ICES Journal of Marine Science, 59: S356–S362. 2002
doi:10.1006/jmsc.2002.1223, available online at http://www.idealibrary.com on
Influence of artificial reefs on the surrounding infauna: analysis
of meiofauna
R. Danovaro, C. Gambi, A. Mazzola, and S. Mirto
Danovaro, R., Gambi, C., Mazzola, A., and Mirto, S. 2002. Influence of artificial reefs
on the surrounding infauna: analysis of meiofauna. – ICES Journal of Marine Science,
59: S356–S362.
We adopted a bottom-up approach in studying the effect of two artificial reefs in
contrasting environmental conditions (sandy-mud and meso-eutrophic in the Adriatic
Sea versus coarse sands and oligotrophic in the Tyrrhenian Sea) on the surrounding
environment by assessing changes in the meiofauna. The spatial distribution of meiofaunal assemblages was established along a transect running from within each reef to well
outside its direct sphere of influence, along with information on the trophic conditions of
sediments (chloropigments, proteins, carbohydrates, and total organic matter). Although
total densities were significantly higher in the Adriatic than in the Tyrrhenian, the
meiofauna displayed a similar spatial distribution at the two sites, with highest densities
being reached between 2 and 20 m away from the reef area and lowest densities among
the reef blocks. This pattern corresponded largely with variations in grain size and oxygen
penetration in the sediment. Total densities inside the reef areas were significantly lower
than at the control station 50 m from the reef, suggesting that processes influencing
meiofaunal assemblages largely reflect the interaction between reef and surrounding soft
sediments, independently of differences in latitude, sediment texture, and trophic conditions. The results indicate that the proximity of artificial structures altered the composition of meiofaunal assemblages significantly, with potentially important implications
for their role in secondary production and energy transfer to higher trophic levels.
2002 International Council for the Exploration of the Sea. Published by Elsevier Science Ltd.
All rights reserved.
Keywords: Adriatic Sea, artificial reefs, meiofauna, organic matter, Tyrrhenian Sea.
Accepted 1 February 2002.
R. Danovaro, C. Gambi, and S. Mirto: Institute of Marine Sciences, University of
Ancona, Via Brecce Bianche, Monte D’Ago 60131, Ancona, Italy; tel: +39 71 2204654;
fax: +39 71 2204650; e-mail: [email protected]. A. Mazzola: Department of Animal
Biology, University of Palermo, Via Archirafi 18, 90123 Palermo, Italy.
Introduction
Thirty years have passed since the first artificial reef was
installed in the Mediterranean. Since then, a large
number of studies have been carried out to assess their
ecological role on coastal marine ecosystems (Bombace,
1989; Jensen et al., 2000). Despite such efforts, scientific
investigations have failed to cover exhaustively and
systematically the different ecological compartments.
Artificial reefs have been investigated almost exclusively
in relation to their effects on fish populations and
nearshore fisheries (even as a tool for protecting areas
from trawling, with important consequences on coastal
management), but whether the effects observed are the
result of fish attraction or new biomass production
is still an open question (Fabi and Fiorentini,
1994; Lindquist et al., 1994; Relini and Relini, 1996;
Badalamenti and D’Anna, 1996).
1054–3139/02/0S0356+07 $35.00/0
The presence of hard substratum might allow the
settlement of a wide range of benthic invertebrates that
otherwise could not find suitable habitats for their
crucial post-recruitment survival (Jensen and Collins,
1996). Macrofaunal settlement, in turn, might represent
an important food source for several bentho-nektonic
fish species (Relini et al., 1994). Man-made structures
might also have a strong impact on benthic communities
living in adjacent soft-bottom sediments by changing
current speed and direction, sediment erosion, sedimentation rates, grain-size distribution and sorting, and
organic matter content (Turner et al., 1969; Davis et al.,
1982), but information on effects on soft sediments
around the reef is limited (Ambrose and Anderson,
1990).
Most investigations on foodwebs associated with
artificial reefs have utilized a top-down approach
(i.e. looking at the fish biomass and relative stomach
2002 International Council for the Exploration of the Sea. Published by Elsevier Science Ltd. All rights reserved.
Influence of artificial reefs on the surrounding infauna
contents). However, an increased biomass in higher
trophic levels might result from a higher efficiency of
material and energy transfer through trophic levels, or
from an increased primary production. Both aspects
have been almost completely neglected so far (Bohnsack,
1989; Bombace, 1989; Jensen et al., 1994; Relini and
Relini, 1996). A possible alternative to assessing the
ecological implications is the use of a bottom-up
approach (i.e. assessing the actual role of the artificial
reef in enhancing primary production and its transfer to
the lower trophic levels of the benthic foodwebs).
Knowledge about these aspects is crucial in evaluating
the possible role of artificial reefs in influencing
microphytobenthic biomass, bacterial production, and
meiofaunal abundance.
Meiofauna is thought to respond rapidly to environmental changes such as grain size, redox potential, and
food availability (Soyer, 1985; Danovaro, 1996). Moreover, meiofauna is the main link between primary producers and higher trophic levels (i.e. macrobenthos and
juveniles of several nekto-benthic species, Lindquist
et al., 1994). However, literature dealing with meiobenthic responses to the presence of artificial reefs is, to
our knowledge, practically non-existent (Fricke et al.,
1986).
This study was designed to investigate the effects of
artificial reefs on nearby bottom sediments and associated meiofaunal assemblages. Two reefs located in areas
characterized by different environmental and trophic
conditions (Northern Adriatic and Southern Tyrrhenian
Seas) were compared: (a) to assess effects on softsediment grain size, microphytobenthic biomass, and
organic matter quality and quantity; (b) to assess differences in meiofaunal assemblages in relation to different
trophic conditions; and (c) to identify seasonal changes
in meiofaunal community structure along gradients of
increasing distance from the reefs.
Materials and methods
Study areas
Two reefs were selected: Senigallia artificial reef (SAR)
in the Adriatic Sea and the Palermo artificial reef (PAR)
in the Tyrrhenian Sea (Figure 1). SAR, deployed in 1987
in 11 m of water, is situated 25 km NW of Ancona, 1 km
offshore on a sand-muddy seabed, remote from natural
hard substratum (Bombace et al., 2000). The reef has 29
pyramids arranged in a rectangle at intervals of 15 m,
each pyramid consisting of 5 blocks (222 m). PAR
was deployed in 1992 in 20 m of water. The six reef
pyramids are also arranged in a rectangle and have been
deployed on a sandy seabed within a seagrass bed
(Posidonia oceanica), 300 m from shore (Toccaceli et al.,
1996; Riggio et al., 2000). In this case, the pyramids are
about 100 m apart.
S357
12°
8°E
46°N
SAR
Adriatic
Sea
42°
Tyrrhenian
Sea
PAR
38°
Figure 1. Study area and location of the two artificial reefs
investigated: the Senigallia artificial reef (SAR) in the northern
Adriatic and the Palermo artificial reef (PAR) in the southern
Tyrrhenian.
Sampling
Both reef areas were sampled during the winter
(November 1998 and February 1999 for PAR and SAR,
respectively) and the summer period (June 1999 in both
cases). In both reefs, sampling strategy was aimed at
covering a gradient of reef influence on the surrounding
sediments. Along a transect parallel to the coast and in
the dominant downcurrent direction, five stations were
sampled during each season: the first station was within
the area surrounded by the pyramids (3 m from the
edge of the rectangle), the second station was selected
between the blocks of a reef pyramid (0 m), followed by
stations at 2, 20, and 50 m from the reefs. In both areas,
the control site was assumed to be the station at 50-m
distance from the artificial reefs, which is considered
sufficient to exclude reef effects on bottom sediments
(Ambrose and Anderson, 1990).
All sediment samples were taken manually by SCUBA
divers, using PVC corers (4.6 cm diameter). For meiofaunal analyses, three replicates were taken at each
station and season down to 10 cm depth and preserved
in buffered 4% formalin solution, using 0.45 m prefiltered artificial seawater containing 80 g l 1 MgCl2
and stained with about 200 l of Rose Bengal (1‰). For
organic matter analysis (i.e. Chl a, chloroplastic pigment
equivalents, carbohydrates, proteins, total organic
matter, and carbonates), the surface sediment (0–1 cm)
of 2–3 additional cores was taken only during summer
and frozen at 20C.
Environmental parameters
Redox potential discontinuity depth (RPD in cm) was
visually estimated as the depth at which sediment colour
S358
R. Danovaro et al.
Table 1. Mean (standard deviation in parentheses) parameter values for redox potential discontinuity depth (RPD; cm), percentage
sand (S%), total organic matter (TOM; %), Chl a (g g 1), chloroplastic pigment equivalents (CPE; g g 1), carbohydrates (GE:
glucose equivalents; g g 1), and proteins (AE: albumin equivalents; g g 1) by reef area (SAR, PAR) and station (St).
RPD
SAR
PAR
St
S%
SAR
PAR
3
0.7
5.5
5.2
96.6
0
0.4
1.7
1.7
91.9
2
1.7
2.8
40.4
91.0
20
2.5
8.0
62.9
97.5
50
0.7
3.3
16.7
96.8
% TOM
SAR
PAR
Chl a
SAR
PAR
CPE
SAR
PAR
SAR
PAR
SAR
PAR
4.7
(0.2)
4.1
(0.2)
5.2
(0.2)
5.1
(0.3)
7.1
(0.6)
7.7
(4.1)
6.0
(1.3)
0.7
(0.2)
16.5
(4.1)
14.7
(5.7)
21.5
(5.1)
14.5
(41.1)
1.4
(0.8)
27.4
(5.5)
31.6
(5.0)
1025
(191)
105
(n.d.)
877
(159)
706
(86)
714
(124)
602
(3)
332
(149)
333
(n.d.)
405
(7)
224
(14)
3731
(236)
1744
(291)
2661
(382)
2385
(675)
3994
(955)
680
(97)
513
(109)
722
(177)
534
(80)
313
(9)
3.9
(0.4)
4.9
(1.0)
3.3
(0.3)
3.4
(0.1)
2.9
(0.1)
turned from brown to black. Grain-size distribution was
analysed using a dry sieve technique (% sand=fraction
>0.625 mm). Total organic matter content (TOM) was
determined by ignition loss (450C, 6 h; Fabiano and
Danovaro, 1994) after sediment desiccation (105C,
24 h) and removal of carbonates by acidification with
0.1 N HCl. Chl a analyses were carried out according to
Lorenzen and Jeffrey (1980). Pigments were extracted
with 90% acetone; after centrifugation, the supernatant
was acidified with 0.1 N HCl and used to determine
Chl a and phaeopigment concentrations. Chloroplastic
pigment equivalents (CPE) were referred as the sum of
Chl a and phaeopigment concentrations. Carbohydrates
(expressed as glucose equivalents) were analysed
according to Gerchacov and Hatcher (1972). Proteins
(PRT; expressed as albumin equivalents) were analysed
according to Hartree (1972).
Meiofaunal analysis
Sediment samples were sieved through 1000 and
37 m mesh net to retain even the smaller meiofaunal
organisms. The fraction remaining on the 37 m sieve
was centrifuged three times with Ludox HS 40 (density
1.15 g cm 3) as described by Heip et al. (1985). All
meiobenthic animals were counted and taxonomically
classified under a stereomicroscope (40 or 80;
Zeiss, Stemi 2000). Soft-body meiofauna was mounted
on slides and identified as far as possible with a microscope at 400–1000 (Zeiss, Axiolab HBO).
Statistical analyses
A t-test with replicates was carried out for comparing
the values of all parameters at the inner (3 m) and
control (50 m) stations. Differences among areas and
transect stations were tested using a two-way ANOVA
with replicates. Relationships between environmental
3.2
(0.5)
2.2
(0.5)
3.4
(0.3)
5.9
(1.1)
1.9
(0.1)
4.9
(0.4)
5.9
(1.6)
4.3
(0.6)
7.4
(1.4)
2.1
(0.1)
GE
AE
and meiofaunal parameters were explored using the
Spearman rank correlation analysis.
Results
Environmental parameters
Generally, RPD values at SAR in the Adriatic were
lower than at PAR in the Tyrrhenian (Table 1). Sediment grain size in the two areas displayed evident
differences. SAR stations were dominated by muddy
sediment, except at the 20 m station, whereas PAR
stations were strongly dominated by sands. Total
organic matter (TOM) did not display consistent differences between the two areas, but the spatial patterns
along the transects differed. At SAR, TOM increased
from the pyramids (Station 0: 4.1%) to the control
station (Station 50: 7.1%), whereas TOM content at
PAR decreased over the same trajectory (from 4.9%
to 2.9%).
All biochemical parameters differed significantly
between Adriatic and Tyrrhenian sediments (Table 2).
Chl a and CPE displayed similar spatial patterns in the
two areas with highest values generally reported at 20 m
outside the reef (Table 1). At SAR, the lowest values
were encountered outside the reef at the 2 m station,
whereas at PAR the lowest values were reported at the
50-m station. Carbohydrates displayed a similar spatial
pattern in the two areas, with highest concentrations at
the 3 m station between the pyramids and lowest
values within the pyramids. In the Adriatic, protein
concentrations reached highest values at the 3 m and
50-m stations, whereas in the Tyrrhenian, proteins
showed higher values at the 3 m and 2 m stations.
In the Tyrrhenian, differences between the control
(50 m) station and the reef (3 m) station were significant (t-test, p<0.05) for all biochemical parameters,
whereas in the Adriatic differences were statistically
Influence of artificial reefs on the surrounding infauna
Table 2. p-values for statistical differences between the two
areas (AREA) and among stations with SAR and PAR (twoway ANOVA).
600
AREA
SAR st.
PAR st.
400
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.032
0.006
0.000
0.004
0.002
0.000
0.000
0.011
0.000
n.s.
n.s.
n.s.
n.s.
0.008
n.s.
0.000
0.003
0.002
0.000
n.s.
0.000
0.007
0.006
0.007
0.005
n.s.
n.s.
n.s.
n.s.
n.s.
n.s.
n.s.
200
Adriatic
0
600
Ind 10 cm–2
Chl a
CPE
Carbohydrates
Proteins
Total organic matter
Meiofauna
Nematodes
Copepods
Nauplii
Polychaetes
Kinorhynchs
Gastrotrics
Bivalves
Others
S359
Winter
Summer
Tyrrhenian
400
200
0
significant only for chloroplastic pigment equivalents
and carbohydrates.
600
Annual average
Adriatic
Tyrrhenian
400
Meiofauna
Average total meiofauna density was significantly
higher in the Adriatic than in the Tyrrhenian (Table 2;
Figure 2). However, density in the Adriatic was much
higher during summer than in winter, whereas in the
Tyrrhenian meiofauna density did not display significant
seasonal changes. In both areas, meiofauna reached
highest densities just outside the reef area (between 2
and 20 m) and the lowest densities at the 0-m stations.
Total meiofauna density inside a reef area was always
significantly different from the control station (t-test,
p<0.05).
Nematodes were the dominant taxon in both areas
and their relative importance was higher in winter than
in summer (Figures 3 and 4). In winter in the Adriatic,
nematode percentage was over 90 at all stations, whereas
in the Tyrrhenian it ranged from 55 to 95, increasing
from the artificial reef to the control station. In summer,
relative contribution was reduced to 56–74% and
50–80% in the Adriatic and Tyrrhenian, respectively,
and presented a less consistent spatial pattern (Figure 4).
At least in the Adriatic, the reduction in relative contribution of nematodes was caused by the greatly increased
number of harpacticoid copepods and nauplii at all
stations (Figure 3). Polychaetes, kinorhynchs and gastrotrichs represented less abundant groups and their
contribution to the total density was mostly low in both
areas (0–10%; Figure 4).
Discussion
The results indicate clear influences of artificial reefs on
the adjacent sediments. Changes in grain size and other
200
0
–3 m
0m
2m
20 m
50 m
Figure 2. Spatial and temporal distribution of total meiofaunal
density (+s.d.) at SAR (top panel) and PAR (middle), and
comparison of the annual averages in the two areas (bottom).
benthic parameters are presumably caused by the modified hydrodynamic conditions and micro-scale bottom
topography. In the Adriatic, the reduced sand fraction
within the reef suggests reduced turbulence as a direct
consequence of the blocks, but such an effect was not
evident in the Tyrrhenian. Fricke et al. (1986), studying
a scuttled ship on a sandy seabed, calculated that the
hydrodynamic energy resulting from its presence could
easily re-suspend detrital particles and meiofauna even
in calm weather conditions, leading to micro-habitat
differentiation. Information on hydrodynamic changes
induced by concrete blocks is limited (Ambrose and
Anderson, 1990; Badalamenti and D’Anna, 1996), but
similar changes at the sediment–water interface have
also been reported for disused oil platforms (Davis et al.,
1982).
The reef influence on sediments was evident also in
terms of redox potential discontinuity depth, which
is often reduced in areas characterized by higher deposition rates (such as between blocks; Ambrose and
Anderson, 1990). At SAR, RPD effects were less evident
within the reef compared to the control site, but the
sediments at this reef were generally characterized by
low RPD values, indicating low oxygen penetration
S360
R. Danovaro et al.
Adriatic
(a) Nematodes
Tyrrhenian
(b) Nematodes
Adriatic
Tyrrhenian
100%
4000
3000
80%
2000
60%
W
1000
0
1000
(c) Copepods
40%
(d) Copepods
20%
750
Ind 10 cm–2
500
0%
250
100%
0
800 (e) Nauplii
(f) Nauplii
80%
600
60%
S
400
200
40%
0
(g) Polychaetes
200
(h) Polychaetes
Winter
Summer
20%
0%
–3 m
0
2 m 20 m 50 m
–3 m
0
2 m 20 m 50 m
100
0
–3 m 0 m 2 m 20 m 50 m
Nematodes
Copepods
Nauplii
Polychaetes
Kynorhynchs
Gastrotrichs
Bivalves
Others
–3 m 0 m 2 m 20 m 50 m
Figure 3. Spatial and temporal distribution of the four
main taxa (+s.d.) at SAR (left panels) and PAR (right): (a)
nematodes; (b) copepods; (c) nauplii; and (d) polychaetes.
rates. However, in both areas, effects were strongest
between blocks, where the silt-clay fraction was also
largest.
Both Chl a concentration and chloroplastic pigment
equivalents inside the SAR area were slightly lower than
at the control station, but phytopigments were significantly depressed between the blocks and immediately
outside both reef areas. This effect may be related to the
modified soft-bottom structure and light regime between
blocks, but patterns can be further complicated by the
current system. Nonetheless, accumulation of fine sediments and debris inside the reef area may be responsible
also for accumulation of labile organic compounds
in both reef areas. In other words, organic matter
deposited may not have been produced in situ, but rather
have been imported from outside the reef area. While
carbohydrates reached significantly higher concentrations within the reefs than at the controls (comparing
stations 3 and 50 m) in both areas, proteins were not
enhanced. This indicates a different quality of the
organic matter load inside and outside the reef, even
though total organic matter remained fairly constant
along the transects.
Figure 4. Taxonomic composition of meiofaunal assemblages
at SAR (left panels) and PAR (right) during winter (W; top)
and summer (S; bottom).
Artificial reefs might affect the infaunal assemblages
in various ways: (a) by altering the hydrodynamic
regime and the physical characteristics of the substrate;
(b) by modifying the distribution and/or composition
of the available food sources; and (c) by altering
the biological interactions between different parts of the
foodweb. One of these factors might prevail over the
others or the different forcing functions might act
simultaneously resulting in complex responses of the
infaunal assemblages.
The limited number of studies conducted so far on
infaunal communities from soft bottoms close to artificial reefs has provided contrasting results. Some authors
have reported changes in community structure as a
result of altered sediment texture. Ambrose and
Anderson (1990) found a reduced density of some taxa
near the reef, and Nelson et al. (1994) observed a strong
reduction in the zone less than 1 m from the edge of the
man-made structure. Conversely, Davis et al. (1982) did
not find any decrease in density at a distance of at least
4 m from the edge of two artificial reefs off California
(i.e. outside the most affected area). Their results might
have two possible explanations: predation effects were
Influence of artificial reefs on the surrounding infauna
obscured by enhancement of infaunal densities caused
by changes in the physical environment. Ambrose and
Anderson (1990) suggested that physical parameters
may have influenced infaunal abundance patterns more
than predation and that the influence on adjacent softbottom communities is essentially a function of distance
from the reef. Jensen et al. (1994) did not find a
reduction in macrofauna densities around a reef in the
English Channel, suggesting that a feeding halo had not
been established.
On an annual basis, we observed a significant decrease
in meiofaunal densities inside both reef areas and
between the actual blocks. However, no reduction was
observed in the close, downstream vicinity of the reef
(2 m station). The lower density inside the reef areas
seems best explained by the higher silt/clay fraction and
possibly the slightly reduced oxygen penetration.
Fricke et al. (1986) reported enhanced meiofaunal
densities in coastal sediments close to a scuttled ship
which were closely associated with increases in the fine
sediment fraction. Unfortunately, the lack of information on OM availability from this South African
study does not allow clarification of potential effects of
modified trophic conditions.
Meiofaunal densities were significantly higher in
the meso-eutrophic Adriatic than in the oligotrophic
Tyrrhenian. The difference in trophic conditions
between the two areas is clearly emphasized by the larger
amounts of organic compounds in the SAR sediments.
Also seasonal changes in density were much larger in the
Adriatic, pointing to a strong effect of seasonal changes
in food availability. Climatological effects related to the
different latitudes of the two areas may also be involved,
and appear to be related to the much wider seasonal
changes in food input reported at SAR compared to the
lack of clear changes reported at PAR. In this regard,
Manini et al. (2000) reported protein and carbohydrate
concentrations in the northern Adriatic (close to SAR)
to be two to four times higher in June than in February.
Nevertheless, the similarity of some spatial patterns
observed in the two areas suggest that processes
influencing meiofaunal assemblages largely reflect the
interaction between reef and surrounding sediments,
independent of latitude, sediment texture, and trophic
conditions.
The reduction in total meiofaunal density inside the
reef area largely reflected the reduced abundance of
nematodes, the predominant taxon. Other taxa did not
decrease or even increase in the proximity of the reef,
resulting in spatial differences in meiofaunal composition. Crustacean nauplii, harpacticoid copepods, and
polychaetes displayed highest densities inside the reef,
particularly at SAR during summer. Even though these
differences were not always significant (Table 2), the
spatial patterns displayed by these taxa might suggest a
preference for different trophic sources (such as carbo-
S361
hydrates accumulating inside the reef). Fricke et al.
(1986) also reported changes in assemblage composition,
with nematodes and oligochaetes showing the clearest
response (even to small changes in grain size), but also
turbellarians and polychaetes differed significantly
from the control. The conclusion that the proximity of
artificial reefs significantly alters the composition of
meiofaunal assemblages, with potentially important
implications for their secondary production and energy
transfer to higher trophic levels, seems justified.
Acknowledgements
We are particularly indebted to Dr G. Fabi (IRPeMCNR, Ancona) and Dr M. Sinopoli (University of
Palermo) for collaboration during sampling. Thanks
also to Dr A. Pusceddu for ANOVA statistical analysis.
Dr A. Jensen is acknowledged for valuable suggestions
on the manuscript. The research was supported by
a grant from the Ministero dell’Università e Ricerca
Scientifica e Tecnologica, Italy.
References
Ambrose, R. F., and Anderson, T. W. 1990. Influence of an
artificial reef on the surrounding infaunal community.
Marine Biology, 107: 41–52.
Badalamenti, F., and D’Anna, G. 1996. Monitoring techniques
for zoobenthic communities: influence of the artificial reef
on the surrounding infaunal community. In European
Artificial Reef Research, pp. 347–358. Proceedings of the
1st Conference of the European Artificial Reef Research
Network, Ancona, Italy, 26–30 March 1996. Southampton
Oceanography Centre.
Bohnsack, J. A. 1989. Are high densities of fishes at artificial
reefs the result of habitat limitation or behavioural preference? Bulletin of Marine Science, 44: 631–645.
Bombace, G. 1989. Artificial reefs in the Mediterranean Sea.
Bulletin of Marine Science, 44: 1023–1032.
Bombace, G., Fabi, G., and Fiorentini, L. 2000. Artificial reefs
in the Adriatic Sea. In Artificial reefs in European seas,
pp. 31–63. Ed. by A. C. Jensen, K. J. Collins, and A. P. M.
Lockwood. Kluwer, Dordrecht. 508 pp.
Danovaro, R. 1996. Detritus–bacteria–meiofauna interactions in a seagrass bed (Posidonia oceanica) of the NW
Mediterranean. Marine Biology, 119: 489–500.
Davis, N., Van Blaricom, G. R., and Dayton, P. K. 1982.
Man-made structures on marine sediments: effects on adjacent benthic communities. Marine Biology, 70: 295–303.
Fabi, G., and Fiorentini, L. 1994. Comparison between an
artificial reef and a control site in the Adriatic Sea: analysis of
four years of monitoring. Bulletin of Marine Science, 55:
538–558.
Fabiano, M., and Danovaro, R. 1994. Composition of organic
matter in sediment facing a river estuary (Tyrrhenian Sea):
relationships with bacteria and microphytobenthic biomass.
Hydrobiologia, 277: 71–84.
Fricke, A. H., Koop, K., and Cliff, G. 1986. Modification of
sediment texture and enhancement of interstitial meiofauna
by an artificial reef. Transactions of the Royal Society of
South Africa, 46(1): 27–34.
S362
R. Danovaro et al.
Gerchakov, S. M., and Hatcher, P. G. 1972. Improved technique for analysis of carbohydrates in sediment. Limnology
and Oceanography, 17: 938–943.
Hartree, E. F. 1972. Determination of protein: a modification
of the Lowry method that gives a linear photometric
response. Analytic Biochemistry, 48: 422–427.
Heip, C., Vincx, M., and Vranken, G. 1985. The ecology of
marine nematodes. Oceanography Marine Biology a Review,
23: 399–489.
Jensen, A., and Collins, K. 1996. The use of artificial reefs in
crustacean fisheries enhancement. In European Artificial
Reef Research, pp. 115–121. Proceedings of the 1st Conference of the European Artificial Reef Research Network,
Ancona, Italy, 26–30 March 1996. Southampton Oceanography Centre.
Jensen, A., Collins, K., and Lockwood, A. P. M. 2000. Artificial reefs in European seas. Kluwer, Dordrecht. 508 pp.
Jensen, A., Collins, K., Lockwood, A. P. M., Mallison, J. J.,
and Turnpenny, W. H. 1994. Colonisation and fishery potential of a coal-ash artificial reef, Poole Bay, United Kingdom.
Bulletin of Marine Science, 55: 1263–1276.
Lindquist, D. G., Cahoon, L. B., Clavijo, I. E., Posey, M. H.,
Bolden, S. K., Pike, L. A., and Burk, S. W., et al. 1994. Reef
fish stomach contents and prey abundance on reef and sand
substrata associated with adjacent artificial and natural reefs
in Onslow Bay, North Carolina. Bulletin of Marine Science,
55: 308–318.
Lorenzen, C., and Jeffrey, J. 1980. Determination of chlorophyll in seawater. Technical Paper in Marine Science
(UNESCO), 35: 574–576.
Manini, E., Fabiano, M., and Danovaro, R. 2000. Benthic
response to mucilaginous aggregates in the northern Adriatic
Sea: biochemical indicators of eutrophication. Chemistry and
Ecology, 17: 171–179.
Nelson, W. G., Neff, T., Navratil, P., and Rodda, J. 1994.
Disturbance effects on marine infaunal near stabilised oil-ash
reefs: spatial and temporal alteration of impacts. Bulletin of
Marine Science, 55: 1384.
Relini, G., and Relini, M. 1996. Biomass on artificial reefs. In
European Artificial Reef Research, pp. 61–83. Proceedings of
the 1st Conference of the European Artificial Reef Research
Network, Ancona, Italy, 26–30 March 1996. Southampton
Oceanography Centre.
Relini, G., Zamboni, N., Tixi, F., and Torchia, G. 1994.
Patterns of sessile macrobenthos community development
on an artificial reef in the Gulf of Genoa (Northwestern
Mediterranean). Bulletin of Marine Science, 55: 745–771.
Riggio, S., Badalamenti, F., and D’Anna, G. 2000. Artificial
reefs in Sicily: an overview. In Artificial Reefs in European
Seas, pp. 65–73. Ed. by A. C. Jensen, K. J. Collins, and
A. P. M. Lockwood. Kluwer, Dordrecht. 508 pp.
Soyer, J. 1985. Mediterranean sea meiobenthos. In
Mediterranean Marine Ecosystem, pp. 85–108. Ed. by M.
Moraitou-Apostoloupolou, and V. Kiortsis. Plenum
Publishing Corporation, New York.
Toccaceli, M., Gristina, M., and Parisi, R. 1996. Primi dati
sugli insediamenti bentonici di due barriere artificiali nei
fondali costieri della provincia di Palermo (Sicilia NordOccidentale). Biologia Marina Mediterranea, 3(1): 493–
495.
Turner, C. H., Ebert, E. E., and Given, R. R. 1969. Man-made
reef ecology. California Department Fish Game Bulletin,
146: 1–221.