The late Quaternary stratigraphy of coastal dunes and associated deposits in southern Africa

2021 ◽  
Author(s):  
J. Knight
Keyword(s):  
Sea Level ◽  
Southern Africa ◽  
Sand Dune ◽  
Late Quaternary ◽  
Sand Dunes ◽  
Coastal Sand Dunes ◽  
Coastal Sand Dune ◽  
African Coast ◽  
Coastal Sand ◽  
And Sea Level

Abstract Coastal sand dune sediments with associated intraformational aeolianite, palaeosols and beachrock are found throughout much of the southern African coast, and have important roles as both Quaternary environmental archives and in recording the interplay of sediment supply, coastal processes and sea-level change. This paper examines the stratigraphy and palaeoenvironmental significance of coastal sand dunes and associated sediments, using examples mainly from South Africa but also with reference to the sandy coasts of Namibia and southern Mozambique. Based on morphological, sedimentary and dating evidence reported in the diverse literature, the stratigraphic relationship of coastal sand dune sediments to Marine Isotope Stages (MIS) is summarized, and a chronostratigraphic diagram for the period MIS 6 to 1 along the South African coast is used to identify spatially coherent sedimentary units that correspond to different regional climatic and sea-level phases. This framework provides a stratigraphic context to better examine the relationship between coastal sand dunes and external forcing during the late Quaternary in southern Africa, and to guide future field studies.

Adaptations of plants to burial in coastal sand dunes

1998 ◽  
Vol 76 (5) ◽  
pp. 713-738 ◽  
Author(s):  
M A Maun
Keyword(s):  
Sand Dune ◽  
Sand Dunes ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Threshold Level ◽  
Coastal Sand Dune ◽  
Bare Area ◽  
Plant Vigour ◽  
Storage Organs ◽  
Coastal Sand

One of the most obvious features on the foredunes and strands of coasts and lakes is recurrent burial in sand. Burial levels vary in different coastal sand dune systems and influence the physical and biotic microenvironment of the plant and soil. Foredune plants along coasts possess numerous adaptations to withstand burial. Studies show that below a certain threshold level of burial, the growth of all foredune plant species is stimulated probably because of multiple factors, namely improved soil resources, increase in soil volume, reactive plant growth, and enhanced mycorrhizal activity. However, as the level of burial increases, the positive response starts to decline until it becomes a negative value. For example, burial may reduce seed germination, seedling emergence, survival, and growth of seedlings and adult plants. At the community level, burial acts as a filter and selectively eliminates susceptible species, reduces the relative abundance of less tolerant species, and increases the abundance of tolerant and sand-dependent species. However, if sand deposition continues unabated, even the sand-dependent species are eliminated and a bare area is created. The emergence of a plant from a burial deposit primarily depends on the energy reserves in its storage organs and the speed, depth, and frequency of burial. Upon burial the plants shift resources from the belowground to the aboveground parts. Different plants show varied morphological responses to sand accretion. For example, the culms of grasses emerge by an increase in the number of nodes per culm and the elongation of internodes. Similarly, the emergent trunks and woody branches of tolerant trees and shrubs produce new buds and suckers at a higher level on the stem. In response to burial, the coastal sand dune species produce shootborne roots close to the new soil surface probably because of decreased oxygen levels.Key words: sand accretion, adaptations to burial, zonation of vegetation, burial of seeds, plant vigour, impact on communities, modes of emergence.

scholarly journals Effect of coastal dune restoration on the population of endangered Mongolian racerunner (Eremias argus) in the Republic of Korea

2021 ◽  
Vol 25 (2) ◽  
Author(s):  
Min Ho Chang ◽  
Jae Young Song ◽  
Kyo Soung Koo
Keyword(s):  
Sand Dune ◽  
Sand Dunes ◽  
In Situ Conservation ◽  
Coastal Region ◽  
Coastal Sand Dunes ◽  
Dune Restoration ◽  
Coastal Sand ◽  
The Republic ◽  
Special Protection

AbstractThe endangered species Mongolian racerunner (Eremias Argus), with a limited distribution in South Korea, is found only in sand dunes near waterside and forests. Therefore, species trends in this particular habitat are directly affected by habitat contamination and destruction. In this study, we examined the effects of coastal sand dune restoration on the distribution and population of E. argus. We conducted a field survey in Baramarye special protection zone, called Baramarye Coast, a part of the Taeanhaean National Park, during April and June 2016. We searched and recorded the location of E. argus and tagged them using the toe clipping method. The size of the E. argus population was estimated using the Peterson method. After the restoration of coastal sand dunes in Baramarye Coast, the population size of E. argus increased by 126–137 (21.1–55.7%) compared with that in 2008. The home range of E. argus in coastal sand dunes was significantly expanded by 4.8-fold for 95% Kernel density (KD) and 3.6-fold for 50% KD compared with that in 2008. Moreover, we confirmed that the distribution of E. argus was expanded to the restored area. Our study showed that in situ conservation is effective for endangered E. argus, distributed in particular environments such as coastal region. This study provides one more reason why coastal region must be conserved.

scholarly journals Geomorphology of the Coastal Sand Dune Fields and Their Association with the Palaeolandscape Evolution of Akrotiri Peninsula, Lemesos, Cyprus

Geosciences ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 448
Author(s):  
Miltiadis Polidorou ◽  
Niki Evelpidou
Keyword(s):  
Sea Level ◽  
Late Holocene ◽  
Sand Dune ◽  
Salt Lake ◽  
Sea Level Changes ◽  
Coastal Sand Dune ◽  
Relative Sea Level ◽  
Upper Pleistocene ◽  
Dune Field ◽  
Coastal Sand

Two well-developed late Pleistocene dune fields have been identified on the western and eastern side of Akrotiri promontory (Lemesos, Cyprus). The dune fields extend immediately from the low level of their source beaches onto higher ground (>48 m amsl). Geomorphic observations supported by OSL dating and sedimentological data provided evidence of the dune development and for the palaeogeographic reconstruction of the area. Relative sea level changes and wave action during the upper Pleistocene and Holocene played an important role into the development of the palaeolandscape and affected the formation of the dunes. From the collected data the development of the western dune field started at 56.2 ± 5.5 ka when the relative sea level was at approximately −60 m and contributed to the development of the western tombolo of the area whereas the eastern dune field developed in the late Holocene, after the formation of the eastern spit that resulted in the formation of the Akrotiri Salt lake.

scholarly journals PROCESS BASED NUMERICAL MODELING AND LABORATORY EXPERIMENTS ON THE MORPHOLOGICAL CHANGE OF COASTAL SAND DUNE

2018 ◽  
pp. 36
Author(s):  
Sungwon Shin ◽  
Kideok Do ◽  
Daniel Cox
Keyword(s):  
Numerical Modeling ◽  
Large Scale ◽  
Laboratory Experiments ◽  
Sand Dune ◽  
Sand Dunes ◽  
Coastal Sand Dunes ◽  
Reliable Prediction ◽  
Sand Supply ◽  
Morphological Modeling ◽  
Coastal Sand

Coastal sand dunes are important in the nearshore environment with respect to the sand supply, ecosystem, and hazard mitigation. While the reliable prediction of the dune erosion is important, numerical modeling of this phenomenon is still challenging. In this study, a process based morphological modeling was performed and the results were compared with large-scale laboratory experimental data.

scholarly journals Resurrection of a regionally extinct taxon in Croatia – the case of Ammophila arenaria (L.) Link (Poaceae)

2018 ◽  
Vol 77 (2) ◽  
pp. 214-217
Author(s):  
Sandro Bogdanović ◽  
Vedran Šegota ◽  
Antun Alegro
Keyword(s):  
Sand Dune ◽  
Sand Dunes ◽  
Anthropogenic Influence ◽  
Ammophila Arenaria ◽  
Coastal Sand Dune ◽  
Northern Adriatic ◽  
Active Protection ◽  
Coastal Sand ◽  
The Town ◽  
Extinct Taxon

Abstract A regionally extinct taxon, Ammophila arenaria (L.) Link subsp. arundinacea H. Lindb., has been rediscovered in the Croatian flora after 78 years. Previously it was known only from two coastal sand dune sites in Northern Dalmatia. The habitat at the locality of Crnika near Lopar on the northern Adriatic island of Rab is destroyed and A. arenaria subsp. arundinacea does not grow there anymore. At the second locality, on the sand dunes of Kraljičina plaža in the vicinity of the town of Nin, A. arenaria subsp. arundinacea was rediscovered and confirmed after 174 years. This is the only population of this taxon in Croatia, counting 48 mature individuals where the psammophylous habitat of Kraljičina plaža is under strong anthropogenic influence. This taxon is now classified as critically endangered (CR) and merits adequate active protection and conservation of its psammophylous habitat.

scholarly journals Genetic Diversity of Rhizobia Associated with Acacia longifolia in Two Stages of Invasion of Coastal Sand Dunes

2007 ◽  
Vol 73 (15) ◽  
pp. 5066-5070 ◽  
Author(s):  
Susana Rodríguez-Echeverría ◽  
João A. Crisóstomo ◽  
Helena Freitas
Keyword(s):  
Genetic Diversity ◽  
Sand Dune ◽  
Root Nodule ◽  
Sand Dunes ◽  
Nodule Bacteria ◽  
Coastal Sand Dunes ◽  
Dune System ◽  
Coastal Sand ◽  
Acacia Longifolia ◽  
Two Stages

ABSTRACT We examined the genetic diversity of root nodule bacteria associated with the Australian legume Acacia longifolia in two stages of invasion of a coastal sand dune system. All isolates belonged to the genus Bradyrhizobium. A higher diversity was found in the long-established trees. The results suggest the introduction of exotic bradyrhizobia with the plant.

Mycorrhizas and Root Attributes of Plants of Coastal Sand-Dunes of New South Wales

1989 ◽  
Vol 16 (1) ◽  
pp. 141 ◽  
Author(s):  
VS Logan ◽  
PJ Clarke ◽  
WG Allaway
Keyword(s):  
Root Length ◽  
Sand Dune ◽  
New South ◽  
Sand Dunes ◽  
New South Wales ◽  
Arbuscular Mycorrhizal ◽  
Coastal Sand Dunes ◽  
South Wales ◽  
Vesicular Arbuscular ◽  
Coastal Sand

Root samples of 41 sand-dune plant species in 28 families were collected from sites along the coast of New South Wales during spring 1987. Of the species, 36 had vesicular-arbuscular mycorrhizas, with vesicles and internal and external hyphae. Among these species there was great variation in the pro- portion of root length colonised by vesicular-arbuscular mycorrhizal fungi (from 1 to 96%); in 33 species over 10% of root length was infected. Of the vesicular-arbuscular mycorrhizal species, 21 showed arbuscules, and 16 had intracellular hyphal coils. In four plant species mycorrhizas were not found in the single samples examined; ericoid mycorrhizas were present in the remaining species, Leucopogon parviflorus, but its vesicular-arbuscular mycorrhizal status could not be assessed. The results, though preliminary, may reflect a high vesicular-arbuscular mycorrhizal status of vegetation of coastal sand-dunes of New South Wales. This would be likely to enhance plant nutrition and sandbinding, and to have implications for sand-dune management.

Nước dưới đất trong cồn cát ven biển phía nam Quảng Bình và định hướng khai thác sử dụng

2018 ◽  
Vol 28 (3) ◽  
pp. 336-345
Author(s):  
Nguyễn Xuân Tặng
Keyword(s):  
Sand Dune ◽  
Coastal Sand Dune ◽  
The South ◽  
Coastal Sand ◽  
Dune Area

Groundwater in coastal sand dune area in the south of Quang Binh province and posibility for exploitation

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