Abstract
This study examines diatom assemblages and environmental gradients along an intertidal transect in Hangzhou Bay, eastern China. Key environmental variables—salinity, pH, total organic carbon (TOC), and sediment particle size distribution—showed distinct zonation. TOC and silt/mud content were significantly higher in vegetated zones (TOC: 2.7–3.0%) than in unvegetated mudflats (ca. 1.2%), with fine-grained sediments (<63 µm) dominating throughout (>90% on average). Salinity varied spatially, with lower values in mudflats, while pH remained consistently weakly alkaline (7–8).Diatom analysis identified a total of 68 species from 28 genera, with 24 dominant taxa examined. Marine/brackish-water species dominated all zones, exceeding 90% abundance in mudflats—over 20% higher than in vegetated areas. Freshwater diatoms were most abundant in high-elevation Zones A and B (>20%), declining to ca. 1% in mudflats. Planktonic forms peaked in Zone A, whereas benthic species prevailed in mudflats and decreased with elevation.
Vegetated zones exhibited distinct diatom trends: Zones A and B supported higher freshwater abundances dominated by planktonic taxa such as Cyclotella striata, while Zone C maintained high marine/brackish representation. The mudflat was overwhelmingly dominated by marine/brackish taxa, notably Cyclotella striata (24.3%), with minimal freshwater presence.
These findings illustrate strong linkages among diatom composition, elevation, and vegetation, establishing a baseline for understanding ecological gradients in Hangzhou Bay’s intertidal ecosystems.
| Date of Award | 15 Nov 2025 |
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| Original language | English |
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| Supervisor | Tengwen Long (Supervisor), Jun He (Supervisor) & George Swann (Supervisor) |