Effects of sediment disturbance on deep-sea nematode communities: Results from an in-situ experiment at the arctic LTER observatory HAUSGARTEN

Abstract. In the Arctic Ocean, increased sea surface temperature and sea ice retreat have triggered shifts in phytoplankton communities. In Fram Strait, coccolithophorids have been occasionally observed to replace diatoms as the dominating taxon of spring blooms. Deep-sea benthic communities depend strongly on such blooms but with a change in quality and quantity of primarily produced organic matter [OM] input, this may likely have implications for deep-sea life. We compared the in situ responses of Arctic deep-sea benthos to input of phytodetritus from a diatom (Thalassiosira sp.) and a coccolithophorid (Emiliania huxleyi) species. We traced the fate of 13C and 15N labelled phytodetritus into respiration, assimilation by bacteria and infauna in a 4 d and 14 d experiment. Bacteria were key assimilators in the Thalassiosira OM degradation whereas Foraminifera and other infauna were at least as important as bacteria in the Emiliania OM assimilation. After 14 d, 5 times less carbon and 3.8 times less nitrogen of the Emiliania detritus was recycled compared to Thalassiosira detritus. This implies that the utilization of Emiliania OM may be less efficient than for Thalassiosira OM. Our results indicate that a shift from diatom-dominated input to a coccolithophorid-dominated pulse could entail a delay in OM cycling, which may affect bentho-pelagic coupling.

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Carbon and nitrogen turnover in the Arctic deep sea: in situ benthic community response to diatom and coccolithophorid phytodetritus

Biogeosciences ◽

10.5194/bg-15-6537-2018 ◽

2018 ◽

Vol 15 (21) ◽

pp. 6537-6557 ◽

Cited By ~ 3

Author(s):

Ulrike Braeckman ◽

Felix Janssen ◽

Gaute Lavik ◽

Marcus Elvert ◽

Hannah Marchant ◽

...

Keyword(s):

Deep Sea ◽

Benthic Communities ◽

Community Response ◽

The Arctic ◽

Carbon And Nitrogen ◽

Nitrogen Turnover ◽

Phytoplankton Communities ◽

Ice Retreat ◽

Sea Ice Retreat

Abstract. In the Arctic Ocean, increased sea surface temperature and sea ice retreat have triggered shifts in phytoplankton communities. In Fram Strait, coccolithophorids have been occasionally observed to replace diatoms as the dominating taxon of spring blooms. Deep-sea benthic communities depend strongly on such blooms, but with a change in quality and quantity of primarily produced organic matter (OM) input, this may likely have implications for deep-sea life. We compared the in situ responses of Arctic deep-sea benthos to input of phytodetritus from a diatom (Thalassiosira sp.) and a coccolithophorid (Emiliania huxleyi) species. We traced the fate of 13C- and 15N-labelled phytodetritus into respiration, assimilation by bacteria and infauna in a 4-day and 14-day experiment. Bacteria were key assimilators in the Thalassiosira OM degradation, whereas Foraminifera and other infauna were at least as important as bacteria in the Emiliania OM assimilation. After 14 days, 5 times less carbon and 3.8 times less nitrogen of the Emiliania detritus was recycled compared to Thalassiosira detritus. This implies that the utilization of Emiliania OM may be less efficient than for Thalassiosira OM. Our results indicate that a shift from diatom-dominated input to a coccolithophorid-dominated pulse could entail a delay in OM cycling, which may affect benthopelagic coupling.

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Distribution of PAHs and the PAH-degrading bacteria in the deep-sea sediments of the high-latitude Arctic Ocean

Biogeosciences Discussions ◽

10.5194/bgd-11-13985-2014 ◽

2014 ◽

Vol 11 (9) ◽

pp. 13985-14021 ◽

Cited By ~ 4

Author(s):

C. Dong ◽

X. Bai ◽

H. Sheng ◽

L. Jiao ◽

H. Zhou ◽

...

Keyword(s):

Arctic Ocean ◽

Deep Sea ◽

High Throughput Sequencing ◽

The Arctic ◽

Rrna Gene ◽

Long Distance ◽

Degrading Bacteria ◽

The Arctic Ocean ◽

Deep Sea Sediments

Abstract. Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants, which can be transferred to a long distance and tend to accumulation in marine sediment. However, PAHs distribution and natural bioattenuation is less known in open sea, especially in the Arctic Ocean. In this report, sediment samples were collected at four sites from the Chukchi Plateau to Makarov Basin in the summer of 2010. PAH composition and total concentrations were examined with GC-MS, we found that the concentrations of 16 EPA-priority PAHs varied from 2.0 to 41.6 ng g−1 dry weight in total and decreased with sediment depths and as well as from the southern to northern sites. Among the targeted PAHs, phenanthrene was relatively abundant in all sediments. To learn the diversity of bacteria involved in PAHs degradation in situ, the 16S rRNA gene of the total environmental DNA was analyzed with Illumina high throughput sequencing (IHTS). In all the sediments, occurred the potential degraders including Cycloclasticus, Pseudomonas, Halomonas, Pseudoalteromonas, Marinomonas, Bacillus, Dietzia, Colwellia, Acinetobacter, Alcanivorax, Salinisphaera and Shewanella, with Dietzia as the most abundant. Meanwhile on board, enrichment with PAHs was initiated and repeated transfer in laboratory to obtain the degrading consortia. Most above mentioned bacteria in addition to Hahella, Oleispira, Oceanobacter and Hyphomonas, occurred alternately as a predominant member in enrichment cultures from different sediments, as revealed with IHTS and PCR-DGGE. To reconfirm their role in PAH degradation, 40 different bacteria were isolated and characterized, among which Cycloclasticus and Pseudomonas showed the best degradation capability under low temperature. Taken together, PAHs and PAH-degrading bacteria were widespread in the deep-sea sediments of the Arctic Ocean. We propose that bacteria of Cycloclasticus, Pseudomonas, Pseudoalteromonas, Halomonas, Marinomonas and Dietzia may play the most important role in PAHs mineralization in situ.

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Supplementary material to "Carbon and nitrogen turnover in the Arctic deep sea: in situ benthic community response to diatom and coccolithophorid phytodetritus"

10.5194/bg-2018-264-supplement ◽

2018 ◽

Author(s):

Ulrike Braeckman ◽

Felix Janssen ◽

Gaute Lavik ◽

Marcus Elvert ◽

Hannah Marchant ◽

...

Keyword(s):

Deep Sea ◽

Benthic Community ◽

Community Response ◽

The Arctic ◽

Carbon And Nitrogen ◽

Nitrogen Turnover ◽

Supplementary Material

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Calcium carbonate dissolution rates in deep-sea bivalve shells on the East Pacific Rise at 21°N: results of an 8-year in-situ experiment

Palaeogeography Palaeoclimatology Palaeoecology ◽

10.1016/s0031-0182(99)00102-9 ◽

1999 ◽

Vol 154 (4) ◽

pp. 293-299 ◽

Cited By ~ 21

Author(s):

Michael J Kennish ◽

Richard A Lutz

Keyword(s):

Calcium Carbonate ◽

Deep Sea ◽

East Pacific Rise ◽

Carbonate Dissolution ◽

In Situ Experiment ◽

Dissolution Rates ◽

East Pacific ◽

Calcium Carbonate Dissolution ◽

Bivalve Shells

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Local effects of large food-falls on nematode diversity at an arctic deep-sea site: Results from an in situ experiment at the deep-sea observatory HAUSGARTEN

Journal of Experimental Marine Biology and Ecology ◽

10.1016/j.jembe.2017.03.002 ◽

2018 ◽

Vol 502 ◽

pp. 129-141 ◽

Cited By ~ 7

Author(s):

Thomas Soltwedel ◽

Katja Guilini ◽

Eberhard Sauter ◽

Ingo Schewe ◽

Christiane Hasemann

Keyword(s):

Deep Sea ◽

In Situ Experiment ◽

Local Effects ◽

Nematode Diversity ◽

Food Falls

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Distribution of PAHs and the PAH-degrading bacteria in the deep-sea sediments of the high-latitude Arctic Ocean

Biogeosciences ◽

10.5194/bg-12-2163-2015 ◽

2015 ◽

Vol 12 (7) ◽

pp. 2163-2177 ◽

Cited By ~ 42

Author(s):

C. Dong ◽

X. Bai ◽

H. Sheng ◽

L. Jiao ◽

H. Zhou ◽

...

Keyword(s):

Arctic Ocean ◽

Deep Sea ◽

The Arctic ◽

Rrna Gene ◽

Sediment Samples ◽

Pah Degradation ◽

Degrading Bacteria ◽

The Arctic Ocean ◽

Deep Sea Sediments

Abstract. Polycyclic aromatic hydrocarbons (PAHs) are common organic pollutants that can be transferred long distances and tend to accumulate in marine sediments. However, less is known regarding the distribution of PAHs and their natural bioattenuation in the open sea, especially the Arctic Ocean. In this report, sediment samples were collected at four sites from the Chukchi Plateau to the Makarov Basin in the summer of 2010. PAH compositions and total concentrations were examined with GC-MS. The concentrations of 16 EPA-priority PAHs varied from 2.0 to 41.6 ng g−1 dry weight and decreased with sediment depth and movement from the southern to the northern sites. Among the targeted PAHs, phenanthrene was relatively abundant in all sediments. The 16S rRNA gene of the total environmental DNA was analyzed with Illumina high-throughput sequencing (IHTS) to determine the diversity of bacteria involved in PAH degradation in situ. The potential degraders including Cycloclasticus, Pseudomonas, Halomonas, Pseudoalteromonas, Marinomonas, Bacillus, Dietzia, Colwellia, Acinetobacter, Alcanivorax, Salinisphaera and Shewanella, with Dietzia as the most abundant, occurred in all sediment samples. Meanwhile, enrichment with PAHs was initiated onboard and transferred to the laboratory for further enrichment and to obtain the degrading consortia. Most of the abovementioned bacteria in addition to Hahella, Oleispira, Oceanobacter and Hyphomonas occurred alternately as predominant members in the enrichment cultures from different sediments based on IHTS and PCR-DGGE analysis. To reconfirm their role in PAH degradation, 40 different bacteria were isolated and characterized, among which Cycloclasticus Pseudomonas showed the best degradation capability under low temperatures. Taken together, PAHs and PAH-degrading bacteria were widespread in the deep-sea sediments of the Arctic Ocean. We propose that bacteria of Cycloclasticus, Pseudomonas, Pseudoalteromonas, Halomonas, Marinomonas and Dietzia may play the most important role in PAH mineralization in situ.

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