Radioisotope Thermoelectric Generators Emplaced in the Deep Ocean, Recover or Dispose in Situ

Deep ocean mining in a hydrothermal area needs careful environmental impact assessments in terms of preservation and mitigation of biodiversity. The General Environmental Technos Co. Ltd., or KANSO TECHNOS, for short, has participated in environmental impact assessments in hydrothermal areas in the Izu-Ogasawara and the East China Sea areas (Ishida et al., 2011). Through the experience, we suggest a method of using acoustic systems such as acoustic Doppler current profilers (ADCPs) for monitoring of suspended matters and benthos in hydrothermal areas. Thus, we try to do in-situ observations, called Tow-yo (or Towing) observations with ADCPs (Komaki and Ura, 2009; Komaki et al., 2010). This system has a great advantage in enabling the measurement of great environmental factors, echo intensity and current velocity in a large range. To confirm exactly what the substances are and how large they are from the measured echo intensity data, we tried laboratory experiments in water tanks with echo sounders and turbidity sensors. These results will finally be integrated in a simulation model to predict substances from in-situ data in deep water for future monitoring systems.

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Becoming symbiotic – the symbiont acquisition and the early development of bathymodiolin mussels

10.1101/2020.10.09.333211 ◽

2020 ◽

Author(s):

Maximilian Franke ◽

Benedikt Geier ◽

Jörg U. Hammel ◽

Nicole Dubilier ◽

Nikolaus Leisch

Keyword(s):

Early Development ◽

Light And Electron Microscopy ◽

Deep Ocean ◽

Life Stages ◽

Sea Floor ◽

Symbiotic Associations ◽

Nutritional Strategy ◽

Early Developmental ◽

Symbiont Acquisition

AbstractSymbiotic associations between animals and microorganisms are widespread and have a profound impact on the ecology, behaviour, physiology, and evolution of the host. Research on deep-sea mussels of the genus Bathymodiolus has revealed how chemosynthetic symbionts sustain their host with energy, allowing them to survive in the nutrient-poor environment of the deep ocean. However, to date, we know little about the initial symbiont colonization and how this is integrated into the early development of these mussels. Here we analysed the early developmental life stages of B. azoricus, “B”. childressi and B. puteoserpentis and the changes that occur once the mussels are colonized by symbionts. We combined synchrotron-radiation based μCT, correlative light and electron microscopy and fluorescence in situ hybridization to show that the symbiont colonization started when the animal settled on the sea floor and began its metamorphosis into an adult animal. Furthermore, we observed aposymbiotic life stages with a fully developed digestive system which was streamlined after symbiont acquisition. This suggests that bathymodiolin mussels change their nutritional strategy from initial filter-feeding to relying on the energy provided by their symbionts. After ~35 years of research on bathymodiolin mussels, we are beginning to answer fundamental ecological questions concerning their life cycle and the establishment of symbiosis.

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Spatial scales of temperature and salinity variability estimated from Argo observations

Ocean Science Discussions ◽

10.5194/osd-12-1793-2015 ◽

2015 ◽

Vol 12 (4) ◽

pp. 1793-1814

Author(s):

F. Ninove ◽

P. Y. Le Traon ◽

E. Remy ◽

S. Guinehut

Keyword(s):

Large Scale ◽

Spatial Scales ◽

Deep Ocean ◽

General Tendency ◽

Zero Crossing ◽

Tropical Regions ◽

Covariance Functions ◽

Salinity Variability ◽

First Time

Abstract. Argo observations from 2005 to 2013 are used to characterize spatial scales temperature and salinity variations from the surface down to 1500 m. Simulations are first performed to analyze the sensitivity of results to Argo sampling; they show that several years of Argo observations are required to estimate the spatial scales of ocean variability over 20° × 20° boxes. Spatial scales are then computed over several large scale areas. Zonal and meridional spatial scales (Lx and Ly which are also zero crossing of covariance functions) vary as expected with latitudes. Scales are of about 100 km at high latitudes and more of 700 km in the Indian and Pacific equatorial/tropical regions. Zonal and meridional scales are similar: except in these tropical/equatorial regions where zonal scales are much larger (by a factor of 2 to 3) than meridional scales. Spatial scales are the largest close to the surface and have a general tendency for temperature to increase in deeper layers. There are significant differences between temperature and salinity scales, in particular, in the deep ocean. Results are consistent with previous studies based on sparse in-situ observations or satellite altimetry. They provide, however, for the first time a global description of temperature and salinity scales of variability and a characterization of their variations according to depths.

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Impact of Argo Observation on the Regional Ocean Reanalysis of China Coastal Waters and Adjacent Seas: A Twin-Experiment Study

Advances in Meteorology ◽

10.1155/2015/793825 ◽

2015 ◽

Vol 2015 ◽

pp. 1-15 ◽

Cited By ~ 1

Author(s):

Caixia Shao ◽

Lili Xuan ◽

Yingzhi Cao ◽

Xiaojian Cui ◽

Siyu Gao

Keyword(s):

Coastal Waters ◽

Unique Feature ◽

Information Service ◽

Deep Ocean ◽

Ocean Reanalysis ◽

Rms Error ◽

Regional Reanalysis ◽

Argo Profiles ◽

The Impact

A regional ocean reanalysis system of China coastal waters and adjacent seas, called CORA (China ocean reanalysis), has been recently developed at the National Marine Data and Information Service (NMDIS). In this study, based on CORA, the impact of Argo profiles on the regional reanalysis is evaluated using a twin-experiment approach. It is found that, by assimilating Argo observations, the reanalysis quality is much improved: the root mean square (RMS) error of temperature and salinity can be further reduced by about 10% and the RMS error of current can be further reduced by 18%, compared to the case only assimilating conventional in situ temperature and salinity observations. Consistent with the unique feature of Argo observations, the temperature is improved in all levels and the largest improvement of salinity happens in the deep ocean. Argo profile data have a significant impact on the regional ocean reanalysis through improvements of both hydrographic and dynamic fields.

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On the Quality of Real-Time Altimeter Gridded Fields: Comparison with In Situ Data

Journal of Atmospheric and Oceanic Technology ◽

10.1175/2008jtecho556.1 ◽

2009 ◽

Vol 26 (3) ◽

pp. 556-569 ◽

Cited By ~ 29

Author(s):

Ananda Pascual ◽

Christine Boone ◽

Gilles Larnicol ◽

Pierre-Yves Le Traon

Keyword(s):

Real Time ◽

Sea Level ◽

Tide Gauge ◽

Deep Ocean ◽

Velocity Estimation ◽

Time Data ◽

In Situ Data ◽

Delayed Time

Abstract The timeliness of satellite altimeter measurements has a significant effect on their value for operational oceanography. In this paper, an Observing System Experiment (OSE) approach is used to assess the quality of real-time altimeter products, a key issue for robust monitoring and forecasting of the ocean state. In addition, the effect of two improved geophysical corrections and the number of missions that are combined in the altimeter products are also analyzed. The improved tidal and atmospheric corrections have a significant effect in coastal areas (0–100 km from the shore), and a comparison with tide gauge observations shows a slightly better agreement with the gridded delayed-time sea level anomalies (SLAs) with two altimeters [Jason-1 and European Remote Sensing Satellite-2 (ERS-2)/Envisat] using the new geophysical corrections (mean square differences in percent of tide gauge variance of 35.3%) than those with four missions [Jason-1, ERS/Envisat, Ocean Topography Experiment (TOPEX)/Poseidoninterlaced, and Geosat Follow-On] but using the old corrections (36.7%). In the deep ocean, however, the correction improvements have little influence. The performance of fast delivery products versus delayed-time data is compared using independent in situ data (tide gauge and drifter data). It clearly highlights the degradation of real-time SLA maps versus the delayed-time SLA maps: four altimeters are needed in real time to get the similar quality performance as two altimeters in delayed time (sea level error misfit around 36%, and zonal and meridional velocity estimation errors of 27% and 33%, respectively). This study proves that the continuous improvement of geophysical corrections is very important, and that it is essential to stay above a minimum threshold of four available altimetric missions to capture the main space and time oceanic scales in fast delivery products.

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Shifting ocean circulation warms the Subpolar North Atlantic since 2016

10.5194/egusphere-egu21-940 ◽

2021 ◽

Author(s):

Damien Desbruyères ◽

Léon Chafik ◽

Guillaume Maze

Keyword(s):

Ocean Circulation ◽

North Atlantic ◽

Large Scale ◽

Deep Ocean ◽

Ocean Heat Uptake ◽

Driving Mechanisms ◽

Temperature Trends ◽

Meridional Overturning ◽

Ocean Observing

<p>The Subpolar North Atlantic (SPNA) is known for rapid reversals of decadal temperature trends, with ramifications encompassing the large-scale meridional overturning and gyre circulations, Arctic heat and mass balances, or extreme continental weather. Here, we combine datasets derived from sustained ocean observing systems (satellite and in situ), and idealized observation-based modelling (advection-diffusion of a passive tracer) and machine learning technique (ocean profile clustering) to document and explain the most-recent and ongoing cooling-to-warming transition of the SPNA. Following a gradual cooling of the region that was persisting since 2006, a surface-intensified and large-scale warming sharply emerged in 2016 following an ocean circulation shift that enhanced the northeastward penetration of warm and saline waters from the western subtropics. Driving mechanisms and ramification for deep ocean heat uptake will be discussed.</p>

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The MPL sound velocimeter: An instrument for in situ sound velocity measurements in the deep ocean

The Journal of the Acoustical Society of America ◽

10.1121/1.420579 ◽

1997 ◽

Vol 102 (5) ◽

pp. 3119-3119 ◽

Cited By ~ 1

Author(s):

Aaron D. Sweeney ◽

Fred N. Spiess ◽

Dwight E. Boegeman ◽

David M. Jabson ◽

Richard Zimmerman

Keyword(s):

Sound Velocity ◽

Deep Ocean ◽

Velocity Measurements

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Symmetrical and Asymmetrical Rectifications Employed for Deeper Ocean Extrapolations of In Situ CTD Data and Subsequent Sound Speed Profiles

Symmetry ◽

10.3390/sym12091455 ◽

2020 ◽

Vol 12 (9) ◽

pp. 1455

Author(s):

Kashif Iqbal ◽

Minghui Zhang ◽

Shengchun Piao

Keyword(s):

Ocean Circulation ◽

Sound Speed ◽

Transmission Loss ◽

Spatial Scales ◽

Deep Ocean ◽

The United States ◽

Critical Parameters ◽

Argo Data ◽

Argo Floats

The multinational Argo program, which was initiated in 1999, has completed its global requirement of 3000 floats deployed by 2007. This program has revolutionized ocean observations with the provision of varying data in the upper half of the ocean. However, various studies have reiterated the requirement for deep ocean coverage, since the ocean below 2000 meters (m) is warming. In this regard, full-depth studies are mandatory in order to estimate the rising sea level due to thermal expansion and analyze critical parameters of deep ocean circulation sub 2000 m; further, data below 2000 m are mandatory for multifarious model simulations. As a landmark initiative, in mid-2015, the “Deep Argo Implementation Workshop” was held in Hobart. An array comprising 1228 floats was suggested by G. C. Johnson, rendering coverage of 5° latitude × 5° longitude × 15-day cycles. This was conclusively agreed to be an affordable solution for varying scientific needs for assessing data in abyssal oceans. Thence, Deep New profilINg float of JApan (NINJA) and Deep Arvor floats were developed by Japan and France, respectively, to cover depths of 0–4000 m. Similarly, Deep Autonomous Profiling Explorer (APEX) and Deep Sounding Oceanographic Lagrangian Observer (SOLO) by the United States were designed to cover 0–6000 m. The data offered by this underdeveloped deep pilot array are scarce on both temporal and spatial scales. This particular study offers an ingenious and novel approach to extrapolating conductivity–temperature–depth (CTD) profiles, as well as sound speed profiles (SSPs), in abyssal oceans below 2000 m. The primitive results of this method exhibited certain discrepancies which were subsequently rectified by modifying the aforementioned method both symmetrically and asymmetrically in an innovative way. The final outcomes of this method are almost identical to the in situ values obtained from Deep Argo floats, and in this way, offer a way to compute deep ocean calculations both spatially and temporally since Deep Argo floats are aimed at relatively sparse deployments and require a longer duration to provide data (5° latitude × 5° longitude × 15-day cycles) as compared to Core Argo data (3° latitude × 3° longitude × 10-day cycles). The SSP computations were conducted by employing multiple equations such as Chen and Millero, Del Grosso, and UNESCO (United Nations Educational, Scientific, and Cultural Organization) algorithms. The study concludes by offering transmission loss rectifications by employing the aforementioned method as a future course of action.

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Growth of the coccolithophore <i>Emiliania huxleyi</i> in light- and nutrient-limited batch reactors: relevance for the BIOSOPE deep ecological niche of coccolithophores

Biogeosciences ◽

10.5194/bg-13-5983-2016 ◽

2016 ◽

Vol 13 (21) ◽

pp. 5983-6001 ◽

Cited By ~ 12

Author(s):

Laura Perrin ◽

Ian Probert ◽

Gerald Langer ◽

Giovanni Aloisi

Keyword(s):

Ecological Niche ◽

Deep Ocean ◽

Emiliania Huxleyi ◽

Physiological Parameters ◽

Phosphate Limitation ◽

Batch Reactors ◽

In Situ Data ◽

Physiological Modelling ◽

In Situ Conditions

Abstract. Coccolithophores are unicellular calcifying marine algae that play an important role in the oceanic carbon cycle via their cellular processes of photosynthesis (a CO2 sink) and calcification (a CO2 source). In contrast to the well-studied, surface-water coccolithophore blooms visible from satellites, the lower photic zone is a poorly known but potentially important ecological niche for coccolithophores in terms of primary production and carbon export to the deep ocean. In this study, the physiological responses of an Emiliania huxleyi strain to conditions simulating the deep niche in the oligotrophic gyres along the BIOSOPE transect in the South Pacific Gyre were investigated. We carried out batch culture experiments with an E. huxleyi strain isolated from the BIOSOPE transect, reproducing the in situ conditions of light and nutrient (nitrate and phosphate) limitation. By simulating coccolithophore growth using an internal stores (Droop) model, we were able to constrain fundamental physiological parameters for this E. huxleyi strain. We show that simple batch experiments, in conjunction with physiological modelling, can provide reliable estimates of fundamental physiological parameters for E. huxleyi that are usually obtained experimentally in more time-consuming and costly chemostat experiments. The combination of culture experiments, physiological modelling and in situ data from the BIOSOPE cruise show that E. huxleyi growth in the deep BIOSOPE niche is limited by availability of light and nitrate. This study contributes more widely to the understanding of E. huxleyi physiology and behaviour in a low-light and oligotrophic environment of the ocean.

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