Deep-sea Plankton Research Articles

Microplastic volumes in Tokyo Bay

Microplastic (MP) pollution is a rising environmental concern. This study investigated MP concentrations in Tokyo Bay using neuston net for surface sampling and deep-sea plankton pump for underwater sampling across six stations at multiple depths. Results revealed substantial variation in MP concentrations. Surface large microplastics (LMP, > 350 μm) ranged from 0.21 × 10−3 to 3.34 × 10−3 pieces L−1, averaging 1.26 × 10−3 pieces L−1, while surface small microplastics (SMP, 60 μm to 350 μm) were highest at head of the bay (11.5 ± 3.05 pieces L−1). SMP concentrations varied with depth and position, peaking at center of the bay (5.79 ± 1.63 pieces L−1 at 2 m). Additionally, the total amount of surface LMP was estimated at 10.3 m3 and SMP at 15.0 m3 in the Tokyo Bay. This study provides a comprehensive picture of the spatial and vertical distribution of MP in Tokyo Bay.

Detection of the Deep-Sea Plankton Community in Marine Ecosystem with Underwater Robotic Platform.

Variations in the quantity of plankton impact the entire marine ecosystem. It is of great significance to accurately assess the dynamic evolution of the plankton for monitoring the marine environment and global climate change. In this paper, a novel method is introduced for deep-sea plankton community detection in marine ecosystem using an underwater robotic platform. The videos were sampled at a distance of 1.5 m from the ocean floor, with a focal length of 1.5–2.5 m. The optical flow field is used to detect plankton community. We showed that for each of the moving plankton that do not overlap in space in two consecutive video frames, the time gradient of the spatial position of the plankton are opposite to each other in two consecutive optical flow fields. Further, the lateral and vertical gradients have the same value and orientation in two consecutive optical flow fields. Accordingly, moving plankton can be accurately detected under the complex dynamic background in the deep-sea environment. Experimental comparison with manual ground-truth fully validated the efficacy of the proposed methodology, which outperforms six state-of-the-art approaches.

Composition and distribution patterns of eukaryotic microbial plankton in the ultra-oligotrophic Eastern Mediterranean Sea

Marine microbial eukaryotes play crucial roles in water-column ecosystems; however, there are regional gaps in the investigation of natural microbial eukaryote communities, and uncertainties concerning their distribution persevere. This study combined 18S rRNA metabarcoding, biomass measurements and statistical analyses of multiple environmental variables to examine the distribution of planktonic microbial eukaryotes at different sites and water layers in the ultra-oligotrophic Eastern Mediterranean Sea (Western Levantine Basin). Our results showed that microbial eukaryotic communities were structured by depth. In surface waters, different sites shared high percentages of molecular operational taxonomic units (MOTUs), but this was not the case for deep-sea communities (≥1000 m). Plankton biomass was significantly different among sites, implying that communities of a similar composition may not support the same activity or population size. The deep-sea communities showed high percentages of unassigned MOTUs, highlighting the sparsity of the existing information on deep-sea plankton eukaryotes. Water temperature and dissolved organic matter significantly affected community distribution. Micro-eukaryotic distribution was additionally affected by the nitrogen to phosphorus ratio and viral abundance, while nano- and pico-communities were affected by zooplankton. The present study explores microbial plankton eukaryotes in their natural oligotrophic environment and highlights that, even within restricted oceanic areas, marine plankton may follow distribution patterns that are largely controlled by environmental variables.

Food web structure and trophodynamics of deep-sea plankton from the Bari Canyon and adjacent slope (Southern Adriatic, central Mediterranean Sea)

Zooplankton represent a key component of deep-sea ecosystems, linking Particulate Organic Matter (POM) to higher trophic levels through both vertical migrations from the photic zone and being prey of several megafaunal species, including demersal and benthopelagic organisms. Nevertheless, this key group in deep-sea ecosystems is far to be well known, especially concerning trophic aspects. In this study, we aimed to depict the trophic web structure of deep-sea zooplankton collected in sediment traps from the Southern Adriatic, central Mediterranean Sea, and adjacent slope from 600 to 1200 m, and its trophodynamics. To achieve these objectives, we considered a long time-series set of samples, from March 2010 to October 2012 and we used stable isotope analysis of nitrogen and carbon. The area is characterised by cascading events of dense shelf waters, and the possible influence of this periodic phenomenon on seasonal changes in the isotopic composition of deep-sea zooplanktonic species was also analysed. Our results evidenced a complex structure for the deep-sea zooplankton food web with taxa organized in three trophic levels from POM feeders to ultra-specialized carnivores. Temporal changes in the isotopic signatures of deep-sea zooplankton species were observed, although the influence of cascading events was not so clear. The high swimming capability of deep-sea zooplankton and their ability to perform vertical migrations may be the cause of such unclear relationship, with species more relying on vertical fluxes from surface primary production than on lateral advective transport of organic particles.

深层海洋浮游植物研究综述

PDF HTML阅读 XML下载 导出引用 引用提醒 深层海洋浮游植物研究综述 DOI: 10.5846/stxb201306011264 作者: 作者单位: 中国科学院海洋研究所,中国科学院海洋研究所,中国科学院海洋研究所,中国科学院海洋研究所,中国科学院海洋研究所,中国科学院海洋研究所,天津科技大学 作者简介: 通讯作者: 中图分类号: 基金项目: 中国科学院战略性先导科技专项（XDA11030202.2）；国家重点基础研究发展规划项目（2014CB441504）；国家自然科学基金（41176136，41276124） Phytoplankton in the deep sea, a review Author: Affiliation: Institute of Oceanology, CAS,,,,,,Tianjin University of Science and Technology Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:对深层海洋（> 200 m）浮游生物的研究是我国海洋浮游生物研究的前沿，已有的深层海洋浮游生物知识是我国相关研究的基础。浮游植物需要阳光进行光合作用，大多数浮游植物沉降到深海中会死亡，但有些浮游植物却能在深海中生存。综述深层海洋中存活的浮游植物的研究进展，为我国的研究提供参考。在深层海洋发现的浮游植物（> 2 μm）种类不多，共有18种，最深分布在4000 m，颗石藻的丰度大于硅藻和甲藻，最大丰度为2220个/L，出现在500 m。在1911-1985年期间，曾经发现橄榄绿细胞，由于研究手段有限，一直没有对其进行分类学研究。1985年以后的研究怀疑这些橄榄绿细胞就是聚球藻蓝细菌，聚球藻蓝细菌在太平洋、大西洋和地中海的几个站位能分布到2750 m，在深层海洋的最大丰度为3.5 ×105 个/mL，出现在800 m。在许多海区200-700 m发现有浮游植物色素荧光的高值，但对引起高值的原因尚不清楚。浮游植物生物量在深层海洋的垂直剖面研究不多，已有的研究表明浮游植物生物量在300 m以深为0.001-0.1 μg C/L，且其随深度增加而降低。 Abstract:The study of deep sea (>200 m) plankton is the frontier of marine biology and ecology research in China. Summarizing existing knowledge of deep sea plankton is important to Chinese research in this field. Most phytoplankton will die when they settle out of the euphotic zone. However, some phytoplankton manages to survive in the deep sea despite of the darkness. This review synthesized the research of living phytoplankton in deep sea. Phytoplankton needs sunlight to carry out photosynthesis. There were only 18 species of phytoplankton found in the deep sea with the maximum depth of 4000 m. The abundance of coccolithphore was higher than that of diatoms and dinoflagellates. Maximum abundance of coccolithphore in the deep sea was 2220 cells/L in the depth of 500 m. In the years 1911-1985, the olive green cells were found in deep seas. There was no extensive taxonomic definition of olive green cells due to limited research devices. After the year 1985, the olive green cells was deemed as Synechococcus spp., which was found in 2750 m. Maximum abundance of Synechococcus spp. found in deep sea was 3.5 ×105 cells/mL at a depth of 800 m. In situ fluorescence profiles in the deep sea found tertiary phytoplankton pigment maxima in 20-700 m depth. However, we are not sure what organisms caused the fluorescent maxima. There was little information about the biomass of phytoplankton in the deep sea. In the limited studies, phytoplankton biomass (0.001-0.1μg C/L) decreased with depth from 300 m to the bottom. 参考文献 相似文献 引证文献

Diel Vertical Migration in Deep Sea Plankton Is Finely Tuned to Latitudinal and Seasonal Day Length

Diel vertical migration (DVM) is a ubiquitous phenomenon in marine and freshwater plankton communities. Most commonly, plankton migrate to surface waters at dusk and return to deeper waters at dawn. Up until recently, it was thought that DVM was triggered by a relative change in visible light intensity. However, evidence has shown that DVM also occurs in the deep sea where no direct and background sunlight penetrates. To identify whether such DVM is associated with latitudinal and seasonal day light variation, one and a half years of recorded acoustic data, a measure of zooplankton abundance and movement, were examined. Acoustic Doppler current profilers, moored at eight different sub-tropical latitudes in the North-Atlantic Ocean, measured in the vertical range of 500–1600 m. DVM was observed to follow day length variation with a change in season and latitude at all depths. DVM followed the rhythm of local sunrise and sunset precisely between 500 and 650 m. It continued below 650 m, where the deepest penetrable irradiance level are <10−7 times their near-surface values, but plankton shortened their time at depth by up to about 63% at 1600 m. This suggests light was no longer a cue for DVM. This trend stayed consistent both across latitudes and between the different seasons. It is hypothesized that another mechanism, rather than light, viz. a precise biochemical clock could maintain the solar diurnal and seasonal rhythms in deep sea plankton motions. In accordance with this hypothesis, the deepest plankton were consistently the first to migrate upwards.

Comparative metagenomics of bathypelagic plankton and bottom sediment from the Sea of Marmara

To extend comparative metagenomic analyses of the deep-sea, we produced metagenomic data by direct 454 pyrosequencing from bathypelagic plankton (1000 m depth) and bottom sediment of the Sea of Marmara, the gateway between the Eastern Mediterranean and the Black Seas. Data from small subunit ribosomal RNA (SSU rRNA) gene libraries and direct pyrosequencing of the same samples indicated that Gamma- and Alpha-proteobacteria, followed by Bacteroidetes, dominated the bacterial fraction in Marmara deep-sea plankton, whereas Planctomycetes, Delta- and Gamma-proteobacteria were the most abundant groups in high bacterial-diversity sediment. Group I Crenarchaeota/Thaumarchaeota dominated the archaeal plankton fraction, although group II and III Euryarchaeota were also present. Eukaryotes were highly diverse in SSU rRNA gene libraries, with group I (Duboscquellida) and II (Syndiniales) alveolates and Radiozoa dominating plankton, and Opisthokonta and Alveolates, sediment. However, eukaryotic sequences were scarce in pyrosequence data. Archaeal amo genes were abundant in plankton, suggesting that Marmara planktonic Thaumarchaeota are ammonia oxidizers. Genes involved in sulfate reduction, carbon monoxide oxidation, anammox and sulfatases were over-represented in sediment. Genome recruitment analyses showed that Alteromonas macleodii 'surface ecotype', Pelagibacter ubique and Nitrosopumilus maritimus were highly represented in 1000 m-deep plankton. A comparative analysis of Marmara metagenomes with ALOHA deep-sea and surface plankton, whale carcasses, Peru subsurface sediment and soil metagenomes clustered deep-sea Marmara plankton with deep-ALOHA plankton and whale carcasses, likely because of the suboxic conditions in the deep Marmara water column. The Marmara sediment clustered with the soil metagenome, highlighting the common ecological role of both types of microbial communities in the degradation of organic matter and the completion of biogeochemical cycles.

Pan‐oceanic distribution of new highly diverse clades of deep‐sea diplonemids

Molecular rRNA gene surveys reveal a considerable diversity of microbial eukaryotes in different environments. Even within a single clade, the number of distinct phylotypes retrieved often goes beyond previous expectations. Here, we have used specific 18S rRNA PCR primers to investigate the diversity of diplonemids, a poorly known group of flagellates with only a few described species. We analysed surface and deep-sea plankton samples from different oceanic regions, including the water-column in the Marmara Sea. We retrieved a large diversity of diplonemid phylotypes, most of which formed two novel distinct clades without cultured representatives. Although most marine diplonemid phylotypes appeared to be cosmopolitan, they showed a marked stratified distribution through the water column, being very scarce or absent in surface waters. The small and specific diplonemid diversity found in surface samples and the fact that most sequences of uncultured diplonemids found in other studies came from deep-sea environments suggest that the two major uncultured diplonemid clades group species preferentially inhabit the deep ocean.

Comparative analysis of genome fragments of Acidobacteria from deep Mediterranean plankton

Acidobacteria constitute a still poorly studied phylum that is well represented in soils. Recent studies suggest that members of this phylum may be also abundant in deep-sea plankton, but their relative abundance and ecological role in this ecosystem are completely unknown. A recent screening of three metagenomic deep-sea libraries of bathypelagic plankton from the South Atlantic (1000 m depth), the Adriatic (1000 m depth) and the Ionian (3000 m depth) seas in the Mediterranean revealed an unexpected relative proportion of acidobacterial fosmids, which affiliated to the Solibacterales (Group 3), to the Group 11 and, most frequently, to the Group 6 of this diverse phylum. Here, we present the comparative analysis of 11 acidobacterial genome fragments containing the rrn operon from these Mediterranean libraries. A highly conserved syntenic region spanning up to 30 kb and containing up to 25 open reading frames was shared by Group 6 Acidobacteria. Synteny was also partially conserved in distantly related acidobacterial genome fragments derived from a metagenomic soil library, indicating a remarkable conservation of this genomic region within these Acidobacteria. A search for Acidobacteria-specific hits in directly comparable, available fosmid-end sequences from soil and marine metagenomic libraries showed a significant increase of their relative proportion in plankton libraries as a function of increasing depth reaching, at high depth, levels nearly comparable to those of soil. Thus, our results suggest that Acidobacteria are abundant and represent a significant proportion of the microbial community in the deep-sea ecosystem.

Stable warm tropical climate through the Eocene Epoch

Earth's climate cooled from a period of extreme warmth in the early Eocene Epoch (ca. 50 Ma) to the early Oligocene (ca. 33 Ma), when a large ice cap first appeared on Antarctica. Evidence from the planktonic foraminifer oxygen isotope record in deep-sea cores has suggested that tropical sea-surface temperatures declined by 5-10 degrees over this interval, eventually becoming much cooler than modern temperatures. Here we present paleotemperature estimates from foraminifer isotopes and the membrane lipids of marine Crenarcheota from new drill cores in Tanzania that indicate a warm and generally stable tropical climate over this period. We reinterpret the previously published isotope records in the light of comparative textural analysis of the deep-sea foraminifer shells, which shows that in contrast to the Tanzanian material, they have been diagenetically recrystallized. We suggest that increasingly severe alteration of the deep-sea plankton shells through the Eocene produced a diagenetic overprint on their oxygen isotope ratios that imparts the false appearance of a tropical sea-surface cooling trend. This implies that the long-term Eocene climatic cooling trend occurred mainly at the poles and had little effect at lower latitudes.

Autochthonous eukaryotic diversity in hydrothermal sediment and experimental microcolonizers at the Mid-Atlantic Ridge.

The diversity and mode of life of microbial eukaryotes in hydrothermal systems is very poorly known. We carried out a molecular survey based on 18S ribosomal RNA genes of eukaryotes present in different hydrothermal niches at the Mid-Atlantic Ridge. These included metal-rich and rare-earth-element-rich hydrothermal sediments of the Rainbow site, fluid-seawater mixing regions, and colonization devices (microcolonizers) containing organic, iron-rich, and porous mineral substrates that were exposed for 15 days to a fluid source. We identified considerable phylogenetic diversity, both at kingdom level and within kinetoplastids and alveolates. None of our sequences affiliates to photosynthesizing lineages, suggesting that we are targeting only autochthonous deep-sea communities. Although sediment harbored most phylogenetic diversity, microcolonizers predominantly contained bodonids and ciliates, indicating that these protists pioneer the colonization process. Given the large variety of divergent lineages detected within the alveolates in deep-sea plankton, hydrothermal sediments, and vents, alveolates seem to dominate the deep ocean in terms of diversity. Compared with data from the Pacific Guaymas basin, some protist lineages seem ubiquitous in hydrothermal areas, whereas others, notably kinetoplastid lineages, very abundant and diverse in our samples, so far have been detected only in Atlantic systems. Unexpectedly, although alvinellid polychaetes are considered endemic of Pacific vents, we detected alvinellid-related sequences at the fluid-seawater interface and in microcolonizers. This finding can boost further studies on deep-sea vent animal biology and biogeography.

Vertical Distribution of Gelatinous Macroplankton in the North Pacific Observed by Manned Submersibles Mir-1 and Mir-2

The vertical distribution of several medusa species in the Kurile-Kamtchatka region of the Pacific Ocean is described. Animals were observed in the light cone from deep-sea submersibles Mir-1 and Mir-2 throughout the water column, from the surface to 5000–6000 m at four different sites. Bathy- and abyssopelagic species are noted along with the species living in an extremely wide depth range. A faunistic border is revealed at a depth of 3000 m. The contribution of gelatinous animals (medusae, siphonophores, salps) to the total deep-sea plankton biomass was estimated using a wire reference cube during nine dives in the highly productive areas of the northwest Pacific, eastern Pacific (California, Costa-Rica Dome), and subtropical oligotrophic areas.

Restriction of body size spectra within species of deep-sea plankton

Restriction of body size spectra within species of deep-sea plankton

Biological oceanography of the red oceanic system

Biological oceanography of the red oceanic system

The biomass of the deep-sea benthopelagic plankton

Deep-sea benthopelagic plankton samples were collected with a specially designed opening-closing net system 10 to 100 m above the bottom in five different oceanic regions at depths from 1000 to 4700 m. Benthopelagic plankton biomasses decrease exponentially with depth. At 1000 m the biomass is about 1% that of the surface zooplankton, at 5000 m about 0.1%. Effects of differences in surface primary productivity on deep-sea plankton biomass are much less than the effect of depth and are detectable only in a few comparisons of extreme oceanic regions. The biomass at 10 m above the bottom is greater than that at 100 m above the bottom (in a three-sample comparison), which could be a consequence of an enriched near-bottom environment. The deep-sea plankton biomass in the Red Sea is anomalously low. This may be due to increased decomposition rates in the warm (22°C) deep Red Sea water, which prevent much detritus from reaching the deep sea. A model of organic carbon utilization in the benthic boundary layer (bottom 100 m), incorporating results from deep-sea sediment trap and respiration studies, indicates that the benthopelagic plankton use only a small amount of the organic carbon flux. A large fraction of the flux is unaccounted for by present estimates of benthic and benthopelagic respiration.

The Food of Deep-Sea Copepods

The question of how organisms living below 1000 metres depth in the oceans obtain food in sufficient quantity to survive has lately received a lot of attention (Vinogradov, 1968; Sanders &amp; Hessler, 1969; Fournier, 1972). The oldest and simplest theory, first advocated by Agassiz (1888), is that deep-sea organisms are nourished by a ‘rain’ of organic detritus from overlying surface waters. Detritus is defined to include all organic particles, living and dead, which sink passively. An alternate proposal by Riley (1951), Vinogradov (1962) and Wickstead (1962) is that the main supply of food for deep-sea plankton is conveyed from the euphotic zone by overlapping vertical migratory plankters.

Quantitative distribution of deep-sea plankton in the western Pacific and its relation to deep-water circulation

Quantitative distribution of deep-sea plankton in the western Pacific and its relation to deep-water circulation