# Biogeographic classification of the Caspian Sea

Author(s) Fendereski, F., Vogt, M., Payne, M.R., Lachkar, Z., Gruber, N., Salmanmahiny, A., Hosseini, S.A.
Publication Type Journal Items, Publication Status: Published
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Title Biogeographic classification of the Caspian Sea
Author(s) Fendereski, F.
Vogt, M.
Payne, M.R.
Lachkar, Z.
Gruber, N.
Salmanmahiny, A.
Hosseini, S.A.
Description 20 p.
Journal or Series Title Biogeosciences
Volume Number 11
Issue Number 22
Start Page 6451
End Page 6470
ISSN 1726-4170
1726-4189
Publisher Copernicus
Publication Place S.l.
Publication Date 2014
Abstract Like other inland seas, the Caspian Sea (CS) has been influenced by climate change and anthropogenic disturbance during recent decades, yet the scientific understanding of this water body remains poor. In this study, an eco-geographical classification of the CS based on physical information derived from space and in situ data is developed and tested against a set of biological observations. We used a two-step classification procedure, consisting of (i) a data reduction with self-organizing maps (SOMs) and (ii) a synthesis of the most relevant features into a reduced number of marine ecoregions using the hierarchical agglomerative clustering (HAC) method. From an initial set of 12 potential physical variables, 6 independent variables were selected for the classification algorithm, i.e., sea surface temperature (SST), bathymetry, sea ice, seasonal variation of sea surface salinity (DSSS), total suspended matter (TSM) and its seasonal variation (DTSM). The classification results reveal a robust separation between the northern and the middle/southern basins as well as a separation of the shallow nearshore waters from those offshore. The observed patterns in ecoregions can be attributed to differences in climate and geochemical factors such as distance from river, water depth and currents. A comparison of the annual and monthly mean Chl a concentrations between the different ecoregions shows significant differences (one-way ANOVA, P < 0.05). In particular, we found differences in phytoplankton phenology, with differences in the date of bloom initiation, its duration and amplitude between ecoregions. A first qualitative evaluation of differences in community composition based on recorded presence–absence patterns of 25 different species of plankton, fish and benthic invertebrate also confirms the relevance of the ecoregions as proxies for habitats with common biological characteristics.
DOI 10.5194/bg-11-6451-2014
Additional Notes Received 29 January 2014, Published in Biogeosciences Discuss. 20 March 2014, Revised 18 September 2014, Accepted 7 October 2014, Published 27 November 2014
Document Type Article
Publication Status Published
Language English
Assigned Organisational Unit(s) 03731
Organisational Unit(s)
NEBIS System Number 006289717
Source Database ID SCOPUS-84913573326
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@article{Fndrsk2014,
author = "Fendereski, F. and Vogt, M. and Payne, M.R. and Lachkar, Z. and Gruber, N. and Salmanmahiny, A. and Hosseini, S.A.",
title = "{B}iogeographic classification of the {C}aspian {S}ea",
journal = "Biogeosciences",
year = 2014,
volume = "11",
number = "22",
pages = "6451--6470",
}


E-Citations record created: Tue, 16 Dec 2014, 10:22:22 CET