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| Titel |
Invasive symbiont bearing (and other) foraminifera altering the community structure of eastern Mediterranean rocky reefs environments |
| VerfasserIn |
Orit Hyams-Kaphzan, Lydia Perelis Grossowicz, Ahuva Almogi-Labin |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250109936
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| Publikation (Nr.) |
 EGU/EGU2015-9890.pdf |
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| Zusammenfassung |
| The rocky reefs of the Israeli eastern Mediterranean shelf constitute a highly diverse marine
ecosystem rich in macroalgae and calcareous organisms. The benthic foraminiferal
community living in this ecosystem is rapidly changing due to massive invasion
of symbiont bearing foraminifera (SBF) as well as other foraminiferal species of
tropical origin. This trend facilitated by the ongoing increase in temperature enables
more tropical species to adjust to the eastern Mediterranean habitats. In order to
document the status of the benthic foraminiferal community structure rocky reefs
at Akhziv (AK) and Carmel Head (CH), northern Israel were sampled by scuba
diving. Different macroalgae species, including invasive ones, accommodating
the live epiphytic benthic foraminifera were sampled twice a year at AK and in
each season at CH in three depth intervals between 5-20 m, during 2013-4. The
numerical abundance of the group ranges between 170-3500 #/10cc (wet macroalgae
volume) without any significant difference in standing stocks within regions, water
depths or macroalgae preference. In total 77 benthic foraminiferal species were
identified 71 in CH and only 43 at AK. Species richness per site varied between 3 and
42 with higher values at CH. 25% of all species were aliens, mostly Lessepsian,
that comprise on average 70% - 84% of the numerical abundance of AK and CH
respectively. Cluster analysis using benthic foraminifera relative abundance data did
not correlate with the different macroalgae species, water depths or seasonality,
indicating that the foraminiferal community in the two regions is quite homogenous.
Amphistegina lobifera a Lessepsian migrant is by far the most common species
on the Israeli rocky reefs occurring in all samples and comprising 18-93% of the
foraminiferal community. Heterostegina depressa behaves similarly to A. lobifera
though it occurs in lower numbers. Pararotalia calcariformata, a recently arriving
SBF occupies mainly shallow water sites at CH, with maximum of 63%, replacing
apparently A. lobifera. Peneroplis planatus and P. pertusus occur in low numbers
mainly at AK sites. Sorites orbiculus, another Lesspsian SBF recently found alive
on pebbles at 0.2 m off Shikmona is quite rare in our material comprising ≈¤2%
at CH and ≈¤1% at AK. This study indicates that the Israeli rocky reefs represent
a dynamic ecosystem prone to rapid changes that did not reach yet equilibrium. |
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