Fluxes of phytopigments and labile organic matter to the deep ocean in the NE Atlantic Ocean

Fabiano, M.; Pusceddu, Antonio; Dell’Anno, Antonio; Armeni, Monica; Vanucci, Silvana; Lampitt, Richard S.; Wolff, George A.; Danovaro, Roberto

doi:10.1016/s0079-6611(01)00049-0

Cited by 54 publications

(28 citation statements)

References 60 publications

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“…There is an increasing consensus that deep-sea ecosystems are more dynamic than previously hypothesized (Smith and Kaufmann, 1999;Danovaro et al, 2001b;Ruhl and Smith, 2004;Ruhl et al, 2008;Billett et al, 2010), and that important changes in quantity and composition of bioavailable organic matter deposited on the ocean floor occur both at seasonal and inter-annual time scales (Danovaro et al, 2001a;Fabiano et al, 2001;Smith et al, 2010). Our results from the Catalan margin reinforce this view and suggest that DSWC events may amplify the temporal variability of the trophic state of benthic deep-sea ecosystems related to changes in biological production of the photic zone.…”

Section: Discussionsupporting

confidence: 75%

“…Phytodetritus sinking from the water column represents a major source of bioavailable organic matter to the deepsea floor (Fabiano et al, 2001;. In this study we found a significant relationship between enzymatically hydrolyzed protein concentrations and phytopigment contents in the sediments of the Portuguese margin (n = 8, r = 0.723, p < 0.05), though this was not the case for the Catalan margin.…”

Section: Discussioncontrasting

confidence: 63%

“…However, chlorophyll a is rapidly converted into degradation products during particle sinking to the ocean floor (Fabiano et al, 2001) and rapidly decays in the sediments (Sun et al, 1991). Moreover, the pool size of labile organic matter in the sediment estimated from chlorophyll a concentrations can vary depending on the conversion factor applied, i.e.…”

Section: Discussionmentioning

confidence: 99%

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Trophic state of benthic deep-sea ecosystems from two different continental margins off Iberia

et al. 2013

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The bioavailability of organic matter in benthic deep-sea ecosystems, commonly used to define their trophic state, can greatly influence key ecological processes such as biomass production and nutrient cycling. Here, we assess the trophic state of deep-sea sediments from open slopes and canyons of the Catalan (NW Mediterranean) and Portuguese (NE Atlantic) continental margins, offshore east and west Iberia, respectively, by using a biomimetic approach based on enzymatic digestion of protein and carbohydrate pools. Patterns of sediment trophic state were analyzed in relation to increasing water depth, including repeated samplings over a 3 yr period in the Catalan margin. Two out of the three sam- pling periods occurred a few months after dense shelf water cascading events. The benthic deep-sea ecosystems investi- gated in this study were characterized by high amounts of bioavailable organic matter when compared to other deep- sea sediments. Bioavailable organic matter and its nutritional value were significantly higher in the Portuguese margin than in the Catalan margin, thus reflecting differences in pri- mary productivity of surface waters reported for the two re- gions. Similarly, sediments of the Catalan margin were char- acterized by significantly higher food quantity and quality in spring, when the phytoplankton bloom occurs in surface wa- ters, than in summer and autumn. Differences in the benthic trophic state of canyons against open slopes were more ev- ident in the Portuguese than in the Catalan margin. In both continental margins, bioavailable organic C concentrations did not vary or increase with increasing water depth. Overall our findings suggest that the intensity of primary production processes along with the lateral transfer of organic particles, even amplified by episodic events, can have a role in controlling the quantity and distribution of bioavailable organic detritus and its nutritional value along these continental margin ecosystems

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Section: Discussionsupporting

confidence: 75%

Section: Discussioncontrasting

confidence: 63%

Section: Discussionmentioning

confidence: 99%

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Trophic state of benthic deep-sea ecosystems from two different continental margins off Iberia

et al. 2013

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“…upper limit of the semi-labile detritus pool was defined as the sum of characterizable biopolymers (i.e., amino acids, lipids, and carbohydrates, Fabiano et al 2001) as semilabile detritus, similarly as in a recent food web study of the Nazaré Canyon (Van Oevelen et al 2011b). We acknowledge that the proposed classification does not do full justice to the complexity of organic matter diagenesis.…”

Section: Discussionmentioning

confidence: 99%

Carbon flows in the benthic food web of the Porcupine Abyssal Plain: The (un)importance of labile detritus in supporting microbial and faunal carbon demands

Oevelen

Soetaert

Heip

2012

Limnology & Oceanography

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Carbon flows in the benthic food web of the Porcupine Abyssal Plain (4850 m, northeast Atlantic) were reconstructed using linear inverse modeling based on mass balances of the various compartments, biomass data, carbon flux measurements, physiological constraints, and data from a previously published 13 C-phytodetritus pulse-chase experiment. Food web compartments consisted of bacteria, Foraminifera, three feeding types of nematodes and of macrofauna, and four feeding types of megafauna. Three lability classes of detritus were defined to clarify especially the possible role of labile detritus in this abyssal plain food web. Total detritus inputs to the food web were 0.56 mmol C m 22 d 21 , with only a minor (3.8%) contribution of labile detritus. The dominant pathway in the food web was dissolution of more refractory detritus, uptake by bacteria, and subsequent respiration (0.36 mmol C m 22 d 21 , 80% of the community respiration). Lower contributions to community respiration were found for surface-deposit-feeding macrobenthos (5.6%), Foraminifera (4.9%), predatory macrobenthos (3.8%), and other deposit-feeding macrobenthos (3.1%). Contributions by other benthic compartments were , 1%. 13 C-phytodetritus transfer data strongly constrained the carbon source for bacteria, Foraminifera, and the nematode and macrobenthic compartments. Surprisingly, labile detritus contributed , 5% of the total carbon requirements for all these compartments. Carbon sources were much less constrained for the megabenthic compartments because for these compartments no 13 C pulse-chase data were available. The carbon flow model evidently shows a limited role of labile detritus in the food web.

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“…1) at a water depth of 1153 m. The area is characterized by seasonal phytoplankton succession involving diatom dominance in the early spring. Downward fluxes of organic matter, including chlorophyll and its transformation products, peak in spring and early summer (Fabiano et al 2001). The analyzed core section spans from 24.5 kyr to 14.5 kyr before present, across the last glacial maximum and Heinrich events 1 and 2 (H1 and H2).…”

Section: Methodsmentioning

confidence: 99%

Crenarchaea and phytoplankton coupling in sedimentary archives: Common trigger or metabolic dependence?

Fietz

Martínez‐García

Rueda

et al. 2011

Limnology & Oceanography

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The concentrations of chlorins (chlorophyll transformation products indicative of phytoplankton production) and crenarchaeol (a marker for Crenarchaea abundance) are significantly positively correlated (Spearman's rank correlation coefficient r s . 0.75) in four core records from freshwater (Lake Baikal) and marine settings (Southern, Atlantic, and Arctic Oceans). This suggests a close relationship between Crenarchaea abundance and phytoplankton production. Degradation and transport mechanisms, as well as a common environmental trigger, may in part account for our observations, but these mechanisms alone cannot fully explain them. Instead our findings point to a metabolic dependence of Crenarchaea on resources released by phytoplankton, such as organic carbon or ammonium.

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Fluxes of phytopigments and labile organic matter to the deep ocean in the NE Atlantic Ocean

Cited by 54 publications

References 60 publications

Trophic state of benthic deep-sea ecosystems from two different continental margins off Iberia

Trophic state of benthic deep-sea ecosystems from two different continental margins off Iberia

Carbon flows in the benthic food web of the Porcupine Abyssal Plain: The (un)importance of labile detritus in supporting microbial and faunal carbon demands

Crenarchaea and phytoplankton coupling in sedimentary archives: Common trigger or metabolic dependence?

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