Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 12.813
Filtrar
1.
Chemosphere ; 262: 128374, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182088

RESUMO

Lipophilic marine algal toxins (LMATs) are highly toxic secondary metabolites produced by marine microalgae that pose a great threat to marine aquaculture organisms and human health. In this study, a novel and automated method for the simultaneous determination of six groups of LMATs in seawater was developed by on-line solid phase extraction (SPE) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Condition optimization and method validation were performed, and the recoveries of all 14 target LMATs featuring different properties ranged from 83.5% to 96.0%. The limits of detection of most target compounds were within ≤3.000 ng/L with good precision (relative standard deviation ≤ 12.1%) and linearity (R2≥0.9916). Compared with off-line SPE methods, the proposed on-line SPE method has better recovery, sensitivity, repeatability, and throughput; in addition, the volume of seawater sample necessary to conduct determinations is greatly reduced in the present method. Finally, the method was applied to determine LMATs in actual seawater samples collected from the Bohai and South Yellow Seas of China in summer, and okadaic acid and pectenotoxin-2 were detected in all seawater samples. The highest concentration of ∑LMATs (22.23 ng/L) occurred in the coastal mariculture area of Shandong Province. Therefore, routine monitoring of LMATs in seawater of the coastal mariculture zone is necessary to prevent shellfish contamination especially in summer, and the proposed on-line SPE-LC-MS/MS method is a powerful way for direct and automatic detection of various LMATs in coastal mariculture area.


Assuntos
Monitoramento Ambiental/métodos , Toxinas Marinhas/análise , Água do Mar/química , Aquicultura , China , Cromatografia Líquida/métodos , Furanos , Humanos , Oceanos e Mares , Ácido Okadáico/análise , Piranos , Frutos do Mar/análise , Extração em Fase Sólida/métodos , Espectrometria de Massas em Tandem/métodos
2.
Sci Total Environ ; 750: 142252, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33182220

RESUMO

The biogeography of active microbial communities and the underlying mechanisms in marine sediments are important in microbial ecology but remain unclear. Here, using qPCR and high-throughput sequencing, we investigated bacterial and archaeal community abundances and activities by quantifying the abundance and expression of the 16S rRNA gene respectively, RNA-derived bacterial and archaeal community biogeography, assembly mechanisms and co-occurrence relationships in surface sediment samples from the Bohai Sea (BS), South Yellow Sea (SYS) and the north East China Sea (NECS) of the eastern Chinese marginal seas. The results revealed a higher heterogeneity of bacterial and archaeal community activities than of abundances and heterogeneous ecological functions among areas reflected by community compositions. Furthermore, clear geographic groups (i.e., the BS, SYS and NECS groups) were observed for all, abundant and rare active bacterial and archaeal communities, accompanied by significant distance-decay patterns. However, the abundant and rare taxa showed inconsistent geographic patterns. More importantly, deterministic processes played a greater role than stochastic processes in active bacterial and archaeal community assembly. The rare taxa had weaker abilities to disperse and/or adapt and more complex ecological processes than the abundant taxa. In addition, this study also showed that intertaxa competition was the dominant interaction between active bacterial and archaeal members, which could greatly contribute to dispersal limitation. Moreover, active bacterial and archaeal co-occurrence patterns showed significant distance-decay patterns, which were consistent with the community compositions.


Assuntos
Archaea , Bactérias , Archaea/genética , Bactérias/genética , China , Sedimentos Geológicos , Oceanos e Mares , Filogenia , RNA Ribossômico 16S/genética
3.
Mar Pollut Bull ; 160: 111620, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33181919

RESUMO

Marine ecosystem pollution with microplastics (MPs) is a global problem. The current study aimed to assess the occurrence of MPs in the sediments of the Caspian Sea southern coasts. For sampling, two distinct areas were selected including recreational-tourism areas (No = 24), and non-tourist areas (No = 24). MPs were studied in 5 and 5-15 cm from the top sediment surface. All 96 samples were taken and analyzed according to the methodology provided by the US national oceanic and atmospheric administration (NOAA). The combination of observational techniques, FTIR, and SEM analysis was applied to identify MPs. MPs were classified into two categories in terms of size: small MPs and large MPs. The average, maximum, and minimum abundance of MPs (based on dry weight) in sediments of the southern coast of the Caspian Sea was 183.5 ± 154.4 MP/kg, 542 MP/kg, and 13 MP/kg, respectively. On the basis of morphology, fragment-shaped (30.3%) MPs showed the highest prevalence, while film-shaped (18.7%) MPs were the least contributory. Polyethylene (PE) and polyethylene terephthalate (PET), each of them with a 20% share, were the most common MPs found in the studied samples. The distribution of MPs on the southern coasts of the Caspian Sea revealed a sporadic and irregular spatial pattern. Correspondingly, it can be concluded that probably environmental factors (the current of the sea surface water from west to east), enclosed environment of the Caspian Sea, anthropogenic activities (e.g., industrialization and urbanization, improper waste management, fishing, and tourism activity, residential wastewater), and also discharging of rivers (which can carry plastics) into the sea, have all influenced the abundance and polymer diversity of MPs in the sediments of the southern coast of the sea. More attention should be paid to the health and environmental effects of MPs and to the protection of this sensitive marine ecosystem through implementing proper waste management system by all surrounding littoral countries.


Assuntos
Plásticos , Poluentes Químicos da Água , Mar Cáspio , Ecossistema , Monitoramento Ambiental , Sedimentos Geológicos , Microplásticos , Oceanos e Mares , Poluentes Químicos da Água/análise
4.
Mar Pollut Bull ; 160: 111660, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33181937

RESUMO

The article presents the results from a research project investigating acoustic climate changes in the Gdansk Deep based on data extending from 1902 to 2019. This part of the southern Gotland Basin, is rarely discussed in the scientific literature. The speed of sound in the seawater is a function of temperature, salinity, and depth. In such shallow sea as Baltic Sea, the impact of depth is not substantial. The other two factors shape the hydroacoustic conditions. In the upper layer of seawater, the dominating factor is heat exchange at the water-atmosphere interface. The observed climate warming is reflected in the water temperature rise, which results in an increased speed of sound in the upper water layer. After years of sporadic salty inflows from the North Sea, the frequency of the phenomenon has increased since 2014. As a result, the salinity at the bottom exceeds values typical for that area.


Assuntos
Mudança Climática , Água do Mar , Países Bálticos , Mar do Norte , Oceanos e Mares , Som
5.
Mar Pollut Bull ; 160: 111669, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33181943

RESUMO

Legislations and commitments regulate Baltic Sea status assessments and monitoring. These assessments suffer from monitoring gaps that need prioritization. We used three sources of information; scientific articles, project reports and a stakeholder survey to identify gaps in relation to requirements set by the HELCOM's Baltic Sea Action Plan, the Marine Strategy Framework Directive and the Water Framework Directive. The most frequently mentioned gap was that key requirements are not sufficiently monitored in space and time. Biodiversity monitoring was the category containing most gaps. However, whereas more than half of the gaps in reports related to biodiversity, scientific articles pointed out many gaps in the monitoring of pollution and water quality. An important finding was that the three sources differed notably with respect to which gaps were mentioned most often. Thus, conclusions about gap prioritization for management should be drawn after carefully considering the different viewpoints of scientists and stakeholders.


Assuntos
Biodiversidade , Monitoramento Ambiental , Países Bálticos , Oceanos e Mares
6.
Mar Pollut Bull ; 160: 111676, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33181949

RESUMO

Seabirds are used as bioindicators of marine ecosystems, especially for quantifying and tracking pollution sources. The objective of this study was to evaluate the contamination in feathers of young kelp gulls by lead (Pb), chromium (Cr), mercury (Hg) and zinc (Zn) on three islands of southern Brazil. The highest values for Pb (2.1310 µg g-1) and Hg (0.0010 µg g-1) were observed in Lobos. Zn was common in all samples with a median around 41.7487 µg g-1 and Cr values were below the quantification limit (0.0300 µg g-1). The Kruskal-Wallis test indicated significant differences in Pb (H = 21.84; p < 0.05) and Zn (H = 958.80; p < 0.05), but no differences were observed in Cr (H = 3.08; p < 0.05) and Hg (H = 3.0; p < 0.05). This study was important to show the impact of trace element pollutants on the seabird communities and oceans.


Assuntos
Charadriiformes , Kelp , Mercúrio , Oligoelementos , Animais , Brasil , Ecossistema , Monitoramento Ambiental , Plumas/química , Mercúrio/análise , Oceanos e Mares , Oligoelementos/análise
7.
Environ Monit Assess ; 192(11): 686, 2020 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-33029673

RESUMO

The paper describes the hydrography and vertical current structure along the shelf edge of South East Arabian Sea (SEAS) during summer and winter monsoons based on current profiles from moving Acoustic Doppler Current Profiler (ADCP). During summer monsoon, SEAS was characterized by upwelling with low saline water at the surface along the southern sector (8° N to 11° N). During winter, thermal structure was vertically homogeneous in the upper 80 m, and intrusion of low saline Bay of Bengal waters were found up to 14° N. In the southern sector, turbidity was more than the northern sector during winter and summer seasons. ADCP-derived current profiles during summer along 200-m isobath show dominant northward flow in the south, and southeasterly in the north as part of the West India Coastal Current (WICC). A comparison between ADCP current profiles and Ekman currents during summer indicates dominance of remote forcing (coastal Kelvin waves) over the local wind forcing in the 8-9° N sector whereas a combined influence of both remote forcing and wind in the 9-15° N sector. During winter, the direction of surface current reversed and was poleward generally except at the southern sector (7-8° N) where the flow was southwestward. Sector-wise comparison of ADCP and Ekman current showed less influence of wind on current fields throughout the sector except at south; wind has a major role in the current generation, whereas along the 8-15° N sector, the remote forcing dominates over the wind.


Assuntos
Tempestades Ciclônicas , Monitoramento Ambiental , Oceanos e Mares , Estações do Ano , Vento
8.
Zootaxa ; 4793(1): zootaxa.4793.1.1, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-33056690

RESUMO

Numerous specimens belonging to the syllid genus Anguillosyllis Day were collected during several deep-sea studies conducted between 1970 and 2011 in depths ranging from 180 to nearly 5000 m. These quantitative studies demonstrated that members of this genus are not as uncommon as once thought but can be among the 10 most common infaunal species at some deep-sea locations. Study areas included Georges Bank (New England), the North, Mid, and South Atlantic Continental Slope and Rise (east coast of North America), the Gulf of Mexico (off Louisiana), off San Francisco, California, the Clarion-Clipperton Fracture Zone (Pacific Ocean), the South China Sea (off Brunei), the abyssal plain in the South Atlantic Ocean, and Antarctica (Scotia Sea, Weddell Sea). Sixteen new species are described, bringing the total number of described Anguillosyllis species to 20; one additional species that cannot be fully characterized is also noted. The new species include eight with palps that are entirely or partially free (Anguillosyllis aciculata n. sp., A. acsara, n. sp., A. carolina n. sp., A. denaria n. sp., A. hadra, n. sp., A. hampsoni n. sp., A. taleola n. sp., and A. truebloodi n. sp.) and eight species with completely fused palps (A. andeepia n. sp., A. blakei n. sp., A. bruneiensis n. sp., A. elegantissima n. sp., A. enneapoda n. sp., A. hessleri n. sp., A. inornata n. sp., and A. sepula n. sp.). Type specimens of A. palpata (Hartman) from off Cape Horn and A. pupa (Hartman) from off New England were examined; A. capensis Day from South Africa and A. lanai Barroso, Paiva, Nogueira Fukuda from Brazil are discussed. All adult Anguillosyllis have a fixed number of setigers, either 8, 9, 10, or 11, with 11 setigers being the most common. Species differ in the number of setigers, degree of fusion of the palps, degree of development of parapodial lobes, structure and number of internal and external glands, number of setae in anterior setigers, shape and size of proventricle, and annulation of the dorsum. All species for which the anal cirri had not been lost were found to have four, including two long, thin, ventromedial ones and two shorter, usually oval, lateral ones. Reproduction is poorly known in the genus; the present study shows eggs are found in the posterior (post-proventricle) setigers of most species and enter the parapodia from the coelom of several specimens; egg diameters generally ranged from 50-85 µm with A. sepula n. sp. having eggs up to 120 µm, the largest reported for the genus.


Assuntos
Anelídeos , Animais , Oceanos e Mares , Água
9.
Zootaxa ; 4802(2): zootaxa.4802.2.9, 2020 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-33056624

RESUMO

Though research about sea spiders limited in China seas, a complete checklist has not yet exist so far. After checking recent collections obtained from Shandong, Zhejiang, Fujian and the East China Sea, all these sixty-eight specimens were identified as six species belonged to four families and five genera, including three ones new to China. We described and illustrated them in this study, and also revised all previous records about Chinese pycnogonids and provided a checklist for the presently known forty-one species.


Assuntos
Artrópodes , Animais , China , Oceanos e Mares
10.
Mar Environ Res ; 161: 105049, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33070930

RESUMO

Cephalopods represent an important pathway for mercury transfer through food webs. Due to the general difficulties in capturing oceanic squid, beaks found in the diet of top predators can be used to study their life-cycles and ecological role. Using upper beaks of the giant warty squid Moroteuthopsis longimana (major prey in the Southern Ocean), we describe a method to assess mercury concentrations along the life of cephalopods through the segmentary analysis of beak sections (i.e. tip of the rostrum and subsections along the hood). Distinct total mercury concentrations in the different subsections support that beaks can be used to study mercury levels in different periods of cephalopods' life-cycle. Mercury values in the anterior (1.3-7.9 µg kg-1 dw) and posterior (7.8-12.5 µg kg-1 dw) subsections of the hood reflect juvenile and adult stages, respectively. Furthermore, these results confirm that mercury bioaccumulates continuously throughout the individuals' life, with adults doubling their mercury concentrations to juveniles.


Assuntos
Cefalópodes , Mercúrio , Poluentes Químicos da Água , Animais , Bico/química , Decapodiformes , Cadeia Alimentar , Humanos , Mercúrio/análise , Oceanos e Mares , Poluentes Químicos da Água/análise
11.
Nat Commun ; 11(1): 5364, 2020 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-33097697

RESUMO

Over the last ten years, satellite and geographically constrained in situ observations largely focused on the northern hemisphere have suggested that annual phytoplankton biomass cycles cannot be fully understood from environmental properties controlling phytoplankton division rates (e.g., nutrients and light), as they omit the role of ecological and environmental loss processes (e.g., grazing, viruses, sinking). Here, we use multi-year observations from a very large array of robotic drifting floats in the Southern Ocean to determine key factors governing phytoplankton biomass dynamics over the annual cycle. Our analysis reveals seasonal phytoplankton accumulation ('blooming') events occurring during periods of declining modeled division rates, an observation that highlights the importance of loss processes in dictating the evolution of the seasonal cycle in biomass. In the open Southern Ocean, the spring bloom magnitude is found to be greatest in areas with high dissolved iron concentrations, consistent with iron being a well-established primary limiting nutrient in this region. Under ice observations show that biomass starts increasing in early winter, well before sea ice begins to retreat. The average theoretical sensitivity of the Southern Ocean to potential changes in seasonal nutrient and light availability suggests that a 10% change in phytoplankton division rate may be associated with a 50% reduction in mean bloom magnitude and annual primary productivity, assuming simple changes in the seasonal magnitude of phytoplankton division rates. Overall, our results highlight the importance of quantifying and accounting for both division and loss processes when modeling future changes in phytoplankton biomass cycles.


Assuntos
Biomassa , Fitoplâncton/crescimento & desenvolvimento , Estações do Ano , Água do Mar/microbiologia , Biodiversidade , Carbono/análise , Clorofila/análise , Clima , Ecologia , Camada de Gelo , Luz , Biologia Marinha , Meteorologia , Nutrientes , Oceanos e Mares , Dinâmica Populacional , Microbiologia da Água
12.
Water Res ; 185: 116295, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-33086459

RESUMO

The Three Gorges Dam (TGD) is the world's largest hydropower construction. It can significantly impact contaminant transport in the Yangtze River-East China Sea Continuum (YR-ECSC). In addition to evaluating the impact of the TGD on the deposition of contaminants in the reservoir, we also address their cycles in the river below the dam and in the coastal East China Sea. A comprehensive study of metal contaminant transport along the YR-ECSC has not been previously attempted. We quantified the fates of mercury (Hg), arsenic (As), lead (Pb), cadmium (Cd) and chromium (Cr) within the YR-ECSC, and the impacts of the TGD, by sampling water and suspended particles along the Yangtze River during spring, summer, fall, and winter and by modeling. We found that the Yangtze River transports substantial amounts of heavy metals into the coastal ocean. In 2016, riverine transport amounted to 48, 5900, 11,000, 230, and 15,000 megagrams (Mg) for Hg, As, Pb, Cd, and Cr, respectively, while other terrestrial contributions were negligible. Metal flux into the coastal ocean was primarily derived from the downstream portion of the river (84-97%), while metals transported from upstream were largely trapped in the Three Gorges Reservoir (TGR, 72%-96%). For example, 34 Mg of Hg accumulated in the TGR owing to river damming, large-scale soil erosion, and anthropogenic point source releases, while 21 Mg of Hg was depleted from the riverbed downstream owing to the altered river hydrology caused by the TGD. Overall the construction of TGD resulted in a 6.9% net decrease in the Hg burden of the East China Sea, compared to the pre-TGD period.


Assuntos
Monitoramento Ambiental , Metais Pesados , China , Metais Pesados/análise , Oceanos e Mares , Rios
13.
Nat Commun ; 11(1): 5069, 2020 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-33093493

RESUMO

Ongoing climate change is predicted to trigger major shifts in the geographic distribution of marine plankton species. However, it remains unclear whether species will successfully track optimal habitats to new regions, or face extinction. Here we show that one significant zooplankton group, the radiolaria, underwent a severe decline in high latitude species richness presaged by ecologic reorganization during the late Neogene, a time of amplified polar cooling. We find that the majority (71%) of affected species did not relocate to the warmer low latitudes, but went extinct. This indicates that some plankton species cannot track optimal temperatures on a global scale as assumed by ecologic models; instead, assemblages undergo restructuring and extinction once local environmental thresholds are exceeded. This pattern forewarns profound diversity loss of high latitude radiolaria in the near future, which may have cascading effects on the ocean food web and carbon cycle.


Assuntos
Mudança Climática/história , Ecossistema , Rhizaria/fisiologia , Zooplâncton/fisiologia , Aclimatação/fisiologia , Animais , Regiões Antárticas , Biodiversidade , Evolução Biológica , Extinção Biológica , História Antiga , Modelos Biológicos , Oceanos e Mares , Oceano Pacífico , Temperatura
14.
Sci Total Environ ; 748: 142448, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-33113697

RESUMO

In the Southern Ocean, warming and freshening are expected to be prominent signals of climate change and the reduced ability of Antarctic marine organisms to cope with changing environmental conditions could challenge their future survival. The Antarctic limpet Nacella concinna is a macroinvertebrate of rocky ecosystems, which occurs in high densities in the shallow subtidal zone. Subtidal individuals were exposed to a combination of temperatures (1, 4, 8, 11, 14 °C) and salinities (20 and 30 psu) for a 60-day period. A drastic increment in mortality was observed with seawater warming, showing that N. concinna is highly stenothermal, with limited ability to survive at temperatures warmer than 4 °C, although there was some degree of acclimation at 4 °C and ambient salinity (30 psu). This study confirmed the stenohaline characteristic of this species, with mortality reaching 50% and lower scope for growth at low salinity (20 psu) even at the control temperature (1 °C). At the sub-cellular level, limpets' low tolerance to out-of range salinity is illustrated by the activation of cell remodelling processes whereas the down-regulation of chaperones proteins and plasma membrane ATPase suggest that under the combination of warming and freshening N. concinna experiences a severe level of stress and devote much of its energy to somatic maintenance and survival. The drastic effect observed can be explained by its subtidal origin, an environment with more stable conditions. The surviving individuals at 1 °C and lowered salinity (20 psu) were either more tolerant or showing signs of acclimation after 60 days, but the combination of warming and freshening have a greater combined stress. Projections of climate change for end of the century for this part of the Antarctic can, therefore, result in a significant diminution of the subtidal population of N. concinna, affecting ecological interactions and diversity of the food web.


Assuntos
Ecossistema , Gastrópodes , Animais , Regiões Antárticas , Humanos , Oceanos e Mares , Água do Mar , Temperatura , Transcriptoma
15.
PLoS One ; 15(10): e0230763, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33002022

RESUMO

Scalloped Hammerhead shark (Sphyrna lewini) is an endangered species which its populations have been declining globally including in Indonesia, the world's top shark fishing country. However, there is a lack of information on the recent population structure of this species to promote proper management and its conservation status. This study aimed to investigate the genetic diversity, population structure, and connectivity of the S. lewini population, in three major shark landing sites: Aceh (n = 41), Balikpapan (n = 30), and Lombok (n = 29). Meanwhile, additional sequences were retrieved from West Papua (n = 14) and the Western Indian Ocean (n = 65) populations. From the analyses of the mitochondrial CO1 gene, a total of 179 sequences of S. lewini, with an average size of 594 bp, and 40 polymorphic loci in four and eight haplotypes for the Indonesian population and the Western Indian Ocean population were identified. The overall values of genetic diversity were high (h = 0.717; π = 0.013), with the highest values recorded in Aceh (h = 0.668; π = 0.002) and the lowest in Papua (h = 0.143; π = 0.000). On the contrary, the overall value was fairly low in the Western Indian Ocean (h = 0.232; π = 0.001). Furthermore, AMOVA and FST showed three significant subdivisions in Indonesia (FST = 0.442; P < 0.001), with separated populations for Aceh and West Papua, and mixed between Balikpapan and Lombok (FST = 0.044; P = 0.091). In contrast, genetic homogeneity was observed within the population of the Western Indian Ocean (FST = -0.013; P = 0.612). The establishment of a haplotype network provided evidence of a significantly different population and a limited genetic distribution between the Indonesian and the Western Indian Ocean populations (FST = 0.740; P < 0.001). This study showed the presence of a complex population of S. lewini with limited connectivity only in Indonesia separated from the Western Indian Ocean and requiring specific management measures based on the population structure at the regional level.


Assuntos
Espécies em Perigo de Extinção , Tubarões/genética , Animais , DNA Mitocondrial/genética , Complexo IV da Cadeia de Transporte de Elétrons/genética , Genética Populacional , Haplótipos , Oceano Índico , Indonésia , Oceanos e Mares
16.
Mar Environ Res ; 162: 105165, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33068920

RESUMO

Pelagic seabirds exhibit plasticity in foraging characteristics in relation to oceanographic conditions. This should be particularly relevant in tropical marine environments where food resources are naturally more unpredictable. We studied how inter-annual variations (2013-2018) in tropical oceanographic conditions (driver of oceanic productivity) can influence the spatial and trophic ecology of Cape Verde shearwater (Calonectris edwardsii) during the breeding season. During years of poor oceanographic conditions around the colony, birds engaged in longer trips to West Africa, showed higher spatial and behavioural consistency, and presented a wider isotopic niche. Opposite patterns were generally found for years of good oceanographic conditions, when birds foraged more on their colony surroundings. New foraging areas off West Africa were highlighted as relevant, especially during years of poor environmental conditions. This study highlights the need for long-term studies to assess variation in foraging areas and foraging decisions by seabird populations.


Assuntos
Aves , Ecologia , Animais , Estado Nutricional , Oceanos e Mares , Estações do Ano
17.
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
18.
Mar Environ Res ; 162: 105189, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33126113

RESUMO

Munitions introduced to the sea during military activities, including naval combat and mine warfare represent only a fraction of military material present in seas and oceans. Huge amounts of obsolete conventional munitions and chemical munitions were dumped to the sea until 1975, when London convention put a stop of sea dumping. Such munitions are a threat for maritime workers, but also for environment. Corroding shells release toxic degradation products to sediments and bottom water, and unlike other contaminants, they cannot be reduced by land measures. Only removal of source can reduce the contamination. Much work has been done in the last decade, and mechanisms of toxicity and bioaccumulation are being recognized, as well as transport and spreading mechanisms. The full assessment of the risk associated with munitions now depends on broad application of developed techniques.


Assuntos
Poluentes Químicos da Água , Sedimentos Geológicos , Humanos , Oceanos e Mares , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
19.
Mar Environ Res ; 162: 105194, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33126114

RESUMO

Changing oceans represent a serious threat for a wide range of marine organisms, with severe cascading effects on ecosystems and their services. Sea urchins are particularly sensitive to decreased pH expected for the end of the century and their key ecological role in regulating community structure and functioning could be seriously compromised. An integrated approach of laboratory and field experiments has been implemented to investigate the effects of decreased pH on predator-prey interaction involving sea urchins and their predators. Our results suggest that under future Ocean Acidification scenarios adult sea urchins defence strategies, such as spine length, test robustness and oral plate thickness, could be compromised together with their survival chance to natural predators. Sea urchins represent the critical linkage between top-down and bottom-up processes along Mediterranean rocky reefs, and the cumulative impacts of global and local stressors could lead to a decline producing cascading effects on benthic ecosystems.


Assuntos
Ecossistema , Água do Mar , Animais , Peixes , Concentração de Íons de Hidrogênio , Oceanos e Mares , Ouriços-do-Mar
20.
Proc Biol Sci ; 287(1934): 20201506, 2020 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-32900308

RESUMO

The sea urchin embryo develops a calcitic endoskeleton through intracellular formation of amorphous calcium carbonate (ACC). Intracellular precipitation of ACC, requires [Formula: see text] concentrating as well as proton export mechanisms to promote calcification. These processes are of fundamental importance in biological mineralization, but remain largely unexplored. Here, we demonstrate that the calcifying primary mesenchyme cells (PMCs) use Na+/H+-exchange (NHE) mechanisms to control cellular pH homeostasis during maintenance of the skeleton. During skeleton re-calcification, pHi of PMCs is increased accompanied by substantial elevation in intracellular [Formula: see text] mediated by the [Formula: see text] cotransporter Sp_Slc4a10. However, PMCs lower their pHi regulatory capacities associated with a reduction in NHE activity. Live-cell imaging using green fluorescent protein reporter constructs in combination with intravesicular pH measurements demonstrated alkaline and acidic populations of vesicles in PMCs and extensive trafficking of large V-type H+-ATPase (VHA)-rich acidic vesicles in blastocoelar filopodial cells. Pharmacological and gene expression analyses underline a central role of the VHA isoforms Sp_ATP6V0a1, Sp_ATP6V01_1 and Sp_ATPa1-4 for the process of skeleton re-calcification. These results highlight novel pH regulatory strategies in calcifying cells of a marine species with important implications for our understanding of the mineralization process in times of rapid changes in oceanic pH.


Assuntos
Bicarbonatos/metabolismo , Ouriços-do-Mar/fisiologia , Animais , Transporte Biológico , Calcificação Fisiológica , Carbonato de Cálcio , Concentração de Íons de Hidrogênio , Oceanos e Mares , Prótons , Água do Mar
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA