Channel function shift around a recently-colonised estuarine mangrove shoal

IF 2.6 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Marine Geology Pub Date : 2024-11-26 DOI:10.1016/j.margeo.2024.107440

Amin Rahdarian , Karin R. Bryan , Mick Van Der Wegen

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引用次数: 0

Abstract

Large sediment loading to the coast can accelerate estuarine infilling, which promotes the establishment of salt marsh or mangroves. Bio-geomorphic feedback ensues where channels and shoals gradually evolve in tandem as the vegetation gains a foothold. The aim of this work is to explore the governing dynamics of a recently evolving estuarine, mangrove-covered channel-shoal system in Whitianga Estuary, Aotearoa New Zealand. Observations of water level, flow velocity, suspended sediment concentration (SSC) and bed sediment characteristics were used to infer flow asymmetry and sediment transport pathways around the shoal. Historical images were combined with the measurements to qualitatively link the observed, short-term processes to the influence of expanding vegetation on multi-decadal evolution. Comparisons of flow asymmetry in two contrasting drainage channels (in close proximity) on the shoal show that rapid colonisation by mangroves can quickly change the flow asymmetry from flood to ebb dominant. Mangroves opportunistically colonise the higher ground at the centre of the shoal. Meanwhile they become eco-engineers creating their own environment as evidenced by the abrupt change in the sediment textural environment, even outside the immediate area of new vegetation. Although many studies have focused on spatial flow patterns associated with mangrove vegetation, our observations show evidence of the speed at which colonisation fuels geomorphologic change.

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来源期刊

Marine Geology 地学-地球科学综合

CiteScore

6.10

自引率

6.90%

发文量

175

审稿时长

21.9 weeks

期刊介绍： Marine Geology is the premier international journal on marine geological processes in the broadest sense. We seek papers that are comprehensive, interdisciplinary and synthetic that will be lasting contributions to the field. Although most papers are based on regional studies, they must demonstrate new findings of international significance. We accept papers on subjects as diverse as seafloor hydrothermal systems, beach dynamics, early diagenesis, microbiological studies in sediments, palaeoclimate studies and geophysical studies of the seabed. We encourage papers that address emerging new fields, for example the influence of anthropogenic processes on coastal/marine geology and coastal/marine geoarchaeology. We insist that the papers are concerned with the marine realm and that they deal with geology: with rocks, sediments, and physical and chemical processes affecting them. Papers should address scientific hypotheses: highly descriptive data compilations or papers that deal only with marine management and risk assessment should be submitted to other journals. Papers on laboratory or modelling studies must demonstrate direct relevance to marine processes or deposits. The primary criteria for acceptance of papers is that the science is of high quality, novel, significant, and of broad international interest.