The functional group approach to bioturbation: The effects of biodiffusers and gallery-diffusers of the Macoma balthica community on sediment oxygen uptake

Michaud, Emma; Desrosiers, Gaston; Mermillod‐Blondin, Florian; Sundby, Bjørn; Stora, Georges

doi:10.1016/j.jembe.2005.05.016

Cited by 126 publications

(78 citation statements)

References 48 publications

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“…Although sediment oxygen consumption is widely used as a proxy for benthic remineralisation (Glud, 2008;Grebmeier et al, 2006;Holstein and Hensen, 2010;Michaud et al, 2005), our results show that spatial groups of benthic remineralisation are not strictely related to the oxygen flux. In our study, the major differences between the shallow Mackenzie Shelf and all other sites are equally based on different oxygen, nitrate and phosphate fluxes while the eastern Mackenzie Shelf remineralisation differs greatly from the central shelf in silicic acid and ammonium release (see Table 3).…”

Section: Ineffectiveness Of Oxygen Flux As Proxy For Spatial Patternscontrasting

confidence: 61%

Multivariate benthic ecosystem functioning in the Arctic – benthic fluxes explained by environmental parameters in the southeastern Beaufort Sea

et al. 2013

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Abstract. The effects of climate change on Arctic marine ecosystems and their biogeochemical cycles are difficult to predict given the complex physical, biological and chemical interactions among the ecosystem components. We studied benthic biogeochemical fluxes in the Arctic and the influence of short-term (seasonal to annual), long-term (annual to decadal) and other environmental variability on their spatial distribution to provide a baseline for estimates of the impact of future changes. In summer 2009, we measured fluxes of dissolved oxygen, nitrate, nitrite, ammonia, soluble reactive phosphate and silicic acid at the sediment–water interface at eight sites in the southeastern Beaufort Sea at water depths from 45 to 580 m. The spatial pattern of the measured benthic boundary fluxes was heterogeneous. Multivariate analysis of flux data showed that no single or reduced combination of fluxes could explain the majority of spatial variation, indicating that oxygen flux is not representative of other nutrient sink–source dynamics. We tested the influence of eight environmental parameters on single benthic fluxes. Short-term environmental parameters (sinking flux of particulate organic carbon above the bottom, sediment surface Chl a) were most important for explaining oxygen, ammonium and nitrate fluxes. Long-term parameters (porosity, surface manganese and iron concentration, bottom water oxygen concentrations) together with δ13Corg signature explained most of the spatial variation in phosphate, nitrate and nitrite fluxes. Variation in pigments at the sediment surface was most important to explain variation in fluxes of silicic acid. In a model including all fluxes synchronously, the overall spatial distribution could be best explained (57%) by the combination of sediment Chl a, phaeopigments, δ13Corg, surficial manganese and bottom water oxygen concentration. We conclude that it is necessary to consider long-term environmental variability along with rapidly ongoing environmental changes to predict the flux of oxygen and nutrients across Arctic sediments even at short timescales. Our results contribute to improve ecological models predicting the impact of climate change on the functioning of marine ecosystems.

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Section: Ineffectiveness Of Oxygen Flux As Proxy For Spatial Patternscontrasting

confidence: 61%

Multivariate benthic ecosystem functioning in the Arctic – benthic fluxes explained by environmental parameters in the southeastern Beaufort Sea

et al. 2013

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“…Second, the difference in benthic activity patterns between 2004 and 2008 may also be caused by differences in faunal composition. The results of Michaud et al (2005) show that sediment oxygen uptake is strongly influenced by the functional groups of species present. Renaud et al (2007a) have reported very high densities of amphipods at some sites in 2004, which were never observed in 2008.…”

Section: Discussionmentioning

confidence: 99%

“…Local community composition can be quite variable (Cusson et al 2007), which involves changes in trophic positions and, therefore, in carbon cycling efficiency (Tamelander et al 2006;Sun et al 2009). A better proxy than mere biomass would be achieved if functional Polar Biol (2011) 34:2025-20382033 123 composition of benthic communities were considered in the analysis (Bolam et al 2002;Michaud et al 2005), and hence, we coarsely separated biomass into infauna and foraminifera for analysis of driving factors. We did not determine the biomass of microbes and meiofauna, which have higher reproduction and growth rates and are thus more likely to show a detectable shortterm biomass increase in response to organic matter input (Soltwedel 2000;Rex et al 2006).…”

Section: Discussionmentioning

confidence: 99%

Spring-to-summer changes and regional variability of benthic processes in the western Canadian Arctic

et al. 2011

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Seasonal dynamics in the activity of Arctic shelf benthos have been the subject of few local studies, and the pronounced among-site variability characterizing their results makes it difficult to upscale and generalize their conclusions. In a regional study encompassing five sites at 100-595 m water depth in the southeastern Beaufort Sea, we found that total pigment concentrations in surficial sediments, used as proxies of general food supply to the benthos, rose significantly after the transition from ice-covered conditions in spring (March-June 2008) to open-water conditions in summer (June-August 2008), whereas sediment Chl a concentrations, typical markers of fresh food input, did not. Macrobenthic biomass (including agglutinated foraminifera [500 lm) varied significantly among sites (1.2-6.4 g C m -2 in spring, 1.1-12.6 g C m -2 in summer), whereas a general spring-to-summer increase was not detected. Benthic carbon remineralisation also ranged significantly among sites (11.9-33.2 mg C m -2 day -1 in spring, 11.6-44.4 mg C m -2 day -1 in summer) and did in addition exhibit a general significant increase from spring-to-summer. Multiple regression analysis suggests that in both spring and summer, sediment Chl a concentration is the prime determinant of benthic carbon remineralisation, but other factors have a significant secondary influence, such as foraminiferan biomass (negative in both seasons), water depth (in spring) and infaunal biomass (in summer). Our findings indicate the importance of the combined and dynamic effects of food supply and benthic community patterns on the carbon remineralisation of the polar shelf benthos in seasonally ice-covered seas.

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“…Worm characteristics that could influence hydrolysis rates are peristaltic movement and bioturbation [26][27][28], although the latter is expected to be of minor importance in a turbulent environment such as a WWTP. It has also been suggested that oligochaete worms consume bacteria [29][30][31][32] and change the microbial diversity in natural sediments [30] or the sludge [33] that the aquatic worms inhabit.…”

Section: Introductionmentioning

confidence: 99%

Physical and biochemical changes in sludge uponTubifex tubifexpredation

Valk

Khadem

Foreman

et al. 2016

Environmental Technology

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Worm predation (WP) on activated sludge leads to increased sludge degradation rates, irrespective of the type of worm used or reactor conditions employed. However, the cause of the increased sludge degradation rates remains unknown. This paper presents a comparative analysis of the physical and biochemical aspects of predated sludge, providing insight into the hydrolytic mechanisms underlying WP. To this end, the sessile worm Tubifex tubifex was used as a model oligochaete and was batch cultivated in an 18-L airlift reactor. Predation on activated sludge showed an average reduction rate of 12 ± 3.8%/d versus 2 ± 1.3%/d for endogenous respirated sludge. Sludge predation resulted in an increased release of inorganic nitrogen, phosphate and soluble chemical oxygen demand (sCOD). The sCOD consisted mainly of polysaccharides; however, fluorescence excitation emission matrix spectroscopy analysis also revealed the presence of Tryptophan-protein-like substances. Results suggest that the released polysaccharides contain a protein-like element. Additionally, soluble iron increased slightly in concentration after WP. The extent of hydrolysis seemed to reach an average plateau of about 40% volatile solids (VS) reduction after 4 days, which is substantially higher than the 29% VS reduction for endogenous decay of activated sludge after 30 days. Furthermore, T. tubifex predominantly consumed the protein fraction of the extracellular polymeric substances. Results suggest that that the worms specifically target a fraction of the sludge that is predominantly biodegradable under aerobic conditions, albeit at significantly higher degradation rates when compared to the endogenous decay of waste activated sludge. ARTICLE HISTORY

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The functional group approach to bioturbation: The effects of biodiffusers and gallery-diffusers of the Macoma balthica community on sediment oxygen uptake

Cited by 126 publications

References 48 publications

Multivariate benthic ecosystem functioning in the Arctic – benthic fluxes explained by environmental parameters in the southeastern Beaufort Sea

Multivariate benthic ecosystem functioning in the Arctic – benthic fluxes explained by environmental parameters in the southeastern Beaufort Sea

Spring-to-summer changes and regional variability of benthic processes in the western Canadian Arctic

Physical and biochemical changes in sludge uponTubifex tubifexpredation

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