Macroalgae mitigation potential for fish aquaculture effluents: an approach coupling nitrogen uptake and metabolic pathways using Ulva rigida and Enteromorpha clathrata

Abstract

Aquaculture effluents are rich in nitrogen compounds that may enhance local primary productivity, leading to the development of algae blooms. The goal of this study was to assess the potential use of naturally occurring green macroalgae (Ulva and Enteromorpha) as bioremediators for nitrogen-rich effluents from a fish aquaculture plant, by evaluating their respective uptake dynamics under controlled conditions. Ulva and Enteromorpha were incubated separately in aquaculture effluent from a local pilot station. Algae tissue and water samples were collected periodically along 4 h. For each sample, nitrate, nitrite, and ammonia concentrations were quantified in the effluent, while internal algae reserve pools and nitrate reductase activity (NRA) were determined within the algae tissues. Both macroalgae absorbed all dissolved inorganic nitrogen compounds in less than 1 h, favoring ammonia over nitrate. Ulva stored nitrate temporarily as an internal reserve and only used it after ammonia availability decreased, whereas Enteromorpha stored and metabolized ammonia and nitrate simultaneously. These distinct dynamics of ammonia and nitrate uptake supported an increase in NRA during the experiment. This study supports the hypothesis that Ulva or Enteromorpha can be used as bioremediators in aquaculture effluents to mitigate excess of dissolved inorganic nitrogen.

WITHDRAWN: Nutrient Removal Effectivity of Seaweeds as Biofilter and Water Pollution Control in Hybrid Grouper Aquaculture Wastewater at Low Salinity

“…Seaweed utilization in biofilter and bioremediator have been widely studied, such as Ulva, Palmaria palmata, Gracilaria, Kappaphycus, and Hypnea aspera (Tremblay-Gratton et al 2018;Laramore et al 2018;Neori et al 2003;Marinho-Soriano et al 2009;Andayani et al 2016;Adharini & Trianti 2020;Castelar et al 2015;Anibal et al 2013;Carneiro et al 2011;Elizondo-González et al 2018;Ribeiro et al 2017;Kang et al 2011;Hayashi et al 2008).…”

Cloning and characterization of nitrate reductase gene in Ulva prolifera (Ulvophyceae, Chlorophyta)

“…Indeed, the repression of UpNR transcript by ammonium was too strong to be removed by addition of extra nitrate, implying that the uptake of ammonium was preferred over nitrate in U. prolifera , as revealed in other Ulva species and Chlorella vulgaris (Zeiler and Solomonson , Anibal et al. ). Likewise, when nitrate was supplied as the sole N source, the decrease in NR gene transcript level from the peak might represent a repression by accumulated ammonium as the end product of nitrate assimilation (Wang et al.…”

“…, Anibal et al. ), it is reasonable to presume that such competitive advantages in nitrate assimilation contribute greatly to the blooming of Ulva . Therefore, detailed research on NRs from Ulva would help to clarify unique features and mechanism of N metabolism in Ulva species, which may be an important biotic factor in formation of green tide.…”

“…In recent years, green tide, mainly caused by Ulva species, has occurred in an accelerated rate around the world (Smetacek and Zingone 2013). Since various Ulva species displayed faster nitrate uptake rate, larger intracellular N pool, and higher NR activity than other seaweeds (Lartigue and Sherman 2006, Chung et al 2011, Anibal et al 2014, it is reasonable to presume that such competitive advantages in nitrate assimilation contribute greatly to the blooming of Ulva. Therefore, detailed research on NRs from Ulva would help to clarify unique features and mechanism of N metabolism in Ulva species, which may be an important biotic factor in formation of green tide.…”

Growth‐promoting bacteria for the green seaweed Ulva clathrata

“…In the case of aquatic animal production, it has shown benefits on growth when used as additive or partial substitute of balanced feed (Cruz‐Suárez et al, ; Cruz‐Suárez, Tapia‐Salazar, Nieto‐López, Guajardo‐Barbosa, & Ricque‐Marie, ; Gamboa‐Delgado, Peña‐Rodríguez, Ricque‐Marie, & Cruz‐Suárez, ; Peña‐Rodríguez, Elizondo‐González, et al, ; Peña‐Rodríguez, Magallón‐Barajas, et al, ) or to improve water quality when used as biofilter (Copertino, Tormena, & Seeliger, ; Lu, Lin, & Liu, ). This alga is also harvested for soil cover and fertilizer, in traditional agricultural techniques (Copertino et al, ), for bioremediation or in integrated aquaculture systems (Aníbal et al, ; Copertino et al, ; Cruz‐Suárez et al, ; Lu et al, ; Moll & Deikman, ; Peña‐Rodríguez, Magallón‐Barajas, et al, ).…”