The impact of urea on toxic diatoms – Potential effects of fertilizer silo breakdown on a Pseudo-nitzschia bloom

Abstract

In spring 2016, two silos containing liquid nitrogen-containing fertilizer collapsed on a harbor in Fredericia, Denmark. More than 2,750 tons of fertilizer spilled into inner Danish waters. A bloom of Pseudo-nitzschia occurred approximately one month after the incident. The bloom caused a 5-week quarantine of numerous musselharvesting areas along the eastern coast of Jutland. The levels of domoic acid measured up to 49 mg kg −1 in mussel meat after the bloom. In the months following the event, the species diversity of phytoplankton was low, while the abundance was high comprising few dominant species including Pseudo-nitzschia. The main part of the liquid nitrogen-containing compound was urea, chemically produced for agricultural use.To investigate the potential impact of urea on Pseudo-nitzschia, four strains, including one strain of P. delicatissima, two of P. seriata and one of P. obtusa, were exposed each to three concentrations of urea in a batch culture experiment: 10 μM, 20 μM and 100 μM N urea, and for comparison one concentration of nitrate (10 μM). Nitrate, ammonium, and urea were metabolized at different rates. Pseudo-nitzschia obtusa produced domoic acid and grew best at low urea concentrations. Both P. seriata strains had a positive correlation between urea concentration and growth rate, and the highest growth rate in the nitrate treatment. One strain of P. seriata produced domoic acid peaking at low N loads (10 µM N urea and 10 µM N nitrate). In conclusion, the ability to adapt to the available nitrogen source and retain a high growth rate was exceedingly varying and not only species-specific but also strain specific.

Salinity, a climate-change factor affecting growth, domoic acid and isodomoic acid C content in the diatomPseudo-nitzschia seriata(Bacillariophyceae)

“…Pseudo-nitzschia species are globally distributed diatoms, particularly abundant in coastal areas where they form harmful blooms (Doucette et al 2008). Pseudo-nitzschia seriata (Cleve) H. Peragallo is commonly found in Arctic, Subarctic, and (Northern) temperate waters (Fehling et al 2004;Hansen et al 2011;Tammilehto et al 2012;Harðardóttir et al 2015;Stonik & Orlova 2018;Olesen et al 2020). Reports of P. seriata from warmer regions such as Singapore and the Black Sea need to be confirmed (Terenko & Terenko 2012;Tan et al 2016).…”

“…Presently, two Arctic species, P. seriata and P. obtusa (Hasle) Hasle & Lundholm, have been shown to be toxic (Hansen et al 2011;Tammilehto et al 2012;Harðardóttir et al 2015). Arctic P. seriata strains are potent toxin producers with toxic strains found in Greenland, Iceland, Scotland, and Denmark (Lundholm et al 1994;Fehling et al 2004;Hansen et al 2011;Olesen et al 2020). These are areas where toxic blooms of P. seriata have caused DA accumulation in blue mussels (Mytilus edulis) up to ten times above the EU regulatory limit (20 mg DA kg -1 ) (Fehling et al 2004;Lundholm et al 2005;Olesen et al 2020).…”

“…Arctic P. seriata strains are potent toxin producers with toxic strains found in Greenland, Iceland, Scotland, and Denmark (Lundholm et al 1994;Fehling et al 2004;Hansen et al 2011;Olesen et al 2020). These are areas where toxic blooms of P. seriata have caused DA accumulation in blue mussels (Mytilus edulis) up to ten times above the EU regulatory limit (20 mg DA kg -1 ) (Fehling et al 2004;Lundholm et al 2005;Olesen et al 2020). Under-reporting of toxin syndromes due to toxic phytoplankton is a major problem in Alaska (Lewitus et al 2012) and presumably also in other Arctic areas.…”

Microbial Fuel Cell Based on Nitrogen-Fixing Rhizobium anhuiense Bacteria

“…This process leads to hypoxia in the coastal zone and other surface water bodies. Algae blooms are also triggered by nitrogen (N) uptake from agricultural land [ 5 , 6 ]. Therefore, intensive agricultural systems emit reactive nitrogen-based gases, particularly ammonia and various nitrogen oxides, which act as powerful greenhouse gases in the troposphere [ 7 , 8 , 9 ].…”

Interactions Between Ultraviolet B Radiation, Warming, and Changing Nitrogen Source May Reduce the Accumulation of Toxic Pseudo-nitzschia multiseries Biomass in Future Coastal Oceans

“…bloom occurred along the West Coast of the United States that was thought to be the result of high nutrient influxes from upwelling combined with warming (McCabe et al, 2016;McKibben et al, 2017). An accident washing >2,750 tons of urea-dominant fertilizer into Danish waters induced a highly toxic multi-species Pseudo-nitzschia bloom in 2016 (Olesen et al, 2020). Furthermore, Pseudo-nitzschia abundances have been positively correlated with high rainfall, as this runoff can deliver large amounts agricultural nitrogen to the ocean (Rees et al, 2009;Downes-Tettmar et al, 2013).…”