Variations of Dissolved Inorganic Nutrient Flux through the Seomjin River Estuary

Park, Mi-Ok; Lee, Jae‐Seong; Kim, Seong-Soo; Kim, Seong‐Gil; Lee, Suk-Mo; Lee, Yong-Woo

doi:10.5322/jesi.2014.23.6.1049

Cited by 1 publication

(1 citation statement)

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“…In the upper estuarine channel, waterresidence times are very short (4.4-12.2 days during spring and neap tides) (Shaha et al, 2012), and thus planktonic organisms may be advected from the estuarine channel to the deep bay (Shaha et al, 2010). Dilution of dissolved inorganic nutrients by freshwater-seawater mixing and their rapid assimilation by phytoplankton lowers nutrient concentrations in the estuarine channel, leading to spatial and seasonal variations (Kwon et al, 2001(Kwon et al, , 2004Jang et al, 2005;Lee and Kang, 2010). Furthermore, because autochthonous POM is of nutritional importance to the bay's food-web base (Kang et al, 2003;Chen et al, 2018;Kim et al, 2020), the spatial and temporal dynamics of biogenic elements and phytoplankton may be crucial to the bay ecosystem.…”

Section: Introductionmentioning

confidence: 99%

Dominance of Autochthonous Phytoplankton-Derived Particulate Organic Matter in a Low-Turbidity Temperate Estuarine Embayment, Gwangyang Bay, Korea

et al. 2020

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In estuaries, the sources of organic matter, its composition, and its functional role in the coastal ecosystem food web are all influenced by dominant estuarine processes. We investigated seasonal variations in the quantity and composition of dissolved inorganic nutrients, suspended particulate matter (SPM), and phytoplankton across a low-turbidity estuarine-coastal continuum in Gwangyang Bay, South Korea. The narrow estuarine channel has a sharp salinity gradient (from 0 to around 30) and low SPM concentrations (<20 mg L −1). The channel carries river discharge, with a large quantity of nutrients (NO 3 and SiO 2), into the bay. The especially low SPM concentrations in the estuary (range: 2.0-29.1 mg L −1), and generous nutrient source, create an exceptionally low-turbidity condition in the water column and high primary productivity with no conspicuous spatial or seasonal trends. Gradually increasing δ 13 C values, low POC:Chla (<200), and low molar C:N (4-8) in the SPM, together with higher Chla concentrations at low SPM locations along the longitudinal transect, suggest that local production of phytoplankton has a strong influence on the distributional patterns of particulate organic matter. Short water-residence times, within the bay system, impede the accumulation of diverseorigin organic matter. The community composition of phytoplankton, distinguished by their size group, also plays a role in characterizing SPM quantity and composition. The results indicate that autochthonous pelagic production governs biogeochemical features in the low-turbidity estuarine embayment, contrasting with a prevalence of allochthonous organic matter, and its active processing, in highly turbid and/or longer residence-time systems.

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