Abstract
AbstractHaze particles as a key air pollutant contain high level of toxins, which were hypothesized to inhibit phytoplankton growth when deposited to the ocean, and thus indirectly affect the climate. However, field observations have yet to provide conclusive evidence to confirm this hypothesis. Onboard microcosm experiments in the Northwest Pacific Ocean (NWPO) show that haze particles collected at the East Asia continent had an inhibition impact on phytoplankton growth only when at very high particle loading (2 mg/L). In contrast, haze particles at low and medium loadings (0.03–0.6 mg/L) stimulated phytoplankton growth and shifted phytoplankton size structure toward larger cells, primarily due to the supply of inorganic nitrogen nutrients from the particles. Model simulations showed that haze particle loading in NWPO surface seawater was usually more than an order of magnitude lower than 2 mg/L. This indicates that haze particles are unlikely to cause harm but to stimulate phytoplankton growth in the nitrogen‐limited NWPO. Ocean biogeochemical modeling further shows that deposited nitrogen significantly enhanced surface ocean chlorophyll a concentration in the winter and spring of 2014. Overall, these results demonstrate that haze particles stimulate rather than inhibit primary production in the NWPO.
Highlights
With the rapid growth of population and economy, air pollutant emissions in China contribute a large fraction of the global emissions (Zhao et al, 2012)
Onboard microcosm experiments in the Northwest Pacific Ocean (NWPO) show that haze particles collected at the East Asia continent had an inhibition impact on phytoplankton growth only when at very high particle loading (2 mg/L)
These results suggest a higher trophic state in the China coastal seas compared with the subtropical gyre of the NWPO (S‐NWPO)
Summary
With the rapid growth of population and economy, air pollutant emissions in China contribute a large fraction of the global emissions (Zhao et al, 2012). Such high emissions lead to increasing occurrence of haze events (often defined as daily fine particle PM2.5 concentration > 75 μg m−3 and visibility less than 5 km for over 6 hr) across China, increasing from ~20 days per year (d/year) in the 1990s to 40 d/year in the 2000s and to ~90.5 d/year in 2013 (Su et al, 2014). Haze pollution causes visibility degradation that influences transport and economy (Tie et al, 2016). Haze pollution has become a severe public health problem associated with industrialization and urbanization in China
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
