Articles | Volume 18, issue 5
https://doi.org/10.5194/bg-18-1873-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/bg-18-1873-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
18 Mar 2021
Research article |
| 18 Mar 2021
| 18 Mar 2021
A 2-decade (1988–2009) record of diatom fluxes in the Mauritanian coastal upwelling: impact of low-frequency forcing and a two-step shift in the species composition
MARUM – Center for Marine Environmental Sciences, University of
Bremen, Leobener Str. 8, Bremen 28359, Germany
Alfred Wegener Institute, Helmholtz Centre for Polar and Marine
Research, Am Alten Hafen 26, Bremerhaven 27568, Germany
Simon Ramondenc
MARUM – Center for Marine Environmental Sciences, University of
Bremen, Leobener Str. 8, Bremen 28359, Germany
Alfred Wegener Institute, Helmholtz Centre for Polar and Marine
Research, Am Alten Hafen 26, Bremerhaven 27568, Germany
Gerhard Fischer
MARUM – Center for Marine Environmental Sciences, University of
Bremen, Leobener Str. 8, Bremen 28359, Germany
University of Bremen, Geosciences Department, Klagenfurter Str., Bremen 28359, Germany
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J. Karstensen, B. Fiedler, F. Schütte, P. Brandt, A. Körtzinger, G. Fischer, R. Zantopp, J. Hahn, M. Visbeck, and D. Wallace
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O. Cartapanis, K. Tachikawa, O. E. Romero, and E. Bard
Clim. Past, 10, 405–418, https://doi.org/10.5194/cp-10-405-2014, https://doi.org/10.5194/cp-10-405-2014, 2014
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In oceanic waters, the accumulation of phytoplankton biomass in winter, when light still limits growth, is attributed to a decrease in grazing as the mixed layer deepens. However, in coastal areas, it is not clear whether winter biomass can accumulate without this deepening. Using 21 years of weekly data, we found that in the Scottish coastal North Sea, the seasonal increase in light availability triggers the accumulation of phytoplankton biomass in winter, when light limitation is strongest.
Birgit Koehler, Mårten Erlandsson, Martin Karlsson, and Lena Bergström
Biogeosciences, 19, 2295–2312, https://doi.org/10.5194/bg-19-2295-2022, https://doi.org/10.5194/bg-19-2295-2022, 2022
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Understanding species richness patterns remains a challenge for biodiversity management. We estimated fish species richness over a coastal salinity gradient (3–32) with a method that allowed comparing data from various sources. Species richness was 3-fold higher at high vs. low salinity, and salinity influenced species’ habitat preference, mobility and feeding type. If climate change causes upper-layer freshening of the Baltic Sea, further shifts along the identified patterns may be expected.
Uri Obolski, Thomas Wichard, Alvaro Israel, Alexander Golberg, and Alexander Liberzon
Biogeosciences, 19, 2263–2271, https://doi.org/10.5194/bg-19-2263-2022, https://doi.org/10.5194/bg-19-2263-2022, 2022
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The algal genus Ulva plays a major role in coastal ecosystems worldwide and is a promising prospect as an seagriculture crop. A substantial hindrance to cultivating Ulva arises from sudden sporulation, leading to biomass loss. This process is not yet well understood. Here, we characterize the dynamics of Ulva growth, considering the potential impact of sporulation inhibitors, using a mathematical model. Our findings are an essential step towards understanding the dynamics of Ulva growth.
Emanuela Fanelli, Samuele Menicucci, Sara Malavolti, Andrea De Felice, and Iole Leonori
Biogeosciences, 19, 1833–1851, https://doi.org/10.5194/bg-19-1833-2022, https://doi.org/10.5194/bg-19-1833-2022, 2022
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Zooplankton play a key role in marine ecosystems, forming the base of the marine food web and a link between primary producers and higher-order consumers, such as fish. This aspect is crucial in the Adriatic basin, one of the most productive and overexploited areas of the Mediterranean Sea. A better understanding of community and food web structure and their response to water mass changes is essential under a global warming scenario, as zooplankton are sensitive to climate change.
Masaya Yoshikai, Takashi Nakamura, Rempei Suwa, Sahadev Sharma, Rene Rollon, Jun Yasuoka, Ryohei Egawa, and Kazuo Nadaoka
Biogeosciences, 19, 1813–1832, https://doi.org/10.5194/bg-19-1813-2022, https://doi.org/10.5194/bg-19-1813-2022, 2022
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This study presents a new individual-based vegetation model to investigate salinity control on mangrove productivity. The model incorporates plant hydraulics and tree competition and predicts unique and complex patterns of mangrove forest structures that vary across soil salinity gradients. The presented model does not hold an empirical expression of salinity influence on productivity and thus may provide a better understanding of mangrove forest dynamics in future climate change.
Coulson A. Lantz, William Leggat, Jessica L. Bergman, Alexander Fordyce, Charlotte Page, Thomas Mesaglio, and Tracy D. Ainsworth
Biogeosciences, 19, 891–906, https://doi.org/10.5194/bg-19-891-2022, https://doi.org/10.5194/bg-19-891-2022, 2022
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Coral bleaching events continue to drive the degradation of coral reefs worldwide. In this study we measured rates of daytime coral reef community calcification and photosynthesis during a reef-wide bleaching event. Despite a measured decline in coral health across several taxa, there was no change in overall daytime community calcification and photosynthesis. These findings highlight potential limitations of these community-level metrics to reflect actual changes in coral health.
Hyewon Heather Kim, Jeff S. Bowman, Ya-Wei Luo, Hugh W. Ducklow, Oscar M. Schofield, Deborah K. Steinberg, and Scott C. Doney
Biogeosciences, 19, 117–136, https://doi.org/10.5194/bg-19-117-2022, https://doi.org/10.5194/bg-19-117-2022, 2022
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Heterotrophic marine bacteria are tiny organisms responsible for taking up organic matter in the ocean. Using a modeling approach, this study shows that characteristics (taxonomy and physiology) of bacteria are associated with a subset of ecological processes in the coastal West Antarctic Peninsula region, a system susceptible to global climate change. This study also suggests that bacteria will become more active, in particular large-sized cells, in response to changing climates in the region.
Alice E. Webb, Didier M. de Bakker, Karline Soetaert, Tamara da Costa, Steven M. A. C. van Heuven, Fleur C. van Duyl, Gert-Jan Reichart, and Lennart J. de Nooijer
Biogeosciences, 18, 6501–6516, https://doi.org/10.5194/bg-18-6501-2021, https://doi.org/10.5194/bg-18-6501-2021, 2021
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The biogeochemical behaviour of shallow reef communities is quantified to better understand the impact of habitat degradation and species composition shifts on reef functioning. The reef communities investigated barely support reef functions that are usually ascribed to conventional coral reefs, and the overall biogeochemical behaviour is found to be similar regardless of substrate type. This suggests a decrease in functional diversity which may therefore limit services provided by this reef.
Emmanuel Devred, Andrea Hilborn, and Cornelia Elizabeth den Heyer
Biogeosciences, 18, 6115–6132, https://doi.org/10.5194/bg-18-6115-2021, https://doi.org/10.5194/bg-18-6115-2021, 2021
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A theoretical model of grey seal seasonal abundance on Sable Island (SI) coupled with chlorophyll-a concentration [chl-a] measured by satellite revealed the impact of seal nitrogen fertilization on the surrounding waters of SI, Canada. The increase in seals from about 100 000 in 2003 to about 360 000 in 2018 during the breeding season is consistent with an increase in [chl-a] leeward of SI. The increase in seal abundance explains 8 % of the [chl-a] increase.
Julie Meilland, Michael Siccha, Maike Kaffenberger, Jelle Bijma, and Michal Kucera
Biogeosciences, 18, 5789–5809, https://doi.org/10.5194/bg-18-5789-2021, https://doi.org/10.5194/bg-18-5789-2021, 2021
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Planktonic foraminifera population dynamics has long been assumed to be controlled by synchronous reproduction and ontogenetic vertical migration (OVM). Due to contradictory observations, this concept became controversial. We here test it in the Atlantic ocean for four species of foraminifera representing the main clades. Our observations support the existence of synchronised reproduction and OVM but show that more than half of the population does not follow the canonical trajectory.
Federica Maggioni, Mireille Pujo-Pay, Jérome Aucan, Carlo Cerrano, Barbara Calcinai, Claude Payri, Francesca Benzoni, Yves Letourneur, and Riccardo Rodolfo-Metalpa
Biogeosciences, 18, 5117–5140, https://doi.org/10.5194/bg-18-5117-2021, https://doi.org/10.5194/bg-18-5117-2021, 2021
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Based on current experimental evidence, climate change will affect up to 90 % of coral reefs worldwide. The originality of this study arises from our recent discovery of an exceptional study site where environmental conditions (temperature, pH, and oxygen) are even worse than those forecasted for the future.
While these conditions are generally recognized as unfavorable for marine life, we found a rich and abundant coral reef thriving under such extreme environmental conditions.
Nisan Sariaslan and Martin R. Langer
Biogeosciences, 18, 4073–4090, https://doi.org/10.5194/bg-18-4073-2021, https://doi.org/10.5194/bg-18-4073-2021, 2021
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Analyses of foraminiferal assemblages from the Mamanguape mangrove estuary (northern Brazil) revealed highly diverse, species-rich, and structurally complex biotas. The atypical fauna resembles shallow-water offshore assemblages and are interpreted to be the result of highly saline ocean waters penetrating deep into the estuary. The findings contrast with previous studies, have implications for the fossil record, and provide novel perspectives for reconstructing mangrove environments.
Jutta E. Wollenburg, Jelle Bijma, Charlotte Cremer, Ulf Bickmeyer, and Zora Mila Colomba Zittier
Biogeosciences, 18, 3903–3915, https://doi.org/10.5194/bg-18-3903-2021, https://doi.org/10.5194/bg-18-3903-2021, 2021
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Cultured at in situ high-pressure conditions Cibicides and Cibicidoides taxa develop lasting ectoplasmic structures that cannot be retracted or resorbed. An ectoplasmic envelope surrounds their test and may protect the shell, e.g. versus carbonate aggressive bottom water conditions. Ectoplasmic roots likely anchor the specimens in areas of strong bottom water currents, trees enable them to elevate themselves above ground, and twigs stabilize and guide the retractable pseudopodial network.
Kumar Nimit
Biogeosciences, 18, 3631–3635, https://doi.org/10.5194/bg-18-3631-2021, https://doi.org/10.5194/bg-18-3631-2021, 2021
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The Indian Ocean Rim hosts many of the underdeveloped and emerging economies that depend on ocean resources for the livelihood of millions. Operational ocean information services cater to the requirements of resource managers and end-users to efficiently harness resources, mitigate threats and ensure safety. This paper outlines existing tools and explores the ongoing research that has the potential to convert the findings into operational services in the near- to midterm.
Finn Mielck, Rune Michaelis, H. Christian Hass, Sarah Hertel, Caroline Ganal, and Werner Armonies
Biogeosciences, 18, 3565–3577, https://doi.org/10.5194/bg-18-3565-2021, https://doi.org/10.5194/bg-18-3565-2021, 2021
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Marine sand mining is becoming more and more important to nourish fragile coastlines that face global change. We investigated the largest sand extraction site in the German Bight. The study reveals that after more than 35 years of mining, the excavation pits are still detectable on the seafloor while the sediment composition has largely changed. The organic communities living in and on the seafloor were strongly decimated, and no recovery is observable towards previous conditions.
France Van Wambeke, Elvira Pulido, Philippe Catala, Julie Dinasquet, Kahina Djaoudi, Anja Engel, Marc Garel, Sophie Guasco, Barbara Marie, Sandra Nunige, Vincent Taillandier, Birthe Zäncker, and Christian Tamburini
Biogeosciences, 18, 2301–2323, https://doi.org/10.5194/bg-18-2301-2021, https://doi.org/10.5194/bg-18-2301-2021, 2021
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Michaelis–Menten kinetics were determined for alkaline phosphatase, aminopeptidase and β-glucosidase in the Mediterranean Sea. Although the ectoenzymatic-hydrolysis contribution to heterotrophic prokaryotic needs was high in terms of N, it was low in terms of C. This study points out the biases in interpretation of the relative differences in activities among the three tested enzymes in regard to the choice of added concentrations of fluorogenic substrates.
Katharine T. Bigham, Ashley A. Rowden, Daniel Leduc, and David A. Bowden
Biogeosciences, 18, 1893–1908, https://doi.org/10.5194/bg-18-1893-2021, https://doi.org/10.5194/bg-18-1893-2021, 2021
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Turbidity flows – underwater avalanches – are large-scale physical disturbances believed to have profound impacts on productivity and diversity of benthic communities in the deep sea. We reviewed published studies and found that current evidence for changes in productivity is ambiguous at best, but the influence on regional and local diversity is clearer. We suggest study design criteria that may lead to a better understanding of large-scale disturbance effects on deep-sea benthos.
Phillip Williamson, Hans-Otto Pörtner, Steve Widdicombe, and Jean-Pierre Gattuso
Biogeosciences, 18, 1787–1792, https://doi.org/10.5194/bg-18-1787-2021, https://doi.org/10.5194/bg-18-1787-2021, 2021
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The reliability of ocean acidification research was challenged in early 2020 when a high-profile paper failed to corroborate previously observed impacts of high CO2 on the behaviour of coral reef fish. We now know the reason why: the
replicatedstudies differed in many ways. Open-minded and collaborative assessment of all research results, both negative and positive, remains the best way to develop process-based understanding of the impacts of ocean acidification on marine organisms.
Michael Lintner, Bianca Lintner, Wolfgang Wanek, Nina Keul, and Petra Heinz
Biogeosciences, 18, 1395–1406, https://doi.org/10.5194/bg-18-1395-2021, https://doi.org/10.5194/bg-18-1395-2021, 2021
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Foraminifera are unicellular marine organisms that play an important role in the marine element cycle. Changes of environmental parameters such as salinity or temperature have a significant impact on the faunal assemblages. Our experiments show that changes in salinity immediately influence the foraminiferal activity. Also the light regime has a significant impact on carbon or nitrogen processing in foraminifera which contain no kleptoplasts.
Michele Casini, Martin Hansson, Alessandro Orio, and Karin Limburg
Biogeosciences, 18, 1321–1331, https://doi.org/10.5194/bg-18-1321-2021, https://doi.org/10.5194/bg-18-1321-2021, 2021
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In the past 20 years the condition of the eastern Baltic cod has dropped, with large implications for the fishery. Our results show that simultaneously the cod population has moved deeper while low-oxygenated waters detrimental for cod growth have become shallower. Cod have thus dwelled more in detrimental waters, explaining the drop in its condition. This study, using long-term fish and hydrological monitoring data, evidences the impact of deoxygenation on fish biology and fishing.
Elizabeth D. LaBone, Kenneth A. Rose, Dubravko Justic, Haosheng Huang, and Lixia Wang
Biogeosciences, 18, 487–507, https://doi.org/10.5194/bg-18-487-2021, https://doi.org/10.5194/bg-18-487-2021, 2021
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The hypoxic zone is an area of low dissolved oxygen (DO) in the Gulf of Mexico. Fish can be killed by exposure to hypoxia and can be negatively impacted by exposure to low, nonlethal DO concentrations (sublethal DO). We found that high sublethal area resulted in higher exposure and DO variability had a small effect on exposure. There was a large variation in exposure among individuals, which when combined with spatial variability of DO, can result in an underestimation of exposure when averaged.
Svenja Reents, Peter Mueller, Hao Tang, Kai Jensen, and Stefanie Nolte
Biogeosciences, 18, 403–411, https://doi.org/10.5194/bg-18-403-2021, https://doi.org/10.5194/bg-18-403-2021, 2021
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By conducting a flooding experiment with two genotypes of the salt-marsh grass Elymus athericus, we show considerable differences in biomass response to flooding within the same species. As biomass production plays a major role in sedimentation processes and thereby salt-marsh accretion, we emphasise the importance of taking intraspecific differences into account when evaluating ecosystem resilience to accelerated sea level rise.
Cara Nissen and Meike Vogt
Biogeosciences, 18, 251–283, https://doi.org/10.5194/bg-18-251-2021, https://doi.org/10.5194/bg-18-251-2021, 2021
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Using a regional Southern Ocean ecosystem model, we find that the relative importance of Phaeocystis and diatoms at high latitudes is controlled by iron and temperature variability, with light levels controlling the seasonal succession in coastal areas. Yet, biomass losses via aggregation and grazing matter as well. We show that the seasonal succession of Phaeocystis and diatoms impacts the seasonality of carbon export fluxes with ramifications for nutrient cycling and food web dynamics.
Jiangtao Li, Lingyuan Gu, Shijie Bai, Jie Wang, Lei Su, Bingbing Wei, Li Zhang, and Jiasong Fang
Biogeosciences, 18, 113–133, https://doi.org/10.5194/bg-18-113-2021, https://doi.org/10.5194/bg-18-113-2021, 2021
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Few studies have focused on the particle-attached (PA) and free-living (FL) microbes of the deep ocean. Here we determined PA and FL microbial communities along depth profiles of the SCS. PA and FL fractions accommodated divergent microbial compositions, and most of them are potentially generalists with PA and FL dual lifestyles. A potential vertical connectivity between surface-specific microbes and those in the deep ocean was indicated, likely through microbial attachment to sinking particles.
Saskia Brix, Karen J. Osborn, Stefanie Kaiser, Sarit B. Truskey, Sarah M. Schnurr, Nils Brenke, Marina Malyutina, and Pedro Martinez Arbizu
Biogeosciences, 17, 6163–6184, https://doi.org/10.5194/bg-17-6163-2020, https://doi.org/10.5194/bg-17-6163-2020, 2020
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The Clarion–Clipperton Fracture Zone (CCZ) located in the Pacific is commercially the most important area of proposed manganese nodule mining. Extraction of this will influence the life and distribution of small deep-sea invertebrates like peracarid crustaceans, of which >90 % are undescribed species new to science. We are doing a species delimitation approach as baseline for an ecological interpretation of species distribution and discuss the results in light of future deep-sea conservation.
Amal Jayakumar and Bess B. Ward
Biogeosciences, 17, 5953–5966, https://doi.org/10.5194/bg-17-5953-2020, https://doi.org/10.5194/bg-17-5953-2020, 2020
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Diversity and community composition of nitrogen-fixing microbes in the three main oxygen minimum zones of the world ocean were investigated using nifH clone libraries. Representatives of three main clusters of nifH genes were detected. Sequences were most diverse in the surface waters. The most abundant OTUs were affiliated with Alpha- and Gammaproteobacteria. The sequences were biogeographically distinct and the dominance of a few OTUs was commonly observed in OMZs in this (and other) studies.
Guillermo Feliú, Marc Pagano, Pamela Hidalgo, and François Carlotti
Biogeosciences, 17, 5417–5441, https://doi.org/10.5194/bg-17-5417-2020, https://doi.org/10.5194/bg-17-5417-2020, 2020
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The impact of Saharan dust deposition events on the Mediterranean Sea ecosystem was studied during a basin-scale survey (PEACETIME cruise, May–June 2017). Short-term responses of the zooplankton community were observed after episodic dust deposition events, highlighting the impact of these events on productivity up to the zooplankton level in the poorly fertilized pelagic ecosystems of the southern Mediterranean Sea.
Douglas Lessa, Raphaël Morard, Lukas Jonkers, Igor M. Venancio, Runa Reuter, Adrian Baumeister, Ana Luiza Albuquerque, and Michal Kucera
Biogeosciences, 17, 4313–4342, https://doi.org/10.5194/bg-17-4313-2020, https://doi.org/10.5194/bg-17-4313-2020, 2020
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We observed that living planktonic foraminifera had distinct vertically distributed communities across the Subtropical South Atlantic. In addition, a hierarchic alternation of environmental parameters was measured to control the distribution of planktonic foraminifer's species depending on the water depth. This implies that not only temperature but also productivity and subsurface processes are signed in fossil assemblages, which could be used to perform paleoceanographic reconstructions.
Karl M. Attard and Ronnie N. Glud
Biogeosciences, 17, 4343–4353, https://doi.org/10.5194/bg-17-4343-2020, https://doi.org/10.5194/bg-17-4343-2020, 2020
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Light-use efficiency defines the ability of primary producers to convert sunlight energy to primary production. This report provides a framework to compute hourly and daily light-use efficiency using underwater eddy covariance, a recent technological development that produces habitat-scale rates of primary production for many different habitat types. The approach, tested on measured flux data, provides a useful means to compare habitat productivity across time and space.
Stacy Deppeler, Kai G. Schulz, Alyce Hancock, Penelope Pascoe, John McKinlay, and Andrew Davidson
Biogeosciences, 17, 4153–4171, https://doi.org/10.5194/bg-17-4153-2020, https://doi.org/10.5194/bg-17-4153-2020, 2020
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Our study showed how ocean acidification can exert both direct and indirect influences on the interactions among trophic levels within the microbial loop. Microbial grazer abundance was reduced at CO2 concentrations at and above 634 µatm, while microbial communities increased in abundance, likely due to a reduction in being grazed. Such changes in predator–prey interactions with ocean acidification could have significant effects on the food web and biogeochemistry in the Southern Ocean.
Mirjana Najdek, Marino Korlević, Paolo Paliaga, Marsej Markovski, Ingrid Ivančić, Ljiljana Iveša, Igor Felja, and Gerhard J. Herndl
Biogeosciences, 17, 3299–3315, https://doi.org/10.5194/bg-17-3299-2020, https://doi.org/10.5194/bg-17-3299-2020, 2020
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The response of Cymodocea nodosa to environmental changes was reported during a 15-month period. The meadow decline was triggered in spring by the simultaneous reduction of available light in the water column and the creation of anoxic conditions in the rooted area. This disturbance was critical for the plant since it took place during its recruitment phase when metabolic needs are maximal and stored reserves minimal. The loss of such habitat-forming seagrass is a major environmental concern.
Timm Schoening, Autun Purser, Daniel Langenkämper, Inken Suck, James Taylor, Daphne Cuvelier, Lidia Lins, Erik Simon-Lledó, Yann Marcon, Daniel O. B. Jones, Tim Nattkemper, Kevin Köser, Martin Zurowietz, Jens Greinert, and Jose Gomes-Pereira
Biogeosciences, 17, 3115–3133, https://doi.org/10.5194/bg-17-3115-2020, https://doi.org/10.5194/bg-17-3115-2020, 2020
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Seafloor imaging is widely used in marine science and industry to explore and monitor areas of interest. The selection of the most appropriate imaging gear and deployment strategy depends on the target application. This paper compares imaging platforms like autonomous vehicles or towed camera frames and different deployment strategies of those in assessing the megafauna abundance of polymetallic-nodule fields. The deep-sea mining industry needs that information for robust impact monitoring.
Tatsuro Tanioka and Katsumi Matsumoto
Biogeosciences, 17, 2939–2954, https://doi.org/10.5194/bg-17-2939-2020, https://doi.org/10.5194/bg-17-2939-2020, 2020
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We conducted an extensive literature survey (meta-analysis) on how the C : N : P ratio varies with change in key environmental drivers. We found that the expected reduction in nutrients and warming under the future climate change scenario is likely to result in increased C : P and C : N of marine phytoplankton. Further, our findings highlight the greater stoichiometric plasticity of eukaryotes over prokaryotes, which provide us insights on how to understand and model plankton.
Vanessa Joglar, Antero Prieto, Esther Barber-Lluch, Marta Hernández-Ruiz, Emilio Fernández, and Eva Teira
Biogeosciences, 17, 2807–2823, https://doi.org/10.5194/bg-17-2807-2020, https://doi.org/10.5194/bg-17-2807-2020, 2020
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Coastal marine ecosystems are among the most ecologically and economically productive areas providing a large fraction of ecosystem goods and services to human populations, and B vitamins have long been considered important growth factors for phytoplankton. Our findings indicate that the responses of microbial plankton to B-vitamin supply are mainly driven by the bacterial community composition and that microbial plankton in this area seems to be well adapted to cope with B-vitamin shortage.
Tasnim Patel, Henri Robert, Cedric D'Udekem D'Acoz, Koen Martens, Ilse De Mesel, Steven Degraer, and Isa Schön
Biogeosciences, 17, 2731–2744, https://doi.org/10.5194/bg-17-2731-2020, https://doi.org/10.5194/bg-17-2731-2020, 2020
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Exploitation of deep-sea resources in one of the largest ecosystems on the planet has rendered research of its biodiversity more urgent than ever before. We investigated the known habitats and connectivity of deep-sea scavenging amphipods and obtained important knowledge about several species. We also demonstrated that a long-term disturbance experiment has possibly reduced amphipod biodiversity. These data and further sampling expeditions are instrumental for formulating sustainable policies.
Daphne Cuvelier, Pedro A. Ribeiro, Sofia P. Ramalho, Daniel Kersken, Pedro Martinez Arbizu, and Ana Colaço
Biogeosciences, 17, 2657–2680, https://doi.org/10.5194/bg-17-2657-2020, https://doi.org/10.5194/bg-17-2657-2020, 2020
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Polymetallic nodule mining will remove hard substrata from the abyssal deep-sea floor. The only neighbouring ecosystems featuring hard substratum are seamounts, and their inhabiting fauna could aid in recovery post-mining. Nevertheless, first observations of seamount megafauna were very different from nodule-associated megafauna and showed little overlap. The possible uniqueness of these ecosystems implies that they should be included in management plans for the conservation of biodiversity.
Karen F. Wishner, Brad Seibel, and Dawn Outram
Biogeosciences, 17, 2315–2339, https://doi.org/10.5194/bg-17-2315-2020, https://doi.org/10.5194/bg-17-2315-2020, 2020
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Increasing deoxygenation and oxygen minimum zone expansion are consequences of global warming. Copepod species had different vertical distribution strategies and physiologies associated with oxygen profile variability (0–1000 m). Species (1) changed vertical distributions and maximum abundance depth, (2) shifted diapause depth, (3) changed diel vertical migration depths, or (4) changed epipelagic depth range in the aerobic mixed layer. Present-day variability helps predict future scenarios.
Magdalini Christodoulou, Timothy O'Hara, Andrew F. Hugall, Sahar Khodami, Clara F. Rodrigues, Ana Hilario, Annemiek Vink, and Pedro Martinez Arbizu
Biogeosciences, 17, 1845–1876, https://doi.org/10.5194/bg-17-1845-2020, https://doi.org/10.5194/bg-17-1845-2020, 2020
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Unexpectedly high diversity was revealed in areas licenced for polymetallic nodule mining exploration in the Pacific Ocean. For the first time, a comprehensive reference library including 287 novel ophiuroid sequences allocated to 43 species was produced. Differences in food availability along the nodule province of CCZ were reflected in the biodiversity patterns observed. The APEI3's dissimilarity with the exploration contract areas questions its ability to serve as a biodiversity reservoir.
Julie Meilland, Hélène Howa, Vivien Hulot, Isaline Demangel, Joëlle Salaün, and Thierry Garlan
Biogeosciences, 17, 1437–1450, https://doi.org/10.5194/bg-17-1437-2020, https://doi.org/10.5194/bg-17-1437-2020, 2020
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This study reports on planktonic foraminifera (PF) diversity and distribution in the Barents Sea. The species Globigerinita uvula and Turborotalita quinqueloba dominate the water column while surface sediments are dominated by Neogloboquadrina pachyderma. We hypothesize the unusual dominance of G. uvula in the water to be a seasonal signal or a result of climate forcing. Size-normalized-protein concentrations of PF show a northward decrease, suggesting biomass to vary with the environment.
Julien Richirt, Bettina Riedel, Aurélia Mouret, Magali Schweizer, Dewi Langlet, Dorina Seitaj, Filip J. R. Meysman, Caroline P. Slomp, and Frans J. Jorissen
Biogeosciences, 17, 1415–1435, https://doi.org/10.5194/bg-17-1415-2020, https://doi.org/10.5194/bg-17-1415-2020, 2020
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The paper presents the response of benthic foraminiferal communities to seasonal absence of oxygen coupled with the presence of hydrogen sulfide, considered very harmful for several living organisms.
Our results suggest that the foraminiferal community mainly responds as a function of the duration of the adverse conditions.
This knowledge is especially useful to better understand the ecology of benthic foraminifera but also in the context of palaeoceanographic interpretations.
Xiangqi Yi, Fei-Xue Fu, David A. Hutchins, and Kunshan Gao
Biogeosciences, 17, 1169–1180, https://doi.org/10.5194/bg-17-1169-2020, https://doi.org/10.5194/bg-17-1169-2020, 2020
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Combined effects of warming and light intensity were estimated in N2-fixing cyanobacterium Trichodesmium. Its physiological responses to warming were significantly modulated by light, with growth peaking at 27 °C under the light-saturating condition but being non-responsive across the range of 23–31 °C under the light-limiting condition. Light shortage also weakened the acclimation ability of Trichodesmium to warming, making light-limited Trichodesmium more sensitive to acute temperature change.
Jan Goleń, Jarosław Tyszka, Ulf Bickmeyer, and Jelle Bijma
Biogeosciences, 17, 995–1011, https://doi.org/10.5194/bg-17-995-2020, https://doi.org/10.5194/bg-17-995-2020, 2020
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We studied the organisation and dynamics of actin in foraminifera. Actin is one of the key structural proteins in most lifeforms. Our investigations show that in foraminifera it forms small granules, around 1 µm in diameter, that display rapid movement. This granularity is unusual in comparison to other organisms. We suppose that these granules are most likely involved in the formation of all types of pseudopods responsible for movement, food capturing, biomineralisation, and other functions.
Paulo Bonifácio, Pedro Martínez Arbizu, and Lénaïck Menot
Biogeosciences, 17, 865–886, https://doi.org/10.5194/bg-17-865-2020, https://doi.org/10.5194/bg-17-865-2020, 2020
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The patterns observed in the composition of polychaete assemblages were attributed to variations in food supply at the regional scale and nodule density at the local scale. The high levels of species replacement were mainly driven by rare species, leading to regional species pool estimates between 498 and 240 000 species. The high proportion of singletons seems reflect an under-sampling bias that is currently preventing the assessment of potential biodiversity loss due to nodule mining.
Cited articles
Abrantes, F., Meggers, H., Nave, S., Bollman, J., Palma, S., Sprengel, C., Henderiks, J., Spies, A., Salgueiro, E., Moita, T., and Neuer, S.: Fluxes of micro-organisms along a productivity gradient in the Canary Islands region (29∘ N): implications for paleoreconstructions, Deep-Sea Res. Pt. II, 49, 3599–3629, 2002.
Andrews, G. W.: Revision of the diatom genus Delphineis and morphology of Delphineis surirella (Ehrenberg) G. W. Andrews, n. comb, edited by: Ross, R., Proc. Sixth Diatom Symp., Otto Koeltz, Koenigstein, 81–92, 1981.
Arístegui, J., Barton, E. C., Aìlvarez-Salgado, X. A., Santos, A. M. P., Figueiras, F. G., Kifani, S., Hernaìndez-Leoìn, S., Mason, E., Machuì, E., and Demarcq, H.: Sub-regional ecosystem variability in the Canary Current upwelling, Prog. Oceanogr., 83, 33–48, https://doi.org/10.1016/j.pocean.2009.07.031, 2009.
Bakun, A.: Global climate change and intensification of coastal ocean upwelling, Science, 247, 198–201, 1990.
Bakun, A., Field, D. B., Redondo-Rodriguez, A., and Weeks, S. J.: Greenhouse gas, upwelling-favorable winds, and the future of coastal ocean upwelling ecosystems, Global Change Biol., 16, 1213–1228, 2010.
Bárcena, M. A., Flores, J. A., Sierro, F. J., Pérez-Folgado, M., Fabres, J., Calafat, A., and Canals, M: Planktonic response to main oceanographic changes in the Alboran Sea (Western Mediterranean) as documented in sediment traps and surface sediments, Mar. Micropalaleontol., 53, 423–445, 2004.
Barton, E. D., Field, D. B., and Roy, C.: Canary current upwelling: More or less?, Prog. Oceanogr., 116, 167–178, 2013.
Behrenfeld, M. J., Randerson, J. T., McClain, C. R., Feldman, G. C., Los, S. O., Tucker, C. J., Falkowski, P. G., Field, C. B., Frouin, R., Esaias, W. E., Kolber, D. D., and Pollack, N. H.: Biospheric Primary Production During an ENSO Transition, Science, 291, 2594–2597, 2001.
Buckley, M. W. and Marshall, J.: Observations, inferences, and mechanisms of Atlantic Meridional Overturning Circulation variability, Rev. Geophys., 54, 5–63, https://doi.org/10.1002/2015RG000493, 2016.
Buesseler, K. O., Antia, A. A., Chen, M., Fowler, S. W., Gardner, W. D., Gustafsson, O., Harada, K., Michaels, A. F., Rutgers van der Loeff, M., Sarin, M., Steinberg, D. K., and Trull, T.: An assessment of the use of sediment traps for estimating upper ocean particle fluxes, J. Mar. Res., 65, 345–416, 2007.
Chavez, F. P. and Messié, M.: A comparison of Eastern Boundary Upwelling Ecosystems, Prog. Oceanogr., 83, 80–96, 2009.
Clement, A., Bellomo, K., Murphy, L. N., Cane, M. A., Mauritsen, T., Rädel, G., and Stevens, B.: The Atlantic Multidecadal Oscillation without a role for ocean circulation, Science, 350, 320–324, https://doi.org/10.1126/science.aab3980, 2015.
Cropper, T. E., Hanna, E., and Bigg, G. R.: Spatial and temporal seasonal trends in coastal upwelling off Northwest Africa, 1981–2012, Deep-Sea Res. Pt. I, 86, 94–111, 2014.
Crosta, X., Romero, O. E., Ther, O., and Schneider, R. R.: Climatically-controlled siliceous productivity in the eastern Gulf of Guinea during the last 40 000 yr, Clim. Past, 8, 415–431, https://doi.org/10.5194/cp-8-415-2012, 2012.
Dong, B., Sutton, R. T., and Scaife, A. A.: Multidecadal modulation of El Niño-Southern Oscillation (ENSO) variance by Atlantic Ocean sea surface temperatures, Geophys. Res. Lett., 33, L08705, https://doi.org/10.1029/2006GL025766, 2006.
Enfield, D. B., Mestas-Nuñez, A. M., and Trimble, P. J.: The Atlantic Multidecadal Oscillation and its relation to rainfall and river flows in the continental U. S., Geophys. Res. Lett., 28, 2077–2080, 2001.
Fischer, G. and Karakaş, G.: Sinking rates and ballast composition of particles in the Atlantic Ocean: implications for the organic carbon fluxes to the deep ocean, Biogeosciences, 6, 85–102, https://doi.org/10.5194/bg-6-85-2009, 2009.
Fischer, G., Krause, S. G., Neuer, S., and Wefer, G.: Short-term sedimentation pulses recorded with a chlorophyll sensor and sediment traps in 900 m water depth in the Canary Basin, Limnol. Oceanogr., 41, 1354–1359, https://doi.org/10.4319/lo.1996.41.6.1354, 1996.
Fischer, G., Reuter, C., Karakaş, G., Nowald, N., and Wefer, G.: Offshore advection of particles within the Cape Blanc filament, Mauritania: Results from observational and modelling studies, Prog. Oceanogr., 83, 322–330, 2009.
Fischer, G., Romero, O., Merkel, U., Donner, B., Iversen, M., Nowald, N., Ratmeyer, V., Ruhland, G., Klann, M., and Wefer, G.: Deep ocean mass fluxes in the coastal upwelling off Mauritania from 1988 to 2012: variability on seasonal to decadal timescales, Biogeosciences, 13, 3071–3090, https://doi.org/10.5194/bg-13-3071-2016, 2016.
Fischer, G., Romero, O. E., Toby, E., Iversen, M., Donner, B., Mollenhauer, G., Nowald, N., Ruhland, G., Klann, M., Hamady, B., and Wefer, G.: Changes in the Dust-Influenced Biological Carbon Pump in the Canary Current System: Implications from a Coastal and an Offshore Sediment Trap Record Off Cape Blanc, Mauritania, Global Biogeochem. Cy., 33, 1100–1128, 2019.
Fréon, P., Barange, M., and Arístegui, J.: Eastern Boundary Upwelling Ecosystems: Integrative and comparative approaches, Prog. Oceanogr., 83, 1–14, https://doi.org/10.1016/j.pocean.2009.08.001, 2009.
Friese, C. A., van Hateren, J. A., Vogt, C., Fischer, G., and Stuut, J.-B. W.: Seasonal provenance changes in present-day Saharan dust collected in and off Mauritania, Atmos. Chem. Phys., 17, 10163–10193, https://doi.org/10.5194/acp-17-10163-2017, 2017.
Gabric, A. J., Garcia, L., Van Camp, L., Nykjaer, L., Eifler, W., and Schrimpf, W.: Offshore export of shelf production in the Cape Blanc (Mauritania) giant filament as derived from Coastal Zone Color Scanner Imagery, J. Geophys. Res., 98, 4697–4712, 1993.
Gómez-Gesteira, M., De Castro, M., Álvarez, I., Lorenzo, M. N.,
Gesteira, J. L. G., and Crespo, A. J. C.: Spatio-temporal Upwelling Trends along the Canary Upwelling System (1967–2006), Ann. NY. Acad. Sci., 1146, 320–337, https://doi.org/10.1196/annals.1446.004, 2008.
Hagen, E.: Northwest African upwelling scenario, Oceanol. Acta, 24, S113–S128, 2001.
Hasle, G. A. and Syvertsen, E. E.: Marine diatoms, in: Identifying marine diatoms and dinoflagellates, edited by: Thomas, C., Academic Press, Inc., San Diego, CA, 1–385, 1996.
Helmke, P., Romero, O. E., and Fischer, G.: Northwest African upwelling and its effect on off-shore organic carbon export to the deep sea, Global Biogeochem. Cy., 19, GB4015, https://doi.org/10.1029/2004GB002265, 2005.
Hurrell, J. W.: Decadal Trends in the North Atlantic Oscillation, Science, 269, 676–679, https://doi.org/10.1126/science.269.5224.676, 1995.
Jungclaus, J. H., Haak, H., Latif, M., and Mikolajewicz, U.: Arctic-North Atlantic interactions and multidecadal variability of the meridional overturning circulation, J. Climate, 18, 4013–4031, 2005.
Karakaş, G., Nowald, N., Blaas, M., Marchesiello, P., Frickenhaus, S., and Schlitzer, R.: High-resolution modeling of sediment erosion and particle transport across the northwest African shelf, J. Geophys. Res., 111, C06025, https://doi.org/10.1029/2005JC003296, 2006.
Karakaş, G., Nowald, N., Schäfer-Neth, C., Iversen, M., Barkmann, W., Fischer, G., Marchesiello, P., and Schlitzer, R.: Impact of particle aggregation on vertical fluxes of organic matter, Prog. Oceanogr., 83, 331–341, 2009.
Knight, J. R., Allan, R. J., Folland, C. K., Vellinga, M., and Mann, M. E.: A signature of persistent natural thermohaline circulation cycles in observed climate, Geophys. Res. Lett., 32, L20708, https://doi.org/10.1029/2005GL024233, 2005.
Kremling, K., Lentz, U., Zeitzschell, B., Schulz-Bull, D. E., and Duinker, J. C.: New type of time-series sediment trap for the reliable collection of inorganic and organic trace chemical substances, Rev. Sci. Instrum., 67, 4360–4363, 1996.
Lange, C. B., Romero, O. E., Wefer, G., and Gabric, A. J.: Offshore influence of coastal upwelling off Mauretania, NW Africa, as recorded by diatoms in sediment traps at 2195 m water depth, Deep-Sea Res. Pt. I, 45, 985–1013, 1998.
Lange, C. B., Weinheimer, A. L., Reid, F. M. H., Tappa, E., and Thunell, R. C.: Response of siliceous microplankton from the Santa Barbara Basin to the 1997–98 El Niño Event, Cal. Coop. Ocean. Fish, 41, 186–193, 2000.
Lathuilière, C., Echevin, V., and Levy, M.: Seasonal and intraseasonal surface chlorophyll-a variability along the north-west African coast, J. Geophys. Res.-Oceans, 13, C05007, https://doi.org/10.1029/2007JC004433, 2008.
Legendre, P. and Legendre, L. F.: Numerical ecology, Developments in
Environmental Modelling, Vol. 24, Elsevier, Amsterdam, 2012.
Levine, A. F. Z., McPhaden, M. J., and Frierson, D. M. W.: The impact of the AMO on multidecadal ENSO variability, Geophys. Res. Lett., 44, 3877–3886, 2017.
McCarthy, G. D., Smeed, D. A., Johns, W. E., Frajka-Williams, E., Moat, B. I., Rayner, D., Baringer, M. O., Meinen, C. S., Collins, J., and Bryden, H. J., Measuring the Atlantic Meridional Overturning Circulation at 26∘ N, Prog. Oceanogr., 130, 91–111, https://doi.org/10.1016/j.pocean.2014.10.006, 2015.
McPhaden, M. J.: Genesis and Evolution of the 1997–98 El Niño, Science, 283, 950–954, 1999.
Medhaug, I. and Furevik, T.: North Atlantic 20th century multidecadal variability in coupled climate models: sea surface temperature and ocean overturning circulation, Ocean Sci., 7, 389–404, https://doi.org/10.5194/os-7-389-2011, 2011.
Meunier, T., Barton, E. D., Barreiro, B., and Torres, R.: Upwelling filaments off Cape Blanc: interaction of the NW African upwelling current and the Cape Verde frontal zone eddy field?, J. Geophys. Res.-Oceans, 117, C08031, https://doi.org/10.1029/2012JC007905, 2012.
Mittelstaedt, E.: The upwelling area off Northwest Africa – a description of phenomena related to coastal upwelling, Prog. Oceanogr., 12, 307–331, 1983.
Mittelstaedt, E.: The ocean boundary along the northwest African coast: Circulation and oceanographic properties at the sea surface, Prog. Oceanogr., 26, 307–355, 1991.
Narayan, N., Paul, A., Mulitza, S., and Schulz, M.: Trends in coastal upwelling intensity during the late 20th century, Ocean Sci., 6, 815–823, https://doi.org/10.5194/os-6-815-2010, 2010.
Nave, S., Freitas, P., and Abrantes, F.: Coastal upwelling in the Canary Island region: spatial variability reflected by the surface sediment diatom record, Mar. Micropaleontol., 42, 1–23, 2001.
Nowald, N., Iversen, M. H., Fischer, G., Ratmeyer, V., and Wefer, G.: Time series of in-situ particle properties and sediment trap fluxes in the coastal upwelling filament off Cape Blanc, Mauritania, Prog. Oceanogr., 137, 1–11, 2015.
Nykjær, L. and Van Camp, L.: Seasonal and interannual variability of the coastal upwelling along northwest Africa and Portugal from 1981 to 1991, J. Geophys. Res., 99, 14197–14207, 1994.
O'Reilly, C. H., Huber, L. M., Woollings, T., and Zanna, L.: The signature of low-frequency oceanic forcing in the Atlantic Multidecadal Oscillation, Geophys. Res. Lett., 43, 2810–2818, https://doi.org/10.1002/2016GL067925, 2016.
Pardo, P., Padín, X., Gilcoto, M., Farina-Busto, L., and Pèrez, F.: Evolution of upwelling systems coupled to the long term variability in sea surface temperature and Ekman transport, Clim. Res., 48, 231–246, 2011.
Patti, B., Guisande, C. Riveiro, I., Thejll, P., Cuttitta, A., Bonanno, A., Basilone, G., Buscaino, G., and Mazzola, S.: Effect of atmospheric CO2 and solar activity on wind regime and water column stability in the major global upwelling areas, Estuar. Coast. Shelf S., 88, 45–52, https://doi.org/10.1016/j.ecss.2010.03.004, 2010.
Pelegrí, J. L., Marrero-Díaz, A., and Ratsimandresy, A. W.: Nutrient irrigation of the North Atlantic, Prog. Oceanogr., 70, 366–406, 2006.
Pelegrí, J. L., Peña-Izquierdo, J., Machín, F., Meiners, C., and
Presas-Navarro, C.: Oceanography of the Cape Verde Basin and Mauritanian Slope Waters, in: Deep-Sea Ecosystems Off Mauritania, edited by: Ramos, A.,
Ramil, F., and Sanz, J., Springer, Dordrecht, 119–153, https://doi.org/10.1007/978-94-024-1023-5_3, 2017.
Pradhan, Y., Lavender, S. J., Hardman-Mountford, N. J., and Aiken, J.: Seasonal and inter-annual variability of chlorophyll-a concentration in the Mauritanian upwelling: Observation of an anomalous event during 1998–199, Deep-Sea Res. Pt. I, 53, 1548–1559, 2006.
Ragueneau, O., Tréguer, P., Leynaert, A., Anderson, R. F., Brzezinski, M. A., DeMaster, D. J., Dugdale, R. C., Dymond, J., Fischer, G., François, R., Heinze, C., Maier-Reimer, E., Martin-Jézéquel, V., Nelson, D. M., and Quéguiner, B.: A review of the Si cycle in the modern ocean: recent progress and missing gaps in the application of biogenic opal as a paleoproductivity proxy, Global Planet. Change, 26, 317–365, 2000.
Rigual-Hernández, A. S., Bárcena, M. A., Jordan, R. W., Sierro, F. J., Flores, J. A., Meier, K. J. S., Beaufort, L., and Heussner, S.: Diatom fluxes in the NW Mediterranean: evidence from a 12-year sediment trap record and surficial sediments, J. Plankton Res., 35, 1109–1125, 2013.
Rines, J. E. B. and Hargraves, P. E.: The Chaetoceros Ehrenberg
(Bacillariophyceae) Flora of Narrangansett Bay, Rhode Island, U.S.A., 79,
Bibl. Diatomol., J. Cramer, Berlin, Stuttgart, 196 pp., 1988.
Romero, O. E.: Total flux of diatoms and relative composition of diatom groups in trap samples at the CBmeso (= Cape Blanc mesotrophic), off Mauritania, PANGAEA, https://doi.org/10.1594/PANGAEA.922784, 2020.
Romero, O. E. and Armand, L. K.: Marine diatoms as indicators of modern changes in oceanographic conditions, in: The Diatoms, Applications for the Environmental and Earth Sciences, 2nd Edn., edited by: Smol, J. P. and Stoermer, E. F., Cambridge University Press, Cambridge, 373–400, 2010.
Romero, O. E. and Fischer, G.: Shift in the species composition of the diatom community in the eutrophic Mauritanian coastal upwelling: Results from a multi-year sediment trap experiment (2003–2010), Prog. Oceanogr., 159, 31–44, 2017.
Romero, O. E., Lange, C. B., Fischer, G., Treppke, U. F., and Wefer, G.:
Variability in export production documented by downward fluxes and species
composition of marine planktonic diatoms: Observations from the tropical and
equatorial Atlantic, in: The Use of Proxies in Paleoceanography – Examples
from the South Atlantic, edited by: Fischer, G. and Wefer, G., Springer Verlag, Berlin, Heidelberg, 365–392, 1999a.
Romero, O. E., Lange, C. B., Swap, R. J., and Wefer, G.: Eolian-transported freshwater diatoms and phytoliths across the equatorial Atlantic record temporal changes in Saharan dust transport patterns, J. Geophys. Res., 104, 3211–3222, 1999b.
Romero, O. E., Hebbeln, D., and Wefer, G.: Temporal and spatial distribution in export production in the SE Pacific Ocean: evidence from siliceous plankton fluxes and surface sediment assemblages, Deep-Sea Res. Pt. I, 48, 2673–2697, 2001.
Romero, O. E., Lange, C. B., and Wefer, G.: Interannual variability (1988–1991) of siliceous phytoplankton fluxes off northwest
Africa, J. Plankton. Res. 24, 1035–1046, https://doi.org/10.1093/plankt/24.10.1035, 2002.
Romero, O. E., Dupont, L., Wyputta, U., Jahns, S., and Wefer, G.: Temporal variability of fluxes of eolian-transported freshwater diatoms, phytoliths, and pollen grains off Cape Blanc as reflection of land-atmosphere-ocean interactions in northwest Africa, J. Geophys. Res., 108, 3153, https://doi.org/10.1029/2000JC000375, 2003.
Romero, O. E., Armand, L. K., Crosta, X., and Pichon, J.-J.: The biogeography of major diatom taxa in Southern Ocean surface sediments: 3. Tropical/Subtropical species, Palaeogeogr. Palaeocl., 223, 49–65, 2005.
Romero, O. E., Rixen, T., and Herunadi, B.: Effects of hydrographic and climatic forcing on diatom production and export in the tropical southeastern Indian Ocean, Mar. Ecol. Progr. Ser., 384, 69–82, https://doi.org/10.3354/meps08013, 2009a.
Romero, O. E., Thunell, R. C., Astor, Y., and Varela, R.: Seasonal and
interannual dynamics in diatom production in the Cariaco Basin, Venezuela,
Deep-Sea Res. Pt. I, 56, 571–581, https://doi.org/10.1016/j.dsr.2008.12.005, 2009b.
Romero, O. E., Baumann, K.-H., Zonneveld, K. A. F., Donner, B., Hefter, J., Hamady, B., Pospelova, V., and Fischer, G.: Flux variability of phyto- and zooplankton communities in the Mauritanian coastal upwelling between 2003 and 2008, Biogeosciences, 17, 187–214, https://doi.org/10.5194/bg-17-187-2020, 2020.
Round, F. E., Crawford, R. M., and Mann, D. G.: The diatoms, Cambridge University Press, Cambridge, 747 pp., 1990.
Sancetta, C. and Calvert, S. E.: The annual cycle of sedimentation in Saanich Inlet, British Columbia: implications for the interpretation of diatom fossil assemblages, Deep-Sea Res., 35, 71–90, 1988.
Schrader, H.-J. and Gersonde, R.: Diatoms and silicoflagellates, in: Micropaleontological counting methods and techniques – an exercise on an eight meter section of the Lower Pliocene of Capo Rosello, Sicily, edited by: Zachariasse, W. J., Riedel, W. R., Sanfilippo, A., Schmidt, R. R., Brolsma, M. J., Schrader, H., Ger- sonde, R., Drooger, M. M., and Broekman, J. A., Utrecht Micropaleontological Bulletin, Utrecht, 17, 129–176, 1978.
Takahashi, K.: Response of subarctic Pacific diatom fluxes to the 1982–1983 El Niño disturbance, J. Geophys. Res, 93, 387–392, 1987.
Van Camp, L., Nykjær, L., Mittelstaedt, E., and Schlittenhardt, P.: Upwelling and boundary circulation off Northwest Africa as depicted by infrared and visible satellite observations, Prog. Oceanogr., 26, 357–402, 1991.
Wang, C. and Zhang, L.: Multidecadal Ocean Temperature and Salinity Variability in the Tropical North Atlantic: Linking with the AMO, AMOC, and Subtropical Cell, J. Climate, 26, 6137–6162, https://doi.org/10.1175/JCLI-D-12-00721.1, 2013.
Wittenberg, A. T.: Are historical records sufficient to constrain ENSO simulations, Geophys. Res. Lett., 36, L12702, https://doi.org/10.1029/2009GL038710, 2009.
Yamamoto, A. and Palter, J. B.: The absence of an Atlantic imprint on the
multidecadal variability of wintertime European temperature, Nat. Commun., 7,
10930, https://doi.org/10.1038/ncomms10930, 2016.
Zeeberg, J., Corten, A., Tjoe-Awie, P., Coca, J., and Hamady, B.: Climate modulates the effects of Sardinella aurita fisheries off Northwest Africa, Fish. Res., 89, 65–75, 2008.
Zenk, W., Klein, B., and Schröder, M.: Cape Verde Frontal Zone, Deep-Sea Res., 38, S505–S530, 1991.
Zhang, W., Mei, X., Geng, X., Turner, A. G., and Jin, F.-F.: A Nonstationary ENSO-NAO Relationship Due to AMO Modulation, J. Climate, 32, 33–43, 2019.
Short summary
Upwelling intensity along NW Africa varies on the interannual to decadal timescale. Understanding its changes is key for the prediction of future changes of CO2 sequestration in the northeastern Atlantic. Based on a multiyear (1988–2009) sediment trap experiment at the site CBmeso, fluxes and the species composition of the diatom assemblage are presented. Our data help in establishing the scientific basis for forecasting and modeling future states of this ecosystem and its decadal changes.
Upwelling intensity along NW Africa varies on the interannual to decadal timescale....
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