Supply of organic matter to the sediment in the northern North Sea during a spring phytoplankton bloom

1984 ◽  
Vol 78 (3) ◽  
pp. 315-324 ◽  
Author(s):  
J. M. Davies ◽  
R. Payne
Keyword(s):  
Organic Matter ◽  
North Sea ◽  
Phytoplankton Bloom ◽  
Spring Phytoplankton Bloom ◽  
Northern North Sea

scholarly journals Short-term changes in polysaccharide utilization mechanisms of marine bacterioplankton during a spring phytoplankton bloom

2020 ◽  
Author(s):  
Greta Reintjes ◽  
Bernhard M. Fuchs ◽  
Mirco Scharfe ◽  
Karen H. Wiltshire ◽  
Rudolf Amann ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Bacterial Community ◽  
North Sea ◽  
Extracellular Enzymes ◽  
Heterotrophic Bacteria ◽  
Phytoplankton Bloom ◽  
Low Molecular Weight ◽  
Spring Phytoplankton Bloom ◽  
Hydrolysis Rates

SummarySpring phytoplankton blooms in temperate environments contribute disproportionately to global marine productivity. Bloom-derived organic matter, much of it occurring as polysaccharides, fuels biogeochemical cycles driven by interacting autotrophic and heterotrophic communities. We tracked changes in the mode of polysaccharide utilization by heterotrophic bacteria during the course of a diatom-dominated bloom in the German Bight, North Sea. Polysaccharides can be taken up in a ‘selfish’ mode, where initial hydrolysis is coupled to transport into the periplasm, such that little to no low molecular weight (LMW) products are externally released to the environment. Alternatively, polysaccharides hydrolyzed by cell-surface attached or free extracellular enzymes (external hydrolysis) yield LMW products available to the wider bacterioplankton community. In the early bloom phase, selfish activity was accompanied by low extracellular hydrolysis rates of a few polysaccharides. As the bloom progressed, selfish uptake increased markedly, and external hydrolysis rates increased, but only for a limited range of substrates. The late bloom phase was characterized by high external hydrolysis rates of a broad range of polysaccharides, and reduced selfish uptake of polysaccharides, except for laminarin. Substrate utilization mode is related both to substrate structural complexity and to the bloom-stage dependent composition of the heterotrophic bacterial community.Originality statementThe means by which heterotrophic bacteria cooperate and compete to obtain substrates is a key factor determining the rate and location at which organic matter is cycled in the ocean. Much of this organic matter is high molecular weight (HMW), and must be enzymatically hydrolyzed to smaller pieces to be processed by bacterial communities. Some of these enzyme-producing bacteria are ‘selfish’, processing HMW organic matter without releasing low molecular weight (LMW) products to the environment. Other bacteria hydrolyze HMW substrates in a manner that releases LMW products to the wider bacterial community. How these mechanisms of substrate hydrolysis work against a changing background of organic matter supply is unclear. Here, we measured changing rates and mechanisms of substrate processing during the course of a natural phytoplankton bloom in the North Sea. Selfish bacteria generally dominate in the initial bloom stages, but a greater supply of increasingly complex substrates in later bloom stages leads to external hydrolysis of a wider range of substrates, increasing the supply of LMW hydrolysis products to the wider bacterial community.

Gametogenesis and the reproductive cycle in the deep-sea anemone Paracalliactis stephensoni (Cnidaria: Actiniaria)

1990 ◽  
Vol 70 (1) ◽  
pp. 163-172 ◽  
Author(s):  
Michel Praet-Van
Keyword(s):  
Organic Matter ◽  
Shallow Water ◽  
Deep Sea ◽  
Phytoplankton Bloom ◽  
Sea Anemone ◽  
Bay Of Biscay ◽  
Sea Anemones ◽  
Spring Phytoplankton Bloom ◽  
Sea Floor ◽  
Ultrastructural Investigation

This ultrastructural investigation of gametogenesis in a deep-sea anemone of the Bay of Biscay trawled around 2000 m depth, contributes to the knowledge of biology and strategy of reproduction of deep-sea benthos.This sea anemone is dioecious. The sperm appears very similar to those of shallow water sea anemones of the genus, Calliactis. The ultrastructural investigation of oogenesis allows the characteristics of the stages of previtellogenesis and vitellogenesis to be defined. The latter begins with a period of lipogenesis correlated with the formation of a trophonema. Mature oocytes measure up to 180 (im in diameter. Study of spermatogenesis and oogenesis reveals that spawning occurs in April/May. In males, the main area of testicular cysts, full of sperm, reaches maximal development from March to May and, in females, the percentage of mature oocytes decreases from 33% in April to 1% in May.Spawning may be induced by the advent in the deep-sea of the products of the spring phytoplankton bloom. This period of spawning, during the increased deposition of organic matter to the deep-sea floor, may be an advantageous strategy for early development of Paracalliactis.

scholarly journals Seasonal changes in the D  /  H ratio of fatty acids of pelagic microorganisms in the coastal North Sea

2016 ◽  
Vol 13 (19) ◽  
pp. 5527-5539 ◽  
Author(s):  
Sandra Mariam Heinzelmann ◽  
Nicole Jane Bale ◽  
Laura Villanueva ◽  
Danielle Sinke-Schoen ◽  
Catharina Johanna Maria Philippart ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Isotopic Composition ◽  
North Sea ◽  
Phytoplankton Bloom ◽  
Isotopic Fractionation ◽  
Spring Phytoplankton Bloom ◽  
Fractionation Factor ◽  
Culture Studies ◽  
Hydrogen Isotopic Composition

Abstract. Culture studies of microorganisms have shown that the hydrogen isotopic composition of fatty acids depends on their metabolism, but there are only few environmental studies available to confirm this observation. Here we studied the seasonal variability of the deuterium-to-hydrogen (D / H) ratio of fatty acids in the coastal Dutch North Sea and compared this with the diversity of the phyto- and bacterioplankton. Over the year, the stable hydrogen isotopic fractionation factor ε between fatty acids and water (εlipid/water) ranged between −172 and −237 ‰, the algal-derived polyunsaturated fatty acid nC20:5 generally being the most D-depleted (−177 to −235 ‰) and nC18:0 the least D-depleted fatty acid (−172 to −210 ‰). The in general highly D-depleted nC20:5 is in agreement with culture studies, which indicates that photoautotrophic microorganisms produce fatty acids which are significantly depleted in D relative to water. The εlipid/water of all fatty acids showed a transient shift towards increased fractionation during the spring phytoplankton bloom, indicated by increasing chlorophyll a concentrations and relative abundance of the nC20:5 polyunsaturated fatty acids, suggesting increased contributions of photoautotrophy. Time periods with decreased fractionation (less negative εlipid/water values) can potentially be explained by an increased contribution of heterotrophy to the fatty acid pool. Our results show that the hydrogen isotopic composition of fatty acids is a promising tool to assess the community metabolism of coastal plankton potentially in combination with the isotopic analysis of more specific biomarker lipids.

scholarly journals Changes in structural and functional diversity of nematode communities during a spring phytoplankton bloom in the southern North Sea

2004 ◽  
Vol 52 (4) ◽  
pp. 281-292 ◽  
Author(s):  
Jan Vanaverbeke ◽  
Maaike Steyaert ◽  
Karline Soetaert ◽  
Véronique Rousseau ◽  
Dirk Van Gansbeke ◽  
...  
Keyword(s):  
Functional Diversity ◽  
North Sea ◽  
Phytoplankton Bloom ◽  
Spring Phytoplankton Bloom ◽  
Nematode Communities ◽  
Southern North Sea

scholarly journals High-throughput cultivation of heterotrophic bacteria during a spring phytoplankton bloom in the North Sea

2020 ◽  
Vol 43 (2) ◽  
pp. 126066
Author(s):  
Carlota Alejandre-Colomo ◽  
Jens Harder ◽  
Bernhard M. Fuchs ◽  
Ramon Rosselló-Móra ◽  
Rudolf Amann
Keyword(s):  
North Sea ◽  
High Throughput ◽  
Heterotrophic Bacteria ◽  
Phytoplankton Bloom ◽  
Spring Phytoplankton Bloom ◽  
The North ◽  
The North Sea

Dilution cultivation of marine heterotrophic bacteria abundant after a spring phytoplankton bloom in the North Sea

2014 ◽  
Vol 17 (10) ◽  
pp. 3515-3526 ◽  
Author(s):  
Richard L. Hahnke ◽  
Christin M. Bennke ◽  
Bernhard M. Fuchs ◽  
Alexander J. Mann ◽  
Erhard Rhiel ◽  
...  
Keyword(s):  
North Sea ◽  
Heterotrophic Bacteria ◽  
Phytoplankton Bloom ◽  
Spring Phytoplankton Bloom ◽  
The North ◽  
Marine Heterotrophic Bacteria ◽  
The North Sea

scholarly journals Seasonal changes in the D/H ratio of fatty acids of pelagic microorganisms in the coastal North Sea

2016 ◽  
Author(s):  
Sandra Mariam Heinzelmann ◽  
Nicole Jane Bale ◽  
Laura Villanueva ◽  
Danielle Sinke-Schoen ◽  
Katja Philippart ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Isotopic Composition ◽  
North Sea ◽  
Phytoplankton Bloom ◽  
Isotopic Fractionation ◽  
Spring Phytoplankton Bloom ◽  
Fractionation Factor ◽  
Culture Studies ◽  
Hydrogen Isotopic Composition

Abstract. Culture studies of microorganisms have shown that the hydrogen isotopic composition of fatty acids depends on their metabolism, but there are only few environmental studies available to confirm this observation. Here we studied the seasonal variability of the deuterium/hydrogen (D/H) ratio of fatty acids in the coastal Dutch North Sea and compared this with the diversity of the phyto- and bacterioplankton. Over the year, the stable hydrogen isotopic fractionation factor ε between fatty acids and water ranged between −172 ‰ and −237 ‰, the algal-derived polyunsaturated fatty acid nC20:5 being the most D-depleted and nC18:0 the least D-depleted fatty acid. The D-depleted nC20:5 is in agreement with culture studies, which indicates that photoautotrophic microorganisms produce fatty acids which are significantly depleted in D relative to water. The εlipid/water of all fatty acids showed a transient shift towards increased fractionation during the spring phytoplankton bloom, indicated by increasing chlorophyll a concentrations and relative abundance of the nC20:5 PUFA, suggesting increased contributions of photoautotrophy. Time periods with decreased fractionation (less negative εlipid/water values) can be explained by an increased contribution by heterotrophy to the fatty acid pool. Our results show that the hydrogen isotopic composition of fatty acids is a useful tool to assess the community metabolism of coastal plankton.

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