European Diatom Database-North African Dataset
Entry ID: uk_nc_eddi_african

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Summary
Abstract: The European Diatom Database (EDDI) is a web-based information system designed
to enhance the application of diatom analysis to problems of surface water
acidification, eutrophication and climate change.

The North African dataset consists from samples from Tunisia (66), Algeria (3),
Morocco (26), and Niger (20). In Tunisia, samples were collected from the
Mediterranean northern regions to the margins of the Sahara southwards by L.
Ben Khelifa and F. Gasse (1985-1989). In southern Tunisia, samples were taken
from small permanent groundwater-fed waterbodies and temporary salt lakes,
small artificial ponds developed around boreholes, and in mini reservoir lakes
and swamps along Wadi el Akarit. Samples from hydrothermal springs have been
collected throughout the country. In northern Tunisia, freshwater samples were
also taken from the Mejerda Channel. Waters range from fresh to metasaline.
Most samples are of the sodium/chloride or calcium-magnesium/ sulphate type.
Diatoms were counted by L. Ben Khelifa. Details of diatom and hydrochemical
analyses are given in Ben Khelifa (1989). Sites from southern Algeria,
collected by F. Gasse en 1985, show clear similarities with the waterbodies of
southern Tunisia. The 26 samples from Morroco were collected by F. Gasse in
1989 from 17 localities situated between 30?30-34?30N and 5?-7?30E, at altitude
ranging from 300 to 2050 m. Sites are distributued in the western plains close
to Casablanca, the Middle Atlas mountains, and the more arid southweast margins
of the Atlas ranges, from a large variety of waterbodies (permanent and
temporary natural lakes, man-made lakes, and wadis. Conductivities range from
195 to 3900 ?S cm-1. Freshwaters are of the calcium-sodium/bicarbonate type,
while oligosaline waters are of the sodium/chloride type. Diatom samples were
counted by F. Gasse. In southern Niger, samples were collected from the Niger
River, the Bara salt pond near Niamey, and from interdunal depressions on the
Manga Plateau occupied by permanent or ephemeral waterbodies. A few samples
from northern Niger (A?r) have also been collected from groundwater-supplied
ponds. Most waterbodies are of the sodium/carbonate-bicarbonate type. Samples
from Niger were collected and analyzed by F. Gasse, except those from the Bara
pond (M.-C. Lang). The main characteristics of the water chemistry and diatom
communities of the Niger samples are presented in Gasse (1987).

Parent DIF
This data set description is a member of a collection. The collection is described in
uk_nc_eddi


Geographic Coverage
 N: 37.07 S: 31.0  E: 10.5  W: -6.5

Data Set Citation
Dataset Originator/Creator: Leila Ben Khelifa, Francoise Gasse
Dataset Title: European Diatom Database-North African Dataset
Dataset Release Place: Newcastle upon Tyne, United Kingdom
Dataset Publisher: The University of Newcastle
Online Resource: http://craticula.ncl.ac.uk/Eddi/jsp/datasetdesc.jsp?DatasetId=AfricaN


Temporal Coverage
Start Date: 1975-01-01
Stop Date: 1986-12-31


Location Keywords
CONTINENT > AFRICA > NORTHERN AFRICA > ALGERIA
CONTINENT > AFRICA > NORTHERN AFRICA > MOROCCO
CONTINENT > AFRICA > WESTERN AFRICA > NIGER
CONTINENT > AFRICA > NORTHERN AFRICA > TUNISIA


Science Keywords
TERRESTRIAL HYDROSPHERE >GROUND WATER >GROUNDWATER CHEMISTRY    [Definition]
TERRESTRIAL HYDROSPHERE >GROUND WATER >SALTWATER INTRUSION    [Definition]
TERRESTRIAL HYDROSPHERE >SURFACE WATER >LAKES >LAKEWATER CHEMICAL DATA    [Definition]
TERRESTRIAL HYDROSPHERE >SURFACE WATER >RIVERS/STREAMS >NIGER RIVER    [Definition]
TERRESTRIAL HYDROSPHERE >WATER QUALITY/WATER CHEMISTRY >ALKALINITY    [Definition]
TERRESTRIAL HYDROSPHERE >WATER QUALITY/WATER CHEMISTRY >CONDUCTIVITY    [Definition]
TERRESTRIAL HYDROSPHERE >WATER QUALITY/WATER CHEMISTRY >PH >LAKEWATER PH TRANSFER FUNCTION    [Definition]
TERRESTRIAL HYDROSPHERE >WATER QUALITY/WATER CHEMISTRY >TRACE METALS    [Definition]
LAND SURFACE >EROSION/SEDIMENTATION >SEDIMENT CHEMISTRY >SURFACE SEDIMENT SAMPLES    [Definition]
LAND SURFACE >EROSION/SEDIMENTATION >SEDIMENTS >SURFACE SEDIMENT SAMPLES    [Definition]
BIOLOGICAL CLASSIFICATION >PROTISTS >DIATOMS    [Definition]
BIOLOGICAL CLASSIFICATION >PLANTS >MICROALGAE >DIATOMS
BIOSPHERE >AQUATIC ECOSYSTEMS >LAKES    [Definition]
BIOSPHERE >AQUATIC ECOSYSTEMS >LAKES >SALINE LAKES >BARA SALT POND    [Definition]


ISO Topic Category
BIOTA
ENVIRONMENT
GEOSCIENTIFIC INFORMATION
INLAND WATERS


Access Constraints
None


Use Constraints
None


Keywords
The European Diatom Database
surface-sediment diatom assemblages
surface water acidification
eutrophication
climate change
Plantae
Plant
Chromista
Bacillariophyta
alkalinity
calcium
chloride
conductivity
magnesium
maximum depth of lake
pH
potassium
salinity
silica
site surface area at time of sampling
sodium
sulphate
total phosphorus
water depth of diatom sample


Data Set Progress
COMPLETE


Data Center
European Diatom Database, University of Newcastle, UK    [Information]
Data Center URL: http://craticula.ncl.ac.uk/Eddi/jsp/
Dataset ID: AfricaN

Data Center Personnel
Name: STEPHEN JUGGINS
Phone: 44 191 222 8799
Fax: 44 191 222 5421
Email: Stephen.Juggins at ncl.ac.uk
Contact Address:
University of Newcastle
Department of Geography
Newcastle upon Tyne
NEI 7RU
Country: UNITED KINGDOM



Distribution
Fees: None


Personnel
FRANCOISE GASSE
Role: TECHNICAL CONTACT
Phone: 33 4 42 97 15 70
Fax: 33 4 42 97 15 95
Email: gasse at cerege.fr
Contact Address:
CNRS-CEREGE, Europole Mediterraneen de l'Arbois- BP80
City: Aix en Provence Cedex 04
Postal Code: 13545
Country: France


TYLER B. STEVENS
Role: DIF AUTHOR
Phone: (301) 614-6898
Fax: 301-614-5268
Email: Tyler.B.Stevens at nasa.gov
Contact Address:
NASA Goddard Space Flight Center
Global Change Master Directory
City: Greenbelt
Province or State: MD
Postal Code: 20771
Country: USA


Publications/References
Ben Khelifa, L., 1989. Diatom?es continentales et pal?omilieux du Sud-Tunisien
(Palhydaf Site 1) au Quaternaire sup?rieur. Approche statistique bas?e sur les
diatom?es et les milieux naturels. Thesis. Univ. Paris-Sud, 233 pp.

Carvalho, L.R., Cox, E.J., Fritz, S.C., Juggins, S., Sims, PA., Gasse, F., and
Battarbee, R.W., 1995, Standardizing the taxonomy of saline lake Cyclotella
spp. Diatom Research, 10 (2) 229-240.

El Hamouti, N., Lamb, H., Fontes, J.Ch. et Gasse, F., 1991. Changements
hydroclimatiques abrupts dans le Moyen Atlas marocain depuis le dernier maximum
glaciaire. C. R. Acad. Sci., Paris. 313 , 259-265.

Fontes, J.Ch., Gasse, F., Callot, Y., Plaziat, J.C., Carbonel, P., Dupeuple,
P.A. & Kaczmarska, I., 1985. Freshwater to marine-like environments from
holocene lakes in Northern Sahara. Nature, 317, 608-610.

Gasse, F., Fontes, J.Ch., Plaziat, J.C., Carbonel, P., Kaczmarska, I. , De
Deckker, P., Souli?-Marsche, I., Callot, Y., & Dupeuple, P.A., 1987. Biological
remains, geochemistry and stable isotopes for the reconstruction of
environmental and hydrological changes in the Holocene lakes from North Sahara.
Paleoecol., Palaeogeogr , Palaeoclimat., 60, 1-46.

Gasse, F., 1987. Diatoms for reconstructing palaeoenvironments and
palaeohydrologyn tropical semi-arid zones. Example of some lakes from Niger
since 12,000 BP. Hydrobiologia, 154 : 127-163.

Gasse, F., T?het, R., Durand, A., Gibert, E., Fontes, J.Ch., 1990. The
arid-humid transition in the Sahara and the Sahel during the last deglaciation.
Nature, vol. 346(6280):141-156.

Gasse, F., Van Campo, E., 1994. Abrupt post-glacial climate events in West Asia
and North Africa monsoon domains. EPSL, 126, 435-456.

Lamb, H.F., Gasse, F., Ben Kaddour, A., El Hamouti, N., Van der Kaars,
S., Perkins, W.T., Pearce, N.J., Roberts, C.N., 1995. Relation between
century-scale Holocene arid intervals in tropical and temperate
zones. Nature, 373,134-137.

Creation and Review Dates
DIF Creation Date: 2002-09-23
Last DIF Revision Date: 2012-12-21
Future DIF Review Date: 2003-09-23

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