Satellite Tracking Reveals the Speed Up of the Lacustrine Algal Bloom Drift in Response to Climate Change.

Satellite evidence indicates a global increase in lacustrine algal blooms. These blooms can drift with winds, resulting in significant changes of the algal biomass spatial distribution, which is crucial in bloom formation. However, the lack of long-term, large-scale observational data has limited our understanding of bloom drift. Here, we have developed a novel method to track the drift using multi-source remote sensing satellites and presented a comprehensive bloom drift data set for four typical lakes: Lake Taihu (China, 2011-2021), Lake Chaohu (China, 2011-2020), Lake Dianchi (China, 2003-2021), and Lake Erie (North America, 2003-2021). We found that blooms closer to the water surface tend to drift faster. Higher temperatures and lower wind speeds bring blooms closer to the water surface, therefore accelerating drift and increasing biomass transportation. Under ongoing climate change, algal blooms are increasingly likely to spread over larger areas and accumulate in downwind waters, thereby posing a heightened risk to water resources. Our research greatly improves the understanding of algal bloom dynamics and provides new insights into the driving factors behind the global expansion of algal blooms. Our bloom-drift-tracking methodology also paves the way for the development of high-precision algal bloom prediction models.

Dynamics of soliton solutions of the nonlocal Kundu-nonlinear Schrödinger equation.

In this paper, we investigate the nonlocal Kundu-nonlinear Schrödinger (Kundu-NLS) equation, which can be obtained from the reduction of the coupled Kundu-NLS system. Based on the analysis of the eigenfunctions, a Riemann-Hilbert problem is constructed to derive the N-soliton solutions of the coupled Kundu-NLS system. The N-soliton solutions of the nonlocal Kundu-NLS equation are then deduced with properly chosen symmetry relations on the scattering data. The dynamics of the solitons in the nonlocal Kundu-NLS equation are explored. The impact of the gauge function on the solitons is displayed for one-solitons. Compared with the dynamics of the two-solitons in the local Kundu-NLS equation, the two-solitons in the nonlocal Kundu-NLS equation display many differences. The repeated collapsing is a common feature of the singular solitons, and it seems that some of them are not the superposition of one-solitons. The singular solitons exhibit various behaviors in different eigenvalue configurations in the spectral space. Besides that, three kinds of bounded solutions are presented according to these eigenvalue configurations. In addition, two kinds of degenerate solutions are presented, and in particular, the positon solutions are discussed in detail. The decomposition of the positon solutions is analyzed and their trajectories are given approximately.