Distribution of Alexandrium fundyense (Dinophyceae) cysts in Greenland and Iceland, with an emphasis on viability and growth in the Arctic

Abstract

The bloom-forming dinoflagellate Alexandrium fundyense has been extensively studied due its toxin-producing capabilities and consequent impacts to human health and economies. This study investigated the prevalence of resting cysts of A. fundyense in western Greenland and Iceland to assess the historical presence and magnitude of bloom populations in the region, and to characterize environmental conditions during summer, when bloom development may occur. Analysis of sediments collected from these locations showed that Alexandrium cysts were present at low to moderate densities in most areas surveyed, with highest densities observed in western Iceland. Additionally, laboratory experiments were conducted on clonal cultures established from isolated cysts or vegetative cells from Greenland, Iceland, and the Chukchi Sea (near Alaska) to examine the effects of photoperiod interval and irradiance levels on growth. Growth rates in response to the experimental treatments varied among isolates, but were generally highest under conditions that included both the shortest photoperiod interval (16h:8h light:dark) and higher irradiance levels (~146–366 μmol photons m−2 s−1), followed by growth under an extended photoperiod interval and low irradiance level (~37 μmol photons m−2 s−1). Based on field and laboratory data, we hypothesize that blooms in Greenland are primarily derived from advected Alexandrium populations, as low bottom temperatures and limited light availability would likely preclude in situ bloom development. In contrast, the bays and fjords in Iceland may provide more favorable habitat for germling cell survival and growth, and therefore may support indigenous, self-seeding blooms.

Fjord light regime: Bio‐optical variability, absorption budget, and hyperspectral light availability in Sognefjord and Trondheimsfjord, Norway

“…The shift in the wavelength of maximum penetrating wavelength as a result of increased turbidity upstream is also evident in Richlen et al . [], wherein a shift from lower (490–502 nm) to higher (536–567 nm) wavelength is reported with decrease in 1% PAR depth in Greenland and Iceland.…”

Review Article: How does glacier discharge affect marine biogeochemistry and primary production in the Arctic?

“…Moreover, many known toxin-producing species in the Arctic are mixotrophic, further complicating their interactions with other microbial groups (Stoecker and Lavrentyev, 2018). Whilst HAB associated species are known to be present in Arctic waters (Lefebvre et al, 2016;Richlen et al, 2016) and HAB events appear to be associated with glacier retreat in Patagonia (León-Muñoz et al, 2018) (Richlen et al, 2016).…”

90 years of Arctic Ocean Exploration at the Woods Hole Oceanographic Institution

“…Two cruises along the west coast of Greenland documented the presence of Alexandrium catenella, the organism responsible for a widespread HAB human poisoning syndrome called paralytic shellfish poisoning (PSP). In western Greenland, A. catenella cysts were present in bottom sediments at most stations sampled, even those near 76°N, but concentrations were very low (Richlen et al, 2016), as were the counts of vegetative cells in surface waters. The species is thus present, but was not thriving or blooming in large numbers along that coast.…”