After an opening welcome by Herman Hummel and Bob Kennedy, the first day started with four talks about climate change.
Opening speaker is Professor Jason Hall Spencer from Plymouth University, England. Jason and his team are focusing their research this year on deep coral reefs in the Arctic, satellite tracking of fishing vessels in order to identify possible marine protected areas, as well as studies of underwater volcanoes and how to use these to predict the effects of acidification by elevated levels of carbon dioxide in the atmosphere.
An increased amount of carbon dioxide in the atmosphere affects the balance of carbonate and bicarbonate in the sea, and thus all the animals that build shells and skeletons of lime (clams, snails, corals, echinoderms, etc.). The effect is an ocean acidification (OA). Acidification is measured as pH, where a value above 7 is alkaline and below 7 is acidic. The pH of the ocean has fallen from 8.20 in year 1800 to 8.05 in year 2000. It may seem little, but one should keep in mind that pH is measured on a logarithmic scale. One can already see the effects of mussel larvae, which is 20% fewer larvae in water with lower pH.
Another effect of the increased amount of carbon dioxide in the atmosphere is increasing temperature. This affects several marine species, who are unable to survive in high temperatures. Temperature in combination with acidification can have devastating consequences for marine life on a global scale.
To try to understand how acidification and temperature rise will affect the different ecosystems of the oceans, researchers are trying to conduct experiments that extend over a longer period of time, preferably over a few generations of different organisms, in order to distinguish the cause from the effect. The difficulty is to include all parameters when doing an experiment in the lab, and time is always in short supply for ecologists.
Naturally acidic areas in the ocean can be found outside Sicily, where cracks from Mount Vesuvius are bubbling up carbon dioxide into the water column. Here, the researchers have placed various organisms and examined how they were affected by the lowered pH. Several of our larger species, such as the sea grass Posidonia, seems unaffected, but many of the species found in seaweed beds are adversely affected, sometimes missing altogether. It is mainly red algae with a high calcareous content disappears.
Another potential problem is that other invasive species will gladly take over where seaweed has disappeared. It may seem good that someone fills in the gaps, but these algae do not have the same ecological function as seagrass, and also prevents the seaweed from reestablishing. There is a difference between macrophyte and macrophyte, indeed.
What happens if you move animals with calcareous skeletons between low and high (normal) pH? Depending on the organism you move, they are affected more or less. Some clearly show that they are capable of moving between normal and acidic pH as long as it’s cold, but if it occurs during the summer when it’s really hot in the water, they die.
Jason concludes that we must classify carbon dioxide as a marine pollutant, and the faster we can get policy makers and politicians to understand this, the better.
Dr. Andrea Gori continued in the same vein by showing how beautiful cold-water corals, mainly Dendrophyllia cornigera, are affected by rising temperatures and acidification. Dendrophyllia can be found at 200 m depth off the Canary Islands, where it is the dominant benthic (bottom-dwelling) species.
The results show that these corals can handle a fairly wide range of temperatures between 8-16 degrees Celsius. The study also shows that the species seem to thrive and grow better in temperate environments (12-16 degrees Celsius) than in cold water, where Lophelia pertusa is the dominant coral species.
Our Finnish colleague Tiina Salo, presented data from studies on Zostera marina (eelgrass), which she performed at Roskilde University in Denmark together with dr. Morten Foldager-Pedersen.
Tiina and Morten have examined the interactive effects of salinity and temperature, which has not previously been done for seaweed. The scenario is particularly relevant for the Baltic Sea, where a reduction in salinity is expected to be the largest impact of the ongoing climate change.
The study shows that salinity and temperature have a combined effect on the seaweed, especially on number of leaves formed in both young seedlings and adult individuals. Generally, young plants are more sensitive than adults, and they died completely in the treatment exposed to the highest temperature and lowest salinity.
Thus, future climate changes affect eelgrass in the Baltic Sea, and its vegetative propagation will be more important for the species’ distribution and survival.
Last out before the coffee break (or tea, this being Ireland), is Dan Smale with a summary of Extreme Climatic Events in the marine environment, or Marine Heat Waves, and how they can affect entire ecosystems.
The example is the heat wave along the west coast of Australia in 2011 caused by extreme El Niño conditions, that lasted for two weeks. Before the heat wave there were dense kelp Forests. These could not survive the heat, as they were already living on the edge of their heat tolerance. When the kelp disappeared, the cleared surface was covered again with dense turf algae that effectively prevent kelp from coming back.
The kelp forest has decreased significantly, and this has in turn affected the amount and species number of fish found in these areas. In the region where the kelp previously existed, were also previously found 6 species of mobile invertebrate fauna (sea urchins, snails, etc.). These species have not succeeded in re-establishing themselves in the affected area, as their base habitat, kelp, is no longer there.
Since only two weeks of heat can have such a major impact on an ecosystem, one dares hardly think of how a long heat wave would affect marine life.
After refreshment of coffee, tea and cake, the last session of the day is opened by Professor Mark J. Costello, a heavy name in marine biology, who among other things, helped to found WoRMS. He starts off by pointing out that in the Bible’s book of Genesis, God gave man the task of naming species (and maybe a few more irrelevant tasks as well), and that he, as a taxonomist, is working on it. The title of his presentation is “Can we discover Earth’s species before they go extinct?”
The estimated number of marine species that we have identified today is between 320,000 to 760,000 if you use the WoRMS database, and 704,000-972,000 using different assumptions and methods, often described as expert estimations. Mark highlights how inadequate sampling methods may produce very large differences, and why it is obvious that there are more species in the oceans than on land, when seas are so much greater.
Hardly surprising, physically large groups, such as birds, whales and turtles, were early discovered and mapped (if not hunted to extinction), while smaller organisms like bryozoans and tube worms have been “discovered” in greater numbers during recent years. Looking at the timeline of species Discovery, it shows a marked peak in year 1900, when some big expeditions went out and collected large amounts of marine animals. The trend, of course, fell during the World Wars, but has climbed steadily since the 1950s. Some species, however, have been described several times. Spermwhale has no less than 19 (!!) different scientific names. Sometimes itis because the species look different as young and adult, or because the male and female have completely different colours.
Mark estimates that only 61-64% of the planets alge are described (micro and macro algae). If you divide up the animals in the micro fauna (less than 1 mm) and macrofauna (larger than 1 mm), one sees that there are ten times as much microfauna than macrofauna. One can discover a lot by seeing the world through a magnifying glass or a microscope.
The humor reaches the nerdiest of levels, when he shows diagrams of how taxonomists (someone who works with describing new species, like Linnaeus) have increased over the years, although rumor has it that they are becoming extinct, how it differs for marine and terrestrial, between single versus co-published species descriptions and across the continents. He concludes by summarizing that taxonomists are not an endangered genus, but that it presumably requires more work to find new species today when so many are already described. He criticizes the articles that claim it is because the species are dying out at an accelerating rate.