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Metabolic activity and functional diversity changes in sediment prokaryotic communities organically enriched with mussel biodeposits.

Pollet T, Cloutier O, Nozais C, McKindsey CW, Archambault P - PLoS ONE (2015)

Bottom Line: The different biodeposit enrichment regimes created, which mimicked the quantity of faeces and pseudo-faeces potentially deposited below mussel farms, show a clear stimulatory effect of this organic enrichment on prokaryotic metabolic activity.This effect was detected once a certain level of biodeposition was attained with a tipping point estimated between 3.25 and 10 g day-1 m-2.However, their functional diversity remained greater than prior to the disturbance suggesting that mussel biodeposit enrichment may disturb the functioning and perhaps the role of prokaryotic communities in benthic ecosystems.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire d'écologie benthique, Institut des sciences de la mer, Université du Québec à Rimouski, Rimouski, Québec, Canada.

ABSTRACT
This experimental microcosm study reports the influence of organic enrichments by mussel biodeposits on the metabolic activity and functional diversity of benthic prokaryotic communities. The different biodeposit enrichment regimes created, which mimicked the quantity of faeces and pseudo-faeces potentially deposited below mussel farms, show a clear stimulatory effect of this organic enrichment on prokaryotic metabolic activity. This effect was detected once a certain level of biodeposition was attained with a tipping point estimated between 3.25 and 10 g day-1 m-2. Prokaryotic communities recovered their initial metabolic activity by 11 days after the cessation of biodeposit additions. However, their functional diversity remained greater than prior to the disturbance suggesting that mussel biodeposit enrichment may disturb the functioning and perhaps the role of prokaryotic communities in benthic ecosystems. This manipulative approach provided new information on the influence of mussel biodeposition on benthic prokaryotic communities and dose-response relationships and may support the development of carrying capacity models for bivalve culture.

No MeSH data available.


Variation in AWCD at D2 and D4.Variation in AWCD values (Mean ± SE) for the treatments Tr1, Tr2, Tr3 and the control (ctrl) at D2 (A) and D4 (B). For each treatment, the mean quantity (g) of mussel biodeposits daily received by prokaryotic communities at these two sampling time points is indicated.
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pone.0123681.g003: Variation in AWCD at D2 and D4.Variation in AWCD values (Mean ± SE) for the treatments Tr1, Tr2, Tr3 and the control (ctrl) at D2 (A) and D4 (B). For each treatment, the mean quantity (g) of mussel biodeposits daily received by prokaryotic communities at these two sampling time points is indicated.

Mentions: Fig 2 shows the AWCD for all treatments at the beginning of the experiment and prior to adding biodeposits (D0), at D2, and D4, corresponding to when treatments had received different total quantities of biodeposits, when all treatments (except the control) had received the same quantity of biodeposits (80g, D9) and one week thereafter, at the end of the experiment (D18). At D0, AWCD did not differ among treatments. At D2 and D4, AWCD values were significantly greater in Tr1 and Tr2 than in Tr3, Ctrl and Ref treatments, the latter which did not differ. At D9 (Fig 2), AWCD was significantly higher in all microcosms that had received organic matter (Tr1, Tr2 and Tr3) than in Ctrl and Ref microcosms, which did not differ. At D18, AWCD did not differ among treatments or from the AWCD values observed at D0. These results seem to indicate that a threshold deposition rate is required to shift prokaryotic metabolic activity. This threshold was reached by D2 in both the Tr1 and Tr2 treatments, which both showed increased (relative to Ref and Ctrl treatments) metabolic activity on both D2 and D4 and on D9. Biodepostion rates to Tr1 and Tr2 microcosms averaged 10 and 24 g day-1 (D2) and 10 and 16.75 g day-1 (D4), respectively (Fig 3A and 3B). In contrast, the Tr3 treatment had been subjected to an average biodeposition rate of only 1.5 and 3.25 g day-1 by D2 and D4, respectively, and only showed increased metabolic activity (relative to Ctrl and Ref treatments) by D9, when the average biodepostion rate over the experiment in Tr1, Tr2, and Tr3 reached 10 g day-1 and all three treatments had increased metabolic activity. It is not clear exactly where the threshold is, but given the above, it appears to be between 3.25 and 10 g day-1.


Metabolic activity and functional diversity changes in sediment prokaryotic communities organically enriched with mussel biodeposits.

Pollet T, Cloutier O, Nozais C, McKindsey CW, Archambault P - PLoS ONE (2015)

Variation in AWCD at D2 and D4.Variation in AWCD values (Mean ± SE) for the treatments Tr1, Tr2, Tr3 and the control (ctrl) at D2 (A) and D4 (B). For each treatment, the mean quantity (g) of mussel biodeposits daily received by prokaryotic communities at these two sampling time points is indicated.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4414560&req=5

pone.0123681.g003: Variation in AWCD at D2 and D4.Variation in AWCD values (Mean ± SE) for the treatments Tr1, Tr2, Tr3 and the control (ctrl) at D2 (A) and D4 (B). For each treatment, the mean quantity (g) of mussel biodeposits daily received by prokaryotic communities at these two sampling time points is indicated.
Mentions: Fig 2 shows the AWCD for all treatments at the beginning of the experiment and prior to adding biodeposits (D0), at D2, and D4, corresponding to when treatments had received different total quantities of biodeposits, when all treatments (except the control) had received the same quantity of biodeposits (80g, D9) and one week thereafter, at the end of the experiment (D18). At D0, AWCD did not differ among treatments. At D2 and D4, AWCD values were significantly greater in Tr1 and Tr2 than in Tr3, Ctrl and Ref treatments, the latter which did not differ. At D9 (Fig 2), AWCD was significantly higher in all microcosms that had received organic matter (Tr1, Tr2 and Tr3) than in Ctrl and Ref microcosms, which did not differ. At D18, AWCD did not differ among treatments or from the AWCD values observed at D0. These results seem to indicate that a threshold deposition rate is required to shift prokaryotic metabolic activity. This threshold was reached by D2 in both the Tr1 and Tr2 treatments, which both showed increased (relative to Ref and Ctrl treatments) metabolic activity on both D2 and D4 and on D9. Biodepostion rates to Tr1 and Tr2 microcosms averaged 10 and 24 g day-1 (D2) and 10 and 16.75 g day-1 (D4), respectively (Fig 3A and 3B). In contrast, the Tr3 treatment had been subjected to an average biodeposition rate of only 1.5 and 3.25 g day-1 by D2 and D4, respectively, and only showed increased metabolic activity (relative to Ctrl and Ref treatments) by D9, when the average biodepostion rate over the experiment in Tr1, Tr2, and Tr3 reached 10 g day-1 and all three treatments had increased metabolic activity. It is not clear exactly where the threshold is, but given the above, it appears to be between 3.25 and 10 g day-1.

Bottom Line: The different biodeposit enrichment regimes created, which mimicked the quantity of faeces and pseudo-faeces potentially deposited below mussel farms, show a clear stimulatory effect of this organic enrichment on prokaryotic metabolic activity.This effect was detected once a certain level of biodeposition was attained with a tipping point estimated between 3.25 and 10 g day-1 m-2.However, their functional diversity remained greater than prior to the disturbance suggesting that mussel biodeposit enrichment may disturb the functioning and perhaps the role of prokaryotic communities in benthic ecosystems.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire d'écologie benthique, Institut des sciences de la mer, Université du Québec à Rimouski, Rimouski, Québec, Canada.

ABSTRACT
This experimental microcosm study reports the influence of organic enrichments by mussel biodeposits on the metabolic activity and functional diversity of benthic prokaryotic communities. The different biodeposit enrichment regimes created, which mimicked the quantity of faeces and pseudo-faeces potentially deposited below mussel farms, show a clear stimulatory effect of this organic enrichment on prokaryotic metabolic activity. This effect was detected once a certain level of biodeposition was attained with a tipping point estimated between 3.25 and 10 g day-1 m-2. Prokaryotic communities recovered their initial metabolic activity by 11 days after the cessation of biodeposit additions. However, their functional diversity remained greater than prior to the disturbance suggesting that mussel biodeposit enrichment may disturb the functioning and perhaps the role of prokaryotic communities in benthic ecosystems. This manipulative approach provided new information on the influence of mussel biodeposition on benthic prokaryotic communities and dose-response relationships and may support the development of carrying capacity models for bivalve culture.

No MeSH data available.