Discovery of microphytobenthos migration in the subtidal zone

Longphuirt, Sorcha Ní; Guarini, Jean‐Marc; Chauvaud, Laurent; Claquin, Pascal; Herlory, Olivier; Amice, Erwan; Huonnic, P.; Ragueneau, Olivier

doi:10.3354/meps328143

Cited by 37 publications

(28 citation statements)

References 42 publications

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“…This migration pattern and its consequences for benthic metabolism must be taken into account in temporal or spatial comparisons between samples. By concomitantly measuring vertical migration and net primary production under constant light conditions, our results experimentally confirm the theoretical model developed by Longphuirt et al (2006). In addition, the strong linear relationship between NDVI and NP (Fig.…”

Section: Vertical Migration and Primary Productionsupporting

confidence: 86%

“…Heterotrophic bacteria might catabolize glutamate and glucose and produce nutrients than can be directly used by the autotrophic compartment. This bacterially mediated source of nutrients could affect migration behavior by counterbalancing the endogenous rhythm of an upward migration (Longphuirt et al 2006), thus leading to an apparent inhibition of the migration signal relative to the control. The opposite trends observed for migration upon organic compound addition at both stations suggest that the responses of microalgae depend on the sampling site and the prevailing environmental conditions.…”

Section: Migration Response To Compound Additionmentioning

confidence: 99%

“…This process is well known for MPB inhabiting intertidal sediments, but it has been only recently observed for MPB inhabiting subtidal sediments (Longphuirt et al 2006). In intertidal environments, the rhythm of vertical migration of MPB is triggered both by the tidal period and by the diurnal period (Consalvey et al 2004), whereas in subtidal sediments, the diurnal period seems to represent the main trigger for up-and downward migration (Longphuirt et al 2006). Migration has strong ecological implications in the sediment functioning.…”

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confidence: 99%

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Subtidal microphytobenthos: effects of inorganic and organic compound supplies on migration, production, and respiration in a tropical coastal environment

Bourgeois¹,

Hochard²,

Pringault³

2010

Aquat. Microb. Ecol.

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Microphytobenthos (MPB) is an important primary producer in coastal ecosystems. In oligotrophic environments, its activity may be controlled by the availability of organic or inorganic compounds but also by its migration behavior. The objective of this study was to determine, in MPBcolonized subtidal sediments, the consequences of short-term enrichments (< 24 h) of organic (alanine, glutamate, and glucose) and inorganic (ammonium, phosphate) compounds on MPB vertical migration and metabolisms, net production (NP), areal gross production (AGP), and community respiration (R). Two contrasting stations located in the southwest lagoon of New Caledonia were investigated: 1 under strong anthropogenic influence and 1 under more oceanic influence. Both stations were dominated by epipelic diatoms. Differences in net primary production were explained by diurnal variation of MPB biomass at the sediment surface, showing the importance of MPB migration in the functioning of these subtidal environments. However, a stimulation or inhibition of MPB migration did not necessarily impact the net primary production of the system; this strongly depends upon the interactions between the autotrophic and heterotrophic compartments, the latter being controlled by the environmental conditions. For the station under low anthropogenic influence, AGP and R were both significantly stimulated by alanine, glucose, and ammonium, and significantly inhibited by phosphate. The similar responses of AGP and R to enrichments suggest that autotrophs and heterotrophs were tightly coupled. Conversely, in the station under strong anthropogenic influence, AGP and R responded differently. Addition of ammonium inhibited AGP without having an impact on R, whereas addition of phosphate inhibited R whilst having no measurable effect on AGP. In this station, the coupling between autotrophs and heterotrophs was weakened, suggesting that the carbon demand of the heterotrophic compartment is probably sustained by the supplies of allochthonous organic matter rather than by exudates from the autotrophic compartment.KEY WORDS: Nutrients · Amino acids · Glucose · Autotroph-heterotroph coupling · Oxygen microelectrode · Reflectance Resale or republication not permitted without written consent of the publisherAquat Microb Ecol 61: [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] 2010 than 50% of the total primary production in some shallow waters (Underwood & Kromkamp 1999). Moreover, MPB also plays an important role in the regulation of nutrient fluxes at the water-sediment interface and thus forms an active filter, reducing the supply of nutrients to the water column (Sundbäck et al. 1991). MPB excretes extracellular polymeric substances (EPS; Goto et al. 1999, de Brouwer & Stal 2001, Underwood & Paterson 2003 and thus plays an important role by stabilizing the sediment through the reduction of resuspension and erosion (Miller et al. 1996). Excretion of organic compounds by MPB can also represent an important source of carbon for hetero...

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Section: Vertical Migration and Primary Productionsupporting

confidence: 86%

Section: Migration Response To Compound Additionmentioning

confidence: 99%

mentioning

confidence: 99%

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Subtidal microphytobenthos: effects of inorganic and organic compound supplies on migration, production, and respiration in a tropical coastal environment

Bourgeois¹,

Hochard²,

Pringault³

2010

Aquat. Microb. Ecol.

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“…Certain aspects of MPB ecology have been comprehensively characterized, e.g. primary production (Underwood & Kromkamp 1999, Serôdio & Catarino 2000, vertical migration in intertidal (Palmer & Round 1965, Underwood et al 2005 and subtidal regions (Ní Longphuirt et al 2006), and their resuspension during tidal flooding (Lucas et al 2000). However, despite the extensive literature available, very little experimentation has been carried out on the direct uptake of dissolved inorganic nutrients by in situ populations (Thornton et al 1999, Leynaert et al 2009), a process which is routinely represented in modelling and nutrient budget studies.…”

Section: Introductionmentioning

confidence: 99%

Dissolved inorganic nitrogen uptake by intertidal microphytobenthos: nutrient concentrations, light availability and migration

Longphuirt¹,

Lim²,

Claquin³

et al. 2009

Mar. Ecol. Prog. Ser.

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The importance of intertidal flats as areas of nitrogen filtering has become increasingly apparent in recent times. To understand fully the cycling of this nutrient in these areas of high metabolic activity, it is necessary to elucidate the influence of microphytobenthos (MPB) on stocks of ammonium and nitrate in surface areas. In this study, we aimed to quantify nitrogen uptake and relate it to the in situ concentrations and environmental conditions to which MPB are exposed. In an estuarine system on the Korean Peninsula, we conducted kinetic experiments using 15 N stable isotopes and core sampling over the tidal cycle to determine the temporal evolution of porewater nutrient concentrations and the migration of MPB. The results revealed a range of K s values between 1.5 and 11.8 μmol l -1 for ammonium and 19.2 μmol l -1 for nitrate. Thus MPB communities vary their affinity for dissolved inorganic nitrogen (DIN), which may be related to the substrate conditions to which they are exposed. Uptake of ammonium under experimentally darkened or natural night conditions was, on average, 50% lower than during light periods. The range of porewater DIN concentrations was large and appeared to be primarily determined by tidal influences. This oscillation, coupled to the vertical migration of the MPB in sediments, is likely to have a substantial effect on uptake over the short term (hours). The results indicate that, contrary to our conceptual model, the MPB largely incorporates DIN at the sediment surface during low tide periods when ammonium concentrations are at their highest. As a result, our representation of the MPB in coastal and estuarine models needs to be reassessed.

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“…The shape of the kinetic curve and the potential advantages it conveys-Many benthic diatoms are motile and migrate vertically in the sediment in a close relationship with the diel cycle in subtidal areas (Ní Longphuirt et al 2006), and the daytime and emersion periods in intertidal zones (Serô dio et al 1997). In muddy sediments, the range of vertical migrations can reach centimeters (Saburova and Polikarpov 2003).…”

Section: Discussionmentioning

confidence: 99%

No limit? The multiphasic uptake of silicic acid by benthic diatoms

Leynaert

Longphuirt

Claquin

et al. 2009

Limnology & Oceanography

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Silicic-acid uptake kinetics for a field population of benthic diatoms were examined using a radioisotope tracer over a concentration range of 0-300 mmol L 21 . The microphytobenthos half saturation constant (54 mmol L 21 ) and specific uptake rates (0.096 h 21 ) for silicic acid were well above those usually found in the pelagic environment. Silicic-acid kinetics were hyperbolic only at low concentrations (,60 mmol L 21 ). At higher concentrations, a second mechanism that did not suggest saturation was activated. Many benthic diatoms are motile and migrate vertically in the upper few centimeters of sediment where there are strong gradients of nutrient concentrations. The multiphasic uptake may allow them to take maximum advantage of the high silicic-acid concentrations found at depth.

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Discovery of microphytobenthos migration in the subtidal zone

Cited by 37 publications

References 42 publications

Subtidal microphytobenthos: effects of inorganic and organic compound supplies on migration, production, and respiration in a tropical coastal environment

Subtidal microphytobenthos: effects of inorganic and organic compound supplies on migration, production, and respiration in a tropical coastal environment

Dissolved inorganic nitrogen uptake by intertidal microphytobenthos: nutrient concentrations, light availability and migration

No limit? The multiphasic uptake of silicic acid by benthic diatoms

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