Environmental heterogeneity caused by large-scale cultivation of Pyropia haitanensis shapes multi-group biodiversity distribution in coastal areas.

The response of marine biodiversity to mariculture has long been a research focus in marine ecology. However, the effects of seaweed cultivation on biological community assembly are poorly understood, especially in diverse communities with distinct ecological characteristics. In this study, we used environmental DNA metabarcoding to investigate the spatial distribution patterns of bacterial, protistan, and metazoan diversity, aiming to reveal the mechanisms of community assembly in the Pyropia haitanensis cultivation zone along the Fujian coast, China. We found that, compared with the biological communities in control zones, those in P. haitanensis cultivation zones exhibited stronger geographic distance-decay patterns and displayed more complex and stable network structures. Deterministic processes (environmental selection) played a more important role in the assembly of bacterial, protistan, and metazoan communities in P. haitanensis cultivation zones, especially metazoan communities. Variance partitioning analysis showed that environmental variables made greater contributions to the diversity of the three types of communities within the P. haitanensis cultivation zones than in the control zones. Partial least squares path modeling analysis identified nitrate­nitrogen (NO3-N), pH, particulate organic carbon (POC), and dissolved organic carbon (DOC) as the key environmental variables affecting biodiversity. Overall, the environmental heterogeneity caused by the large-scale cultivation of P. haitanensis could be the crucial factor influencing the composition and structure of various biological communities. Our results highlight the importance of the responses of multi-group organisms to the cultivation of seaweed, and provide insights into the coexistence patterns of biodiversity at the spatial scale.

A novel self-assembled-derived 1D MnO2@Co3O4 composite as a high-performance Li-ion storage anode material.

Manganese dioxide (MnO2) is a high-performance anodic material and applied widely in lithium-ion batteries (LIBs). However, some intrinsic limitations originate from the low ionic conductivity, high polarization, and severe volume expansion of this type of material. In this work, we generated a one-dimensional porous MnO2@Co3O4 composite from a MnOOH@ZIF-67 precursor, which is synthesized via a self-assembly strategy. The one-dimensional porous structure provided more active sites and shorter-ion/electron-diffusion distance, thereby enabling higher Li+ storage capacity and better rate capability than a transition metal oxide alone. The Co3O4 coating buffered the volume change during Li+ insertion/extraction, leading to increased cycling stability of the electrode. When evaluated as the anode of LIBs, MnO2@Co3O4 exhibited a reversible capacity of 647 mA h g-1 at 2000 mA g-1 after 400 cycles. This excellent performance indicated that the MnO2@Co3O4 material could be an attractive potential candidate for Li+ storage.