NONDESTRUCTIVE TRACING OF MIGRATORY RHYTHMS OF INTERTIDAL BENTHIC MICROALGAE USING IN VIVO CHLOROPHYLL A FLUORESCENCE1,2

Serôdio, João; Silva, Jorge Marques da; Catarino, Fernando

doi:10.1111/j.0022-3646.1997.00542.x

Cited by 193 publications

(146 citation statements)

References 47 publications

Supporting

Mentioning

133

Contrasting

Unclassified

Order By: Relevance

“…The initial phase is an upward migration pulse beginning at least 2-3 h before the daytime emersion period and ending around the time when light exposure is expected to begin (t i ). Previous results that showed a peak of surface biomass occurring sometime after the beginning of tidal exposure (t Bmax > t i ) (Seroˆdio et al, 1997(Seroˆdio et al, , 2005 appear to be a particular case of the general pattern described here, since both studies refer to days when light exposure started with sunrise. Considering the lack of physical (light, temperature) or chemical gradients at the sediment-air interface (after prolonged darkness, the upper and lower layers both become uniformly anoxic), the accumulation of cells at the surface could be explained by an endogenous negative geotactic behaviour (Harper, 1977;Mitbavkar & Anil, 2004).…”

Section: Biofilm Formationsupporting

confidence: 66%

“…Several studies have reported the endogenous nature of the vertical migratory behaviour of benthic microalgae, showing that the vertical movements continue for several days, synchronized with solar and tidal cycles, in the absence of external stimuli (Palmer & Round, 1967;Palmer, 1974;Seroˆdio et al, 1997). However, the motility of benthic microalgae also responds to exogenous cues, such as temperature (Cohn et al, 2003), the presence of sub-surface nutrients (Kingston, 2002), physical disturbance of the sediment (Hopkins, 1966) or wave action (Kingston, 1999b), and sediment desiccation (Coelho et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Endogenous versus environmental control of vertical migration by intertidal benthic microalgae

Coelho

Vieira

Serôdio

2011

European Journal of Phycology

View full text Add to dashboard Cite

The vertical migratory behaviour of estuarine microphytobenthos, i.e. the biofilm-forming microalgae inhabiting intertidal sediments, is probably a significant factor for their success in this extreme and unstable environment. The present work aimed to assess the relative role of endogenous versus environmental control of benthic microalgal vertical migratory behaviour. This was done by comparing the patterns of vertical migration in undisturbed sediment samples kept under constant conditions of darkness and low light with those in ambient light conditions, by measuring the changes in the surface microalgal biomass during daytime low-tide periods. The results showed that the formation of a biofilm was a two-phase process. It began with a relatively small accumulation of cells at the surface, starting hours before the beginning of the light period and endogenously driven. However, the full formation of the biofilm required exposure to light by the expected beginning of the photoperiod, which further promoted upward migration and accelerated the cell accumulation at the surface. In the absence of light, upward migration was interrupted and the incipient biofilm began to disaggregate. The relative importance of the endogenously controlled behaviour varied during the spring-neap tidal cycle, reaching a maximum on those days when low tide occurred in the middle of the day, suggesting its entrainment by the duration of light exposure on previous days. The regulation of the surface cell concentration during daytime low tides was found to be strongly dependent on exogenous factors, particularly irradiance. The spontaneous disaggregation of the biofilm shortly before the end of the low-tide period (due to tidal flood or sunset), both under constant as well as ambient light conditions, suggested the presence of an endogenously controlled positive geotaxis.

show abstract

Section: Biofilm Formationsupporting

confidence: 66%

Section: Introductionmentioning

confidence: 99%

Endogenous versus environmental control of vertical migration by intertidal benthic microalgae

Coelho

Vieira

Serôdio

2011

European Journal of Phycology

View full text Add to dashboard Cite

show abstract

“…However, this suggests a close coupling between water content and cyanobacterial movements. Similarly, migration of benthic diatoms in tidal sediment is strongly influenced by the tide level [13,26], but the causes of the rhythm are not yet clearly understood [13]. The upward migration in the presence of water could simply be a relaxation of a tightly bound population that initiates a random walk; thus part of it reaches the surface in the absence of stimulus.…”

Section: Control Of the Migrationmentioning

confidence: 99%

Hydrotaxis of Cyanobacteria in Desert Crusts

Pringault¹,

García-Pichel

2003

Microb Ecol

View full text Add to dashboard Cite

We studied the migration of cyanobacteria in desert crusts from Las Bárdenas Reales (Spain). The crusts were almost exclusively colonized by the filamentous cyanobacterium Oscillatoria, which formed a dense layer approximately 600 lm thick located between 1.5 and 2.1 mm deep. Laboratory and field experiments showed that saturation of the crust with liquid water induced a migration of the cyanobacteria leading to a significant greening of the surface within a few minutes. Under light and rapid evaporation, the green color rapidly disappeared and the crust surface was completely devoid of filaments within 60 min. In contrast, 260 min was required to recover the original white color of the crust when slow evaporation was experimentally imposed. The up and down migration following wetting and drying occurred also in the dark. This demonstrates that light was not a required stimulus. Addition of ATP synthesis inhibitors prevented the cyanobacterium from migrating down into the crust, with filaments remaining on the surface. Therefore, the disappearance of the green color observed during desiccation can only be attributed to an active cyanobacterial motility response to the decrease in the water content. The simplest explanation that can account for the evidence gathered is the presence of a mechanism that links, directly or indirectly, these motility responses to gradients in water content, namely a form of hydrotaxis.

show abstract

“…The temporal up-scaling issue is transversal to any MPB remote sensing approach and it is based on the drastic change of MPB biomass and specific composition during an emersion period [1,49,50]. In contrast, reflectance images are acquired instantaneously and the derived ETR maps would thus assess primary production at a single acquisition time which would inevitably induce a strong bias for tidal scale as well as daily budget estimation.…”

Section: Remote Sensing Applicationsmentioning

confidence: 99%

Microphytobenthos Primary Production Estimated by Hyperspectral Reflectance

Méléder¹,

Lavaud²,

Barnett³

et al. 2016

Preprint

View full text Add to dashboard Cite

Abstract:Monitoring photosynthesis is a great challenge to improve our knowledge of plant productivity at the ecosystem level, which may be achieved using remote-sensing techniques with synoptic abilities. The main objective of the current study is to take up this challenge for microphytobenthos (MPB) primary production in intertidal mudflats. This was achieved by coupling hyperspectral radiometry (reflectance, ρ and second derivative, δδ) and PAM-fluorometry (non-sequential light curve, NSLC) measurements. The later allowed the estimation of the primary production via the light use efficiency (LUE) and the electron transport rate (ETR) whereas ρ allowed to estimate pigment composition and optical absorption cross-section (a*). Five MPB species representative of the main growth forms: epipelic (benthic motile), epipsammic (benthic motile and non motile) and thycoplanktonic (temporarily resuspended in the water column) were lighted at increasing light intensity from dark to 1950 µmol photons.m -2 .s -1 . After spectral measurements, a* was retrieved using a radiative transfer model and several radiometric indices were tested for their capacity to predict LUE and ETR. The spectral estimation of these two photosynthetic variables was subsequently compared to the values estimated by PAM-fluorometry. Results showed that different responses related to the xanthophyll cycle (de-epoxydation state) were observed for the three growthforms with increasing light levels. However, a single relationship with radiometric index was not affected by species/growth-forms, i.e. δδ 496/508 , called the MPB LUE index to predict LUE and ETR. This index has the potential to be applied to air borne hyperspectral imagery for large-scale assessment of MPB production.

show abstract

NONDESTRUCTIVE TRACING OF MIGRATORY RHYTHMS OF INTERTIDAL BENTHIC MICROALGAE USING IN VIVO CHLOROPHYLL A FLUORESCENCE^1,²

Abstract: In vivo chlorophyll (Chl) a fluorescence was measured in undisturbed intertidal sediments with the purpose of tracing the vertical migratory rhythms of benthic microalgae. A pulse amplitude jluorometer, an instrument which does not require physical contact with the sample, was

Cited by 193 publications

References 47 publications

Endogenous versus environmental control of vertical migration by intertidal benthic microalgae

Endogenous versus environmental control of vertical migration by intertidal benthic microalgae

Hydrotaxis of Cyanobacteria in Desert Crusts

Microphytobenthos Primary Production Estimated by Hyperspectral Reflectance

Contact Info

Product

Resources

About