Contrasting biological features in morphologically cryptic Mediterranean sponges (original) (raw)
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Hydrobiologia, 2012
Recognizing and understanding presentday biodiversity and biogeographical patterns and how these relate to contemporary and past climate is pivotal to predict the effect of future climate on marine biodiversity and promote adequate conservation policies. Sponges constitute an important and dominant component of the marine benthos and are therefore an excellent model group for such investigations. In this study, we assessed the diversity patterns and the Guest editors: M. Maldonado, X. Turon, M. A. Becerro & M. J. Uriz / Ancient animals, new challenges: developments in sponge research
Shallow-water sponge grounds along the Apulian coast (central Mediterranean Sea)
Marine Biodiversity, 2020
Sponge grounds are complex three-dimensional benthic habitats dominated by sponges. These sponge-dominated assemblages have been reported worldwide, from the intertidal zone to the deep sea. In shallow euphotic waters, dense sponge aggregations have been mainly found in tropical areas, and their presence is in some cases related to environmental degradation and coral decline. The Mediterranean Sea is globally recognised as a biodiversity hotspot, where light-exposed rocky reefs are typically dominated by photophilous algae. However, high local anthropogenic pressures, coupled with climate change, are leading to the reorganisation of benthic communities and the occurrence of regime shifts in several areas. Here we report the first description of unusual, shallow-water sponge grounds in Mediterranean light-exposed rocky reefs, in an area previously impacted by the destructive date-mussel fishery. These assemblages, found along the Apulian coast (central Mediterranean Sea), are now (2017) characterised by a mean coverage of sponges ranging between 3% and 33%, with maximum values up to 85%. Variation in the structure of assemblages and in the abundance of individual taxa between depths has been tested by multivariate and univariate techniques. The spatial characterisation has been complemented with the taxonomic analysis of the sponge assemblages, which resulted in the identification of 14 sponge taxa. These findings are compared with results of previous research in the same area and discussed with particular reference to the potential variables involved in sponge dominance and spatial distribution in the present system and elsewhere.
Changes in morphology and physiology of an East Mediterranean sponge in different habitats
Marine Biology, 2005
found in deep-water sponges in June (97±5 lm). In the shallow habitats, a smaller maximal oocyte diameter was found in the cave, in May (56.5±3 lm). Furthermore, oocyte density in shallow-water sponges was highest in May and decreased in June (with 88.2±9 and 19.3±9 oocytes mm À2 , respectively). At the same time (June), oocyte density of deep-water sponges had just reached its maximum (155±33.7 oocytes mm À2 ). The difference in oocyte size and density between deep-and shallow-water individuals indicates an earlier gamete release in the shallow sponge population. The results suggest that plasticity in skeletal design of this sponge indicates a trade off between spicule production and investment in reproduction.
Journal for Nature Conservation, 2013
Sponges are a dominant component of benthic assemblages in hard substratum environments across the world, but despite the importance of sponges, they are generally poorly represented in most marine monitoring programmes. There is considerable need to develop effective monitoring tools to monitor changes in sponge assemblages. Morphological monitoring has been proposed as a suitable method to monitor sponges and while morphological monitoring has already taken place at Skomer Marine Reserve (MNR), Wales, here we investigate whether species level and morphological level data sets are correlated with respect to temporal variation. Furthermore, we examine the environmental factors that correlate with the patterns of temporal variability. Both species and morphological data sets revealed significant seasonal changes and spatial variation in sponge assemblages; these data sets were highly correlated and explained by a number of environmental factors. We conclude that morphological monitoring of sponge assemblages may represents a cost-effective method for assessing temporal and spatial variation in sponges, where full species level monitoring is not possible, as patterns identified from morphological data were a suitable surrogate of species-level data.
Primmorphs formation dynamics: a screening among Mediterranean sponges
Marine Biology, 2006
We performed a screening on 21 Mediterranean sponge species in order to know from which ones primmorphs can be obtained, with a comparison of their formation among the outputs. Thirteen species produced primmorphs, evidencing a high variability among species concerning the number and size of primmorphs, without evidencing any taxonomical specificity. Additionally, the formation process and trend of growth during 1 month of monitoring were studied from a quantitative point of view. The dynamics of primmorphs formation follow different patterns: slow and quick formation, short and long-time survival and in the case of long-time survival, the fission and fusion models are proposed. Besides these patterns, each analysed species showed characteristic trends in the time required for the aggregation of cells, the time required for the production of small primmorphs, growth fluctuation and the acquirement of a final stable size.
Morphological Monitoring of Subtidal Sponge Assemblages
… Ecology Progress Series, 2006
The management of the marine environment requires effective temporal monitoring of communities and assemblages to detect any change above the level of natural variability. Even though sponges are usually abundant in subtidal hard substratum environments and have the ability to significantly influence other community members, they have often been excluded from monitoring programmes because they are taxonomically difficult and often hard to quantify compared to other marine groups. We consider the use of a morphological method to examine photoquadrat data collected at 3 hard substratum sites over a 10 yr period at Skomer Marine Nature Reserve, southwest Wales. Differences in the morphological assemblages and abundance were apparent between years, but the sponge assemblages showed rapid recovery (within 1 yr) to their original assemblage composition and abundance following declines. The changes were attributed to natural biological variation or a short-term impact, rather than any response to prolonged environmental change and there was no correlation between any of the changes in assemblages observed and the environmental variables measured. A comparison of morphological and species data enabled the same sponge assemblages to be identified at different sites, validating the method. This morphological approach to monitoring represents a cost-effective and realistic way of monitoring certain sponge assemblages.
Journal of the Marine Biological Association of the United Kingdom, 2019
Climate change and heavy anthropic pressures are giving rise to important modifications in the rocky benthic communities of the Mediterranean Sea. In particular, sponge assemblages have been deeply affected due to the susceptibility of some species to dramatic phenomena such as mass mortalities or widespread variations in the abundance of other species. For this reason, long-term biodiversity monitoring of the sponge assemblages is important for understanding the direction of changes over time. We studied the sponge fauna living off Tricase Porto (Otranto Strait) and compared its composition with the results of a study conducted in the same area 50 years ago. The comparison indicated that the sponge diversity of this area has strongly increased in the last 50 years and a large number of the sponges recorded in the old survey are still present in the recent community. This evidence matches with other results obtained from different localities of the Mediterranean Sea indicating an in...
Hidden diversity in sympatric sponges: adjusting life-history dynamics to share substrate
Marine Ecology Progress Series, 2008
Marine biodiversity is difficult to assess accurately in part because of the existence of sibling species, which are difficult to discern. This is particularly tricky when sibling species live in sympatry. We investigated biological and ecological traits in 2 sympatric sibling sponge species inhabiting the shallow northwestern Mediterranean: Scopalina lophyropoda Schmidt, 1862 and S. blanensis Blanquer & Uriz, 2008. Growth, fissions, fusions, and survival were monitored twice monthly for 2 yr. S. lophyropoda slightly increased in area over the 2 yr period, whereas S. blanensis did not show effective growth, since gains in autumn to winter were offset by losses in spring to summer. Survival was significantly different in both species. By the end of the study (24 mo), 74% of the individuals of S. lophyropoda and 34% of S. blanensis survived. All individuals of S. lophyropoda and all but 5 of S. blanensis underwent fissions or fusions at least once during the study. The frequencies of multiple fissions and fusions were higher in S. blanensis than in S. lophyropoda. These 2 sympatric sibling species share common traits such as a high dynamism (higher than any other previously studied encrusting sponge species) and intra-species variability in growth. However, they showed contrasting ecological strategies (conservative in S. lophyropoda vs. opportunistic in S. blanensis), which favours species coexistence. This example shows for the first time how seasonality promotes the coexistence of sibling sponge species in the Mediterranean, and may represent an important step towards understanding species coexistence mechanisms.
Marine Ecology Progress Series, 2008
The growth dynamics and survival of the sponge Corticium candelabrum (Demospongiae: Homosclerophorida) were surveyed in the northwestern Mediterranean for more than 3 yr. Growth and regeneration rates, fission and fusion events and survival were monitored monthly. Moreover, in situ punctual clearance experiments were conducted seasonally searching for possible relationships between food uptake and sponge dynamics. The monthly growth rates (GR) of C. candelabrum were low (0.19 ± 0.02 mean [± SE] for the 3 yr of study), variable and seasonal, with the highest values in summer. The cumulative survival function followed a stepped profile with several consecutive months without mortality separated by shorter mortality events, which mainly occurred in cold months (winter-spring). However, an event of high mortality (76% of the monitored individuals died) took place in the particularly warm summer 2003. Fission events were frequent after previous damage (e.g. partial predation) and only one fusion event was recorded along the study period. The diet of C. candelabrum was highly heterogeneous. Differences in clearance rates (CR) among picoplankton types with season indicated that the sponge retained with different efficiency the several picoplankton types present in the water. Survival and GRs were significantly different for small, medium and large individuals (size-classes I, II and III), with the small sponges showing the lowest survival (56.6% cumulative mortality for the last 2 yr of study) and the highest GRs (0.18 ± 0.03 mo-1 , mean ± SE). On the whole, the results indicate that C. candelabrum is a slow-growing but dynamic sponge.