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We examined the effects of crude oil contamination on community assemblages of meiofauna and nematodes after exposure to total petroleum hydrocarbons in the laboratory. We administered a seawater solution that had been contaminated with total petroleum hydrocarbons to seven treatment groups at different concentrations, while the control group received uncontaminated filtered seawater. The average density of total meiofauna in the experimental microcosms diluted with 0.5%, 1%, 2%, and 4% contaminated seawater was higher than the density in the control. The average density of total meiofauna in the 8%, 15%, and 20% microcosms was lower than the density in the control. The density of nematodes was similar to that of the total meiofauna. Cluster analysis divided the microcosms into group 1 (control, 0.5%, 1%, 2%, and 4% microcosms) and group 2 (8%, 15%, and 20% microcosms). However, SIMPROF analysis showed no significant difference between the two groups (p > 0.05). Bolbolaimus spp. (37.1%) were dominant among the nematodes. Cluster analysis showed similar results for nematode and meiofaunal communities. The total meiofaunal density, nematode density, and number of Bolbolaimus spp. individuals were significantly negatively associated with the concentration of total petroleum hydrocarbons (Spearman correlation coefficients, p < 0.05). Within the nematodes, epistrate feeders (group 2A: 46%) were the most abundant trophic group. Among the treatment groups, the abundance of group 2A increased in low-concentration microcosms and decreased in high-concentration microcosms. Thus, our findings provide information on the effects of oil pollution on meiofauna in the intertidal zones of sandy beaches. 相似文献
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Ok Hwan Yu Hyung-Gon Lee Dongsung Kim Jin Hee Wi Kyeong Hong Kim Chan Min Yoo 《Ocean Science Journal》2018,53(2):301-314
Macrofauna in the Clarion-Clipperton Fracture Zone remain poorly understood, due both to gross undersampling and to the fact that most species collected from the area are new to science. Evaluation of the diversity and species distribution of the benthic fauna in this area is critical to predicting and managing the impacts of manganese nodule mining. In this study, we investigated the distribution of macrofauna to understand the natural variability in the macrobenthic community and, by extension, to establish a baseline for environmental risk assessment. Samples were collected from the KR5 block of the Korea Contract Area, within the abyssal area of the Clarion-Clipperton Fracture Zone in the northeastern Pacific Ocean, by the RV Onnuri from 2012–2014. A total of 36 core samples were examined in the survey, from which we identified 183 macrobenthic species in 25 faunal groups with a mean density of 257 ind/m2. Not taking into account meio-faunal groups such as nematodes and harpacticoid copepods, the highest percentage of individuals was represented by Arthropoda. The dominant species (> 1% of total density) were the tanaids Typhlotanais sp.1, and Akanthophoreus spp. and Stenotanais sp., the isopod Macrostylis sp.1, and the polychaetes Cirratulidae spp. and Levinsenia uncinata. The abundances of the two dominant species, the tanaid Typhlotanais sp1. and isopod Macrostylis sp.1., were positively correlated with total organic carbon (TOC). There were no differences in macrofaunal density and community structure between preserved areas (PRA), the potential benthic impacted site (BIS), and other areas near the BIS. In general, higher diversity was associated with homogeneous environmental conditions, with high nodule coverage (> 50%) and TOC. 相似文献
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A new species of free-living marine draconematid nematode, Dracograllus trukensis sp. nov., is described based on the specimens collected from the sediments of a intertidal seagrass bed from Chuuk Islands, Micronesia. Dracograllus trukensis sp. nov. differs from other species of the genus by the combination of the following characteristics: the presence of numerous minute spiny ornamented body cuticular annules in both sexes, eight cephalic adhesion tubes inserted on the head capsule in both sexes, the presence of stiff posteriorly directed setae anterior to posterior adhesion tubes in both sexes, the shape (large, elongated, open loop-shaped in male and large, elongated, closed loop-shaped in female) and position (longer ventral arm extending to the first body annule in male) of amphideal fovea, shorter spicule length (34–42 μm), the presence of sexual dimorphism in shape and length of the non-annulated tail terminus, and number of posterior sublateral adhesion tubes (10 in male and 13–15 in female) and posterior subventral adhesion tubes (8–10 in male and 9–11 in female). A comparative table on the biogeographical and ecological characteristics of the species of Dracograllus is presented. This is the first taxonomic report on the genus Dracograllus from Chuuk Islands, Micronesia, central western Pacific Ocean. 相似文献
4.
During the Dives Nos. 409, 410, 480 and 481 of the Japanese submersible Shinkai 2000, conducted on June 10 and 11, 1989 and on May 16 and 17, 1990, several hydrothermal vents and prosperous vent associated
biological communities were found on the northern slope of the Iheya Ridge in the Mid-Okinawa Trough (27°32.5′ N, 126°58.5′
E: depth 1,400 m). The first site we found, the “Calyptogena Site”, was characterized by a relatively thick blanket of sediments, pleated and/or laminated lava flows, with occasional
lobate pillows and white and yellow stains. Although no remarkable shimmering water and thermal anomalies were detected during
the observations, the extraordinarily dense community must be related to hydrothermal activities. The community was dominated
by the giant white clam, Calyptogena okutanii, in biomass, and by Neolepas-type primitive scalpellids and slender vestimentiferan tube-worms in number. The second site, the “Pyramid Site”, situated
only 200 m northward from the Calyptogena Site has typical clear smokers emitting hot water over 200°C, and is characterized by a hard substratum of volcanic rocks
and hydrothermal slabs. No noteworthy succession was perceived at the Calyptogena Site over a year. Many of the vent members occurred at both sites. However, Calyptogena okutanii, which were confined to the sediment bottom, Neolepas spp. and larger vestimentiferan tube-worms were found to thrive only at the Calyptogena Site, being only minor elements in the Pyramid Site. The global distribution of several groups of organisms is discussed
preliminarily in zoogeographical terms based on comparison with other submersible missions and surveys done by surface vessels.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
5.
Won-Gi Min Dongsung Kim Hyun Soo Rho Sang Bum Chi Seung-Kyu Son 《Ocean Science Journal》2018,53(2):315-336
This study was carried out as part of a baseline long-term environmental project in the proposed mining areas for an environmental impact assessment of future mining in the Clarion-Clipperton Fracture Zone (CCFZ). The community structure and distributional pattern of meiobenthos were investigated in the deep-sea bottom of the Clarion-Clipperton Fracture Zone of the northeastern Pacific in July 1998, 1999, 2001, 2003 and August 2004, 2005. Twenty one meiobenthic groups were found at the stations in the study area. The most abundant meiobenthos comprised nematodes followed by benthic foraminiferans and harpacticoid copepods. The maximum density of meiobenthos was 306 ind/10 cm2 at the station located at 11°N (water depth, 4833 m), and the minimum density was 6 ind/10 cm2 at the station located at 14°N (water depth, 5037 m). Oligotrophic conditions in the CCFZ seem to directly reflect the lower standing stocks of meiobenthos in the CCFZ compared to other deep-sea plains of similar depth. The latitudinal distribution pattern of meiobenthos in the study area seemed to be related with surface water primary productivity, which was connected to the water circulation pattern of the Pacific Ocean near the Equator, diverging at 8ºN latitude and converging at 5°N. The horizontal distribution of meiobenthic organisms in the study area showed high densities at the stations within 135–136°W. The densities of meiobenthic organismas within the CCFZ were high at stations with few manganese nodules on the sediment surface at low-latitude sites. In 1998, the observed relative high values of meiobenthic abundance were at stations from 5° to 6°N. Other stations from 7° to 10°N showed no significant fluctuations during the interannual sampling periods. It is considered that the inter-annual fluctuation of meiobenthos abundance is intimately related with a regime shift that may have occurred in the north Pacific between 1998 and 1999, the El Niño period. Vertical distribution of meiobenthic organisms showed the highest individual numbers in the surface sediment layers of 0～2 cm depth and a steep decreasing trend as sediment becomes deeper at the stations of high latitude located in 16～17°N. Size distribution analyses showed that organisms that fit into the sieve mesh size of 0.063 mm were abundant. 相似文献
6.
Ingestion rates of free-living marine nematodes were measured using colloidal iron as a tracer. Detritus labeled with colloidal
iron was fed to the dominant nematode species and cultured. The iron ingested by the animals was quantified using a scanning
electron microscope equipped with differential X-ray energy analyzer (EDX). Average ingestion rates (μgC ind.−1day−1) measured were 0.28 for Symplocostoma sp., 0.29 for Polygastrophora sp., 0.73 for Mesacanthion sp. and 0.15 for Metachromadora sp. These values were higher than the values determined using radioactive organic materials as tracers, though the present
method is considered to provide conservative values. This result thus strongly suggests that the ingestion rates of nematodes
measured so far were underestimated, and the use of colloidal iron has advantages over the use of radioactive organic matter
as a tracer. 相似文献
7.
Namirimu Teddy Park Mi-Jeong Kim Yun Jae Lim Dhongil Lee Jung-Hyun Shin Ayoung Kim Dongsung Kwon Kae Kyoung 《Ocean Science Journal》2023,58(2):1-15
Since the discovery of hydrothermal vents in the late 1970s, deep-sea hydrothermal vent fields have attracted great attention as biological hotspots. However, compared with other ocean ridges, the structure and function of microbial communities inhabiting vent fields in the Central Indian ridge (CIR) remain understudied. Here, we provide for the first time 16S rRNA gene-based comparative metagenomic analysis of the sediment-associated microbial communities from three newly discovered vent fields in the CIR. Sediment samples collected in the Invent B, Invent E and Onnuri vent fields varied in geochemical properties, elemental concentrations and associated microbial communities. Proteobacteria (Gammaproteobacteria) was the dominant phylum in Invent B and Onnuri vent fields. In contrast, Invent E mainly consisted of Chloroflexi and Euryarchaeota. Predicted functional profiling revealed that the microbial communities in the three vents are dominated by chemoheterotrophic functions. In addition, microbial communities capable of respiration of sulfur compounds, nitrification, nitrite oxidation, methylotrophy, and methanotropy were found to be the main chemolithoautotrophs. Compared to other vent fields, Invent E showed a predominance of archaeal methanogens suggesting it exhibits slightly different geochemistry. Multivariate analysis indicated that the biogeochemical and trace metal differences are reflected in the sediment microbial compositions of the three vent fields. This study expands our current understanding of the microbial community structure and potential ecological functions of the newly discovered hydrothermal vent fields in the CIR.
相似文献
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