Aquaculture Farming Effect on Benthic Respiration and Nutrient Flux in Semi-Enclosed Coastal Waters of Korea

Abstract

Sediment oxygen demand (SOD) and benthic nutrient fluxes (BNFs) were measured using an in situ benthic chamber at a fish farm (FF), oyster farm (OF), and controls (FF-C and OF-C) to assess the impact of aquaculture activities on organic carbon (OC) and nutrients cycles in coastal waters of Korea. The SOD at FF and OF ranged from 60 ± 2 to 157 ± 3 mmol m–2 d–1 and from 77 ± 14 to 84 ± 16 mmol m–2 d–1, respectively, more than five times those of the control sites. The SOD at farm sites is highly correlated with fish stock and food input, suggesting that excess feed input is an important control factor for OC remineralization. The combined analysis of sediment trap and SOD indicates that most of the deposited OC oxidized in the sediment and/or was laterally transported by the current before being buried in the sediment. The benthic nutrient fluxes at farms ranged from 5.45 to 8.95 mmol N m–2 d–1 for nitrogen and from 0.51 to 1.67 mmol P m–2 d–1 for phosphate, respectively, accounting for 37–270% and 52–804% of the N and P required for primary production in the water column. These results indicate that aquaculture farming may profoundly impact biogeochemical cycles in coastal waters.

The Roles of Macrobenthic Molluscs Structure in Assessing Ecological Status at Mangrove and Aquaculture Areas

“…Station 1 of the Aquaculture area for the July 2021 station has the highest diversity and the lowest dominance, thus station 2-mangrove area-July 2021 has the lowest diversity and evenness, Based on Ref [40] statement, if the k-dominance curve is below the other curves, means that the station has the highest value of evenness and diversity, while the curve's position station above the other curves, indicates that the station has the lowest value of evenness and diversity [40]. Aquaculture area had a high diversity rather than mangrove area as a result of aquaculture activities, according on research conducted by Ref [41] shows that Aquaculture activities such as excess feed and unfed pellets will degrade and provide a greater source of organic matter (OM), resulting in an increase in benthic respiration and biological production [41][42]. In addition, aquaculture is one of the activities that degraded the environmental quality of the nearby mangrove ecosystem, resulting in a decrease in macrofaunal diversity [32].…”

“…Aquaculture activities influence the encompassing biological system and demonstrated in various studies [3]. One of the consequences of aquaculture activities such as feed residue, urine and feces of farmed fish can cause enrichment of organic matter to the substrate layer [4].…”

Nutrient Flux under the Influence of Melt Water Runoff from Volcanic Territories and Ecosystem Response of Vilyuchinskaya and Avachinskaya Bays in Southeastern Kamchatka

“…It is known that different types of ash contribute different ratios of DIN and DIP fluxes, and there are differences in ash, depending on the distance from active volcanoes [67]. Additionally, the DIN flux and stimulation of phytoplankton blooms may result from groundwater discharges [3] and porewater exchange [68], as occurs in other regions. In this case, this may be applicable to Kamchatka, since volcanic rocks have a high permeability to groundwater, which is enriched with DIN and DIP during water-soil interactions.…”