Characteristics of Benthic Chlorophyll a and Sediment Properties in the Tidal Flats of Kwangyang Bay, Korea

Abstract

Characteristics of benthic microalgae and sediment properties were investigated for the intertidal flats of Kwangyang Bay, Korea. Sampling stations were selected every 100 m in the intertidal flats from land-side to open ocean at two different sampling sites. Samples were collected in June 2004, July, September, November, February and May 2005. Sediments properties were measured including temperature, water contents, sediment bulk density, nutrient concentrations in porewater. Chlorophyll a concentrations in surface sediment (0.5 cm) were measured and relationships between the chlorophyll a and various sediment properties were analyzed to identify major mechanisms regulating biomass of benthic microalgae in the intertidal flats using simple linear regression analysis. Sediment chlorophyll a concentrations were maximum during winter and minimum during warm seasons ranging from 4.4 mg m -2 to 81.2 mg m -2. No clear spatial variations were observed for the sediment chlorophyll a in the study sites. Results from regression analysis suggested that benthic microalgae biomass was affected by sediment temperature and nutrients especially ammonium and silicate. Grazing effect was estimated using chlorophyll: pheopigments ratio, indirect indicator of grazing activity, and the positive correlation of the ratio and chlorophyll a implied that microalgae biomass is affected by grazing of zoobenthos although direct measurement of grazing activity is required to determine the importance of top-down controls in the benthic microalgae dynamics.

Assessment of the physicochemical conditions sediments in a polluted tidal flat colonized by microbial mats in Bahía Blanca Estuary (Argentina)

“…On the opposite, others authors suggest that it depends on the amount of organic matter produced, since nutrients are released during decomposition (Burdige, 2006). NH 4 + concentrations in porewater recorded here are lower than those found in other works from the Bahía Blanca Estuary (Spetter, 2006;Marcovecchio et al, 2009;Negrin et al, 2011) and from others tidal flats in the world (Magni and Montani, 2006;Sin et al, 2009). On the contrary, NO 3 À values from both sites were in general higher than the ones usually found in other sites of the estuary without microbial mats (Spetter, 2006;Marcovecchio et al, 2009).The high NO 3 À concentrations could be associated with the possible input of nutrients from groundwater (Galloway, 2005), which has not been studied in the area so far, but the groundwater presence has been reported by Cuadrado et al (2013a) at the study site.…”

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“…The highest Chl a content was also recorded in spring at site 7, while the lowest content was found in winter at site 1 ( Figure 8B). These results coincide with findings of Underwood and Paterson (1993), Santos, Pastel, and Souza-Santos (1997) and Sin, Ryu, and Song (2009) who reported that epipelic biomass represented by Chl a often shows the seasonal patterns of increase during the summer months or throughout the year, even in winter. The highest density of macroinvertebrates (approximately 30,000 ind./cm 2 ), in turn, was recorded in spring at site 6 ( Figure 9).…”

Spatial and temporal patterns of microphytobenthos communities along the marine-terrestrial boundary in the German Wadden Sea

“…Effective number of species was also significantly influenced by temperature and sediment characteristics, i.e., mean grain size and mud content. The negative relationship with temperature supported previous findings that show that warmer temperatures often favor dominance of certain MPB groups (Sin et al, 2009;Cartaxana et al, 2015;Ribeiro et al, 2021), whereas diatoms thrive only at lower temperatures (Watermann et al, 1999;Underwood, 2001;Scholz and Liebezeit, 2012b). Janousek (2009) and Semcheski et al (2016) reported higher MPB diversity in muddy sediments than in sandy sediments, a result of the depository nature of more protected muddy sites, and higher resistance of MPB biofilms on muddy sediments against erosion (Cahoon et al, 1999;Herman et al, 2001).…”