scholarly journals Acidification can directly affect olfaction in marine organisms

2021 ◽  
Vol 224 (14) ◽  
Author(s):  
Cosima S. Porteus ◽  
Christina C. Roggatz ◽  
Zelia Velez ◽  
Jörg D. Hardege ◽  
Peter C. Hubbard
Keyword(s):  
Olfactory Bulb ◽  
Ocean Acidification ◽  
Marine Fish ◽  
Low Ph ◽  
Marine Organisms ◽  
Gamma Aminobutyric Acid ◽  
Ion Distribution ◽  
Gabaergic Neurotransmission ◽  
High Co2 ◽  
Olfactory Bulb Neurons

ABSTRACT In the past decade, many studies have investigated the effects of low pH/high CO2 as a proxy for ocean acidification on olfactory-mediated behaviours of marine organisms. The effects of ocean acidification on the behaviour of fish vary from very large to none at all, and most of the maladaptive behaviours observed have been attributed to changes in acid–base regulation, leading to changes in ion distribution over neural membranes, and consequently affecting the functioning of gamma-aminobutyric acid-mediated (GABAergic) neurotransmission. Here, we highlight a possible additional mechanism by which ocean acidification might directly affect olfaction in marine fish and invertebrates. We propose that a decrease in pH can directly affect the protonation, and thereby, 3D conformation and charge distribution of odorants and/or their receptors in the olfactory organs of aquatic animals. This can sometimes enhance signalling, but most of the time the affinity of odorants for their receptors is reduced in high CO2/low pH; therefore, the activity of olfactory receptor neurons decreases as measured using electrophysiology. The reduced signal reception would translate into reduced activation of the olfactory bulb neurons, which are responsible for processing olfactory information in the brain. Over longer exposures of days to weeks, changes in gene expression in the olfactory receptors and olfactory bulb neurons cause these neurons to become less active, exacerbating the problem. A change in olfactory system functioning leads to inappropriate behavioural responses to odorants. We discuss gaps in the literature and suggest some changes to experimental design in order to improve our understanding of the underlying mechanisms and their effects on the associated behaviours to resolve some current controversy in the field regarding the extent of the effects of ocean acidification on marine fish.

scholarly journals Cymodocea nodosa response to simulated CO2-driven ocean acidification: a first insight from global transcriptome profiling

2015 ◽  
Author(s):  
Miriam Ruocco ◽  
Procaccini Gabriele ◽  
Francesco Musacchia ◽  
Remo Sanges ◽  
Irene Olivé ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Molecular Mechanisms ◽  
Transcriptome Assembly ◽  
Co2 Concentration ◽  
Marine Organisms ◽  
Photosynthetic Parameters ◽  
Cymodocea Nodosa ◽  
Field Station ◽  
High Co2 ◽  
Co2 Levels

Global climate changes are imposing multiple pressures to marine organisms. The rising atmospheric CO2 concentration is causing substantial changes in ocean physics, chemistry and biology. At least three synergic environmental stressors have been recognized as primary driven by CO2 emissions: ocean warming, oxygen loss and ocean acidification. The effects of CO2-driven ocean acidification on seagrass metabolism remain largely understudied. A few studies have been conducted near submarine volcanic vents, which mimic the future ocean acidification scenarios, allowing researchers to investigate the performance of marine organisms under long-term exposure to high-CO2 levels. Apart from these, some mesocosm-based experiments have investigated growth and physiological responses to high CO2. For this work, we built an outdoor mesocosm facility at the Centre of Marine Sciences’ field station in Algarve, Portugal, to experimentally manipulate CO2 levels and investigate the effects of high-CO2/low pH on seagrass metabolism and underlying molecular mechanisms. Cymodocea nodosa plants were collected in Cadiz Bay at the end of January 2014 and transported to the mesocosm facility. After a one week acclimation period, C. nodosa were either kept under normal (400 ppm) or elevated (1200 ppm) CO2 concentration for 12 days. Water physico-chemical parameters, irradiance, and chlorophyll-fluorescence-derived photosynthetic parameters were monitored on a daily basis. Here we present, for the first time in this species, results obtained using Illumina RNAseq technology and de-novo transcriptome assembly. Using C. nodosa RNAs extracted at the beginning and the end of the experiment, we assembled more than 70 thousands unique transcripts and were able to annotate more than 90% of them using the Annocript pipeline. Differential expression analysis revealed about 500 transcripts significantly differentially regulated between plants kept under control and high-CO2 conditions. Pathways showing largest changes in gene expression included isoprenoid and amino-acid biosynthesis, porphyrin-containing compound metabolism, amine and polyamine biosynthesis, lipid and carbohydrate metabolism. Transcriptome sequencing also significantly increases the molecular resources available for C. nodosa, almost completely absent before this study.

Differential modulation by zinc and copper of amino acid receptors from rat olfactory bulb neurons

1996 ◽  
Vol 76 (4) ◽  
pp. 2536-2546 ◽  
Author(s):  
P. Q. Trombley ◽  
G. M. Shepherd
Keyword(s):  
Amino Acid ◽  
Olfactory Bulb ◽  
Nmda Receptors ◽  
Gaba Receptors ◽  
Gamma Aminobutyric Acid ◽  
Differential Modulation ◽  
Glycine Receptors ◽  
Amino Acid Receptors ◽  
High Concentrations ◽  
Olfactory Bulb Neurons

1. The olfactory bulb contains high concentrations of zinc and copper. Whole cell recording techniques were used to examine the modulatory actions of zinc and copper on N-methyl-D-aspartate (NMDA), gamma-aminobutyric acid (GABA), and glycine receptors on rat olfactory bulb neurons in culture and acutely isolated from adult animals. 2. Zinc and copper were effective antagonists of both NMDA-and GABA-mediated currents. The median inhibiting concentrations (IC50s) for zinc were 19 microM for NMDA receptors and 17 microM for GABA receptors. The IC50s for copper were 22 microM for NMDA receptors and 18 microM for GABA receptors. 3. Zinc and copper (100 microM) had no effect on the steady-state, desensitized component of currents evoked by high concentrations of glycine (300 microM). In contrast, when low, nondesensitizing concentrations of glycine (30 microM) were used, 100 microM zinc dramatically potentiated the current and 100 microM copper blocked the current. 4. The effects of zinc and copper on NMDA-, GABA-, or glycine-mediated currents were not voltage dependent, irrespective of whether the effect was potentiation or inhibition. 5. These results provide the first evidence for an inhibitory effect of copper on NMDA receptors, and the first evidence that the effects of zinc and copper on glycine receptors are dependent on the state of the receptor. These results suggest that endogenous zinc and copper may act as allosteric neuromodulators of amino acid receptors on olfactory bulb neurons. Furthermore, zinc and copper may provide a mechanism for differential modulation of inhibitory transmission because of their distinct effects on glycine versus GABA receptors.

scholarly journals Cymodocea nodosa response to simulated CO2-driven ocean acidification: a first insight from global transcriptome profiling

2015 ◽  
Author(s):  
Miriam Ruocco ◽  
Procaccini Gabriele ◽  
Francesco Musacchia ◽  
Remo Sanges ◽  
Irene Olivé ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Molecular Mechanisms ◽  
Transcriptome Assembly ◽  
Co2 Concentration ◽  
Marine Organisms ◽  
Photosynthetic Parameters ◽  
Cymodocea Nodosa ◽  
Field Station ◽  
High Co2 ◽  
Co2 Levels

Global climate changes are imposing multiple pressures to marine organisms. The rising atmospheric CO2 concentration is causing substantial changes in ocean physics, chemistry and biology. At least three synergic environmental stressors have been recognized as primary driven by CO2 emissions: ocean warming, oxygen loss and ocean acidification. The effects of CO2-driven ocean acidification on seagrass metabolism remain largely understudied. A few studies have been conducted near submarine volcanic vents, which mimic the future ocean acidification scenarios, allowing researchers to investigate the performance of marine organisms under long-term exposure to high-CO2 levels. Apart from these, some mesocosm-based experiments have investigated growth and physiological responses to high CO2. For this work, we built an outdoor mesocosm facility at the Centre of Marine Sciences’ field station in Algarve, Portugal, to experimentally manipulate CO2 levels and investigate the effects of high-CO2/low pH on seagrass metabolism and underlying molecular mechanisms. Cymodocea nodosa plants were collected in Cadiz Bay at the end of January 2014 and transported to the mesocosm facility. After a one week acclimation period, C. nodosa were either kept under normal (400 ppm) or elevated (1200 ppm) CO2 concentration for 12 days. Water physico-chemical parameters, irradiance, and chlorophyll-fluorescence-derived photosynthetic parameters were monitored on a daily basis. Here we present, for the first time in this species, results obtained using Illumina RNAseq technology and de-novo transcriptome assembly. Using C. nodosa RNAs extracted at the beginning and the end of the experiment, we assembled more than 70 thousands unique transcripts and were able to annotate more than 90% of them using the Annocript pipeline. Differential expression analysis revealed about 500 transcripts significantly differentially regulated between plants kept under control and high-CO2 conditions. Pathways showing largest changes in gene expression included isoprenoid and amino-acid biosynthesis, porphyrin-containing compound metabolism, amine and polyamine biosynthesis, lipid and carbohydrate metabolism. Transcriptome sequencing also significantly increases the molecular resources available for C. nodosa, almost completely absent before this study.

scholarly journals Over-calcified forms of the coccolithophore <i>Emiliania huxleyi</i> in high-CO<sub>2</sub> waters are not preadapted to ocean acidification

2018 ◽  
Vol 15 (5) ◽  
pp. 1515-1534 ◽  
Author(s):  
Peter von Dassow ◽  
Francisco Díaz-Rosas ◽  
El Mahdi Bendif ◽  
Juan-Diego Gaitán-Espitia ◽  
Daniella Mella-Flores ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Large Population ◽  
Emiliania Huxleyi ◽  
Low Ph ◽  
Production Rates ◽  
High Co2 ◽  
Surface Ocean ◽  
Population Sizes ◽  
Multicellular Organisms ◽  
Correlated Factors

Abstract. Marine multicellular organisms inhabiting waters with natural high fluctuations in pH appear more tolerant to acidification than conspecifics occurring in nearby stable waters, suggesting that environments of fluctuating pH hold genetic reservoirs for adaptation of key groups to ocean acidification (OA). The abundant and cosmopolitan calcifying phytoplankton Emiliania huxleyi exhibits a range of morphotypes with varying degrees of coccolith mineralization. We show that E. huxleyi populations in the naturally acidified upwelling waters of the eastern South Pacific, where pH drops below 7.8 as is predicted for the global surface ocean by the year 2100, are dominated by exceptionally over-calcified morphotypes whose distal coccolith shield can be almost solid calcite. Shifts in morphotype composition of E. huxleyi populations correlate with changes in carbonate system parameters. We tested if these correlations indicate that the hyper-calcified morphotype is adapted to OA. In experimental exposures to present-day vs. future pCO2 (400 vs. 1200 µatm), the over-calcified morphotypes showed the same growth inhibition (−29.1±6.3 %) as moderately calcified morphotypes isolated from non-acidified water (−30.7±8.8 %). Under the high-CO2–low-pH condition, production rates of particulate organic carbon (POC) increased, while production rates of particulate inorganic carbon (PIC) were maintained or decreased slightly (but not significantly), leading to lowered PIC ∕ POC ratios in all strains. There were no consistent correlations of response intensity with strain origin. The high-CO2–low-pH condition affected coccolith morphology equally or more strongly in over-calcified strains compared to moderately calcified strains. High-CO2–low-pH conditions appear not to directly select for exceptionally over-calcified morphotypes over other morphotypes, but perhaps indirectly by ecologically correlated factors. More generally, these results suggest that oceanic planktonic microorganisms, despite their rapid turnover and large population sizes, do not necessarily exhibit adaptations to naturally high-CO2 upwellings, and this ubiquitous coccolithophore may be near the limit of its capacity to adapt to ongoing ocean acidification.

Effects and mechanisms of ocean acidification on macromolecules of marine organisms

2013 ◽  
Vol 20 (6) ◽  
pp. 1310-1318
Author(s):  
Zhaokun DING ◽  
Weiru LIU ◽  
Youqing XU
Keyword(s):  
Ocean Acidification ◽  
Marine Organisms

scholarly journals The Influence of Ocean Acidification and Warming on DMSP & DMS in New Zealand Coastal Water

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 181
Author(s):  
Alexia D. Saint-Macary ◽  
Neill Barr ◽  
Evelyn Armstrong ◽  
Karl Safi ◽  
Andrew Marriner ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Coastal Water ◽  
Phytoplankton Community ◽  
Dimethyl Sulfide ◽  
Temperature Treatment ◽  
Low Ph ◽  
Trace Gas ◽  
Mesocosm Experiments ◽  
Future Warming ◽  
Higher Temperature

The cycling of the trace gas dimethyl sulfide (DMS) and its precursor dimethylsulfoniopropionate (DMSP) may be affected by future ocean acidification and warming. DMSP and DMS concentrations were monitored over 20-days in four mesocosm experiments in which the temperature and pH of coastal water were manipulated to projected values for the year 2100 and 2150. This had no effect on DMSP in the two-initial nutrient-depleted experiments; however, in the two nutrient-amended experiments, warmer temperature combined with lower pH had a more significant effect on DMSP & DMS concentrations than lower pH alone. Overall, this indicates that future warming may have greater influence on DMS production than ocean acidification. The observed reduction in DMSP at warmer temperatures was associated with changes in phytoplankton community and in particular with small flagellate biomass. A small decrease in DMS concentration was measured in the treatments relative to other studies, from −2% in the nutrient-amended low pH treatment to −16% in the year 2150 pH and temperature conditions. Temporal variation was also observed with DMS concentration increasing earlier in the higher temperature treatment. Nutrient availability and community composition should be considered in models of future DMS.

scholarly journals Ocean acidification of a coastal Antarctic marine microbial community reveals a critical threshold for CO<sub>2</sub> tolerance in phytoplankton productivity

2018 ◽  
Vol 15 (1) ◽  
pp. 209-231 ◽  
Author(s):  
Stacy Deppeler ◽  
Katherina Petrou ◽  
Kai G. Schulz ◽  
Karen Westwood ◽  
Imojen Pearce ◽  
...  
Keyword(s):  
Organic Matter ◽  
Ocean Acidification ◽  
Primary Productivity ◽  
Phytoplankton Community ◽  
Bacterial Abundance ◽  
Critical Threshold ◽  
Bacterial Productivity ◽  
High Co2 ◽  
Chl A ◽  
Antarctic Marine

Abstract. High-latitude oceans are anticipated to be some of the first regions affected by ocean acidification. Despite this, the effect of ocean acidification on natural communities of Antarctic marine microbes is still not well understood. In this study we exposed an early spring, coastal marine microbial community in Prydz Bay to CO2 levels ranging from ambient (343 µatm) to 1641 µatm in six 650 L minicosms. Productivity assays were performed to identify whether a CO2 threshold existed that led to a change in primary productivity, bacterial productivity, and the accumulation of chlorophyll a (Chl a) and particulate organic matter (POM) in the minicosms. In addition, photophysiological measurements were performed to identify possible mechanisms driving changes in the phytoplankton community. A critical threshold for tolerance to ocean acidification was identified in the phytoplankton community between 953 and 1140 µatm. CO2 levels  ≥ 1140 µatm negatively affected photosynthetic performance and Chl a-normalised primary productivity (csGPP14C), causing significant reductions in gross primary production (GPP14C), Chl a accumulation, nutrient uptake, and POM production. However, there was no effect of CO2 on C : N ratios. Over time, the phytoplankton community acclimated to high CO2 conditions, showing a down-regulation of carbon concentrating mechanisms (CCMs) and likely adjusting other intracellular processes. Bacterial abundance initially increased in CO2 treatments  ≥ 953 µatm (days 3–5), yet gross bacterial production (GBP14C) remained unchanged and cell-specific bacterial productivity (csBP14C) was reduced. Towards the end of the experiment, GBP14C and csBP14C markedly increased across all treatments regardless of CO2 availability. This coincided with increased organic matter availability (POC and PON) combined with improved efficiency of carbon uptake. Changes in phytoplankton community production could have negative effects on the Antarctic food web and the biological pump, resulting in negative feedbacks on anthropogenic CO2 uptake. Increases in bacterial abundance under high CO2 conditions may also increase the efficiency of the microbial loop, resulting in increased organic matter remineralisation and further declines in carbon sequestration.

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