Ocean warming along temperate western boundaries of the Northern Hemisphere promotes an expansion of Cochlodinium polykrikoides blooms

Abstract

Since the early 1990s, ocean temperatures have increased and blooms of the icthyotoxic dinoflagellate Cochlodinium polykrikoides (a.k.a. Margalefidinium polykrikoides ) have become more widespread across the Northern Hemisphere. This study used high-resolution (1–30 km), satellite-based sea surface temperature records since 1982 to model trends in growth and bloom season length for strains of C. polykrikoides inhabiting North American and East Asian coastlines to understand how warming has altered blooms in these regions. Methods provided approximately 180× greater spatial resolution than previous studies of the impacts of warming on harmful algae, providing novel insight into near shore, coastal environments. Along the US East Coast, significant increases in potential growth rates and bloom season length for North American ribotypes were observed with bloom-favourable conditions becoming established earlier and persisting longer from Chesapeake Bay through Cape Cod, areas where blooms have become newly established and/or intensified this century. Within the Sea of Japan, modelled mean potential growth rates and bloom season length of East Asian ribotypes displayed a significant positive correlation with rising sea surface temperatures since 1982, a period during which observed maximal cell densities of C. polykrikoides blooms have significantly increased. Results suggest that warming has contributed, in part, to altering the phenology of C. polykrikoides populations, potentially expanding its realized niche in temperate zones of the Northern Hemisphere.

Using Copernicus Sentinel-2 and Sentinel-3 data to monitor harmful algal blooms in Southern Chile during the COVID-19 lockdown

“…Since the early 1990s, ocean temperatures have increased as well as blooms of the ichthyotoxic dinoflagellate Cochlodinium polykrikoides in the northern hemisphere ( Griffith et al, 2019 ). Onitsuka et al (2010) mentioned an expansion of the same species in western Japan and southern Korea over the last two decades.…”

The harmful algae, Cochlodinium polykrikoides and Aureococcus anophagefferens, elicit stronger transcriptomic and mortality response in larval bivalves (Argopecten irradians) than climate change stressors

“…Climate change, and ocean warming in particular, have enabled and expansion of blooms that grow faster and persist longer (Griffith, A.W., Doherty, O.M., and Gobler, C.J. ). Blooms of C. polykrikoides are capable of causing large‐scale die‐offs of marine organisms, especially among caged and aquacultured organisms (Griffith, Shumway, & Gobler, ; Kim, ; Kim, Lee, & An, ).…”

Considering Harmful Algal Blooms

“…At many instance record shows that HABs intensify as water have warmed closer to temperatures that yield maximal growth [18,45,46]. It becomes essential to notice that in marine systems, warming has been concerned with intensifying multiple HABs in a number of mid and higher latitude regions [45][46][47]. On the other hand, these regions with increasing frequencies and intensities of HABs due to progressive warming may be balanced by region that warms beyond of the optimal range for other HABs [47].…”

“…It becomes essential to notice that in marine systems, warming has been concerned with intensifying multiple HABs in a number of mid and higher latitude regions [45][46][47]. On the other hand, these regions with increasing frequencies and intensities of HABs due to progressive warming may be balanced by region that warms beyond of the optimal range for other HABs [47]. Considering together, all such circumstances hypothesis avowed by several case studies explains that HABs may be migrating pole-ward with progressive warming [46][47][48].…”