Diatom (Bacillariophyceae) assemblages in salt marshes of south‐central Chile: Relations with tidal inundation time and salinity

Abstract

SUMMARYTo reconstruct sea-level history from changes in tidal environments using diatom assemblages, we need to better understand the relations among brackish diatom assemblages and changing environments along elevational gradients from diverse coastal sites. Our statistical analysis reveals relations between environmental variables and brackish benthic diatom assemblages in the little studied region of south-central Chile. Along four transects across salt marshes at two sites, we identified 224 diatom taxa in 112 samples. Detrended canonical correspondence analysis showed that tidal exposure time index and salinity were appropriately regressed against the abundance of diatom species using unimodal-based methods. Our tests of classical and inverse regressions of weighted average and weighted averaging partial least squares (WA-PLS) showed that WA-PLS resulted in the highest coefficient of determination and the lowest root-mean square of the error of prediction. Our regression will be useful in reconstructing environmental variables from fossil diatom assemblages in Chile.

Ecological Study of the Rabigh Lagoon, Eastern Site of the Red Sea, Saudi Arabia with Special Reference to Eutrophication Index

“…Our data agree to some extent with the data obtained by Touliabah [4,16] and Sawai [80].Touliabah [16] recorded the Bacillariophyceae as the second dominant group after Dinophyceae. They reported that, the percentage abundance of this group was 27.9% of the total phytoplankton standing crop in Jeddah.…”

Modern diatom assemblages from Chilean tidal marshes and their application for quantifying deformation during past great earthquakes

“…Diatoms (unicellular algae) are widely used for this purpose due to their vertical zonation in intertidal environments, as well as their high preservation potential in coastal sediments (for full reviews see Pilarczyk et al, 2014 andDura et al, 2016). In Chile, modern diatom data are available only from a limited number of sites (Nelson et al, 2009;Garrett et al, 2013;Sawai et al, 2017). Consequently, as we attempt to reconstruct palaeoseismic deformation at new sites or further back in time, our models may be limited by not having a modern-day equivalent of the past environment we are trying to reconstruct.…”

Contrasting responses of intertidal microphytobenthos and phytoplankton biomass and taxonomic composition to the nutrient loads in the Jiulong River Estuary

“…), and the loss of MPB Chl a may be much higher at JYI than at DYI owing to the turbulent environment from Jiulong River runoff and the tidal current (Sawai et al . ). Thus, the balance between growth and loss of MPB resulted in a lower MPB Chl a at JYI, and the analysis showed differential responses of MPB diatoms to the ENV1 between the two sites (Fig.…”