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1.
Sci Total Environ ; 750: 142254, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33182216

RESUMO

The Arabian Gulf is a natural laboratory for examining the consequences of large-scale disturbances due to global warming on coral reef ecosystems because of its extreme temperature regime. Using a coral reef monitoring time series extending from 1985 to 2015, we examined the long-term ecological changes in fish and macro-invertebrate communities as these habitats suffered heat shocks. We used a GLMM modelling framework to obtain clean annual signals in community indicators from noisy data. We also visualized temporal change in the taxonomic composition of fishes and macro-invertebrates. A phase shift from predominantly reef-building corals to barren grounds occurred between 1996 and 2000. Macro-invertebrates responded rapidly, and most of associated indicators recovered to pre-shift levels in 15 years. Fishes generally had lagged responses to the phase shift and had shifted to a new state with lower abundance, as well as different species composition. Increased levels of herbivory first by macro-invertebrates, mostly sea urchins, and then fishes, could have suppressed macro-algae expansion and consequently led to the dominance of barren ground. When the phase shift occurred, most of the 14 fish families declined in abundance while macro-invertebrate groups increased. Fish families able to utilize non-coral habitats appeared more resilient to the disturbances and subsequent coral degradation. Unlike other regions, we observed high resilience of the coral-dependent butterflyfishes to coral loss, possibly due to local migration from other less-impacted coral reefs. We hypothesized a top-down control mechanism mediated by predation by fishes has contributed to shaping the temporal and spatial patterns of the macro-invertebrates. Our results also revealed differences in spatial preferences among fishes and macro-invertebrate groups, which could be used to set priorities and develop effective conservation and management strategies.


Assuntos
Antozoários , Recifes de Corais , Animais , Ecossistema , Peixes , Invertebrados
2.
Sci Total Environ ; 751: 141628, 2021 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-32896805

RESUMO

In coral reefs, dissolved organic matter (DOM) cycling is a critical process for sustaining ecosystem functioning. However, global and local stressors have caused persistent shifts from coral- to algae-dominated benthic communities. The influence of such phase shifts on DOM nature and its utilization by heterotrophic bacterioplankton remains poorly studied. Every second month for one year, we retrieved seawater samples enriched in DOM produced by coral- and algae-dominated benthic communities in a central Red Sea reef during a full annual cycle. Seawater incubations were conducted in the laboratory under in situ temperature and light conditions by inoculating enriched DOM samples with bacterial assemblages collected in the surrounding waters. Dissolved organic carbon (DOC) concentrations were higher in the warmer months (May-September) in both communities, resulting in higher specific growth rates and bacterial growth efficiencies (BGE). However, these high summer values were significantly enhanced in algal-DOM relative to coral-DOM, suggesting the potential for bacterioplankton biomass increase in reefs with algae replacing healthy coral cover under warmer conditions. The potential exacerbation of heterotrophic bacterial activity in the ongoing widespread regime shift from coral- to algae-dominated communities may have detrimental consequences for the overall health of tropical coral reefs.


Assuntos
Antozoários , Animais , Recifes de Corais , Ecossistema , Processos Heterotróficos , Oceano Índico
3.
Sci Total Environ ; 752: 141866, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32889282

RESUMO

Inshore coral habitats are at high risk of loss due to a combination of climate warming and regional-scale human impacts. As a result, they have undergone significant declines. Direct evidence of acute and chronic disturbance on most inshore coral assemblages is limited. Long-term, periodical surveys and historical baseline data essential for effective management are lacking. Using high-precision uranium-thorium (UTh) dating, we reconstruct a ~100-year-long history of extensive coral loss, changes in coral community structure, and a shifting baseline. The data were collected at Weizhou Island, northern South China Sea (SCS), which has highly disturbed inshore coral habitats that are typical globally. According to our UTh dates, major coral mortalities around Weizhou Island have occurred since the 1950s, with increasing frequency and severity since the 1980s. The extensive loss of branching Acropora and collapse of coral communities with peaks around 1960, 1984, and 1998 are accompanied by a shift toward low coral cover and noncoral-dominated assemblages. Prior to this collapse, the local coral community structure sustained remarkable long-term stability over millennia. The timing of the Acropora loss and massive coral mortalities coincides with multiple acute and chronic, natural and anthropogenic disturbance events. We suggest that priority should be given to directly addressing the causes of degradation and effectively controlling chronic disturbances before attempting to restore reef ecosystems. This is probably the only way to solve the "wicked problem" of sustaining the key functions and ecosystem services of inshore coral habitats such as those of Weizhou Island, northern SCS.


Assuntos
Antozoários , Urânio , Animais , China , Recifes de Corais , Ecossistema , Monitoramento Ambiental , Humanos , Ilhas , Tório
4.
Mar Pollut Bull ; 160: 111643, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33181926

RESUMO

The present study was carried out at 22 stations located on the fringing reefs of the island of Mayotte inside the perimeter of the Marine Natural Park of Mayotte (PNMM). The average assessment of the number of samples of marine litter (ML) collected at these stations was 3.9 ± 1.3 ML per 500 m2 in winter and 3.8 ± 1.1 ML per 500 m2 in summer. Plastic ML was dominant, representing approximately 92% of the litter collected at the stations for the two seasons. The majority was plastic ML from fishing gear (lines, nets etc.). Station 18 presented remarkable average densities of 39 ± 4.2 ML per 500 m2 for the two seasons and differed from the other stations in that the ML came solely from the catchment areas, with a majority of aluminium ML (56%). Approximately half the coral colonies coming into contact with ML presented an impact dominated by the category of "Broken or abraded colonies", with 25% of the colonies being impacted. The colonies most severely impacted by ML were branch or table corals, with the greatest majority for the present study being of the genus Acropora.


Assuntos
Antozoários , Animais , Comores , Recifes de Corais , França , Oceano Índico , Ilhas
5.
Mar Pollut Bull ; 160: 111674, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33181947

RESUMO

This study compares the occurrence and characteristics of microplastics (MPs) and heavy metal contaminants in the water and sediment of three habitats (corals, seagrass-beds and near-shores) of Rameswaram Island, India. The overall mean concentration of MPs varies from 24 ± 9 to 96 ± 57 items/L in water, and from 55 ± 21 to 259 ± 88 items/kg in sediment. The value of abundance is the greatest in the coral reef site CR-1 (96 ± 51 items/L; 259 ± 88 items/kg) followed by the seagrass site SG-2 (94 ± 55 items/L; 203 ± 75 items/kg) and the near-shore site St-15 (95 ± 63 items/L; 193 ± 75 items/kg). PE fiber (<1000 µm) is predominant in water, whereas PP fiber and fragment (between 2000 and 5000 µm) dominate the sediment. The SEM images of MPs reveal features which are characteristic of degradation like surface roughness, cracks, protrusions, and chalking, along with surface precipitates of both chemical and biological origin. EDAX images show the presence of Cr, Fe, Hg, Pb, Cu, As and Cd associated with MP surfaces.


Assuntos
Recifes de Corais , Poluentes Químicos da Água , Animais , Ecossistema , Monitoramento Ambiental , Índia , Ilhas , Microplásticos , Plásticos , Poaceae , Poluentes Químicos da Água/análise
6.
Dis Aquat Organ ; 142: 63-73, 2020 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-33210613

RESUMO

Echinoderms such as sea urchins are important in marine ecosystems, particularly as grazers, and unhealthy sea urchins can have important ecological implications. For instance, unexplained mortalities of Diadema antillarum in the Caribbean were followed by algal overgrowth and subsequent collapse of coral reef ecosystems. Unfortunately, few tools exist to evaluate echinoderm health, making management of mortalities or other health issues problematic. Hematology is often used to assess health in many animal groups, including invertebrates, but is seldom applied to echinoderms. We used a standard gravitometric technique to concentrate fixed coelomocytes from the collector sea urchin Tripneustes gratilla onto microscope slides, permitting staining and enumeration. Using Romanowsky stain and electron microscopy to visualize cell details, we found that urchin cells could be partitioned into different morphotypes. Specifically, we enumerated phagocytes, phagocytes with perinuclear cytoplasmic dots, vibratile cells, colorless spherule cells, red spherule cells, and red spherule cells with pink granules. We also saw cell-in-cell interactions characterized by phagocytes apparently phagocytizing mainly the motile cells including red spherule cells, colorless spherule cells, and vibratile cells disproportionate to underlying populations of circulating cells. Cell-in-cell interactions were seen in 71% of sea urchins, but comprised <1% of circulating cells. Finally, about 40% of sea urchins had circulating phagocytes that were apparently phagocytizing spicules. The coelomic fluid collection and slide preparation methods described here are simple, field portable, and might be a useful complementary tool for assessing health of other marine invertebrates, revealing heretofore unknown physiological phenomena in this animal group.


Assuntos
Ecossistema , Ouriços-do-Mar , Animais , Região do Caribe , Comunicação Celular , Recifes de Corais
7.
PLoS One ; 15(10): e0225676, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33027270

RESUMO

Local flow dynamics play a central role in physiological processes like respiration and nutrient uptake in coral reefs. Despite the importance of corals as hosts to a quarter of all marine life, and the pervasive threats facing corals, characterizing the hydrodynamics between the branches of scleractinian corals has remained a significant challenge. Here, we investigate the effects of colony branch density and surface structure on the local flow field using three-dimensional immersed boundary, large-eddy simulations for four different colony geometries under unidirectional oncoming flow conditions. The first two colonies were from the Pocillopora genus, one with a densely branched geometry, and one with a comparatively loosely branched geometry. The second pair of geometries were derived from a scan of a single Montipora capitata colony, one with the roughness elements called verrucae covering the surface intact, and one with the verrucae removed. For the Pocillopora corals, we found that the mean velocity profiles changed substantially in the center of the dense colony, becoming significantly reduced at middle heights where flow penetration was poor, while the mean velocity profiles in the loosely branched colony remained similar in character from the front to the back of the colony. For the Montipora corals, somewhat counterintuitively, the colony without verrucae produced almost double the maximum Reynolds stress magnitude above the colony compared to the colony without verrucae. This implies that the smooth colony will have enhanced mass transport and higher bed shear stress and friction velocity values relative to the colony with verrucae.


Assuntos
Antozoários/fisiologia , Processamento de Imagem Assistida por Computador/métodos , Animais , Recifes de Corais , Hidrodinâmica , Propriedades de Superfície , Tomografia Computadorizada por Raios X
8.
Mar Environ Res ; 162: 105134, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33032079

RESUMO

Multi-use marine protected areas (MPAs) are increasingly designated towards achieving global conservation targets. To develop effective management, the impact of permitted activities must be understood. Potting for shellfish occurs on temperate rocky reefs globally with impact not fully quantified. This UK-based study used underwater video to quantify (a) benthic condition of rocky reefs, (b) mechanisms of potting interaction and (c) true footprint of potting. Assemblages in static gear areas were more indicative of a healthy reef than those in mixed gear areas. Damage was recorded during pot hauling, but the area of damage was not the entire pot haul path. 25-30% of individuals were damaged (commonly through tissue abrasion) or removed. Notably, damage occurred to some long-lived, slow growing taxa raising concerns over impacts. Potting is more destructive than previously thought and managers must balance ecology with social and economic considerations to determine what level of impact is acceptable.


Assuntos
Conservação dos Recursos Naturais , Ecossistema , Animais , Recifes de Corais , Crustáceos , Ecologia , Peixes , Humanos , Alimentos Marinhos
9.
Mar Environ Res ; 162: 105164, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33099079

RESUMO

Outbreaks of the coral-eating crown-of-thorns starfish Acanthaster spp. (COTS) have become to be amongst the most severe threats to coral reefs worldwide. Although most research has focused on COTS early development, it remains unclear how COTS populations will keep pace with changing ocean conditions. Since reproduction is a key process contributing to outbreaks, we investigated the reproductive success of adult COTS acclimated for 3-4 months to different treatment combinations of ambient conditions, ocean warming (+2 °C) and acidification (-0.35 pH). Our results suggest that the optimal breeding season in New Caledonia is concentrated around the end of the calendar year, when water temperature reaches >26 °C. We found negative effects of temperature on egg metrics, fertilisation success, and GSI, conflicting with previously documented effects of temperature on echinoderm reproductive outputs. Fertilisation success dropped drastically (more than threefold) with elevated temperature during the late breeding season. In contrast, we detected no effects of near-future acidification conditions on fertilisation success nor GSI. This is the first time that COTS reproduction is compared among individuals acclimated to different conditions of warming and acidification. Our results highlight the importance of accounting for adult exposure to better understand how COTS reproduction may be impacted in the face of global change.


Assuntos
Antozoários , Animais , Recifes de Corais , Humanos , Concentração de Íons de Hidrogênio , Nova Caledônia , Oceanos e Mares , Estrelas-do-Mar , Temperatura
10.
Zootaxa ; 4858(4): zootaxa.4858.4.2, 2020 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-33056211

RESUMO

Manaxius paullus, a new species of axiid burrowing shrimp, is described on the basis of a female holotype from the Society Islands, French Polynesia, and a female paratype from the Ryukyu Islands, Japan. Both specimens were collected on shallow coral reefs. The new species is morphologically closest to five of 17 congeners, viz., M. euophthalmus (de Man, 1905), M. izuensis (Komai, 2011), M. mimasensis (Sakai, 1967), M. poupini (Komai, 2016) and M. supia Poore, 2020, but can be separated from all of them by the rostrum being relatively broad and with one pair of lateral spines, in addition to a pair of supraocular spines; the presence of a subdistal spine on the dorsal margin of the cheliped ischium; the presence of additional three or four small spines on each cheliped palm, adjacent to the dorsal margin; and the lack of a spine near the base of the fingers of each cheliped palm.


Assuntos
Recifes de Corais , Decápodes , Distribuição Animal , Estruturas Animais , Animais , Tamanho Corporal , Feminino , Tamanho do Órgão
11.
Zootaxa ; 4766(1): zootaxa.4766.1.4, 2020 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-33056606

RESUMO

Decapod crustaceans symbiotic with echinoderms (sea stars, brittle stars, feather stars, basket stars, sea cucumbers, and sea urchins) possess remarkable diversification in the Indo-Pacific. In the present study, seven species of decapod crustaceans symbiotic with crinoids are recorded based on collections from selected Islands (Agatti, Amini, Bangaram, Kavaratti, Kalpeni, and Minicoy) of Lakshadweep Archipelago. Of these decapods, five caridean shrimps (Alpheidae: Synalpheus carinatus (de Man, 1888), S. comatularum (Haswell, 1882), S. stimpsonii (de Man, 1888); Palaemonidae: Palaemonella pottsi (Borradaile, 1915), Pontoniopsis comanthi (Borradaile, 1915), one brachyuran crab [Pilumnidae: Permanotus purpureus (Gordon, 1934)] and one squat lobster [Galatheidae: Allogalathea elegans (Adams White, 1848)] were identified. The caridean shrimps have associated with the crinoids Comaster multifidus (Müller, 1841), Phanogenia gracilis (Hartlaub, 1893), P. distincta (Carpenter, 1888), P. multibrachiata (Carpenter, 1888) and Stephanometra indica (Smith, 1876). The brachyuran crab was observed in association with the crinoid Phanogenia gracilis whereas the squat lobsters were associated with Stephanometra tenuipinna (Hartlaub, 1890) and S. indica. Except S. stimpsonii and P. purpureus, all other species were recorded for the first time from India. Here, we provide details on morphology, distribution, habitat, and hosts for all species. We recommend further exploration of the sub-shallow coral reef areas of Lakshadweep as there will be many species that certainly remain to be discovered.


Assuntos
Decápodes , Animais , Recifes de Corais , Oceano Índico
12.
Mar Environ Res ; 161: 105053, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32871461

RESUMO

Environmental impacts from wave energy generators on the local mobile mega- and macrofauna community have been investigated in the Lysekil project by Uppsala University. Offshore renewable energy installations provide hard, artificial substrates, and as such, they could act as artificial reefs. Foundations with manufactured holes served as complex habitats and foundations without served as non-complex. In this long-term study, SCUBA surveys of mobile fauna in the years 2007, 2008 and 2016-2019 were analyzed. The results show a distinct reef effect on the foundations with significant greater species richness, total number of individuals, greater values of the Shannon-Wiener biodiversity index, and greater abundance of specific reef fauna. Complex foundations accommodated a greater abundance of brown crabs than non-complex foundations, other taxa did not show differences between the two foundation types. A successional increase of species richness, numbers of individuals and Shannon-Wiener biodiversity could be revealed from the first to the second survey period. Inter-annual variation was visible throughout all taxa and years.


Assuntos
Biodiversidade , Braquiúros , Animais , Recifes de Corais , Ecossistema , Peixes , Energia Renovável
13.
Mar Environ Res ; 161: 105119, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32877877

RESUMO

Tidal algal reefs are considered high biodiversity habitats but have received little attention. Macrobenthos communities were characterized in a gradient of habitat types on the tidal flats in northwestern Taiwan, including algal reefs (R), mixed algal reefs and gravel (RG), mixed sand and gravel (SG) and sand (S). Both hydrodynamic movement and surface rugosity were highest in R, followed by RG, SG, and S. The faster the movement and the higher the rugosity were, the higher the density and taxon richness of the macrobenthos community. The relatively slower movement and accumulated sand in S likely resulted in stress on organisms, which led to a lower density and taxon richness of the macrobenthos community. Our results suggest that the main factors structuring the macrobenthos community in the diverse habitat types were hydrodynamic movement and surface rugosity.


Assuntos
Ecossistema , Invertebrados , Animais , Biodiversidade , Recifes de Corais
14.
Mar Environ Res ; 161: 105095, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32882590

RESUMO

Habitat mapping is essential for the management and conservation of coastal marine habitats. However, accurate and up-to-date habitat maps are rarely available for the marine realm. In this study, we mapped the coastal marine habitats of >400 km of coastline in the north-western United Arab Emirates (UAE) using a combination of data sources including remote sensing, extensive ground-truthing points, local expert knowledge and existing information. We delineated 17 habitats, including critical habitats for marine biodiversity such as coral reefs and mangroves, and previously unreported oyster beds and deep seagrasses. This innovative approach was able to produce a coastal marine habitat map with an overall accuracy of 77%. The approach allowed for the production of a spatial tool well-suited for the needs of environmental management and conservation in a previously data-deficient area of the United Arab Emirates.


Assuntos
Conservação dos Recursos Naturais , Ecossistema , Biodiversidade , Recifes de Corais , Emirados Árabes Unidos
15.
Mar Environ Res ; 161: 105127, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32889445

RESUMO

As foundation species, kelp support productive and species rich communities; however, the effects of kelp structure on mobile species within these complex natural systems are often difficult to assess. We used artificial reefs with transplanted kelp to quantify the influence of kelp patch size and density on fish assemblages including the arrival of recruiting cryptobenthic species. Large patches with dense kelp supported the highest abundance, species richness, and diversity of fishes, with the addition of dense kelp tripling biomass and doubling richness. The abundance of recruits in artificial collectors declined with patch size and was halved on reefs with sparse kelp compared to reefs with dense kelp or no kelp. These results highlight the importance of dense kelp cover in facilitating biodiversity and indicate that kelp addition could support the recovery of degraded coastal ecosystems. Kelp also apparently drives complex interactions affecting the recruitment/behaviour of some cryptobenthic species.


Assuntos
Kelp , Animais , Biodiversidade , Biomassa , Recifes de Corais , Ecossistema , Peixes
16.
Mar Environ Res ; 161: 105118, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32890984

RESUMO

Rivers release freshwater, nutrients and pollutants into reefs. This type of environmental stress reduces coral larvae settlement and alter its energy metabolism. We investigated the tolerance of Favia gravida (Scleractinia) larvae to river discharges. We exposed larvae to (i) different salinities (25, 30, 35 and 40 PSU); and (ii) dilutions of river water containing nutrients and metals (0, 20, 40, 60, 80 and 100% river water) under control salinity of 35 PSU. We then examined settlement and larval enzymatic activity. No differences in settlement were detected among salinities. Settlement was also similar to control for larvae under 100% river water. Enzymatic activity for citrate synthase remained unaltered for all treatments. Lactate dehydrogenase activity was slightly altered under different salinities, suggesting a mild stress response. Findings suggest that F. gravida larvae are tolerant to a wide range of salinity and nutrient conditions and that this is a stress-tolerant species.


Assuntos
Antozoários , Animais , Recifes de Corais , Larva , Nutrientes , Rios , Salinidade
17.
Mar Environ Res ; 161: 105129, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32911251

RESUMO

Ghost fishing is a threat to many marine environments, as lost or discarded fishing gear (e.g., fishing lines, nets) continues to fish by entangling, damaging or killing various organisms. Among the benthic organisms that live on tropical reefs, the group probably most affected, due to their shape, are the branching corals. These corals provide refuge, foraging and breeding sites, especially for fishes and therefore impacts on coral structure could compromise the ecology of associated species. We tested if fishing lines entangled on the branching coral Millepora alcicornis would result in an increase in colony mortality, decrease in abundance and richness of fishes and changes in the behavior of associated reef fish. In the field, we estimated the volume of M. alcicornis colonies and its mortality percentages, and videos were recorded to evaluate abundance and richness of fish assemblages and fish behavior. Our results showed that coral mortality increased with increasing amounts of entangled fishing lines. Fish assemblages were similar in M. alcicornis colonies with or without entangled fishing lines. Nevertheless, we observed a significant decrease in the frequency of feeding attempts in two herbivore fish species (Acanthurus bahianus and Ophioblennius trinitatis) that play an important role in coral-reef dynamics, controlling algae abundances. Therefore, ghost fishing has negative impacts on shallow reef ecosystems, directly affecting branching corals and important coral-fish interactions. Management of tropical shallow reef environments should consider regulation and monitoring of coastal fisheries to ensure reef integrity.


Assuntos
Antozoários , Ecossistema , Animais , Recifes de Corais , Pesqueiros , Peixes , Herbivoria
18.
Mar Pollut Bull ; 160: 111567, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32891963

RESUMO

Here, we examined the coral bleaching responses during the 2016 thermal stress event and post-bleaching changes in coral communities in the heavily disturbed reefs of the Bolinao-Anda Reef Complex (BARC), northwestern Philippines. Less than 25% of colonies bleached, with 77% attributed to five genera (Dipsastrea, Porites, Fungia, Seriatopora, and Montipora). Coral bleaching prevalence was associated with site location, coral composition, and coral abundance, suggesting that small-scale variation (<20 km) in coral communities (taxa and density) influences spatial variation in coral bleaching prevalence. There was no noticeable change in coral composition and cover two years after the bleaching event as exposure to chronic disturbance likely selected for the dominance of stress tolerant coral taxa and communities. Results show that the 2016 thermal stress event caused coral bleaching but with low prevalence at the BARC, which suggests that disturbed reefs may provide spatial refuge to coral communities from thermal stress.


Assuntos
Antozoários , Animais , Recifes de Corais , Filipinas , Prevalência
19.
Mar Pollut Bull ; 160: 111607, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32898740

RESUMO

The present work was undertaken to assess the impact of trace element concentration and the status of potential ecological risk in the reef sediments of the Vembar group of islands, Gulf of Mannar Marine National Park, India. Totally, 114 reef sediments (surface) were collected from the Vembar group of islands (Nallathanni Island - 36 samples; Upputhanni Island - 48 samples; Puluvinichalli Island-30 samples). The reef sediments are enriched with sand-sized calcareous particles. The calcium carbonate percentage (CaCO3) was primarily controlled by the distribution of coral colonies and available lithogenic grains. The pollution load index (PLI) reveals that the majority of the sediments fall under the unpolluted category. Moreover, the potential ecological risk (PERI) and sediment pollution index (SPI) reveals that the Vembar group of islands fall under the low ecological risk category.


Assuntos
Antozoários , Metais Pesados , Oligoelementos , Poluentes Químicos da Água , Animais , Recifes de Corais , Monitoramento Ambiental , Sedimentos Geológicos , Índia , Ilhas , Metais Pesados/análise , Oligoelementos/análise , Poluentes Químicos da Água/análise
20.
Mar Pollut Bull ; 160: 111585, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32911112

RESUMO

We investigated possible synergic effects on coral reefs of the local land reclamation activities in the Himmafushi Island (North Malè atoll, Maldives) and the global bleaching event that affected the Maldives in 2016. A BACI (Before-After Control-Impact) sampling design was adopted to contrast effects of dredging activities before and after the occurrence of both dredging and bleaching. The Reef Check protocol, a standardised and worldwide survey method, was applied to collect data through underwater visual surveys on corals, macro-zoobenthos, and fish communities. The bleaching in 2016 hit all the reefs investigated, but only in the reefs around Himmafushi (i.e., the impact sites) the live hard coral reduced significantly its cover and the sand deposited on reefs showed a fourfold increase. Substrate indicators (i.e., coral community and abiotic components) turned out to be more effective than macro-zoobenthos and fish in this short-term environmental impact study.


Assuntos
Antozoários , Fungicidas Industriais , Animais , Recifes de Corais , Peixes , Ilhas do Oceano Índico
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