds but the population has declined by 60% since the 1980s. Declines have been linked to rising sea surface temperatures (SSTs) that are believed to affect recruitment and growth of the lesser sandeel (Ammodytes marinus), a key kittiwake prey species, in turn causin...
Article
1. Anthropogenic pressures, including climate change, are causing nonlinear changes in ecosystems globally. The development of reliable early warning indicators (EWIs) to predict these changes is vital for the adaptive management of ecosystems and the protection of biodiversity , natural capital and ecosystem services. Increased variance and autoco...
Presentation
Full-text available
Zooplankton organisms play an important role in marine ecosystems, not only in the functioning of the marine food-web, such as being food sources for important commercial fishes, but also in nutrients recycling, vertical carbon export and regulation of the primary production. They thus have the potential to be relevant indicators of ecosystems heal...
Article
Full-text available
In migratory birds, environmental conditions in both breeding and non-breeding areas may affect adult survival rates and hence be significant drivers of demographic processes. In seabirds, poor knowledge of their true distribution outside the breeding season, however, has severely limited such studies. This study explored how annual adult survival...
Article
Full-text available
The temperate waters of the North-Eastern Atlantic have a long history of maritime resource richness and, as a result, the European Union is endeavouring to maintain regional productivity and biodiversity. At the intersection of these aims lies potential conflict, signalling the need for integrated, cross-border management approaches. This paper fo...
Article
Full-text available
The CPR survey records over 500 taxonomic entities and although the number of fish larvae on each sample is counted, they are not routinely identified to species or taxonomic group. The fish larvae project was an ambitious study to identify the fish larvae and transfer the results to a database incorporating the data from an earlier CPR Fish Atlas...
Article
We have examined the inter-and intra-group seasonal succession of 113 diatom and dinoflagellate taxa, as surveyed by the Continuous Plankton Recorder (CPR) in the North Atlantic, by grouping taxa according to two key functional traits: cell size (mg C cell 21) and trophic strategy (photoautotrophy, mixotrophy, or heterotrophy). Mixotrophic dinoflag...
Article
The North Atlantic Oscillation (NAO) is a major mode of variability in the North Atlantic, dominating atmospheric and oceanic conditions. Here, we examine the phytoplankton community-structure response to the NAO using the Continuous Plankton Recorder data set. In the Northeast Atlantic, in the transition region between the gyres, variability in th...
Article
Full-text available
Differential phenological responses to climate among species are predicted to disrupt trophic interactions, but datasets to evaluate this are scarce. We compared phenological trends for species from 4 levels of a North Sea food web over 24 yr when sea surface temperature (SST) increased significantly. We found little consistency in phenological tre...
Article
Full-text available
Regime shifts are sudden changes in ecosystem structure that can be detected across several ecosystem components. The concept that regime shifts are common in marine ecosystems has gained popularity in recent years. Many studies have searched for the step-like changes in ecosystem state expected under a simple interpretation of this idea. However,...
Conference Paper
Full-text available
At the base of the marine foodweb, the free floating plant life of the sea (phytoplankton) provide food for the animal plankton (zooplankton) which in turn provide food for many other marine organisms. The carrying capacity of marine ecosystems in terms of the size of fish resources and recruitment to individual stocks as well as the abundance of m...
Article
We examined how marine plankton interaction networks, as inferred by multivariate autoregressive (MAR) analysis of time-series, differ based on data collected at a fixed sampling location (L4 station in the Western English Channel) and four similar time-series prepared by averaging Continuous Plankton Recorder (CPR) data-points in the region surrou...