DiscussionLakes or wetlands? A comment on ‘The middle Holocene climatic records from Arabia: Reassessing lacustrine environments, shift of ITCZ in Arabian Sea, and impacts of the southwest Indian and African monsoons’ by Enzel et al.
Introduction
The magnitude of climatic and environmental changes throughout the Saharo-Arabian belt during the Late Quaternary and their implications for human evolution, dispersal and behavioural change have been a matter of vivid debate and are not yet fully understood (e.g. Holm, 1960, Büdel, 1963, Kuper and Kröpelin, 2006, Parker, 2010). Therefore, the stimulation of the discussion on whether Holocene lacustrine deposits on the Arabian Peninsula (Fig. 1) indicate the presence of perennial lakes or palustrine wetlands by Enzel et al. (2015) is appreciated. For several sites where such deposits were interpreted as lake relicts, Enzel and colleagues conclude a wetland origin based on a reconsideration of sedimentary and fossil evidence and qualitative interpretation of satellite imagery. In synthesising a large body of published information, the authors contribute in clarifying the existence and spatio-temporal pattern of the Early Holocene Humid Period (EHHP) on the Arabian Peninsula. Furthermore, their article stimulates a much-needed discussion on the atmospheric sources of a possible precipitation surplus in the EHHP for different regions. Enzel et al. (2015) correctly recognize the relevance of the East African Summer Monsoon for creating surface runoff and charging aquifers in Arabia and, thereby, support recent evidence from numerical precipitation modelling (Herold and Lohmann, 2009, Jennings et al., 2015, Guagnin et al., 2016) (Fig. 2). However, we feel obliged to comment on specific aspects of their article, particularly on the existence of palaeolakes across the Arabian Peninsula during MIS 5 and in the EHHP.
Section snippets
Wetlands and lakes — a need for definitions
Clear definitions of terms are essential in the discussion of Arabia's aquatic palaeoenvironments. Ramsar (2016, inside cover) provides an extremely broad definition of wetlands including ‘marshes, peatlands, floodplains, rivers and lakes, and coastal areas such as saltmarshes, mangroves, intertidal mudflats and seagrass beds, and also coral reefs and other marine areas no deeper than 6 m at low tide […]’. According to this definition, lakes are a subtype of wetlands. Enzel et al. (2015, p. 70),
Holocene lakes in Arabia — multiple lines of evidence from multiple places
Given these definitions, we disagree with Enzel et al.'s (2015) characterisation of the published evidence for Late Pleistocene and Holocene lakes on the Arabian Peninsula. Enzel et al. (2015) reinterpret and partly disregard evidence for palaeolakes in order to promote the idea that only wetlands were present during the EHHP. In order to demonstrate the existence of palaeolakes, we compile a site-by-site summary of the main lines of argument for the existence of standing water bodies.
Discussion and conclusions
We show that perennial lakes have occurred at several sites in the Arabian Peninsula during the Late Pleistocene as well as during the Early to Mid-Holocene, where a wide range of micro- and macrofossils provide the strongest, in most places unequivocal evidence. The apparent lack of shoreline deposits and landforms cited by Enzel et al. (2015) as sign of prevailing wetlands, is either the result of low preservation potential due to erosion by strong episodic surface discharge, deflation,
Acknowledgments
The authors' research on the Arabian Peninsula was made possible due to kind support by the following institutions: Saudi Commission for Tourism and National Heritage, Saudi Geological Survey, German Archaeological Institute (Orient Department), and Department of Antiquities and Museums, Ras al-Khaimah. Funding of MDP's work is provided by the European Research Council (No. 295719), ME is supported by the Deutsche Forschungsgemeinschaft (EN977/2-1). Two anonymous reviewers gave insightful
References (78)
- et al.
Environmental controls on foraminifera in Lake Qarun, Egypt
J. Foramin. Res.
(2007) - et al.
Occurrence and distribution of the foraminifer Ammonia beccarii tepida (Cushman) in water bodies, Recent and Quaternary, of the Dead Sea Rift, Israel
Mar. Micropaleontol.
(1995) - et al.
The Pleistocene lake deposits of the NE Baza basin (Spain): salinity variations and ostracod succession
Hydrobiologia
(1986) - et al.
Mediterranean moisture source for an early-Holocene humid period in the northern Red Sea
Science
(2003) - et al.
Late Quaternary chronology of major dune ridge development in the northeast Rub' al-Khali, United Arab Emirates
Quaternary Res.
(2011) - et al.
Holocene development of multiple dune generations in the northeast Rub' al-Khali, United Arab Emirates
Holocene
(2012) - et al.
Late Quaternary humidity and aridity dynamics in the northeast Rub' al-Khali, United Arab Emirates: implications for early human dispersal and occupation of eastern Arabia
Quat. Int.
(2013) Middle Stone Age (MSA) site distributions in eastern Africa and their relationship to Quaternary environmental change, refugia and the evolution of Homo sapiens
Quat. Sci. Rev.
(2008)Charakterisierung von spätpleistozänen und frühholozänen Feuchtphasen in Saudi-Arabien mit Hilfe von Ostrakoden
(2011)- et al.
Remote sensing and GIS techniques for reconstructing Arabian palaeohydrology and identifying archaeological sites
Quat. Int.
(2015)
Palaeohydrological corridors for hominin dispersals in the Middle East c. 250–70,000 years ago
Quat. Sci. Rev.
Holocene marine terraces on two salt diapirs in the Persian Gulf, Iran: age, depositional history and uplift rates
J. Quat. Sci.
Die pliozänen und quartären Pluvialzeiten der Sahara
Eiszeit. Gegenw.
Classification of Wetlands and Deepwater Habitats of the United States
Beyond the Levant: first evidence of a pre-pottery Neolithic incursion into the Nefud Desert, Saudi Arabia
PLoS One
Study of the infiltration and recharge through the sand dunes in arid zones with special reference to the stable isotopes and thermonuclear tritium
J. Hydrol.
When the desert was green: grassland expansion during the early Holocene in northwestern Arabia
Quat. Int.
Ancient watercourses and biogeography of the Sahara explain the peopling of the desert
Proc. Natl. Acad. Sci.
Geoarchaeological research at Tayma
The early Holocene humid period in NW Saudi Arabia — sediments, microfossils and palaeohydrological modelling
Quat. Int.
Barnacles tell no lies — bioclastic deposits and in-situ balanid colonies delineate shorelines of the Holocene palaeolake at Tayma (NW Saudi Arabia)
Geophys. Res. Abstr.
High-resolution Holocene environmental changes in the Thar Desert, northwestern India
Science
The middle Holocene climatic records from Arabia: reassessing lacustrine environments, shift of ITCZ in Arabian Sea, and impacts of the southwest Indian and African monsoons
Glob. Planet. Chang.
Analysis and characterization of the vertical accuracy of digital elevation models from the Shuttle Radar Topography Mission
J. Geophys. Res.
Developing a framework of Quaternary dune accumulation in the northern Rub' al-Khali, Arabia
Quatern. Int.
Barnacle ecology and adaption
Biological remains, geochemistry and stable isotopes for the reconstruction of environmental and hydrological changes in the Holocene lakes from north Sahara
Palaeogeogr. Palaeoclimatol. Palaeoecol.
The late Quaternary environments of Ain al-Faidha/Al-Ain, Abu Dhabi Emirate
Archaeology in the United Arab. Emirates
Faunal evidence of a Holocene pluvial phase in southern Arabia with remarks on the morphological variability of Helenina anderseni
J. Foramin. Res.
Vegetation of the Arabian Peninsula
Holocene chemical precipitates in the continental sabkha of Tayma (NW Saudi Arabia)
J. Arid Environ.
Latest Pleistocene dune construction at the north-eastern edge of the Rub al Khali, United Arab Emirates
Sedimentology
Human occupation of the Arabian Quarter during MIS 5: evidence from Mundafan Al-Buhayrah, Saudi Arabia
Quat. Sci. Rev.
Rock art imagery as a proxy for Holocene environmental change: a view from Shuwaymis, NW Saudi Arabia
Holocene
Near East desertification: evidence from the Dead Sea
Naturwissenschaften
Eemian tropical and subtropical African moisture transport: an isotope modelling study
Clim. Dyn.
Epipalaeolithic occupation and palaeoenvironments of the southern Nefud desert, Saudi Arabia, during the terminal Pleistocene and early Holocene
J. Archaeol. Sci.
Desert geomorphology in the Arabian Peninsula
Science
The greening of Arabia: multiple opportunities for human occupation of the Arabian Peninsula during the late Pleistocene inferred from an ensemble of climate model simulations
Quat. Int.
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