The Vertical Migratory Rhythm of Intertidal Microphytobenthos in Sediment Depends on the Light Photoperiod, Intensity, and Spectrum: Evidence for a Positive Effect of Blue Wavelengths

Abstract

Barnett et al. Intertidal Microphytobenthos Light-Dependent Rhythmic Migration MPB surface accumulation, as compared to other wavelengths (white, green, and red) in patterns that were intensity-dependent and species-dependent. In particular, we found two species, Navicula spartinetensis and Gyrosigma fasciola, which strongly migrate up under blue light and could potentially be used as model species for further studying the light-responses of intertidal MPB.

Diuron effects on photosynthesis and vertical migration of microphytobenthos: Potential rapid bioassessment of herbicide toxicity in coastal sediments

“…Instead, in our conditions, MPB abundance at the surface of sediment indicated by Ft went on varying at the function of photoperiod (and probably of the tidal cycle), with striking increase of Ft before day starts (Fig. 1) as previously reported before (Consalvey et al 2004;Barnett et al 2020). It was consistent with the observation of Staats et al (2000) that in situ patterns of diuron-treated-MPB vertical migration in the dark did not differ from those exposed to light during 24 h field experiment on mudflat surface.…”

“…Physiological photoprotection mainly depends on distinct xanthophyll pigments, diadinoxanthin and diatoxanthin, which support the dissipation of excessive light energy (the so-called non-photochemical quenching process) and protect PSII reaction centres (Barnett et al, 2015;Cartaxana et al, 2016;Frankenbach et al, 2018;Pniewski and Piasecka-Jędrzejak, 2020). Behavioural photoprotection is realized through the vertical migration of MPB within the uppermost layers of sediment, by which motile diatoms position themselves at suitable depth for optimal light conditions (Consalvey et al 2004;Barnett et al, 2020).…”

Mapping the Intertidal Microphytobenthos Gross Primary Production Part I: Coupling Multispectral Remote Sensing and Physical Modeling

“…Such a migration scheme in the GPP algorithm was set according to the observation of the progressive superficial sediment covering by MPB during emersion at our study site (Herlory et al, 2004). However, the migration speed can be faster [a few minutes; see Méléder et al (2003b)] or slower [one hour; see Paterson et al (1998)], and it is mainly controlled by the tidal cycle and the light climate and spectral quality (Pinckney and Zingmark, 1991;Spilmont et al, 2007;Coelho et al, 2011;Barnett et al, 2020;Prins et al, 2020), but also by temperature (Cohn et al, 2003), nutrient availability in the sub-surface of sediment (Kingston, 2002), and desiccation (Coelho et al, 2009). Currently, the GPP-algorithm does not include the short-term variations of MPB photosynthetically active biomass at the sediment surface (i.e., "micro-migrations"), as it has been also observed some days/timings during our field campaigns.…”

Hypersaline tidal flats as important “blue carbon” systems: a case study from three ecosystems

“…In arid and semi-arid estuaries (Ridd and Stieglitz, 2002) or humid tropical supratidal zones with less fluvial contribution (Soares et al, 2017), HTF ecosystems cover an area that exceeds mangrove forests and occupy a substantial proportion of tropical intertidal zones. HTFs occupy the area just below the highest astronomical tides and are thus only flooded for short periods of the year (Ridd and Stieglitz, 2002;Bento et al, 2017). Evaporation, the flat topography and pronounced hydraulic deficit results in hypersaline conditions with salinity as high as 5 times that of seawater (Ridd and Stieglitz, 2002;Shen et al, 2018).…”

“…However, information on OC, nitrogen and phosphorus burial, and sediment CO 2 fluxes from these ecosystems remains scarce (e.g. Bento et al, 2017;Schile et al, 2017). Determining if HTFs are a source or sink of carbon is critical to understanding their importance and value in regards to climate change and coastal carbon sequestration (Lovelock and Duarte, 2019).…”