Biogeographic classification of the Caspian Sea
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...
Published in: | Biogeosciences |
---|---|
Main Authors: | , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
2014
|
Subjects: | |
Online Access: | https://orbit.dtu.dk/en/publications/0412a02d-3790-4e7c-9987-101068bd278b https://doi.org/10.5194/bg-11-6451-2014 https://backend.orbit.dtu.dk/ws/files/102863384/Publishers_version.pdf |
id |
ftdtupubl:oai:pure.atira.dk:publications/0412a02d-3790-4e7c-9987-101068bd278b |
---|---|
record_format |
openpolar |
spelling |
ftdtupubl:oai:pure.atira.dk:publications/0412a02d-3790-4e7c-9987-101068bd278b 2024-04-28T08:37:59+00:00 Biogeographic classification of the Caspian Sea Fendereski, F. Vogt, M. Payne, Mark Lachkar, Z. Gruber, N. Salmanmahiny, A. Hosseini, S. A. 2014 application/pdf https://orbit.dtu.dk/en/publications/0412a02d-3790-4e7c-9987-101068bd278b https://doi.org/10.5194/bg-11-6451-2014 https://backend.orbit.dtu.dk/ws/files/102863384/Publishers_version.pdf eng eng https://orbit.dtu.dk/en/publications/0412a02d-3790-4e7c-9987-101068bd278b info:eu-repo/semantics/openAccess Fendereski , F , Vogt , M , Payne , M , Lachkar , Z , Gruber , N , Salmanmahiny , A & Hosseini , S A 2014 , ' Biogeographic classification of the Caspian Sea ' , Biogeosciences , vol. 11 , no. 22 , pp. 6451-6470 . https://doi.org/10.5194/bg-11-6451-2014 /dk/atira/pure/sustainabledevelopmentgoals/climate_action name=SDG 13 - Climate Action /dk/atira/pure/sustainabledevelopmentgoals/life_below_water name=SDG 14 - Life Below Water article 2014 ftdtupubl https://doi.org/10.5194/bg-11-6451-2014 2024-04-10T14:30:09Z 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 near-shore waters from those off-shore. 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 (Kruskal–Wallis rank test, 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 27 different species of plankton, fish and benthic invertebrate also confirms the relevance of the ecoregions as proxies for habitats with common biological characteristics. Article in Journal/Newspaper Sea ice Technical University of Denmark: DTU Orbit Biogeosciences 11 22 6451 6470 |
institution |
Open Polar |
collection |
Technical University of Denmark: DTU Orbit |
op_collection_id |
ftdtupubl |
language |
English |
topic |
/dk/atira/pure/sustainabledevelopmentgoals/climate_action name=SDG 13 - Climate Action /dk/atira/pure/sustainabledevelopmentgoals/life_below_water name=SDG 14 - Life Below Water |
spellingShingle |
/dk/atira/pure/sustainabledevelopmentgoals/climate_action name=SDG 13 - Climate Action /dk/atira/pure/sustainabledevelopmentgoals/life_below_water name=SDG 14 - Life Below Water Fendereski, F. Vogt, M. Payne, Mark Lachkar, Z. Gruber, N. Salmanmahiny, A. Hosseini, S. A. Biogeographic classification of the Caspian Sea |
topic_facet |
/dk/atira/pure/sustainabledevelopmentgoals/climate_action name=SDG 13 - Climate Action /dk/atira/pure/sustainabledevelopmentgoals/life_below_water name=SDG 14 - Life Below Water |
description |
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 near-shore waters from those off-shore. 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 (Kruskal–Wallis rank test, 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 27 different species of plankton, fish and benthic invertebrate also confirms the relevance of the ecoregions as proxies for habitats with common biological characteristics. |
format |
Article in Journal/Newspaper |
author |
Fendereski, F. Vogt, M. Payne, Mark Lachkar, Z. Gruber, N. Salmanmahiny, A. Hosseini, S. A. |
author_facet |
Fendereski, F. Vogt, M. Payne, Mark Lachkar, Z. Gruber, N. Salmanmahiny, A. Hosseini, S. A. |
author_sort |
Fendereski, F. |
title |
Biogeographic classification of the Caspian Sea |
title_short |
Biogeographic classification of the Caspian Sea |
title_full |
Biogeographic classification of the Caspian Sea |
title_fullStr |
Biogeographic classification of the Caspian Sea |
title_full_unstemmed |
Biogeographic classification of the Caspian Sea |
title_sort |
biogeographic classification of the caspian sea |
publishDate |
2014 |
url |
https://orbit.dtu.dk/en/publications/0412a02d-3790-4e7c-9987-101068bd278b https://doi.org/10.5194/bg-11-6451-2014 https://backend.orbit.dtu.dk/ws/files/102863384/Publishers_version.pdf |
genre |
Sea ice |
genre_facet |
Sea ice |
op_source |
Fendereski , F , Vogt , M , Payne , M , Lachkar , Z , Gruber , N , Salmanmahiny , A & Hosseini , S A 2014 , ' Biogeographic classification of the Caspian Sea ' , Biogeosciences , vol. 11 , no. 22 , pp. 6451-6470 . https://doi.org/10.5194/bg-11-6451-2014 |
op_relation |
https://orbit.dtu.dk/en/publications/0412a02d-3790-4e7c-9987-101068bd278b |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/bg-11-6451-2014 |
container_title |
Biogeosciences |
container_volume |
11 |
container_issue |
22 |
container_start_page |
6451 |
op_container_end_page |
6470 |
_version_ |
1797569200166797312 |