Benthic nutrient fluxes at longline sea squirt and oyster aquaculture farms and their role in coastal ecosystems

Abstract

To assess the impact of aquaculture activities, we measured the primary production, total sediment oxygen consumption, and benthic nutrient flux at two aquaculture farms (sea squirt and oyster) and one reference site. The estimated primary production in the water column ranged from 19-169 mmol C m -2 d -1 . Total sediment oxygen consumption rates ranged from 58 to 328 mmol m -2 d -1 , 1.1 to 40 mmol m -2 d -1 for nitrogen, 0.17 to 3.0 mmol m -2 d -1 for phosphate, and 7.3 to 74 mmol m -2 d -1 for silicate. The average total sediment oxygen consumption at the longline farms was [2.5 times higher than the reference site. Nitrate was significantly removed by denitrification at the longline farms in July and September and ranged from -5.4 to -0.09 mmol m -2 d -1 , which is higher than for other coastal sediments. The benthic fluxes of nitrogen and phosphate at longline farms were up to 16 and six times higher than at the reference site, respectively. The average nitrogen requirements of the primary producers were 9.3 mmol m -2 d -1 at the sea squirt farm, 7.0 mmol m -2 d -1 at the oyster farm, and 13.5 mmol m -2 d -1 at the reference site, corresponding to 88, 316, and 27.2% of the nitrogen supplied by benthic fluxes, respectively. Our results suggest that benthic nutrient fluxes at longline farms are a major nutrient source for primary production in coastal waters.

Effects of diatom concentration in prepared feeds on growth and energy budget of the sea cucumberApostichopus japonicus(Selenka)

“…Although sea cucumber feed contains less protein than shrimp feed in a general way, it is much softer and unstabler, which makes it easily lost in water. Substantial uneaten feed, faeces and dissolved excretory products from aquaculture activities not only result in nutrient pollution and subsequent deterioration of water quality in surrounding waters but also reduce biodiversity, even change biological composition and structure in ecological system (Gao, Xu, Liu, Cheung & Shin ; Forchino, Borja, Brambilla, Rodríguez, Muxikab, Terovaa & STogliaa ; Lee, Kim, Shin, Hyun & Kin ).…”

Impacts of an integrated multi-trophic aquaculture system on benthic nutrient fluxes: a case study in Sanggou Bay, China

“…Assuming DIN and DON released from the sediment was completely consumed by phytoplankton and kelp, the benthic TDN efflux contributed 8% of GPP. The benthic nutrient contributions to GPP were much smaller than that in the Mandovi Estuary (Pratihary et al 2009), on the west coast of Sweden (Sundbäck et al 2003) and in Jinhae Bay (Lee et al 2011), since substantial cultivation of kelp made the highest contribution to GPP in the IMTA system. If only the GPP of kelp is taken into account, the benthic effluxes of DIN and Si(OH) 4 contributed 7 and 18% of algal N and Si demands.…”

“…Increased biodeposits produced by the actively growing animals can result in a substantial increase in the organic content of sediment (Hatcher et al 1994, Christensen et al 2000, Ferrón et al 2009, Lee et al 2011; the mineralization of sedimentation can release substantial nutrients from the sediment to the sea water, which may result in the deterioration of sea water quality (Chau 2002). Hence, the TOC in the sediment and benthic effluxes of nutrients in traditional aquaculture areas were extremely high (Table 3).…”

“…Despite the increasing recognition that nutrients are fundamental to the food web in aquaculture eco -systems, information about the internal nutrient cycles in IMTA systems is still unavailable (Sequeira et al 2008, Troell et al 2009, Tang & Fang 2012, Chopin 2013. Benthic nutrient regeneration is a significant source of nutrients for primary production in coastal waters (Liu et al 2003, Sundbäck et al 2003, Lee et al 2011. Conversely, nutrients can be stored in the sediments via burial and denitrification (Aller et al 1985, Song et al 2013.…”

Rates of Sulfate Reduction and Iron Reduction in the Sediment Associated with Abalone Aquaculture in the Southern Coastal Waters of Korea

“…또한, Lee et al (2011)은 굴 양식장에서의 저층 플럭스를 통해 수층으로 유입된 질소 316%와 인산염 58%가 일차 생산 력을 지지한 것으로 보고하였다. 이렇게 추가적으로 공급 된 영양염들은 일차적으로 일차 생산력을 향상시켜주는 효과를 가지나, 이러한 현상이 지속되면 부영양화를 일으 켜 적조생물의 번식이 일어날 수도 있다 (Richard et al 2007).…”