scholarly journals Physiological and ecological implications of ocean deoxygenation for vision in marine organisms

2017 ◽  
Vol 375 (2102) ◽  
pp. 20160322 ◽  
Author(s):  
Lillian R. McCormick ◽  
Lisa A. Levin
Keyword(s):  
Morphological Changes ◽  
Alternative Hypothesis ◽  
Marine Organisms ◽  
Human Vision ◽  
Marine Biota ◽  
Visual Responses ◽  
Low Oxygen ◽  
Marine Animals ◽  
Warming World ◽  
Ocean Deoxygenation

Climate change has induced ocean deoxygenation and exacerbated eutrophication-driven hypoxia in recent decades, affecting the physiology, behaviour and ecology of marine organisms. The high oxygen demand of visual tissues and the known inhibitory effects of hypoxia on human vision raise the questions if and how ocean deoxygenation alters vision in marine organisms. This is particularly important given the rapid loss of oxygen and strong vertical gradients in oxygen concentration in many areas of the ocean. This review evaluates the potential effects of low oxygen (hypoxia) on visual function in marine animals and their implications for marine biota under current and future ocean deoxygenation based on evidence from terrestrial and a few marine organisms. Evolutionary history shows radiation of eye designs during a period of increasing ocean oxygenation. Physiological effects of hypoxia on photoreceptor function and light sensitivity, in combination with morphological changes that may occur throughout ontogeny, have the potential to alter visual behaviour and, subsequently, the ecology of marine organisms, particularly for fish, cephalopods and arthropods with ‘fast’ vision. Visual responses to hypoxia, including greater light requirements, offer an alternative hypothesis for observed habitat compression and shoaling vertical distributions in visual marine species subject to ocean deoxygenation, which merits further investigation. This article is part of the themed issue ‘Ocean ventilation and deoxygenation in a warming world’.

scholarly journals Ocean deoxygenation, the global phosphorus cycle and the possibility of human-caused large-scale ocean anoxia

2017 ◽  
Vol 375 (2102) ◽  
pp. 20160318 ◽  
Author(s):  
Andrew J. Watson ◽  
Timothy M. Lenton ◽  
Benjamin J. W. Mills
Keyword(s):  
Chemical Weathering ◽  
Large Scale ◽  
Oxygen Demand ◽  
Subsurface Water ◽  
Phosphorus Cycle ◽  
Low Oxygen ◽  
Positive Feedbacks ◽  
Future Possibility ◽  
Warming World ◽  
Ocean Deoxygenation

The major biogeochemical cycles that keep the present-day Earth habitable are linked by a network of feedbacks, which has led to a broadly stable chemical composition of the oceans and atmosphere over hundreds of millions of years. This includes the processes that control both the atmospheric and oceanic concentrations of oxygen. However, one notable exception to the generally well-behaved dynamics of this system is the propensity for episodes of ocean anoxia to occur and to persist for 10 5 –10 6 years, these ocean anoxic events (OAEs) being particularly associated with warm ‘greenhouse’ climates. A powerful mechanism responsible for past OAEs was an increase in phosphorus supply to the oceans, leading to higher ocean productivity and oxygen demand in subsurface water. This can be amplified by positive feedbacks on the nutrient content of the ocean, with low oxygen promoting further release of phosphorus from ocean sediments, leading to a potentially self-sustaining condition of deoxygenation. We use a simple model for phosphorus in the ocean to explore this feedback, and to evaluate the potential for humans to bring on global-scale anoxia by enhancing P supply to the oceans. While this is not an immediate global change concern, it is a future possibility on millennial and longer time scales, when considering both phosphate rock mining and increased chemical weathering due to climate change. Ocean deoxygenation, once begun, may be self-sustaining and eventually could result in long-lasting and unpleasant consequences for the Earth's biosphere. This article is part of the themed issue ‘Ocean ventilation and deoxygenation in a warming world’.

Implications of oil pollution in production of disease in marine organisms

1982 ◽  
Vol 297 (1087) ◽  
pp. 385-399 ◽  
Keyword(s):  
Viral Infections ◽  
Oil Pollution ◽  
Morphological Changes ◽  
Ventricular Myocardium ◽  
Marine Organisms ◽  
Marine Animals ◽  
Marine Habitats ◽  
Fin Ray ◽  
Fish And Shellfish ◽  
Sufficient Concentration

Contamination of marine waters by petroleum, whether as a consequence of acute or chronic events, constitutes an additional source of stress for marine organisms — one often reflected in pathological changes. Morphological, behavioural, physiological or biochemical abnormalities may result from exposure to petroleum or its component chemicals. Among the morphological changes that have been associated, at least circumstantially, with petroleum contamination of marine habitats are (for fish) fin erosion, fin ray deformation, ovarian histopathology, olfactory lesions, degeneration of ventricular myocardium and cytogenetic anomalies; and (for invertebrates) tissue hyperplasia, gill and gut epithelial necrosis, gonadal tumours and kidney tubule occlusion. Literature on petroleum-associated diseases and abnormalities of fish and shellfish can best be summarized in four major categories: that dealing with integumental lesions offish; that concerned with various other kinds ofhistopathologies, usually experimentally induced; that emphasizing neoplasms of molluscs, and that related to genetic and morphological abnormalities in eggs and larvae, as a consequence of exposure to petroleum or its components. A. general conclusion is that petroleum, in sufficient concentration, can be toxic to marine animals, and toxicity may be expressed as morphological changes. . Some of the effects of petroleum, such as the enhancement of latent viral infections in clams and immunosuppression in fish, are quite probably associated with increased stress. The development of neoplasia and hyperplasia in petroleum-exposed marine animals deserves further examination, as does the entire matter of pollution-related integumental lesions.

scholarly journals Discovery of Swimming Males of Paratanaoidea (Tanaidacea)

2014 ◽  
Vol 35 (2) ◽  
pp. 415-453 ◽  
Author(s):  
Magdalena Błażewicz-Paszkowycz ◽  
Robert M. Jennings ◽  
Karen Jeskulke ◽  
Saskia Brix
Keyword(s):  
Morphological Changes ◽  
Species Level ◽  
Morphological Identification ◽  
Sexual Stage ◽  
Marine Animals ◽  
Two Factors ◽  
Secondary Traits ◽  
Parthenogenetic Reproduction ◽  
Juvenile Males ◽  
Multiple Male

AbstractIn Tanaidacea morphological identification of male individuals to the species level is complicated by two factors: the presence of multiple male stages/instars confuse the assessment of sexual stage while strong sexual dimorphism within several families obscures the morphological affinities of undescribed males to described females. Males of Paratanaoidea are often morphologically quite different from females and have not been discovered for most genera so far, which has led to the assumption that some tanaidaceans might have parthenogenetic reproduction or simply have undeveloped secondary sex traits. As a part ofthe IceAGE project (Icelandic marine Animals: Genetics and Ecology), with the support of molecular methods, the first evidence for the existence of highly dimorphic (swimming) males in four families of the superfamily Paratanaoidea (Agathotanaidae, Cryptocopidae, Akanthophoreidae, and Typhlotanaidae) is presented. This study suggests that these males might be the next instars after juvenile or preparatory males, which are morphologically similar to females. It has been assumed that “juvenile” males with a restricted ability for swimming (e.g., undeveloped pleopods) have matured testes, are capable of reproduction, and mate with females nearby, while swimming males can mate with distant females. Our explanation of the dimorphism in Tanaidomorpha lies in the fact that males of some species (e.g.,Nototanais) retain the same lifestyle or niche as the females, so secondary traits improve their ability to guard females and successfully mate. Males of other species that have moved into a regime (niche) different than that of the female have acquired complex morphological changes (e.g.,Typhlotanais).

scholarly journals THE MORPHOLOGICAL CHANGES IN THE TISSUES OF THE RABBIT AS A RESULT OF REDUCED OXIDATION

1918 ◽  
Vol 27 (3) ◽  
pp. 399-412 ◽  
Author(s):  
H. G. Martin ◽  
A. S. Loevenhart ◽  
C. H. Bunting
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Content ◽  
Morphological Changes ◽  
Low Oxygen ◽  
High Carbon ◽  
Red Bone Marrow ◽  
Hydropic Degeneration ◽  
Thyroid Hyperplasia ◽  
High Carbon Dioxide ◽  
Stimulation Of

Exposure of rabbits to an atmosphere of low oxygen content results in a stimulation of the cardiorespiratory systems, in an extension (hyperplasia) of red bone marrow and probably of a thyroid hyperplasia, with the further production of hydropic and hyaline degeneration in the cells of the parenchymatous organs. An atmosphere of high carbon dioxide and normal oxygen content produces, however, a stimulation of the cardiorespiratory systems, but no marrow extension and, in the concentrations used, but slight hydropic degeneration in the parenchyma of the glandular organs.

scholarly journals Dead zone or oasis in the open ocean? Zooplankton distribution and migration in low-oxygen modewater eddies

2016 ◽  
Vol 13 (6) ◽  
pp. 1977-1989 ◽  
Author(s):  
Helena Hauss ◽  
Svenja Christiansen ◽  
Florian Schütte ◽  
Rainer Kiko ◽  
Miryam Edvam Lima ◽  
...  
Keyword(s):  
Surface Layer ◽  
Dead Zone ◽  
Trophic Levels ◽  
Zooplankton Abundance ◽  
Depth Range ◽  
Calanoid Copepods ◽  
Long Term Effects ◽  
Low Oxygen ◽  
Oxygen Concentrations ◽  
Ocean Deoxygenation

Abstract. The eastern tropical North Atlantic (ETNA) features a mesopelagic oxygen minimum zone (OMZ) at approximately 300–600 m depth. Here, oxygen concentrations rarely fall below 40 µmol O2 kg−1, but are expected to decline under future projections of global warming. The recent discovery of mesoscale eddies that harbour a shallow suboxic (< 5 µmol O2 kg−1) OMZ just below the mixed layer could serve to identify zooplankton groups that may be negatively or positively affected by ongoing ocean deoxygenation. In spring 2014, a detailed survey of a suboxic anticyclonic modewater eddy (ACME) was carried out near the Cape Verde Ocean Observatory (CVOO), combining acoustic and optical profiling methods with stratified multinet hauls and hydrography. The multinet data revealed that the eddy was characterized by an approximately 1.5-fold increase in total area-integrated zooplankton abundance. At nighttime, when a large proportion of acoustic scatterers is ascending into the upper 150 m, a drastic reduction in mean volume backscattering (Sv) at 75 kHz (shipboard acoustic Doppler current profiler, ADCP) within the shallow OMZ of the eddy was evident compared to the nighttime distribution outside the eddy. Acoustic scatterers avoided the depth range between approximately 85 to 120 m, where oxygen concentrations were lower than approximately 20 µmol O2 kg−1, indicating habitat compression to the oxygenated surface layer. This observation is confirmed by time series observations of a moored ADCP (upward looking, 300 kHz) during an ACME transit at the CVOO mooring in 2010. Nevertheless, part of the diurnal vertical migration (DVM) from the surface layer to the mesopelagic continued through the shallow OMZ. Based upon vertically stratified multinet hauls, Underwater Vision Profiler (UVP5) and ADCP data, four strategies followed by zooplankton in response to in response to the eddy OMZ have been identified: (i) shallow OMZ avoidance and compression at the surface (e.g. most calanoid copepods, euphausiids); (ii) migration to the shallow OMZ core during daytime, but paying O2 debt at the surface at nighttime (e.g. siphonophores, Oncaea spp., eucalanoid copepods); (iii) residing in the shallow OMZ day and night (e.g. ostracods, polychaetes); and (iv) DVM through the shallow OMZ from deeper oxygenated depths to the surface and back. For strategy (i), (ii) and (iv), compression of the habitable volume in the surface may increase prey–predator encounter rates, rendering zooplankton and micronekton more vulnerable to predation and potentially making the eddy surface a foraging hotspot for higher trophic levels. With respect to long-term effects of ocean deoxygenation, we expect avoidance of the mesopelagic OMZ to set in if oxygen levels decline below approximately 20 µmol O2 kg−1. This may result in a positive feedback on the OMZ oxygen consumption rates, since zooplankton and micronekton respiration within the OMZ as well as active flux of dissolved and particulate organic matter into the OMZ will decline.

Trimethylamine oxide accumulation in marine animals: relationship to acylglycerol storagej

2002 ◽  
Vol 205 (3) ◽  
pp. 297-306 ◽  
Author(s):  
Brad A. Seibel ◽  
Patrick J. Walsh
Keyword(s):  
Compatible Solute ◽  
Marine Organisms ◽  
The Body ◽  
Marine Animals ◽  
Trimethylamine Oxide ◽  
Muscle Tissues ◽  
Compatible Osmolyte ◽  
Hydrolysis Of

SUMMARY Trimethylamine oxide (TMAO) is a common and compatible osmolyte in muscle tissues of marine organisms that is often credited with counteracting protein-destabilizing forces. However, the origin and synthetic pathways of TMAO are actively debated. Here, we examine the distribution of TMAO in marine animals and report a correlation between TMAO and acylglycerol storage. We put forward the hypothesis that TMAO is derived, at least in part, from the hydrolysis of phosphatidylcholine, endogenous or dietary, for storage as diacylglycerol ethers and triacylglycerols. TMAO is synthesized from the trimethylammonium moiety of choline, thus released, and is retained as a compatible solute in concentrations reflecting the amount of lipid stored in the body. A variation on this theme is proposed for sharks.

Arsenic species in Australian temperate marine food chains

2009 ◽  
Vol 60 (9) ◽  
pp. 885 ◽  
Author(s):  
W. Maher ◽  
S. Foster ◽  
F. Krikowa
Keyword(s):  
Metabolic Pathway ◽  
Arsenic Species ◽  
Marine Organisms ◽  
Food Chains ◽  
Arsenic Compounds ◽  
Marine Animals ◽  
Two Stage ◽  
Stage Conversion ◽  
Biochemical Pathways ◽  
Marine Food

Although over 50 arsenic species have been identified in marine organisms, the biochemical pathways by which these species are formed are not known. In this paper, we present an overview of bioconversions of arsenic species that occur in marine food chains based on studies conducted by our laboratory as well as the work of others. Phytoplankton and macroalgae only contain dimethylarsenoribosides or simple methylated arsenic compounds such as dimethylarsenate and dimethylarsenoethanol. Marine animals contain mostly arsenobetaine and a range of other arsenic species that may be precursors of arsenobetaine formation. The formation of arsenobetaine in marine animals from dimethylarsenoribosides may occur through a two-stage conversion pathway: arsenoriboside or trimethylarsonioriboside degradation to arsenocholine followed by quantitative oxidation to arsenobetaine. The minor arsenic species found in marine organisms are sulfur analogues of compounds found in the S-adenosylmethionine-methionine salvage and the dimethylsulfoniopropionate metabolic pathway of animals. A key intermediate in these pathways would be arsenomethionine, which could possibly be formed from dimethylarsinite, dimethylarsenoribosides or an arsenic-containing analogue of S-adenosylmethionine. Examining arsenic species in whole ecosystems has the advantage of using the pattern of arsenic species found to postulate the biochemical pathways of their formation.

Hormone action and plant adaptations to poor aeration

1994 ◽  
Vol 102 ◽  
pp. 391-405
Author(s):  
Michael B. Jackson
Keyword(s):  
Morphological Changes ◽  
Stomatal Closure ◽  
Low Oxygen ◽  
Aerenchyma Formation ◽  
Plant Adaptations ◽  
Endogenous Plant Hormones ◽  
Ethylene Precursor ◽  
Internal Morphology ◽  
Morphological Adaptations ◽  
Partial Pressures

SynopsisThe actions of endogenous plant hormones are invoked to explain several morphological adaptations to poor aeration. These include changes to the growth and internal morphology of inundated roots, the promotion of extension growth by stems or leaves of aquatic and semi-aquatic species by submergence, and morphological changes in shoots where only the roots and lower shoot are inundated. This article considers ethylene-promoted aerenchyma formation in maize (Zea mays) and compares the promoting action of ethylene, low oxygen partial pressures and carbon dioxide on shoot extension in rice (Oryza sativa), a rice mimic Echinochloa oryzoides and a submersed aquatic monocot Potamogeton pecrinatus. Different kinds of hormonal messages (positive, negative, accumulative and debit) passing between roots and shoots co-ordinate shoot development with the roots and their environment. Recent progress in quantifying the delivery of abscisic acid (ABA) or the ethylene precursor 1-aminocyclopropane-1-car-boxylic acid (ACC) from roots to shoots in the transpiration stream is summarised in relation to control of stomatal closure and leaf epinastic curvature in flooded plants.

Effect of MiR-16 on Acute Lung Injury in Neonatal Rats Through Regulating NF-κB Pathway

2020 ◽  
Vol 10 (3) ◽  
pp. 360-364
Author(s):  
Yan Xing ◽  
Yuan Liang ◽  
Changsong Shi ◽  
Yudong Miao ◽  
Jianqin Gu ◽  
...  
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Correlation Analysis ◽  
Western Blotting ◽  
Inflammatory Responses ◽  
Morphological Changes ◽  
Pearson Correlation ◽  
Mrna Levels ◽  
Low Oxygen ◽  
Pearson Correlation Analysis

Acute lung injury represents a widespread, variable type of lung injury characterized by a low oxygen level in the blood, non cardiogenic pulmonary edema, low lung compliance and extensive capillary leakage. In our study, the Wistar rat mode of ALI was established using lipopolysaccharide (LPS). The rats were randomly divided into normal control (NC) group (n = 12) and miR-16 overex-pression group (n = 12), and they were transfected with empty vector and miR-16 overexpression virus, respectively. The lung tissues were extracted in both groups, and then the expression levels of miR-16 and NF-κB were detected via fluorescence quantitative reverse transcription-polymerase chain reaction (qRT-PCR), and the association between their expressions was analyzed via Pearson correlation analysis. Moreover, the morphological changes in lung tissues were detected via hematoxylin-eosin (HE) staining, and the differences in the wet/dry weight (W/D) ratio and the pathomorphological score of lung tissues were compared between the two groups. The expression level of NF-κB was detected via immunohistochemistry (IHC) and Western blotting. Our results showed that, there were different degrees of lung injury in lung tissues in both groups. In miR-16 overexpression group, the W/D ratio was significantly higher than that in NC group (P < 0.05), and the pathomorphological score was also significantly higher than that in NC group (P < 0.05). The results of RT-PCR revealed that the mRNA levels of miR-16 and NF-κB in miR-16 overexpression group were 2.5 and 3.7 times higher than those in NC group. The results of Western blotting and IHC also showed that the activity of NF-κB in lung tissues was evidently enhanced in miR-16 overexpression group compared with that in NC group. According to the Pearson correlation analysis, there was a significant positive correlation between the mRNA levels of miR-16 and NF-κB in lung tissues (r = 0.705, P = 0.012). In conclusion, miR-16 activates the NF-κB pathway to initiate a series of inflammatory responses, thereby contributing to the occurrence of ALI in rats.

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