scholarly journals A total of 219 metagenome-assembled genomes of microorganisms from Icelandic marine waters

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11112
Author(s):  
Clara Jégousse ◽  
Pauline Vannier ◽  
René Groben ◽  
Frank Oliver Glöckner ◽  
Viggó Marteinsson
Keyword(s):  
Current Knowledge ◽  
Sea Surface ◽  
Global Ocean ◽  
Marine Microorganisms ◽  
Complex Environment ◽  
Mock Community ◽  
Marine Food Web ◽  
Marine Food ◽  
And Function ◽  
Marine Microbial Diversity

Marine microorganisms contribute to the health of the global ocean by supporting the marine food web and regulating biogeochemical cycles. Assessing marine microbial diversity is a crucial step towards understanding the global ocean. The waters surrounding Iceland are a complex environment where relatively warm salty waters from the Atlantic cool down and sink down to the deep. Microbial studies in this area have focused on photosynthetic micro- and nanoplankton mainly using microscopy and chlorophyll measurements. However, the diversity and function of the bacterial and archaeal picoplankton remains unknown. Here, we used a co-assembly approach supported by a marine mock community to reconstruct metagenome-assembled genomes (MAGs) from 31 metagenomes from the sea surface and seafloor of four oceanographic sampling stations sampled between 2015 and 2018. The resulting 219 MAGs include 191 bacterial, 26 archaeal and two eukaryotic MAGs to bridge the gap in our current knowledge of the global marine microbiome.

scholarly journals Isotopic fractionation of carbon during uptake by phytoplankton across the South Atlantic subtropical convergence

2019 ◽  
Vol 16 (18) ◽  
pp. 3621-3635 ◽  
Author(s):  
Robyn E. Tuerena ◽  
Raja S. Ganeshram ◽  
Matthew P. Humphreys ◽  
Thomas J. Browning ◽  
Heather Bouman ◽  
...  
Keyword(s):  
Food Web ◽  
Cell Size ◽  
Surface Waters ◽  
Isotopic Fractionation ◽  
Water Masses ◽  
Global Ocean ◽  
Carbon Uptake ◽  
The South ◽  
Marine Food Web ◽  
Marine Food

Abstract. The stable isotopic composition of particulate organic carbon (δ13CPOC) in the surface waters of the global ocean can vary with the aqueous CO2 concentration ([CO2(aq)]) and affects the trophic transfer of carbon isotopes in the marine food web. Other factors such as cell size, growth rate and carbon concentrating mechanisms decouple this observed correlation. Here, the variability in δ13CPOC is investigated in surface waters across the south subtropical convergence (SSTC) in the Atlantic Ocean, to determine carbon isotope fractionation (εp) by phytoplankton and the contrasting mechanisms of carbon uptake in the subantarctic and subtropical water masses. Our results indicate that cell size is the primary determinant of δ13CPOC across the Atlantic SSTC in summer. Combining cell size estimates with CO2 concentrations, we can accurately estimate εp within the varying surface water masses in this region. We further utilize these results to investigate future changes in εp with increased anthropogenic carbon availability. Our results suggest that smaller cells, which are prevalent in the subtropical ocean, will respond less to increased [CO2(aq)] than the larger cells found south of the SSTC and in the wider Southern Ocean. In the subantarctic water masses, isotopic fractionation during carbon uptake will likely increase, both with increasing CO2 availability to the cell, but also if increased stratification leads to decreases in average community cell size. Coupled with decreasing δ13C of [CO2(aq)] due to anthropogenic CO2 emissions, this change in isotopic fractionation and lowering of δ13CPOC may propagate through the marine food web, with implications for the use of δ13CPOC as a tracer of dietary sources in the marine environment.

scholarly journals Isotopic fractionation of carbon during uptake by phytoplankton across the South Atlantic subtropical convergence

2019 ◽  
Author(s):  
Robyn E. Tuerena ◽  
Raja S. Ganeshram ◽  
Matthew P. Humphreys ◽  
Thomas J. Browning ◽  
Heather Bouman ◽  
...  
Keyword(s):  
Food Web ◽  
Cell Size ◽  
Surface Waters ◽  
Isotopic Fractionation ◽  
Water Masses ◽  
Global Ocean ◽  
Carbon Uptake ◽  
The South ◽  
Marine Food Web ◽  
Marine Food

Abstract. The stable isotopic composition of particulate organic carbon (δ13CPOC) in the surface waters of the global ocean can vary with the aqueous CO2 concentration ([CO2(aq)]) and affects the trophic transfer of carbon isotopes in the marine food web. Other factors such as cell size, growth rate and carbon concentrating mechanisms decouple this observed correlation. Here, the variability in δ13CPOC is investigated in surface waters across the south subtropical convergence (SSTC) in the Atlantic Ocean, to determine carbon isotope fractionation (εp) by phytoplankton and the contrasting mechanisms of carbon uptake in the subantarctic and subtropical water masses. Our results indicate that cell size is the primary determinant of δ13CPOC across the Atlantic SSTC in summer. Combining cell size estimates with CO2 concentrations, we can accurately estimate εp within the varying surface water masses in this region. We further utilize these results to investigate future changes in εp with increased anthropogenic carbon availability. Our results suggest that smaller cells, which are prevalent in the subtropical ocean, will respond less to increased [CO2(aq)] than the larger cells found south of the SSTC and in the wider Southern Ocean. In the subantarctic water masses, isotopic fractionation during carbon uptake will likely increase, both with increasing CO2 availability to the cell, but also if increased stratification leads to decreases in average community cell size. Coupled with decreasing δ13C of [CO2(aq)] due to anthropogenic CO2 emissions, this change in isotopic fractionation and lowering of δ13CPOC may propagate through the marine food web, with implications for the use of δ13CPOC as a tracer of dietary sources in the marine environment.

2. Marine biological processes

2020 ◽  
pp. 22-47
Author(s):  
Philip V. Mladenov
Keyword(s):  
Primary Productivity ◽  
Marine Mammals ◽  
Global Ocean ◽  
Biological Processes ◽  
Marine Microbes ◽  
Factors Affecting ◽  
Marine Food Web ◽  
Marine Biological ◽  
Marine System ◽  
Marine Food

Roughly half of the planet’s primary production—the synthesis of organic matter by chlorophyll-bearing organisms using light energy from the sun—is produced within the Global Ocean. The primary producers in the oceans are phytoplanktonic microbes suspended in the sunlit surface layer. These energy-fixing microorganisms form the basis of the marine food web, the network of pathways through which food energy is transferred to all the other organisms in the marine system including other microbes, zooplankton, fish, marine mammals, and, ultimately, humans. ‘Marine biological processes’ outlines the four main groups of marine microbes—bacteria, archaea, protists, and viruses—and discusses the factors affecting marine primary productivity.

scholarly journals Remote sensing of ocean surface currents: a review of what is being observed and what is being assimilated

2017 ◽  
Vol 24 (4) ◽  
pp. 613-643 ◽  
Author(s):  
Jordi Isern-Fontanet ◽  
Joaquim Ballabrera-Poy ◽  
Antonio Turiel ◽  
Emilio García-Ladona
Keyword(s):  
Velocity Field ◽  
Ocean Circulation ◽  
Current Knowledge ◽  
Numerical Models ◽  
Radar Data ◽  
Ocean Currents ◽  
Sea Surface ◽  
Global Ocean ◽  
Surface Currents ◽  
Ocean Surface Currents

Abstract. Ocean currents play a key role in Earth's climate – they impact almost any process taking place in the ocean and are of major importance for navigation and human activities at sea. Nevertheless, their observation and forecasting are still difficult. First, no observing system is able to provide direct measurements of global ocean currents on synoptic scales. Consequently, it has been necessary to use sea surface height and sea surface temperature measurements and refer to dynamical frameworks to derive the velocity field. Second, the assimilation of the velocity field into numerical models of ocean circulation is difficult mainly due to lack of data. Recent experiments that assimilate coastal-based radar data have shown that ocean currents will contribute to increasing the forecast skill of surface currents, but require application in multidata assimilation approaches to better identify the thermohaline structure of the ocean. In this paper we review the current knowledge in these fields and provide a global and systematic view of the technologies to retrieve ocean velocities in the upper ocean and the available approaches to assimilate this information into ocean models.

How many trophic roles can elasmobranchs play in a marine tropical network?

2017 ◽  
Vol 68 (7) ◽  
pp. 1342 ◽  
Author(s):  
Andrés F. Navia ◽  
Paola A. Mejía-Falla ◽  
Juliana López-García ◽  
Alan Giraldo ◽  
Victor H. Cruz-Escalona
Keyword(s):  
Trophic Levels ◽  
Trophic Groups ◽  
Ontogenetic Changes ◽  
Marine Food Web ◽  
Top Predators ◽  
Elasmobranch Species ◽  
Regular Equivalence ◽  
Marine Food ◽  
And Function ◽  
The Web

The aims of the present study were to identify the trophic roles of shark and batoid species in a tropical marine food web and to examine how ontogenetic dietary changes affect these roles. Elasmobranch species at different stages of maturity (juveniles and adults) are distributed at medium and high trophic levels (3.2–4.2), preying on numerous fish and invertebrates. Nine trophic groups comprising species at different stages of maturity were identified. Considering the maturity stages, elasmobranchs were found in five trophic groups and 37.5% of the regular equivalence nodes in the web. These species had roles as both predator and prey in four trophic levels of the web, participating in most of the roles identified, and are highly redundant in their functions as prey and mesopredators, but not in their role as top predators. The results of the present study suggest that elasmobranchs can be fundamental to the structure and function of marine food webs and highlight the need to include the effect of ontogenetic changes in the diet of these predators in future assessments of their ecological relevance.

Effects of Maternal Obesity and Gestational Diabetes Mellitus on the Placenta: Current Knowledge and Targets for Therapeutic Interventions

2020 ◽  
Vol 19 (2) ◽  
pp. 176-192
Author(s):  
Samantha Bedell ◽  
Janine Hutson ◽  
Barbra de Vrijer ◽  
Genevieve Eastabrook
Keyword(s):  
Diabetes Mellitus ◽  
Gestational Diabetes ◽  
Gestational Diabetes Mellitus ◽  
Maternal Obesity ◽  
Environmental Changes ◽  
Current Knowledge ◽  
Therapeutic Interventions ◽  
Placental Development ◽  
Exchange Site ◽  
And Function

: Obesity and gestational diabetes mellitus (GDM) are becoming more common among pregnant women worldwide and are individually associated with a number of placenta-mediated obstetric complications, including preeclampsia, macrosomia, intrauterine growth restriction and stillbirth. The placenta serves several functions throughout pregnancy and is the main exchange site for the transfer of nutrients and gas from mother to fetus. In pregnancies complicated by maternal obesity or GDM, the placenta is exposed to environmental changes, such as increased inflammation and oxidative stress, dyslipidemia, and altered hormone levels. These changes can affect placental development and function and lead to abnormal fetal growth and development as well as metabolic and cardiovascular abnormalities in the offspring. This review aims to summarize current knowledge on the effects of obesity and GDM on placental development and function. Understanding these processes is key in developing therapeutic interventions with the goal of mitigating these effects and preventing future cardiovascular and metabolic pathology in subsequent generations.

DESIGN AND IMPLEMENTATION OF THE OCEANOGRAPHIC MODELING AND OBSERVATION NETWORK (REMO) FOR PHYSICAL OCEANOGRAPHY STUDIES AND OCEAN FORECASTING

2014 ◽  
Vol 31 (2) ◽  
Author(s):  
Jose Antonio Moreira Lima
Keyword(s):  
Atlantic Ocean ◽  
Large Scale ◽  
North Pacific Ocean ◽  
Integrated Approach ◽  
Sea Surface ◽  
Global Ocean ◽  
Height Anomaly ◽  
The North ◽  
Observation Network ◽  
Ocean Forecasting

This paper is concerned with the planning, implementation and some results of the Oceanographic Modeling and Observation Network, named REMO, for Brazilian regional waters. Ocean forecasting has been an important scientific issue over the last decade due to studies related to climate change as well as applications related to short-range oceanic forecasts. The South Atlantic Ocean has a deficit of oceanographic measurements when compared to other ocean basins such as the North Atlantic Ocean and the North Pacific Ocean. It is a challenge to design an ocean forecasting system for a region with poor observational coverage of in-situ data. Fortunately, most ocean forecasting systems heavily rely on the assimilation of surface fields such as sea surface height anomaly (SSHA) or sea surface temperature (SST), acquired by environmental satellites, that can accurately provide information that constrain major surface current systems and their mesoscale activity. An integrated approach is proposed here in which the large scale circulation in the Atlantic Ocean is modeled in a first step, and gradually nested into higher resolution regional models that are able to resolve important processes such as the Brazil Current and associated mesoscale variability, continental shelf waves, local and remote wind forcing, and others. This article presents the overall strategy to develop the models using a network of Brazilian institutions and their related expertise along with international collaboration. This work has some similarity with goals of the international project Global Ocean Data Assimilation Experiment OceanView (GODAE OceanView).

The Oxford Handbook of the Auditory Brainstem

2018 ◽  
Keyword(s):  
Current Knowledge ◽  
Auditory Pathway ◽  
Auditory Brainstem ◽  
Auditory Midbrain ◽  
Current State ◽  
Neuronal Mechanisms ◽  
Maladaptive Plasticity ◽  
And Function ◽  
Auditory Field

The Oxford Handbook of the Auditory Brainstem provides an in-depth reference to the organization and function of ascending and descending auditory pathways in the mammalian brainstem. Individual chapters are organized along the auditory pathway, beginning with the cochlea and ending with the auditory midbrain. Each chapter provides an introduction to the respective area and summarizes our current knowledge before discussing the disputes and challenges that the field currently faces.The handbook emphasizes the numerous forms of plasticity that are increasingly observed in many areas of the auditory brainstem. Several chapters focus on neuronal modulation of function and plasticity on the synaptic, neuronal, and circuit level, especially during development, aging, and following peripheral hearing loss. In addition, the book addresses the role of trauma-induced maladaptive plasticity with respect to its contribution in generating central hearing dysfunction, such as hyperacusis and tinnitus.The book is intended for students and postdoctoral fellows starting in the auditory field and for researchers of related fields who wish to get an authoritative and up-to-date summary of the current state of auditory brainstem research. For clinical practitioners in audiology, otolaryngology, and neurology, the book is a valuable resource of information about the neuronal mechanisms that are currently discussed as major candidates for the generation of central hearing dysfunction.

scholarly journals Complexities of disturbance response in a marine food web

2021 ◽  
Author(s):  
Kristy A. Lewis ◽  
Robert R. Christian ◽  
Charles W. Martin ◽  
Kira L. Allen ◽  
Ashley M. McDonald ◽  
...  
Keyword(s):  
Food Web ◽  
Marine Food Web ◽  
Disturbance Response ◽  
Marine Food
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