Local researcher to reveal problems of acidic oceans

The problems of increasing ocean acidity and its impact on regional marine life will be the subject of the first of a free lecture series hosted by the CCMI and Little Cayman Research Centre later this month. Emma Camp who is currently working on her PhD with the University of Essex and who works for CCMI as a researcher and lab manager will share her specialist knowledge on the subject and the day to day discoveries in the field. The oceans have absorbed excessive CO2, which has resulted in changes to the chemistry of surface seawater. As a result of increased ocean acidification, the future of a variety of critical species and ecosystems is in doubt an important factor for Cayman’s reef life.

The Pacific oyster, Crassostrea gigas, shows negative correlation to naturally elevated carbon dioxide levels: implications for near-term ocean acidification effects

We report results from an oyster hatchery on the Oregon coast, where intake waters experienced variable carbonate chemistry (aragonite saturation state < 0.8 to > 3.2; pH < 7.6 to > 8.2) in the early summer of 2009. Both larval production and midstage growth (∼ 120 to ∼ 150 µm) of the oyster Crassostrea gigas were significantly negatively correlated with the aragonite saturation state of waters in which larval oysters were spawned and reared for the first 48 h of life. The effects of the initial spawning conditions did not have a significant effect on early-stage growth (growth from D-hinge stage to ∼ 120 µm), suggesting a delayed effect of water chemistry on larval development.

The acid test: armor-covered plankton adapt to warming world

Tiny armor-covered creatures that float along with the ocean’s currents may adapt and survive, if badly, as their watery world warms and becomes more acidic, a new study finds.

Even so, the plankton may become flimsier and could turn into more of a “french fry” than a nutritious snack for its consumers.

As more carbon dioxide, a greenhouse gas, gets pumped into the atmosphere, and ultimately dissolves in the oceans, the seas are becoming more acidic. How this will impact life in the oceans is not known, though various studies have undertaken the challenge to find out.

In the new study, a trio of scientists at the Helmholtz Center for Oceanographic Research in Kiel, Germany, bred a variety of phytoplankton, called Emiliania huxleyi, to tolerate higher levels of carbon dioxide dissolved in the water.

Marine life ‘has warming defences’

Marine life may be more tolerant of climate change than previously thought, with new research showing the world’s most important calcifying organism can adapt to ocean acidification.

In a study published in the journal Nature Geoscience today, German scientists found the key micro-organism, a species of coccolithophore important in burying carbon in rocks, evolved a tolerance to higher carbon-dioxide levels over multiple generations, whereas previous studies had tended to look only at a single generation.

Commentary: Ocean acidification: invisible now, soon to become obvious

As I look out on Kachemak Bay, I know that the waters of the Bay, Cook Inlet, and the Gulf of Alaska are teeming with organisms that nourish the fish that I depend on to make a living and to fill my freezer.

Some days, the water is too rough to go fishing, but still, I know the fish are there waiting for when I can go. For more than 30 years, my family and I have enjoyed some of the most sought-after and prized foods in the world, harvested right at our doorsteps. It is only in the last five years that I have learned that the very food web that supports this luxury and sustenance is under attack from a silent killer.

Ocean acidification is the result of the ocean absorbing carbon dioxide from the atmosphere. As the world population has increased, so has the use and demand of energy that is produced by many different methods and fuels. Most of these methods result in the emission of carbon in the atmosphere. As the ocean absorbs this carbon dioxide, the acidity in seawater is increased and this reduces the availability of calcium carbonate minerals, which are the building blocks of shells and skeletons for many marine organisms.

Evolution at the sea – long-term experiments indicate phytoplankton can adapt to ocean acidification

Fossil fuel derived carbon dioxide has a serious impact on global climate but also a disturbing effect on the oceans, know as the other CO2 problem. When CO2 dissolves in seawater it forms carbonic acid and results in a drop in pH, the oceans acidify. A wealth of short-term experiments has shown that calcifying organisms, such as corals, clams and snails, but also micron size phytoplankton are affected by ocean acidification. The potential for organisms to cope with acidified oceanic conditions via evolutionary adaptations has so far been unresolved. Scientists of the Helmholtz Centre for Ocean Research Kiel (GEOMAR) have now for the first demonstrated the potential of the unicellular algae Emiliania huxleyi to adapt to changing pH conditions and thereby at least partly to mitigate negative effects of ocean acidification. These results raised by the biologists Kai Lohbeck, Prof. Ulf Riebesell und Prof. Thorsten Reusch are published in the current issue of Nature Geoscience.

Adaptive evolution of a key phytoplankton species to ocean acidification

Ocean acidification, the drop in seawater pH associated with the ongoing enrichment of marine waters with carbon dioxide from fossil fuel burning, may seriously impair marine calcifying organisms. Our present understanding of the sensitivity of marine life to ocean acidification is based primarily on short-term experiments, in which organisms are exposed to increased concentrations of CO2. However, phytoplankton species with short generation times, in particular, may be able to respond to environmental alterations through adaptive evolution. Here, we examine the ability of the world’s single most important calcifying organism, the coccolithophore Emiliania huxleyi, to evolve in response to ocean acidification in two 500-generation selection experiments. Specifically, we exposed E. huxleyi populations founded by single or multiple clones to increased concentrations of CO2. Around 500 asexual generations later we assessed their fitness. Compared with populations kept at ambient CO2 partial pressure, those selected at increased partial pressure exhibited higher growth rates, in both the single- and multiclone experiment, when tested under ocean acidification conditions. Calcification was partly restored: rates were lower under increased CO2 conditions in all cultures, but were up to 50% higher in adapted compared with non-adapted cultures. We suggest that contemporary evolution could help to maintain the functionality of microbial processes at the base of marine food webs in the face of global change.

Recognising ocean acidification in deep time: an evaluation of the evidence for acidification across the Triassic-Jurassic boundary

While demonstrating ocean acidification in the modern is relatively straightforward (measure increase in atmospheric CO2 and corresponding ocean chemistry change), identifying palaeo-ocean acidification is problematic. The crux of this problem is that the rock record is a constructive archive while ocean acidification is essentially a destructive (and/or inhibitory) phenomenon. This is exacerbated in deep time without the benefit of a deep ocean record. Here, we discuss the feasibility of, and potential criteria for, identifying an acidification event in deep time. Furthermore, we investigate the evidence for ocean acidification during the Triassic-Jurassic (T-J) boundary interval, an excellent test case because 1) it occurs in deep time, beyond the reach of deep sea drilling coverage; 2) a potential trigger for acidification is known; and 3) it is associated with one of the ‘Big Five’ mass extinctions which disproportionately affected modern-style invertebrates.

Three main criteria suggest that acidification may have occurred across the T-J transition. 1) The eruption of the Central Atlantic Magmatic Province (CAMP) and the associated massive and rapid release of CO2 coincident with the end-Triassic mass extinction provide a suitable trigger for an acidification event (full carbonate undersaturation in the surface ocean is possible but improbable). 2) Tentative evidence for a global paucity of carbonate across the end-Triassic mass extinction versus the adjacent stratigraphy is consistent with a predicted sedimentary response to acidification. 3) The end-Triassic mass extinction was particularly selective against acid-sensitive organisms (more so than perhaps any other extinction event) and temporarily eliminated coral reefs. Therefore multiple lines of evidence are consistent with a T-J ocean acidification event within our current resolution to recognise such events in deep time. The conclusion that the end-Triassic extinction was influenced by acidification implies that short-term acidification perturbations may have long-term effects on ecosystems, a repercussion that has previously not been established.

Although anthropogenic emissions are more rapid than any event in the geologic record, events such as the T-J can serve as partial analogues for the present anthropogenic carbon release. Since the T-J was such a pronounced crisis for both modern-style marine invertebrates and scleractinian reefs, it is of particular interest in terms of informing projections about the effects of modern ocean acidification.

SCCOOS projects – 2012 Ocean Acidification

What is ocean acidification?

As the ocean absorbs increasing levels of carbon dioxide (CO2) from the atmosphere, it causes changes in ocean chemistry. When carbon dioxide reacts with water, it creates carbonic acid, decreasing pH and carbonate ion concentration. Lower levels of pH in the ocean result in higher levels of acidity, causing “ocean acidification.”

Click here to view Part 1 and Part 2 of Scripps Institution of Oceanography Professor Andrew Dickson’s “Introduction to CO2 Chemistry in Seawater” lecture on UCTV.

What are the potential impacts?

Ocean acidification can have significant impacts on marine species, especially organisms that rely on calcium carbonate to build and maintain their shells and skeletons, such as clams, oysters, sea urchins, crabs, lobsters, and corals. Ocean acidification can both reduce amounts of calcium carbonate and prove corrosive to shells and corals.

What is SCCOOS doing?

SCCOOS plans to add ocean acidification monitoring to its ongoing observations of the coastal ocean. Sensors that monitor pH, CO2, and dissolved oxygen can be added to pier stations and gliders. These observations will allow for continuous measurements of acidification in the Southern California Bight and will allow for improvements to be made to the models that forecast climate change.

Marine life sandwiched by rising CO2

The oceans have absorbed almost 50 % of the CO2 humans released into the atmosphere, which has driven CO2 in the oceans to rise, causing – because of the effect of increasing CO2 in producing carbonic acid – a decline in ocean pH, termed ocean acidification. Ocean acidification has been argued to threaten calcifying organisms, such as corals and planktonic calcifiers, as coccolhitophores and pteropods.

However, CO2 does not only affect pH, but also affects the efficiency of aquatic aerobic respiration, which depends on the relative partial pressures of oxygen and CO2 in the water with which the organisms are to exchange their gases. In addition, reduced pH reduces the binding affinity for oxygen in blood. As a result, increased partial pressure of CO2 reduces the efficiency of aerobic respiration of aquatic organisms and, most importantly, raises the thresholds of oxygen required to support respiration.