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Correlation between pollution and decline of Scleractinian Cladocora caespitosa (Linnaeus, 1758) in the Gulf of Gabes

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ABSTRACT

During an expedition in 2014 in the Gulf of Gabes that aimed to evaluate the impact of the pollution of the phosphate industry on the marine environment, numerous dead coral fragments were retrieved from several stations along a 18 km long transect in front of the industry complex of Gabes. Detailed taxonomy of these coral fragments shows clearly that all fragments belong to the species Cladocora caespitosa (Linnaeus, 1758). Quantitative analysis of the coral fragments indicates a positive correlation with stations characterized by positive bathymetric anomalies. We suggest the presence of probable small-scaled (up to 4 m high) biogenic (palaeo-) build-ups composed mainly of coral colonies and bryozoans. Radiocarbon dating of three coral fragments show ages as old as 1897, 1985 and 1986 AD and suggests the presence of living C. caespitosa as close as 6 km to the phosphate treatment industry of Gabes at least until 1986 AD. This latter age coincides with the construction of the ammonium phosphate production plant, in 1979, in the Gulf of Gabes with an increase of the natural phosphate production. The higher impact of pollution on the marine environment in the inner part of the Gulf of Gabes likely induced the decline of C. caespitosa. This is well in agreement with enhanced siltation processes suggested by the sedimentary facies and grain-size analyses presently characterizing the Gulf of Gabes nowadays.

No MeSH data available.


A.C. caespitosa fragment from station GBS05; B.C. caespitosa with regrowth suture from station GBS-05; C.C. caespitosa fragment from station GBS-12; D. well preserved of C. caespitosa fragment from station GBS-06; E.C. caespitosa with growth pattern from station GBS-14; F.C. caespitosa fragment from station GBS-16; G.C. caespitosa fragment from station GBS-14.
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fig0025: A.C. caespitosa fragment from station GBS05; B.C. caespitosa with regrowth suture from station GBS-05; C.C. caespitosa fragment from station GBS-12; D. well preserved of C. caespitosa fragment from station GBS-06; E.C. caespitosa with growth pattern from station GBS-14; F.C. caespitosa fragment from station GBS-16; G.C. caespitosa fragment from station GBS-14.

Mentions: All Cladocora caespitosa fragments were collected on the seafloor (first centimeter of the sediment surface) along the transect of the working area. No living fragments were found or collected during the expedition. Coral fragments were mostly eroded and not well preserved; additionally bio-erosion was often present along the corallite wall. However, one fragment collected on the station GBS-06 appeared well preserved especially the calices part (Fig. 5). The dimensions of most C. caespitosa fragments had length spanning between 0.5 and 2 cm with only few fragments reaching 4 to 5 cm. Fragments presented a white coloration, with corallite diameter around 3 mm. Corallites had their own walls, were tubular and were compacted together forming clumps. Septa and pali presented spikes on their distal margins. Septo-costae were in two alternating orders, with only the first order reaching the columella. Columellae and paliform lobes were well developed. Some samples showed sign of boring organisms associated with the coral skeleton. Growth patterns were present on the corallite wall for some C. caespitosa fragments (Fig. 5). Suture lines were visible on the circumference of the corallite wall and can be linked to an annual growth bands (Fig. 5).


Correlation between pollution and decline of Scleractinian Cladocora caespitosa (Linnaeus, 1758) in the Gulf of Gabes
A.C. caespitosa fragment from station GBS05; B.C. caespitosa with regrowth suture from station GBS-05; C.C. caespitosa fragment from station GBS-12; D. well preserved of C. caespitosa fragment from station GBS-06; E.C. caespitosa with growth pattern from station GBS-14; F.C. caespitosa fragment from station GBS-16; G.C. caespitosa fragment from station GBS-14.
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5121140&req=5

fig0025: A.C. caespitosa fragment from station GBS05; B.C. caespitosa with regrowth suture from station GBS-05; C.C. caespitosa fragment from station GBS-12; D. well preserved of C. caespitosa fragment from station GBS-06; E.C. caespitosa with growth pattern from station GBS-14; F.C. caespitosa fragment from station GBS-16; G.C. caespitosa fragment from station GBS-14.
Mentions: All Cladocora caespitosa fragments were collected on the seafloor (first centimeter of the sediment surface) along the transect of the working area. No living fragments were found or collected during the expedition. Coral fragments were mostly eroded and not well preserved; additionally bio-erosion was often present along the corallite wall. However, one fragment collected on the station GBS-06 appeared well preserved especially the calices part (Fig. 5). The dimensions of most C. caespitosa fragments had length spanning between 0.5 and 2 cm with only few fragments reaching 4 to 5 cm. Fragments presented a white coloration, with corallite diameter around 3 mm. Corallites had their own walls, were tubular and were compacted together forming clumps. Septa and pali presented spikes on their distal margins. Septo-costae were in two alternating orders, with only the first order reaching the columella. Columellae and paliform lobes were well developed. Some samples showed sign of boring organisms associated with the coral skeleton. Growth patterns were present on the corallite wall for some C. caespitosa fragments (Fig. 5). Suture lines were visible on the circumference of the corallite wall and can be linked to an annual growth bands (Fig. 5).

View Article: PubMed Central - PubMed

ABSTRACT

During an expedition in 2014 in the Gulf of Gabes that aimed to evaluate the impact of the pollution of the phosphate industry on the marine environment, numerous dead coral fragments were retrieved from several stations along a 18 km long transect in front of the industry complex of Gabes. Detailed taxonomy of these coral fragments shows clearly that all fragments belong to the species Cladocora caespitosa (Linnaeus, 1758). Quantitative analysis of the coral fragments indicates a positive correlation with stations characterized by positive bathymetric anomalies. We suggest the presence of probable small-scaled (up to 4 m high) biogenic (palaeo-) build-ups composed mainly of coral colonies and bryozoans. Radiocarbon dating of three coral fragments show ages as old as 1897, 1985 and 1986 AD and suggests the presence of living C. caespitosa as close as 6 km to the phosphate treatment industry of Gabes at least until 1986 AD. This latter age coincides with the construction of the ammonium phosphate production plant, in 1979, in the Gulf of Gabes with an increase of the natural phosphate production. The higher impact of pollution on the marine environment in the inner part of the Gulf of Gabes likely induced the decline of C. caespitosa. This is well in agreement with enhanced siltation processes suggested by the sedimentary facies and grain-size analyses presently characterizing the Gulf of Gabes nowadays.

No MeSH data available.