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McQuatters-Gollop A.,Sir Alister Hardy Foundation for Ocean Science
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences | Year: 2012

Unprecedented basin-scale ecological changes are occurring in our seas. As temperature and carbon dioxide concentrations increase, the extent of sea ice is decreasing, stratification and nutrient regimes are changing and pH is decreasing. These unparalleled changes present new challenges for managing our seas, as we are only just beginning to understand the ecological manifestations of these climate alterations. The Marine Strategy Framework Directive requires all European Member States to achieve good environmental status (GES) in their seas by 2020; this means management towards GES will take place against a background of climate-driven macroecological change. Each Member State must set environmental targets to achieve GES; however, in order to do so, an understanding of large-scale ecological change in the marine ecosystem is necessary. Much of our knowledge of macroecological change in the North Atlantic is a result of research using data gathered by the Continuous Plankton Recorder (CPR) survey, a nearsurface plankton monitoring programme that has been sampling in the North Atlantic since 1931. CPR data indicate that North Atlantic and North Sea plankton dynamics are responding to both climate and human-induced changes, presenting challenges to the development of pelagic targets for achievement of GES in European Seas. Thus, the continuation of long-term ecological time series such as the CPR survey is crucial for informing and supporting the sustainable management of European seas through policy mechanisms. © 2012 The Royal Society. Source

Batten S.D.,Sir Alister Hardy Foundation for Ocean Science | Gower J.F.R.,Canadian Institute of Ocean Sciences
Journal of Plankton Research | Year: 2014

Deliberate fertilization of a patch of water west of Haida Gwaii, British Columbia, with iron sulphate and oxide occurred in summer 2012 and triggered a phytoplankton bloom strongly visible in satellite imagery in late August and detectable through September 2012. Routine sampling by the Continuous Plankton Recorder Survey from commercial ships occurred in the vicinity of the fertilized patch between April and October that year. Comparisons with samples from the same region in the years 2000-2011 showed that phytoplankton and microzooplankton abundance indices were the lowest recorded over the time series in the autumn of 2012, while crustacean zooplankton were higher than average, and often higher than previously recorded in the autumn. Possible other contributory factors are discussed but this evidence suggests that the iron-induced bloom could have caused an increase in zooplankton that in turn exerted a heavy grazing pressure on the large phytoplankton and microzooplankton by the autumn of 2012. © 2014 The Author. Published by Oxford University Press. All rights reserved. Source

Beaugrand G.,Lille University of Science and Technology | Beaugrand G.,Sir Alister Hardy Foundation for Ocean Science | Rombouts I.,Lille University of Science and Technology | Kirby R.R.,University of Plymouth
Global Ecology and Biogeography | Year: 2013

Aim: Latitudinal gradients in diversity intrigue scientists, and various hypotheses have been proposed to explain why the diversity of so many taxonomic groups increases from the poles to the equator. These hypotheses range from null models to environmental factors, and biotic interactions to those that include patterns of dispersal and speciation. Here, we formulate a new theory based upon the concept of the niche sensu Hutchinson and the principle of competitive exclusion, which shows that the latitudinal diversity gradient in the marine environment may result from an interaction between the thermal tolerances of species and climatic variability. Location: The global ocean. Methods: We design a bioclimatic model that creates pseudospecies from strict stenotherms to large eurytherms and subsequently allows them to colonize a global ocean provided they can tolerate fluctuations in temperature. We test 74 ecologically realistic scenarios that are then correlated with observed patterns of species richness for foraminifers and copepods, two important oceanic planktonic groups. Results: We found that the model accounted for 96% of the latitudinal gradient in foraminifers and 85% for copepods. Our model both reveals how patterns of biodiversity may develop, and suggests why some taxonomic groups appear not to follow the general pattern. While climate ultimately selected species that could establish in any given habitat, we saw a strong mid-domain effect (MDE) in the niche space. We believe this negates some shortcomings of the MDE that is often assumed to occur in the geographical space. Main conclusions: By showing the strong effect of temperature on biodiversity and revealing how it enables the development of a planetary gradient in marine biodiversity, our results offer a way to better understand why temperature is so often positively correlated with global patterns in species richness on a global scale. © 2012 Blackwell Publishing Ltd. Source

Hartmann M.,UK National Oceanography Center | Grob C.,University of Warwick | Tarran G.A.,Plymouth Marine Laboratory | Martin A.P.,UK National Oceanography Center | And 4 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2012

Oligotrophic subtropical gyres are the largest oceanic ecosystems, covering >40% of the Earth's surface. Unicellular cyanobacteria and the smallest algae (plastidic protists) dominate CO 2 fixation in these ecosystems, competing for dissolved inorganic nutrients. Here we present direct evidence from the surface mixed layer of the subtropical gyres and adjacent equatorial and temperate regions of the Atlantic Ocean, collected on three Atlantic Meridional Transect cruises on consecutive years, that bacterioplankton are fed on by plastidic and aplastidic protists at comparable rates. Rates of bacterivory were similar in the light and dark. Furthermore, because of their higher abundance, it is the plastidic protists, rather than the aplastidic forms, that control bacterivory in these waters. These findings change our basic understanding of food web function in the open ocean, because plastidic protists should now be considered as the main bacterivores as well as the main CO 2 fixers in the oligotrophic gyres. Source

Henson S.,UK National Oceanography Center | Lampitt R.,UK National Oceanography Center | Johns D.,Sir Alister Hardy Foundation for Ocean Science
Limnology and Oceanography | Year: 2012

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 the relative influence of subpolar or subtropical-like conditions is reflected in the physical environment. During positive NAO periods, the region experiences subpolar-like conditions, with strong wind stress and deep mixed layers. In contrast, during negative NAO periods, the region shifts toward more subtropical-like conditions. Diatoms dominate the phytoplankton community in positive NAO periods, whereas in negative NAO periods, dinoflagellates outcompete diatoms. The implications for interannual variability in deep ocean carbon flux are examined using data from the Porcupine Abyssal Plain time-series station. Contrary to expectations, carbon flux to 3000 m is enhanced when diatoms are outcompeted by other phytoplankton functional types. Additionally, highest carbon fluxes were not associated with an increase in biomineral content, which implies that ballasting is not playing a dominant role in controlling the flux of material to the deep ocean in this region. In transition zones between gyre systems, phytoplankton populations can change in response to forcing induced by opposing NAO phases. © 2012, by the Association for the Sciences of Limnology and Oceanography, Inc. Source

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