Abiotic factors influencing biomass accumulation of green tide causing Ulva spp. on Pyropia culture rafts in the Yellow Sea, China

Abstract

a b s t r a c t a r t i c l e i n f oAnnually recurrent green-tides in the Yellow Sea have been shown to result from direct disposal into the sea of fouling Ulva from Pyropia aquaculture. The role abiotic factors play in Ulva biomass accumulation on rafts was studied to find ways to mitigate this problem. Dissolved inorganic nitrogen (DIN) was very high at all sites, but the highest Ulva biomass was associated with the lowest DIN and anthropogenic N. Under luxuriant background nutrient conditions, variability in temperature and periods of emersion, rather than pH, light and salinity determined Ulva biomass. Two dominant species of Ulva displayed differing tolerances to temperature and desiccation which helped explain why Ulva prolifera dominates floating green-tides. Rather than trying to mitigate greentides only by reducing nutrient pollution, an earlier harvest of Pyropia in southern Jiangsu Province especially before temperatures increase greatly above 10°C during April, could reduce the biomass of U. prolifera disposed from rafts.Crown

Stable isotopic evidence of nitrogen sources and C4 metabolism driving the world’s largest macroalgal green tides in the Yellow Sea

“…Even in the open Yellow Sea, concentrations of dissolved inorganic nitrogen are 10–80 µM near the coast, and 0.7–5.8 µM offshore 7 . Other reports confirm that concentration of coastal dissolved inorganic nitrogen range 7.4–95 µM 18 and 1–15 µM offshore 10 . Such high concentrations of nitrogen must stimulate the onset and maintain the Ulva bloom.…”

“…The expansive canopies of macroalgae that grow across the Yellow Sea have become known as the largest coastal green tides in the world. They have attracted their share of attention because of the cost of dealing with the annual green tides, the nuisance aspects on shore, disruption to mariculture, and because of scientific interest in the unusual phenomenon 10 . There have been many recent publications 6 , 7 , with much of the focus on the causes and controls of green tides.…”

Biofouling in marine aquaculture: a review of recent research and developments

“…Water temperature also influences the accumulation of fouling species. In general, it has been recommended that cultured seaweeds are harvested before sea temperatures rise in spring and summer to avoid the negative impacts of seasonal biofouling (Park and Hwang 2012;Ateweberhan et al 2015;Marinho et al 2015;Førde et al 2016;Keesing et al 2016).…”

Polyphasic approach to a characteristic Ulva population from a limno-rheocrenic, mineral (chloride, sodium, sulphate) spring in the Siwa Oasis (Western Desert of Egypt)

“…A taxonomic discussion of previously-sampled close relatives, based with notoriously overlapping characteristics (Duan et al 2012;Melton et al 2016). In addition, intraspecific, phenotypic-plasticity phenomena in response to different environmental factors have also been described (e.g., Blomster et al 1999;Messyasz & Rybak 2011;Keesing et al 2016;Rybak 2018). Nevertheless, progress in refined species discrimination has been achieved during the last decades utilizing molecular phylogeny based on several well-sampled genomic markers, such as the nrDNA internal transcribed spacer (ITS) regions, 5S rDNA, the large subunit of RuBisCO (rbcL), and the chloroplast protein synthesis elongation factor Tu (tufA) genes (e.g., Kraft et al 2010;Mareš et al 2011;Kazi et al 2016;Hiraoka et al 2017).…”