Cyclical development and community structure of the intertidal polychaete reefs in the Jeram Mudflat, Peninsular Malaysia / Eeo Jun Jie
It is interesting but not clear how “hard” polychaete reefs can grow up on soft-bottom mudflats in tropical waters. Such polychaete reefs are also generally unknown in terms of their community structure and duration of existence. Ecological aspects of the polychaete reefs on Jeram intertidal mudf...
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| 格式: | Thesis |
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2018
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| 在線閱讀: | http://studentsrepo.um.edu.my/9387/1/Eeo_Jun_Ji.pdf http://studentsrepo.um.edu.my/9387/6/jun_jie.pdf http://studentsrepo.um.edu.my/9387/ |
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| 總結: | It is interesting but not clear how “hard” polychaete reefs can grow up on soft-bottom
mudflats in tropical waters. Such polychaete reefs are also generally unknown in terms
of their community structure and duration of existence. Ecological aspects of the
polychaete reefs on Jeram intertidal mudflat were studied to 1) elucidate the faunal
succession during the life cycle of the reef, in terms of species composition and spatiotemporal
abundance; 2) examine the accompanying changes of the adjacent mudflat
community structure; and 3) determine the relationship between the reef cycle and the
hydrometeorological factors such as the wind field, current, erosion and sedimentation.
Samplings on the polychaete reefs and mudflat were carried out from June 2012 to
January 2014 to study the physical environment and the macrobenthic community. The
macrobenthos were examined on both spatial (horizontal and vertical distribution) and
temporal (monthly changes) scales. The Jeram polychaete reef cycled through four phases
within a year: pre-settlement phase (March–May), growth phase comprising primary
(May –November) and secondary (October–January) successional stages, stagnation
phase (December–January) and destruction phase (January–March). At the onset of the
southwest monsoon (May), strong erosive forces initiate the reef’s primary succession of
the growth phase where the dominant polychaete Sabellaria jeramae (>90 % of the reef
macrobenthos density) colonise on the exposed lag deposits of shells. During the
northeast monsoon (November–March), stronger depositional forces cover the developed
reef with fine sediments. Subsequently, this reef is colonised by another polychaete, the
spionid Polydora cavitensis during the reef’s secondary succession of the growth phase.
Polychaetes are the only inhabitants living inside the ephemeral Jeram reef clumps during all successional phases of the reef cycle, with a total of 21 species. Overall, total
polychaete abundance decreased from surface to deeper zones of the reef. S. jeramae
dominated the entire reef depth during primary succession. A mixed S. jeramae–P.
cavitensis community dominated the surface zone (depth= 0–5cm) during secondary
succession, but no polychaetes except P. cavitensis were found at the surface zone during
the stagnation phase. Five major taxa (Polychaeta, Anomura, Gastropoda, Caridea and
Brachyura) dominated the immediate mudflat macrobenthos. However, the mudflat
macrobenthos play no obvious or direct role in initiating the growth of the reef which is
likely the result of settlement of dispersed polychaete larvae from unknown offshore
reefs. Generally, the reef presence has a positive effect on the presence or abundance of
surrounding mudflat macrobenthos such as mudflat polychaetes, shrimps, crabs and
gastropods. |
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