Archive for December, 2013

Ocean acidification – one of the ‘top 5 ocean stories of 2013’ according to Smithsonian Magazine

Ocean acidification has been identified as one of the ‘top 5 ocean stories of 2013’ by Smithsonian Magazine:

Acid Test

With the warming planet on our minds, it’s easy to forget a less-obvious impact of climate change: ocean acidification, caused by carbon dioxide dissolving into the water from the air.

Continue reading ‘Ocean acidification – one of the ‘top 5 ocean stories of 2013’ according to Smithsonian Magazine’

The influence of increased CO2 on early developmental stages of cobia, Rachycentron canadum

Projected increases in atmospheric CO2 and the resulting decrease in oceanic pH over the course of the 21st century warrant studies on the effects of these changes on marine teleosts. The goal of this dissertation was to assess the impact of projected changes in CO2 on the early physiological dynamics and development of cobia, Rachycentron canadum. Spermatozoa respiration rates displayed a non significant decrease from 1.0 + 0.2 nmol O2/mL semen•sec + S.E. at 380 ppm CO2 to 0.7 + 0.1 nmol O2/mL semen•sec + S.E. at 800 ppm CO2. Spermatozoa velocity decreased from 22.1 + 0.5 to 14.9 + 0.4 µm/sec + S.E. for one male and from 16.9 + 0.4 to 15.5 + 0.5 µm/sec + S.E. for the second male. Both decreases in velocity were statistically significant. Regression analysis of embryo respiration did not show a statistically significant difference across the CO2 levels examined (400, 480, 500, 580, 1020, 2920 ppm). Embryonic development after 9 and 19 hrs exposure to elevated levels of CO2 (876, 949, 957 ppm) were not significantly different. Yolk-sac larvae respiration decreased from 10.7 + 3.4 nmol O2/larvae/hr + S.E. at 380 ppm to 6.6 + 2.3 nmol O2/larvae/hr + S.E. at 800 ppm. Yolk-sac larvae total length decreased from 2.59 + 0.34 to 2.29 + 0.28 mm + S.D. at 560 ppm but increased to 2.89 + 0.28 mm + S.D. at 800 ppm CO2. These results suggest early life history stages of cobia may be resistant to near future CO2 levels.

Continue reading ‘The influence of increased CO2 on early developmental stages of cobia, Rachycentron canadum’

Science on Tap lecture examines impacts of ocean acidification

ASTORIA — If you’ve heard the term “ocean acidification,” it’s likely been in the context of some future threat. Corals disappearing, fish populations harmed, island nations that depend on fish suffering. But ocean acidification is already impacting people and places today – particularly in the Pacific Northwest.

Join the Columbia River Maritime Museum for its next Science on Tap, “Ocean Acidification: From Shellfish to Science, Salmon to Solutions” at 7 p.m. Thursday, Jan. 2 at the Fort George Lovell Showroom.

Continue reading ‘Science on Tap lecture examines impacts of ocean acidification’

Seasonal variability of sea surface carbonate chemistry and temperature

Ocean uptake of anthropogenic CO2 causes ocean acidification, a secular, global-scale decline in the pH of seawater. In order to better understand the implications of contemporary acidification for marine organisms and ecosystems, there is a need to better characterise natural variability in carbonate chemistry. In this thesis, climatological seasonal variability of sea surface pH and aragonite saturation state (OmegaA) in the open ocean is indirectly derived from other parameters of the marine CO2 system, namely total alkalinity (TA) and seawater pCO2/fCO2 (pCO2sw/fCO2sw). New monthly sea surface TA, fCO2sw and temperature climatologies are developed for this purpose, utilising newly-released observational synthesis products (PACIFICA for TA and SOCAT v2 for fCO2sw). Two versions of the new SST climatology are developed, referred to as upper and lower SST (USST and LSST), to test sensitivity to the depth range of the input observations. Annual ranges are generally found to be larger for the USST climatology, derived using observations from the upper 2 m, compared to LSST (which is based on deeper observations). Further, a seasonal cycle is found in the monthly average of the differences between these climatologies north of 30 degN, perhaps partly due to seasonal variation in near-surface stratification. The USST seasonal ranges are also found to be generally larger than in two previous SST climatologies, however, difference in the depth distribution of the input measurements is unlikely the main cause. The new monthly sea surface TA climatology extends coverage into the Nordic seas, excluded from previous climatologies. TA seasonality is found to be small outside of regions with large seasonal ranges in salinity. Large seasonal ranges in salinity and TA are found beneath the Intertropical Convergence Zone, in the Antarctic seasonal sea ice zone and in the western Greenland Sea. Non-salinity driven TA seasonality is found to be large in the Gulf of Alaska, eastern equatorial Pacific and western Greenland Sea. Compared to the Lee et al. (2006) TA climatology, substantially lower annual means and seasonal ranges are found for the subarctic Pacific, a region with greatly improved coverage courtesy of PACIFICA. The pH/OmegaA climatologies derived in the final chapter suggest pH seasonality is predominantly temperature driven in the subtropics and mainly driven by variation in salinity normalised dissolved inorganic carbon (sDIC) in the subpolar north Atlantic, western subarctic Pacific and Southern Ocean. Salinity variation is found to only exert a strong influence on pH seasonality in the western Greenland Sea. Climatological seasonal pH ranges are found to be mostly small in the tropics (0.1) in parts of the Ross, Weddell, Irminger and Iceland Seas and western subarctic Pacific gyre. OmegaA seasonality is found to be predominantly sDIC-driven everywhere except in the western Greenland Sea, with temperature variation generally being of modest influence. Seasonal cycles of pH and OmegaA are found to be in anti-phase where pH is mainly thermally driven and in-phase where pH is mainly sDIC-forced (both pH and OmegaA vary inversely with DIC). Comparison is made between the primary new pH/OmegaA climatology and various open ocean carbonate chemistry time-series. The climatology captures the general form of the climatological seasonal cycles of pH and OmegaA from the time-series, although with some differences in phasing and seasonal range. Analysing the time-series for long-term trends, I find that inter-decadal anthropogenic CO2 uptake driven pH and OmegaA declines can be modulated by trends in temperature, salinity or sTA. Investigation is also conducted into how the amplitude of pH and OmegaA seasonal cycles might change by 2100 for a subpolar and subtropical time-series. Under a high CO2 emissions scenario, the seasonal range of pH is found to be strongly enhanced for the subpolar time-series and moderately reduced for the subtropical time-series, with both being due to changes in seawater buffer capacity.

Continue reading ‘Seasonal variability of sea surface carbonate chemistry and temperature’

Sea water acidification affects osmotic swelling, regulatory volume decrease and discharge in nematocytes of the jellyfish Pelagia noctiluca

Background: Increased acidification/PCO2 of sea water is a threat to the environment and affects the homeostasis of marine animals. In this study, the effect of sea water pH changes on the osmotic phase (OP), regulatory volume decrease (RVD) and discharge of the jellyfish Pelagia noctiluca (Cnidaria, Scyphozoa) nematocytes, collected from the Strait of Messina (Italy), was assessed. Methods: Isolated nematocytes, suspended in artificial sea water (ASW) with pH 7.65, 6.5 and 4.5, were exposed to hyposmotic ASW of the same pH values and their osmotic response and RVD measured optically in a special flow through chamber. Nematocyte discharge was analyzed in situ in ASW at all three pH values. Results: At normal pH (7.65), nematocytes subjected to hyposmotic shock first expanded osmotically and then regulated their cell volume within 15 min. Exposure to hyposmotic ASW pH 6.5 and 4.5 compromised the OP and reduced or totally abrogated the ensuing RVD, respectively. Acidic pH also significantly reduced the nematocyte discharge response. Conclusion: Data indicate that the homeostasis and function of Cnidarians may be altered by environmental changes such as sea water acidification, thereby validating their use as novel bioindicators for the quality of the marine environment.

Continue reading ‘Sea water acidification affects osmotic swelling, regulatory volume decrease and discharge in nematocytes of the jellyfish Pelagia noctiluca’

The impact of ocean acidification on the functional morphology of foraminifera

Culturing experiments were performed on sediment samples from the Ythan Estuary, N. E. Scotland, to assess the impacts of ocean acidification on test surface ornamentation in the benthic foraminifer Haynesina germanica. Specimens were cultured for 36 weeks at either 380, 750 or 1000 ppm atmospheric CO2. Analysis of the test surface using SEM imaging reveals sensitivity of functionally important ornamentation associated with feeding to changing seawater CO2 levels. Specimens incubated at high CO2 levels displayed evidence of shell dissolution, a significant reduction and deformation of ornamentation. It is clear that these calcifying organisms are likely to be vulnerable to ocean acidification. A reduction in functionally important ornamentation could lead to a reduction in feeding efficiency with consequent impacts on this organism’s survival and fitness.

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Sponges erode coral reef under acidification scenarios

OCEAN warming and acidification are leading to an increase in the rate of sponge biomass and bioerosion.

Combined German-Australian research, recently presented at the Ninth World Sponge Conference in Fremantle, used past, present and future climate scenarios to explore how changes are occurring.

The Australian Institute of Marine Science’s Dr Christine Schönberg, based at UWA’s Oceans Institute, planned and shared fieldwork and experiments with German bioerosion expert Dr Max Wisshak.

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A novel method for the measurement of VOCs in seawater using needle traps devices and GC-MS

A novel analytical method using newly developed Needle Trap Devices (NTDs) and a gas chromatograph mass spectrometer (GC-MS) system was developed. It has been applied for the first time on seawater samples to quantify marine volatile organic compounds (VOC) relevant to atmospheric chemistry and climate. By purging gases from small water volumes (10 ml) onto sealable NTDs and then desorbing them thermally within the GC injection port, an effective analysis of a wide range of VOCs (isoprene to α-pinene) was achieved within 23 minutes. Good repeatability (RSDs < 16%), linearity (r2 = 0.96 – 0.99) and limits of detection in the range of pM were obtained for all examined compounds. Following laboratory validation, the NTD method was applied in a mesocosm field study in a Norwegian Fjord. Nine individual mesocosm ecosystems under different CO2 regimes were examined. Dimethylsulphide (DMS), isoprene and monoterpenes were identified and quantified in mesocosm seawater. The DMS measurements are compared with parallel measurements provided by an independent P&T GC-FPD system showing good correlation, r2 = 0.8. Our study indicates that the NTD method can be used successfully in place of the traditionally used extraction techniques (P&T, SPME) in marine environments to extend the suite of species typically measured and improve detection limits.

Continue reading ‘A novel method for the measurement of VOCs in seawater using needle traps devices and GC-MS’

Merry Christmas and a Happy New Year from the OA-ICC!!!

season greetings card copy

Creatures behaving strangely

Our understanding of how souring seas will transform the oceans is growing more sophisticated every day. Here is a glimpse of what scientists are finding in laboratory studies about how ocean acidification could affect marine life.

Brittlestar

This starfish relative is known for its ability to regenerate broken limbs, a feat employed to escape predators. Even small changes in ocean chemistry can cause some baby brittlestars to die in less than a week. Adults of other brittlestar species show loss of muscle mass when regrowing arms in high-carbon dioxide water. And warming water temperatures can make things worse by slowing regrowth. Adults of some brittlestar species appear resistant to ocean-chemistry changes.

Continue reading ‘Creatures behaving strangely’


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Ocean acidification in the IPCC AR5 WG II

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