DOCSLIB.ORG

Factors Controlling Coccolithophore Biogeography in the Southern Ocean

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Factors Controlling Coccolithophore Biogeography in the Southern Ocean Biogeosciences, 15, 6997–7024, 2018 https://doi.org/10.5194/bg-15-6997-2018 © Author(s) 2018. This work is distributed under the Creative Commons Attribution 4.0 License. Factors controlling coccolithophore biogeography in the Southern Ocean Cara Nissen, Meike Vogt, Matthias Münnich, Nicolas Gruber, and F. Alexander Haumann Institute for Biogeochemistry and Pollutant Dynamics, ETH Zürich, Universitätstrasse 16, 8092 Zürich, Switzerland Correspondence: Cara Nissen ([email protected]) Received: 29 March 2018 – Discussion started: 6 April 2018 Revised: 8 November 2018 – Accepted: 9 November 2018 – Published: 22 November 2018 Abstract. The biogeography of Southern Ocean phytoplank- 1 Introduction ton controls the local biogeochemistry and the export of macronutrients to lower latitudes and depth. Of particu- The ocean is changing at an unprecedented rate as a con- lar relevance is the competitive interaction between coc- sequence of increasing anthropogenic CO2 emissions and colithophores and diatoms, with the former being prevalent related climate change. Changes in density stratification along the “Great Calcite Belt” (40–60◦ S), while diatoms and nutrient supply, as well as ocean acidification, lead to tend to dominate the regions south of 60◦ S. To address the changes in phytoplankton community composition and con- factors controlling coccolithophore distribution and the com- sequently ecosystem structure and function. Some of these petition between them and diatoms, we use a regional high- changes are already observable today (e.g., Soppa et al., resolution model (ROMS–BEC) for the Southern Ocean (24– 2016; Winter et al., 2013) and may have cascading effects 78◦ S) that has been extended to include an explicit repre- on global biogeochemical cycles and oceanic carbon uptake sentation of coccolithophores. We assess the relative impor- (Laufkötter et al., 2016; Freeman and Lovenduski, 2015; tance of bottom-up (temperature, nutrients, light) and top- Cermeño et al., 2008). Changes in Southern Ocean (SO) bio- down (grazing by zooplankton) factors in controlling South- geography are especially critical due to the importance of the ern Ocean coccolithophore biogeography over the course of SO in fueling primary production at lower latitudes through the growing season. In our simulations, coccolithophores are the lateral export of nutrients (Sarmiento et al., 2004) and an important member of the Southern Ocean phytoplankton in taking up anthropogenic CO2 (Frölicher et al., 2015). For community, contributing 17 % to annually integrated net pri- the carbon cycle, the ratio of calcifying and noncalcifying mary productivity south of 30◦ S. Coccolithophore biomass phytoplankton is crucial due to the counteracting effects of ◦ is highest north of 50 S in late austral summer, when light calcification and photosynthesis on seawater pCO2, which levels are high and diatoms become limited by silicic acid. ultimately controls CO2 exchange with the atmosphere, and Furthermore, we find top-down factors to be a major control the differing ballasting effect of calcite and silicic acid shells on the relative abundance of diatoms and coccolithophores for organic carbon export. in the Southern Ocean. Consequently, when assessing poten- Calcifying coccolithophores and silicifying diatoms tial future changes in Southern Ocean coccolithophore abun- are globally ubiquitous phytoplankton functional groups dance, both abiotic (temperature, light, and nutrients) and bi- (O’Brien et al., 2013; Leblanc et al., 2012). Diatoms are a otic factors (interaction with diatoms and zooplankton) need major contributor to global phytoplankton biomass (≈ 6 %– to be considered. 70 %; Buitenhuis et al., 2013b) and annual net primary pro- duction (40 % of NPP; Sarthou et al., 2005). In compari- son, coccolithophores contribute less to biomass (≈ 0:04 %– 6 %; Buitenhuis et al., 2013b) and to global NPP (0.4 %– 17 %, model-derived estimates using a variety of coccol- ithophore parameterizations; see O’Brien, 2015; Jin et al., 2006; Moore et al., 2004; Gregg and Casey, 2007a). How- Published by Copernicus Publications on behalf of the European Geosciences Union. 6998 C. Nissen et al.: Southern Ocean coccolithophore biogeography ever, coccolithophores are the major phytoplanktonic calci- lite data from the North Atlantic, Behrenfeld(2014) stresses fier (Iglesias-Rodríguez et al., 2002), thereby significantly the importance of simultaneously considering bottom-up and impacting the global carbon cycle. Diatoms dominate the top-down factors when assessing seasonal phytoplankton phytoplankton community in the SO (e.g., Trull et al., 2018; biomass dynamics and the succession of different phyto- Swan et al., 2016; Wright et al., 2010), but coccolithophores plankton types owing to the spatially and temporally vary- have received increasing attention in recent years. Satel- ing relative importance of the physical–biogeochemical and lite imagery of particulate inorganic carbon (PIC, a proxy the biological environment. In the SO, previous studies have for coccolithophore abundance) revealed the “Great Cal- shown zooplankton grazing to control total phytoplankton cite Belt” (GCB; Balch et al., 2011), an annually reoccur- biomass (Le Quéré et al., 2016), phytoplankton community ring circumpolar band of elevated PIC concentrations be- composition (Scotia Weddell Sea; Granéli et al., 1993), and tween 40 and 60◦ S. In situ observations confirmed coc- ecosystem structure (Smetacek et al., 2004; De Baar, 2005), colithophore abundances of up to 2:4 × 103 cells mL−1 in suggesting that top-down control might also be an important the Atlantic sector (blooms on the Patagonian Shelf), up to driver for the relative abundance of coccolithophores and di- 3:8×102 cells mL−1 in the Indian sector (Balch et al., 2016), atoms. But the role of zooplankton grazing in current Earth and up to 5:4×102 cells mL−1 in the Pacific sector of the SO system models is not well considered (Sailley et al., 2013; (Cubillos et al., 2007) with Emiliania huxleyi being the dom- Hashioka et al., 2013), and the impact of different grazing inant species (Balch et al., 2016; Saavedra-Pellitero et al., formulations on phytoplankton biogeography and diversity is 2014). However, the contribution of coccolithophores to to- subject to ongoing research (e.g., Prowe et al., 2012; Vallina tal SO phytoplankton biomass and NPP has not yet been as- et al., 2014). sessed. Locally, elevated coccolithophore abundance in the While none of the SO in situ studies directly assessed in- GCB has been found to turn surface waters into a source of teractions of diatoms and coccolithophores over the course of CO2 for the atmosphere (Balch et al., 2016), emphasizing the the year, some in situ studies infer a diatom–coccolithophore necessity to understand the controls on their abundance in the succession from depleted silicic acid coinciding with iron SO in the context of the carbon cycle and climate change. levels high enough to sustain elevated coccolithophore abun- While coccolithophores have been observed to have moved dance (high Fe, low Si niche; Balch et al., 2016, 2014; Painter polewards in recent decades (Rivero-Calle et al., 2015; Win- et al., 2010). In contrast to this, recent in situ and satellite ter et al., 2013; Beaugrand et al., 2012), their response to the studies find coccolithophores and diatoms to coexist rather combined effects of future warming and ocean acidification than succeed each other throughout the growth season in the is still subject to debate (Schlüter et al., 2014; Beaugrand North Atlantic (Daniels et al., 2015) and the global open et al., 2012; Beaufort et al., 2011; Iglesias-Rodríguez et al., ocean (Hopkins et al., 2015). In fact, large areas of the GCB 2008; Riebesell et al., 2000). As their response will also cru- have been identified as “coexistence” areas (Hopkins et al., cially depend on future phytoplankton community composi- 2015), thereby putting into question the succession pattern tion and predator–prey interactions (Dutkiewicz et al., 2015), predicted by Margalef’s mandala (Margalef, 1978) and re- it is essential to assess the controls on their abundance in to- sults of in situ studies for the SO (Balch et al., 2016, 2014; day’s climate. Painter et al., 2010). This highlights the necessity to better Coccolithophore biomass is controlled by a combination understand the drivers and seasonal dynamics of the relative of bottom-up (physical–biogeochemical environment) and importance of coccolithophores and diatoms in the SO before top-down factors (predator–prey interactions), but the rela- assessing potential future changes. tive importance of the two has not yet been assessed for coc- In this study, we use a regional high-resolution model for colithophores in the SO. Bottom-up factors directly impact the SO to simultaneously assess the relative importance of phytoplankton growth, and diatoms and coccolithophores are bottom-up versus top-down factors in controlling SO coc- traditionally discriminated based on their differing require- colithophore biogeography over a complete annual cycle. In ments for nutrients, turbulence, and light. Based on this, Mar- particular, we assess the role of diatoms in constraining high galef’s mandala predicts a seasonal succession from diatoms coccolithophore abundance and the importance of microzoo- to coccolithophores as light levels increase and nutrient lev- plankton and macrozooplankton grazing for the relative im- els decline (Margalef, 1978). In situ studies assessing SO portance
Load more

Recommended publications
  • Representative Diatom and Coccolithophore Species Exhibit Divergent Responses Throughout Simulated Upwelling Cycles
    bioRxiv preprint doi: https://doi.org/10.1101/2020.04.30.071480; this version posted May 1, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC 4.0 International license. Representative diatom and coccolithophore species exhibit divergent responses throughout simulated upwelling cycles Robert H. Lampe1,2, Gustavo Hernandez2, Yuan Yu Lin3, and Adrian Marchetti2, 1Integrative Oceanography Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, USA 2Department of Marine Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA Phytoplankton communities in upwelling regions experience a ton blooms following upwelling (2, 5, 6). When upwelling wide range of light and nutrient conditions as a result of up- delivers cells and nutrients into well-lit surface waters, di- welling cycles. These cycles can begin with a bloom at the sur- atoms quickly respond to available nitrate and increase their face followed by cells sinking to depth when nutrients are de- nitrate uptake rates compared to other phytoplankton groups pleted. Cells can then be transported back to the surface with allowing them to bloom (7). This phenomenon may partially upwelled waters to seed another bloom. In spite of the physico- be explained by frontloading nitrate assimilation genes, i.e. chemical extremes associated with these cycles, diatoms consis- high expression before the upwelling event occurs, in addi- tently outcompete other phytoplankton when upwelling events occur. Here we simulated the conditions of a complete upwelling tion to diatom’s unique metabolic integration of nitrogen and cycle with a common diatom, Chaetoceros decipiens, and coccol- carbon metabolic pathways (6, 8).
    [Show full text]
  • Detection of Coccolithophore Blooms with Biogeochemical-Argo Floats L
    Detection of Coccolithophore Blooms With BioGeoChemical-Argo Floats L. Terrats, H. Claustre, M. Cornec, Alain Mangin, G. Neukermans To cite this version: L. Terrats, H. Claustre, M. Cornec, Alain Mangin, G. Neukermans. Detection of Coccolithophore Blooms With BioGeoChemical-Argo Floats. Geophysical Research Letters, American Geophysical Union, 2020, 47 (23), 10.1029/2020GL090559. hal-03099761 HAL Id: hal-03099761 https://hal.archives-ouvertes.fr/hal-03099761 Submitted on 6 Jan 2021 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Distributed under a Creative Commons Attribution - NonCommercial| 4.0 International License RESEARCH LETTER Detection of Coccolithophore Blooms With 10.1029/2020GL090559 BioGeoChemical‐Argo Floats Key Points: L. Terrats1,2 , H. Claustre1 , M. Cornec1 , A. Mangin2, and G. Neukermans3,4 • We matched profiling float trajectories with ocean‐color 1Sorbonne Université, CNRS, Laboratoire d'Océanographie de Villefranche, LOV, Villefranche‐sur‐Mer, France, satellite observations of 2 ‐ 3 coccolithophore blooms ACRI ST, Sophia Antipolis, France, Biology Department, MarSens Research Group, Ghent University, Ghent, Belgium, • Two simple bio‐optical indices 4Flanders Marine Institute (VLIZ), InnovOcean site, Ostend, Belgium permitted successful identification of coccolithophore blooms from floats in the Southern Ocean Coccolithophores (calcifying phytoplankton) form extensive blooms in temperate and subpolar • Abstract A method for identifying ‐ coccolithophore blooms at the global oceans as evidenced from ocean color satellites.
    [Show full text]
  • Effects of Increased Pco2 and Temperature on the North Atlantic Spring Bloom. III. Dimethylsulfoniopropionate
    Vol. 388: 41–49, 2009 MARINE ECOLOGY PROGRESS SERIES Published August 19 doi: 10.3354/meps08135 Mar Ecol Prog Ser Effects of increased pCO2 and temperature on the North Atlantic spring bloom. III. Dimethylsulfoniopropionate Peter A. Lee1,*, Jamie R. Rudisill1, Aimee R. Neeley1, 7, Jennifer M. Maucher2, David A. Hutchins3, 8, Yuanyuan Feng3, 8, Clinton E. Hare3, Karine Leblanc3, 9,10, Julie M. Rose3,11, Steven W. Wilhelm4, Janet M. Rowe4, 5, Giacomo R. DiTullio1, 6 1Hollings Marine Laboratory, College of Charleston, 331 Fort Johnson Road, Charleston, South Carolina 29412, USA 2Center for Coastal Environmental Health and Biomolecular Research, National Oceanic and Atmospheric Administration, 219 Fort Johnson Road, Charleston, South Carolina 29412, USA 3College of Marine and Earth Studies, University of Delaware, 700 Pilottown Road, Lewes, Delaware 19958, USA 4Department of Microbiology, University of Tennessee, 1414 West Cumberland Ave, Knoxville, Tennessee 37996, USA 5Department of Plant Pathology, The University of Nebraska, 205 Morrison Center, Lincoln, Nebraska 68583, USA 6Grice Marine Laboratory, College of Charleston, 205 Fort Johnson Road, Charleston, South Carolina 29412, USA 7Present address: National Aeronautics and Space Administration, Calibration and Validation Office, 1450 S. Rolling Road, Suite 4.111, Halethorpe, Maryland 21227, USA 8Present address: Department of Biological Sciences, University of Southern California, 3616 Trousdale Parkway, Los Angeles, California 90089, USA 9Present address: Aix-Marseille Université, CNRS,
    [Show full text]
  • Surface Seawater Plankton Sampling for Coccolithophores Undertaken During IODP Expedition 359
    Betzler, C., Eberli, G.P., Alvarez Zarikian, C.A., and the Expedition 359 Scientists Proceedings of the International Ocean Discovery Program Volume 359 publications.iodp.org doi:10.14379/iodp.proc.359.111.2017 Contents 1 Abstract Data report: surface seawater plankton 1 Introduction sampling for coccolithophores undertaken 1 Materials and methods 3 Results 1 during IODP Expedition 359 5 Biogeography 6 Acknowledgments Jeremy R. Young, Santi Pratiwi, Xiang Su, and the Expedition 359 Scientists2 6 References 7 Appendix Keywords: International Ocean Discovery Program, IODP, JOIDES Resolution, Expedition 359, Indian Ocean transect, Maldives, coccolithophores Abstract Darwin, Australia, to the Maldives (Figure F1A). This transit pre- sented a valuable opportunity to sample the equatorial assemblages Data on extant coccolithophore assemblages from plankton to determine broad patterns of coccolithophore distribution and samples collected during International Ocean Discovery Program compare them with those recorded previously, notably by Kleijne et Expedition 359 to the Maldives is presented. Samples include 12 al. (1989). Sampling continued within the Maldives drilling area to collected during passage across the Indian Ocean from Darwin, (1) determine whether assemblages within the Maldives show evi- Australia, to the Maldives and 40 collected in the Maldives. Assem- dence of ecological restriction or modified assemblages related to blages were analyzed by light and scanning electron microscopy, the particular environment of the atoll chain, (2) investigate repro- and detailed assemblage data are presented. Comparison with pre- ducibility of assemblage data by repeat sampling within a limited vious data from the region suggests that there are consistent distinc- area over an extended period, and (3) investigate the potential of the tive aspects to Indian Ocean assemblages.
    [Show full text]
  • The Influence of Environmental Variability on the Biogeography of Coccolithophores and Diatoms in the Great Calcite Belt Helen E
    Biogeosciences Discuss., doi:10.5194/bg-2017-110, 2017 Manuscript under review for journal Biogeosciences Discussion started: 13 April 2017 c Author(s) 2017. CC-BY 3.0 License. The Influence of Environmental Variability on the Biogeography of Coccolithophores and Diatoms in the Great Calcite Belt Helen E. K. Smith1,2, Alex J. Poulton1,3, Rebecca Garley4, Jason Hopkins5, Laura C. Lubelczyk5, Dave T. Drapeau5, Sara Rauschenberg5, Ben S. Twining5, Nicholas R. Bates2,4, William M. Balch5 5 1National Oceanography Centre, European Way, Southampton, SO14 3ZH, U.K. 2School of Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton Waterfront Campus, European Way, Southampton, SO14 3ZH, U.K. 3Present address: The Lyell Centre, Heriot-Watt University, Edinburgh, EH14 7JG, U.K. 10 4Bermuda Institute of Ocean Sciences, 17 Biological Station, Ferry Reach, St. George's GE 01, Bermuda. 5Bigelow Laboratory for Ocean Sciences, 60 Bigelow Drive, P.O. Box 380, East Boothbay, Maine 04544, USA. Correspondence to: Helen E.K. Smith ([email protected]) Abstract. The Great Calcite Belt (GCB) of the Southern Ocean is a region of elevated summertime upper ocean calcite 15 concentration derived from coccolithophores, despite the region being known for its diatom predominance. The overlap of two major phytoplankton groups, coccolithophores and diatoms, in the dynamic frontal systems characteristic of this region, provides an ideal setting to study environmental influences on the distribution of different species within these taxonomic groups. Water samples for phytoplankton enumeration were collected from the upper 30 m during two cruises, the first to the South Atlantic sector (Jan-Feb 2011; 60o W-15o E and 36-60o S) and the second in the South Indian sector (Feb-Mar 2012; 20 40-120o E and 36-60o S).
    [Show full text]
  • Modeling Coccolithophores in the Global Oceans
    Modeling Coccolithophores in the Global Oceans Watson W. Gregg Global Modeling and Assimilation Office NASA/Goddard Space Flight Center Greenbelt, MD 20771 [email protected] Nancy W. Casey Science Systems and Applications, Inc. Lanham, MD 20706 [email protected] Deep-Sea Research II Special Issue Submitted March, 2006 Revised May, 2006 Abstract Coccolithophores are important ecological and geochemical components of the global oceans. A global three-dimensional model was used to simulate their distributions in a multi- phytoplankton context. The realism of the simulation was supported by comparisons of model surface nutrients and total chlorophyll with in situ and satellite observations. Nitrate, silica, and dissolved iron surface distributions were positively correlated with in situ data across major oceanographic basins. Global annual departures were +18.9% for nitrate (model high), +5.4% for silica, and +45.0% for iron. Total surface chlorophyll was also positively correlated with satellite and in situ data sets across major basins. Global annual departures were -8.0% with SeaWiFS (model low), +1.1% with Aqua, and -17.1% with in situ data. Global annual primary production estimates were within 1% and 9% of estimates derived from SeaWiFS and Aqua, respectively, using a common primary production algorithm. Coccolithophore annual mean relative abundances were 2.6% lower than observations, but were positively correlated across basins. Two of the other three phytoplankton groups, diatoms and cyanobacteria, were also positively correlated with observations. Distributions of coccolithophores were dependent upon interactions and competition with the other phytoplankton groups. In this model coccolithophores had a competitive advantage over diatoms and chlorophytes by virtue of a greater ability to utilize nutrients and light at low values.
    [Show full text]
  • COCCOLITHOPHORES Optical Properties, Ecology, And
    COCCOLITHOPHORES Optical properties, ecology, and biogeochemistry Griet Neukermans Marie Curie Postdoctoral Fellow Laboratoire Océanographique de Villefranche-sur-Mer Griet Neukermans PhD in optical oceanography MSc. Mathematics (VUB-Belgium) MSc. Oceans & Lakes (VUB-Belgium) Core expertise : development and application of remote and in situ optical sensing of marine particles 2008 Remote sensing and light scattering properties of suspended particles in European coastal waters PhD (PhD, ULCO-France, advisors: H. Loisel and K. Ruddick) 2012 Optical detection of particle concentration, size, and composition in the Arctic Ocean (Postdoc SIO UCSD-USA, advisors: D. Stramski and R. Reynolds) Post doc 1 2014 Impact of climate change on phytoplankton blooms on the Arctic Ocean’s inflow shelves (Banting Postdoctoral Fellow, ULaval-Canada, advisor: M. Babin) Remote sensing of ocean colour and physical environment Postdoc 2 + Modeling the light scattering properties of coccolithophores (with G. Fournier) 2017 Poleward expansion of coccolithophore blooms and their role in sinking carbon in the Subarctic Ocean (Marie Curie Postdoctoral Fellow, LOV-France, advisor: H. Claustre + co-advisors: G. Beaugrand and U. Riebesell) Postdoc 3 Optical remote sensing + Ecological niche modeling + optical modeling + Biogeochemical-Argo now floats When not at work… I ride my bike! This course covers • Coccolithophore biology and ecology – Diversity, distribution, and biomass • Remote sensing of coccolithophores and their calcite mass (PIC) – Bloom observations and
    [Show full text]
  • Phytoplankton 1 9
    DOMAIN Groups (Kingdom) Dinophyta, Haptophyta, & Bacillariophyta 1.Bacteria- cyanobacteria (blue green algae) 2.Archae 3.Eukaryotes 1. Alveolates- dinoflagellates, coccolithophore Chromista 2. Stramenopiles- diatoms, ochrophyta 3. Rhizaria- unicellular amoeboids 4. Excavates- unicellular flagellates 5. Plantae- rhodophyta, chlorophyta, seagrasses 6. Amoebozoans- slimemolds 7. Fungi- heterotrophs with extracellular digestion 8. Choanoflagellates- unicellular Phytoplankton 1 9. Animals- multicellular heterotrophs 2 DOMAIN Eukaryotes Domain Eukaryotes – have a nucei Supergroup Chromista- chloroplasts derived from red algae Chromista = 21,556 spp. chloroplasts derived from red algae Division Haptophyta- 626 spp. coccolithophore contains Alveolates & Stramenopiles according to Algaebase Group Alveolates- unicellular, plasma membrane supported by flattened vesicles Division Haptophyta- 626 spp. coccolithophore Division Dinophyta- 3,310 spp. of dinoflagellates Group Stramenopiles- two unequal flagella, chloroplasts 4 membranes Division Ochrophyta- 3,763spp. brown algae Division Bacillariophyta -13,437 spp diatoms sphere of stone 3 4 1 Division Haptophyta: Coccolithophore Division Haptophyta: Coccolithophore • Pigments? Chl a &c Autotrophic, Phagotrophic & Osmotrophic Carotenoids:B-carotene, diatoxanthin, diadinoxanthin (uptake of nutrients by osmosis) •Carbon Storage? Sugar: Chrysolaminarian Primary producers in polar, subpolar, temperate & tropical waters • Chloroplasts? 4 membrane Coccolhliths- external bod y scales made of calcium carbonate
    [Show full text]
  • Review of Harmful Algal Blooms in the Coastal Mediterranean Sea, with a Focus on Greek Waters
    diversity Review Review of Harmful Algal Blooms in the Coastal Mediterranean Sea, with a Focus on Greek Waters Christina Tsikoti 1 and Savvas Genitsaris 2,* 1 School of Humanities, Social Sciences and Economics, International Hellenic University, 57001 Thermi, Greece; [email protected] 2 Section of Ecology and Taxonomy, School of Biology, Zografou Campus, National and Kapodistrian University of Athens, 16784 Athens, Greece * Correspondence: [email protected]; Tel.: +30-210-7274249 Abstract: Anthropogenic marine eutrophication has been recognized as one of the major threats to aquatic ecosystem health. In recent years, eutrophication phenomena, prompted by global warming and population increase, have stimulated the proliferation of potentially harmful algal taxa resulting in the prevalence of frequent and intense harmful algal blooms (HABs) in coastal areas. Numerous coastal areas of the Mediterranean Sea (MS) are under environmental pressures arising from human activities that are driving ecosystem degradation and resulting in the increase of the supply of nutrient inputs. In this review, we aim to present the recent situation regarding the appearance of HABs in Mediterranean coastal areas linked to anthropogenic eutrophication, to highlight the features and particularities of the MS, and to summarize the harmful phytoplankton outbreaks along the length of coastal areas of many localities. Furthermore, we focus on HABs documented in Greek coastal areas according to the causative algal species, the period of occurrence, and the induced damage in human and ecosystem health. The occurrence of eutrophication-induced HAB incidents during the past two decades is emphasized. Citation: Tsikoti, C.; Genitsaris, S. Review of Harmful Algal Blooms in Keywords: HABs; Mediterranean Sea; eutrophication; coastal; phytoplankton; toxin; ecosystem the Coastal Mediterranean Sea, with a health; disruptive blooms Focus on Greek Waters.
    [Show full text]
  • Article Is Available the Coccolithophore Emiliania Huxleyi, Limnol
    Clim. Past, 16, 1007–1025, 2020 https://doi.org/10.5194/cp-16-1007-2020 © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License. Can morphological features of coccolithophores serve as a reliable proxy to reconstruct environmental conditions of the past? Giulia Faucher1, Ulf Riebesell2, and Lennart Thomas Bach3 1Dipartimento di Scienze della Terra “Ardito Desio”, Università degli Studi di Milano, Milan 20133, Italy 2Biological Oceanography, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel 24105, Germany 3Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia Correspondence: Giulia Faucher ([email protected]) Received: 9 July 2019 – Discussion started: 15 July 2019 Revised: 16 April 2020 – Accepted: 6 May 2020 – Published: 9 June 2020 Abstract. Morphological changes in coccoliths, tiny cal- changing light intensity, Mg=Ca ratio, nutrient availability, cite platelets covering the outer surface of coccolithophores, and temperature in terms of coccolith morphology. The lack can be induced by physiological responses to environmental of a common response reveals the difficulties in using coc- changes. Coccoliths recovered from sedimentary successions colith morphology as a paleo-proxy for these environmen- may therefore provide information on paleo-environmental tal drivers. However, a common response was observed un- conditions prevailing at the time when the coccolithophores der changing seawater carbonate chemistry (i.e., rising CO2), were alive. To calibrate the biomineralization responses of which consistently induced malformations. This commonal- ancient coccolithophore to environmental changes, studies ity provides some confidence that malformations found in the often compared the biological responses of living coccol- sedimentary record could be indicative of adverse carbonate ithophore species with paleo-data from calcareous nannofos- chemistry conditions.
    [Show full text]
  • 1 Coccolithophore Cell Biology: Chalking up Progress 1 2 Authors: 3
    1 Coccolithophore cell biology: chalking up progress 2 3 Authors: 4 *Alison R. Taylor ([email protected]) 5 Department of Biology and Marine Biology, University of North Carolina 6 Wilmington, North Carolina, 28403, USA 7 8 Colin Brownlee ([email protected]) 9 The Marine Biological Association, The Laboratory, Citadel Hill, Plymouth, PL1 2PB, 10 UK. 11 and 12 School of Ocean and Earth Sciences, University of Southampton, National 13 Oceanography Centre, Southampton SO14 3ZH, UK. 14 15 Glen Wheeler ([email protected]) 16 The Marine Biological Association, The Laboratory, Citadel Hill, Plymouth, PL12PB, 17 UK 18 19 *author for correspondence 20 21 22 23 Keywords: Calcification, dimethylsulfoniopropionate, Emiliania, haptophyte, 24 mixotrophy, vesicle, virus. 25 26 1 1 Table of Contents 2 1.0 Introduction to coccolithophores 3 2.0 Evolution of coccolithophores 4 3.0 Cell biology, lifecycle and ecological niches 5 3.1 Life cycle transitions 6 3.2 Mixotrophy 7 4.0 Biotic interactions 8 4.1 Bacteria 9 4.2 Viruses 10 5.0 Coccolithophore metabolism and physiological diversity 11 5.1 Carbon metabolism 12 5.2 Osmoprotectants 13 6.0 Recent insights into functional roles of calcification 14 6.1 Defense from pathogens and grazers 15 6.2 Modulation of diffusion boundary layer 16 6.3 Modulating the light field and energy balance 17 7.0 Opening the ‘black box’ of vital effects in coccolithophores 18 8.0 Calcification mechanism 19 8.1 Ultrastructure and role of intracellular membranes 20 8.2 Role of organic components in calcification 21 8.2.1 Coccolith associated polysaccharide 22 8.2.2 Coccolith associated proteins 23 8.3 Ion transport 24 8.4 The problem of protons 25 8.5 New paradigms for calcification 26 9.0 Coccolithophore distribution, diversity and adaptation 27 10.0 Concluding remarks 28 2 1 Abstract 2 Coccolithophores occupy a special position within the marine phytoplankton due to 3 their production of intricate calcite scales, or coccoliths.
    [Show full text]
  • Primary Production, Calcification and Macromolecular Synthesis in a Bloom of the Coccolithophore Emiliania Huxleyi in the North Sea
    MARINE ECOLOGY PROGRESS SERIES Vol. 157: 61-77.1997 Published October 16 Mar Ecol Prog Ser l Primary production, calcification and macromolecular synthesis in a bloom of the coccolithophore Emiliania huxleyi in the North Sea Emilio Maranon',', Natalia Gonzalez2 'Department of Oceanography, Southampton Oceanography Centre, University of Southampton, European Way, Southampton S014 3ZH, United Kingdom '~nidadde Ecologia, Departamento de Biologia de Organismos y Sistemas, Universidad de Oviedo, E-33071 Oviedo, Spain ABSTRACT: Photosynthesis, calcification and the patterns of carbon (C) incorporation into different biomolecules were investigated during a bloom of the coccolithophore Emiliania huxleyi in the North Sea during June and July 1994. The bloom was confined to an area of ca 3000 km2 centred at 59'50' N. 00°42'E and characterized by enhanced thermal stability and low nitrate concentrations in the upper mlxed layer. Surface E. huxleyi densities within the bloom area ranged between 1 and 6 X 106 cells I-' The mesoscale distribution of E. huxleyi abundance suggested that the bloom formation was related to the presence of low concentrations of nitrate rather than phosphate. The bloom was sampled during an early stage of its development, as indicated by the low calcite-C levels (c50 my C m-3], the low calcite- C to particulate organlc carbon (POC)ratlo (~0.25)and the low density of detached coccoliths (2 to 3 X 10' m1 l). Reduced levels of chlorophyll a (<45 mg m-2) and productivity (<1.2 g C m-L d-') were mea- sured in the coccolithophore-rich waters as compared to stations outside the bloom area.
    [Show full text]