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Microbiomes confer beneficial physiological traits to their host, but microbial diversity is inherently variable, challenging the relationship between microbes and their functional contribution to host health. Here, we compare diversity and architectural complexity of the epidermal microbiome from 74 individual whale sharks (Rhincodon typus) across five aggregations, globally. We hypothesised co-occurrence patterns would occur independently of diversity patterns. Whale shark aggregation was the most important factor discriminating taxonomic diversity patterns. Microbiome network architecture was similar across all aggregations with degree distributions matching Erdos-Renyi graphs. However, networks had greater modularity than expected, indicating definitive microbiome structure. In addition, whale sharks hosted 35 ‘core’ microbiome members supporting the high modularity observed in microbiomes. Therefore, while variability in microbiome diversity is high, network structure and core taxa are inherent characteristics of the microbiome in whale sharks. We suggest host-microbiome and microbe-microbe interactions which drive self-assembly of the microbiome are, in part, the result of emergent functions that support functionally redundant key core microbial members. Teaser Sentence: The skin microbiome of whale sharks has emergent co-occurrences structure despite distinct diversity patterns.

The benefits of composite products are well known to users of data from optical sensors: cloud-cleared composite reflectance or index products are commonly used as an analysis-ready data (ARD) layer. No analogous composite products are currently in widespread use that is based on spaceborne radar satellite backscatter signals. Here, we present a methodology to produce wide-area ARD composite backscatter images. They build on the existing heritage of geometrically and radiometrically terrain corrected level 1 products. By combining backscatter measurements of a single region seen from multiple satellite tracks (incl. ascending and descending), they are able to provide wide-area coverage with low latency. The analysis-ready composite backscatter maps provide flattened backscatter estimates that are geometrically and radiometrically corrected for slope effects. A mask layer annotating the local quality of the composite resolution is introduced. Multiple tracks are combined by weighting each observation by its local resolution, generating seamless wide-area backscatter maps suitable for applications ranging from wet snow monitoring to land cover classification or short-term change detection.