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The significance of sea-level change and ancient submerged landscapes in human dispersal and development: A geoarchaeological perspective

Bailey Geoff, Cawthra Hayley C.

Oceanologia

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2023

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Vol. 65 (1)

50--70

EN

In this paper we highlight the impact of sea-level change on the archaeological record of key developments in human history that took place during the late Pleistocene and the early Holocene. Before modern sea level became established from ∼7 ka onwards, most palaeoshorelines and large areas of coastal hinterland were exposed as habitable land and then drowned again by sea-level rise. We summarise the archaeological implications of this pattern and the conditions in which archaeological and geoarchaeological evidence from these submerged landscapes is preserved despite the potentially destructive erosional impact of sea-level rise. We provide examples of palaeolandscape reconstruction made possible through multi-disciplinary collaboration between archaeology and marine science, drawing on recent underwater research in the North Sea, the Red Sea and on the Cape Coast of South Africa, and discuss evidence of past human responses to sea-level change. We identify the types of modelling procedures that need to be developed to advance this field of research, emphasise the importance of inter-disciplinary collaboration involving two-way exchange of ideas and information between archaeology and marine science, and highlight the value of a long-term perspective in understanding the present and future human impact of sea-level rise.

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Seasonal and annual variability in chlorophyll-a in the shelf region of the Northern Bay of Bengal using MODIS-Aqua data

Abdur Rouf Muhammad, Antu Al-Hasan, Noor Imran

Oceanological and Hydrobiological Studies

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2020

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Vol. 49, No. 4

398--407

EN

Chlorophyll-a (Chl-a) concentration is an important issue in ocean ecosystem management and research. This study investigates seasonal and annual variability in Chl-a and its relationship with sea surface temperature (SST) and river discharge in the shelf region of the Northern Bay of Bengal (BoB), as well as validates satellite data against in-situ data. Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua satellite data on Chl-a concentration and SST from 2002–2018 were used in this study. River discharge data were obtained from the Bangladesh Water Development Board (BWDB). The annual Chl-a concentration ranged from 2.08 to 2.94 mg m−3, with an average of 2.43 ± 0.24 mg m−3. The Chl-a concentration was found higher (2.21 ± 0.56 mg m−3) during the northeast monsoon (October–February) and lower (1.81 ± 1.14 mg m−3) during the pre-monsoon season (March–May). The study revealed a declining trend in Chl-a concentration from 2002 to 2018, and the rate of change was −0.0183 mg m−3 year−1. Chl-a concentration showed a weak inverse relationship with SST, both annually and seasonally, especially in the pre-monsoon season. River discharge masked the effect of SST on Chl-a variability during the southwest and northeast monsoon. A reasonable correlation (r = 0.78) was found between the MODIS-Aqua data and in-situ Chl-a observations.

3

The continental shelf in the law of the sea conventions of 1958 and 1982 and the principal of natural prolongation

Wasilewski T.

Biuletyn Instytutu Morskiego w Gdańsku

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1998

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Vol. 25, No. 2

15--32

EN

The subject of the paper is the evolution of the concept of the continental shelf in international law, shown in the context of natural prolongation of the land territory of a coastal state co-creating this concept. The starting point for the analysis are the determinations of such specialised disciplines of science as: geography, oceanography and geology, and in consequence a possibly accurate topographic description of the sea and ocean floor, determination of the most important physiographic zones and of their characteristic features. This, only formally distinguished, but treated as one whole for meritoric and structural reasons three-element sequence, formed in the order: continental shelf in geographic/physical approach - continental slope -foot of continental slope, forms a common topographic feature called the continental margin. However, the reconstruction of the continental shelf concept in international law is not limited only to the description and characteristic of the continental margin in the horizontal plane. Appropriately to the needs of the paper, and to the extent the competence of the Author allowed, the margin is also described in the vertical dimension, i.e. going deeper into the essence of the natural factor, contained basically in the geomorphologic and geologic structure of the main physiographic provinces forming the continental margin. Such a view of the above problem allowed to obtain knowledge of motivations and of various arguments forming the essence and reach of the external limit of the continental shelf in the Geneva Convention on the continental shelf of I958, called further in text the GC IV ( I958). However, most important was to show and prove the thesis that it was the natural factor that dictated and shaped stipulations in international law with respect to the discussed subject, and that this factor played an extremely important role in the evolution and development of the continental shelf concept during the period after CG IV ( I958) was adopted. The principle, contained in the ITJ ruling on the continental shelf of the North Sea that the continental shelf is a natural prolongation of the territory of a coastal state, the natural prolongation principle, was well substantiated by the geomorphology and geophysical characteristics of the continental margin. This principle was also of primary importance for the shaping of the concept of the continental shelf and of its external boundary in the United Nations Convention on the Law of the Sea of 1982, called below UNCLOS (1982).