| dc.creator |
Muzuka, Alfred N. N. |
|
| dc.creator |
Shaghude, Yohanna W. |
|
| dc.creator |
Wannäs, Kjell O. |
|
| dc.creator |
Nyandwi, Ntahondi |
|
| dc.date |
2016-02-19T09:02:25Z |
|
| dc.date |
2016-02-19T09:02:25Z |
|
| dc.date |
2007 |
|
| dc.date.accessioned |
2018-04-18T11:49:47Z |
|
| dc.date.available |
2018-04-18T11:49:47Z |
|
| dc.identifier |
Muzuka, A.N., Sahghude, Y.W., Wannäs, K.O. and Nyandwi, N., 2007. Sediment sources and their distribution in Chwaka Bay, Zanzibar Island. Western Indian Ocean Journal of Marine Science, 4(2), pp.185-198. |
|
| dc.identifier |
http://hdl.handle.net/123456789/459 |
|
| dc.identifier.uri |
http://hdl.handle.net/123456789/10184 |
|
| dc.description |
http://www.ajol.info/index.php/wiojms/article/view/28487 |
|
| dc.description |
This work establishes sediment sources, character and their distribution in Chwaka
Bay using (i) stable isotopes compositions of organic carbon (OC) and nitrogen, (ii) contents of
OC, nitrogen and CaCO3, (iii) C/N ratios, (iv) distribution of sediment mean grain size and
sorting, and (v) thickness of unconsolidated sediments. The Chwaka Bay is located on the
eastern coast of Zanzibar Island and is about 50 km2. It is a shallow partly sheltered lagoon with
large intertidal area and fringing mangrove forest. The stable isotope values of nitrogen and
OC, which averages 1.5±0.9‰ and -17.5±2.3‰ respectively, increases offshore indicating
decrease in the influence of terrestrial material. Furthermore, nitrogen isotope values ranging
from 0.3 to 3.9% suggest that the values result from nitrogen fixing plants. Because the bay has
high abundance of calcareous green algae Halimeda plants, most likely low δ15N values reflect
the influence of this photosynthetic plant to the total sediment budget. This inference is supported
by low C/N ratio values that averages 7.9 ± 1.4 and with highest values being confined close to
the mangrove forest. The contents of OC and nitrogen, which averages 0.75±0.60% and
0.11±0.08% respectively, are highest close to the mangrove forest. The sediment thickness in
the Bay is higher in the northern part than in the southern part. The character of sediments in
terms of grain size differs between eastern and western parts of the Bay. The eastern part is
characterized by medium to fine white carbonate sand with mean grain size higher than 2φ,
whereas coarse sediments with mean values less than 2φ characterize the western part. The
content of calcium carbonate is very high with values being higher than 90% for the whole Bay
owing to high concentration of carbonate sand-forming Halimeda. |
|
| dc.language |
en |
|
| dc.publisher |
WIOMSA |
|
| dc.subject |
Halimeda |
|
| dc.subject |
Stable isotope |
|
| dc.subject |
sediment distribution |
|
| dc.subject |
Sediment thickness |
|
| dc.title |
Sediment sources and their Distribution in Chwaka Bay, Zanzibar Island |
|
| dc.type |
Journal Article |
|