Analysis of environmental variables and fouling organisms on an experimental artificial reef area of Daya Bay

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Analysis of environmental variables and fouling
organisms on an experimental artificial reef area
of Daya Bay

• Chen haigang
• South China Sea Fisheries Institute, CAFS
  Guangzhou, China

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Goals of the artificial reefs project?
02/13/03 STATUS REPORT FWC DIVISION OF MARINE
FISHERIES NORTHWEST FLORIDA ARTIFICIAL REEF
UNPUBLISHED REEF PROJECT
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How to affect habitat environment?
Firm, stable substrate for attachment
Currents can result in the concentration of
nutrient and plankton, and additional food source
is provided
Increasing biomass for food chain
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CaseYangkeikeng in Daya Bay
Artificial reefs deployment site in
Yangmeikeng Control area1?4?5?6?11?12 Reef area
10 Experimental area2?3?7?8?9
Three deployment types of artificial reefs
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Changes of environmental factors
From Apr-2007 to Nov-2008, the result of linear
fitting showed the increasing tendency of water
temperature was RA(0.502)gtEA(0.371)gtCA(0.294)?
From Apr-2007 to Nov-2008, the result of linear
fitting showed the decreasing tendency of water
salinity was CA(-0.336)gtRA(-0.237)gtEA(-0.228)?
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From Apr-2007 to Nov-2008, the result of linear
fitting showed the decreasing tendency of water
pH value was similar(-0.016)?
From Apr-2007 to Nov-2008, the result of linear
fitting showed the decreasing tendency of
dissolved oxygen was CA(-0.088)gtEA(-0.084)gtRA(-0.0
82)?
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From Apr-2007 to Nov-2008, the result of linear
fitting showed the increasing tendency of
ammonical nitrogen concentration was
CA(6.092)gtEA(3.938)gtRA(2.048)?
From Apr-2007 to Nov-2008, the result of linear
fitting showed the increasing tendency of nitrate
nitrogen concentration was CA(27.696)gtEA(21.851)gtR
A(11.605)?
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From Apr-2007 to Nov-2008, the result of linear
fitting showed the decreasing tendency of
phosphate concentration was CA(-5.308)gtEA(-4.232)gt
RA(-2.444)?
From Apr-2007 to Nov-2008, the result of linear
fitting showed the increasing tendency of
chlorophyll a concentration was
EA(0.156)gtCA(0.040)gtRA(0.014)?
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Scores of the first two principal components (PC1
and PC2), PC1 and PC2 explained 66.99 of the
total variance. Sampling sites are classified in
three different groups, zone 1 mainly comprised
from sampling sites of EA and CA, the sampling
stations included in zone 2 are from RA, and zone
3 included RA and EA. There is a relationship
among Dissolved oxygen, Salinity and Chl-a for
PC1 that is associated with upwelling.
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Changes of fouling organisms
Before deployment of reef
After deployment of reef
After deployment of reef
After deployment of reef
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Seasonal changes of fouling organisms species
A total of 116 species were collected and
identified during four seansonal investigation.
Among them, the species of fouling organisms on
steel reef biofouled more quickly than those on
concrete reef.
species of fouling organisms
Steel reef
Summer
Concrete reef
Spring
Autumn
Winter
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Seasonal changes of fouling biomass
During four seasonal investigation, the
biomass of the communities on concrete reef were
winter?autumn?spring?summer. Among them, Balanus
trigonus, O. plicatula and Pema viridis were the
absolute advantage species, the tendency of which
varied as the following
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Seasonal changes of fouling biomass
During four seasonal investigation, the
biomass of the communities on steel were
winter?spring?autumn?summer. Among them, Balanus
trigonus, O. plicatula and Pema viridis were also
the absolute advantage species as on concrete
reef, the tendency of which varied as the
following
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Seasonal changes of community diversity
Diversity index
Abundance
Evenness value
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Biomass of different reef materials
Among of different reef materials, the
average biomass of fouling organisms on wood reef
reached 28.57 kg/m2. By comparison of 6 reef
materials, effect of biofouling was followed by
wood, plastic, aluminum, steel, tyre and concrete.
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Factors affecting the fouling organism
The results of DCA indicated that each
attaching organism had its own distribution
region. The results of CCA indicated that
temperature and salinity, depth, transparence and
dissolved oxygen were the dominate factors in the
distribution of attaching organisms, and CCA
taxis fairly reflected the correlation between
the distribution of attaching organisms and
environmental factors.
????DCA????
CCA????????
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Thank you!