Microcystin in aquatic food webs of the Baltic and Chesapeake Bay regions

Abstract

We undertook a comparative study of the James River Estuary, a sub-estuary of Chesapeake Bay, and the Curonian Lagoon, a sub-estuary of the Baltic Sea, to better understand the factors that determine the presence and persistence of algal toxins in food webs. Over a 2-year period, we measured microcystin concentrations in water, sediment and biota (fish and shellfish) at both sites. Across both food webs we found highest levels of microcystin among consumers of suspended particulate matter, including planktivorous fishes and filter-feeding shellfish, and lower levels of toxin among piscivores, scavengers and benthic omnivores. Despite similar levels of microcystin in the water column at the two sites, we observed higher toxin levels in fish and sediments of the Curonian Lagoon. We attribute this difference to the legacy of prior toxic cyanobacteria blooms in the Curonian Lagoon and hydrologic factors that result in a predominance of autochthonously-derived organic matter in the sediments at this site. Our results suggest that a consideration of species-specific differences in feeding habits, and organic matter sources supporting food webs are important to understanding the accumulation and persistence of algal toxins in food webs and should therefore be considered in assessment of risks to aquatic biota and human health.

Cyanobacteria and cyanotoxins in estuarine water and sediment

“…To our knowledge, MC occurrence in estuarine sediment has only been reported in Isahaya Bay, Japan (Umehara et al 2012(Umehara et al , 2015, and in sub-estuaries of the Baltic Sea (Paldaviciene et al 2015) and Chesapeake Bay, USA (Bukaveckas et al 2017) while cyanobacterial (e.g. Microcystis) occurrence in estuarine sediment has never been demonstrated.…”

Recent Trends (2012–2016) of N, Si, and P Export from the Nemunas River Watershed: Loads, Unbalanced Stoichiometry, and Threats for Downstream Aquatic Ecosystems

“…Our results show that the seasonality of nutrient transport resulted in a variable ecological stoichiometry of N, Si, and P. In general, we observed a large excess of N in autumn, winter, and spring (DIN:DIP > 16), but a marked N deficiency (and to a minor extent of Si) from May to August during the five analysed years. With respect to downstream water bodies (Curonian Lagoon and Baltic Sea), this strong N and Si summer limitation may favour the succession of phytoplankton communities from diatom-dominated (spring) to cyanobacteria-dominated (summer) [13,24]. During warm months, cyanobacteria have a competitive advantage as they do not require silica for their exoskeleton and can fix relatively inert dinitrogen (N 2 ) when N is limiting.…”

“…Climate change, which affects snow cover period, precipitation intensity, and timing, may favour soil erosion and increase short-term transport of particulate phosphorus (P) and silica (Si) to coastal areas [9][10][11]. The varying precipitation patterns may also result in rapid delivery of dissolved nutrients to coastal areas and saturation of their metabolic capacity, resulting in large inputs to the sea [12,13]. However, at regional scales, ongoing socio-economic changes may produce larger impacts on biogeochemical cycles than those produced by climate changes [14].…”

Drivers of Cyanobacterial Blooms in a Hypertrophic Lagoon

“…Detailed studies of plankton communities in the Curonian Lagoon have examined seasonal patterns, species interactions, production of cyanotoxins and the role of phytoplankton in food web energetics (e.g., Razinkovas, 2006, Razinkovas, 2007;Lesutienė et al, 2014;Bukaveckas et al, 2017). Diatoms dominate the spring phytoplankton community, after which, following a short clear-water phase, cyanobacteria biomass increases (Gasiunaitė et al, 2005;Pilkaitytė and Razinkovas, 2007).…”