CeMEB Advanced Course 2012: marine evolution under climate change

International course for PhD students, post docs and master students

Deadline for registration: 30th September 2012

19 – 23 November 2012, Kristineberg

What determines species-sensitivity to future environmental stressors and how does it relates to species recent evolutionary history? What life-history strategies will be selected in future ocean? How can we assess a species adaptation potential? What is the role of phenotypic plasticity in species resilience? What will be evolutionary rules in future oceans? What is the role of ecological interactions in future ecosystem changes?

This is an international course for PhD students and postdocs to learn more about how climate change (including global warming, ocean acidification, hypoxia) affects evolutionary rules that shape ocean ecosystem.

Growth rates, age determination and calcification levels in Flustra foliacea (L.) (Bryozoa: Cheilostomata): preliminary assessment – Morphology, growth and calcification levels in Flustra foliacea (L.)

Potential consequences for species distribution, abundances and diversity and their imprint in food chains and ecosystems call for more studies of the short and long term impacts of ocean acidification. Bryozoans have been overlooked in this respect even though they play an important role in benthic temperate ecosystems. Flustra foliacea colonies from the North and Baltic Seas were used to assess morphology, growth rates, wall structure and preservation aiming to build up a baseline to use this species as a ‘sentinel’ of acidification levels. Though no significant differences in mean zooid size among the studied basins were found, North Sea colonies show periodic oscillations across generations in mean frontal area index and zooid density. Preliminary geochemistry analyzes show: (1) similar carbon contents (TC, TIC, TOC) in both basins; (2) skeletal walls composed of IMC; (3) over 50% weight loss in dissolution experiments during the first hour. A winter growth stop marked by growth-check lines is postulated. Experimental data are needed to calibrate results and assess collections done over the last 200 years.

Being a bimineralic bryozoan in an acidifying ocean – Ocean acidification and bryozoans

Strongly controlled calcification by bryozoans means that some species maintain complex skeletons formed of more than one mineral. Whether they are mainly intermediate-Mg calcitic with up to 50% aragonite, mainly aragonitic with small amounts of high-Mg calcite (>8 wt.% MgCO3), or formed of both high- and low-Mg calcites, preservation of sediments formed of these bimineralic bryozoan skeletons may be more at risk from ocean acidification than the majority of bryozoan sediments formed of monomineralic skeletons. An acid-bath immersion experiment on seven species reveals that three (Adeonella sp., Adeonella patagonica, and Adeonellopsis sp.) are more resistant to dissolution than the other four. Skeletal carbonate mineralogy appears to influence dissolution history very little: the most soluble aragonite and high-Mg calcite species, Adeonellopsis sp., was more highly resistant to dissolution than species dominated by low-Mg calcite. In the context of ocean acidification, it is likely that bryozoan skeletons with high surface area and small delicate morphologies are at greatest risk of dissolution, irrespective of mineralogical composition.

Patterns of Magnesium-calcite distribution in the skeleton of some polar bryozoan species – Mineralogy of polar bryozoan skeletons

Polar marine environments are already starting to exhibit the effects of climate change. The Arctic is the most rapidly warming place on Earth, and changes of the seawater chemistry of polar oceans have been recorded. Calcifying Bryozoa have diverse skeletal mineralogies making them an ideal model for investigating differences caused by environmental change. The aim of this study is to quantify the skeletal mineralogical diversity of polar bryozoans using X-ray diffraction (XRD). Six species of erect Bryozoa were analysed, three Arctic and three Antarctic species. Within each of the three species from each region, one has a cemented attachment point, one has flexible growth and the third is attached by chitinous rootlets. The analysis shows no significant difference in Mg-calcite distribution along the length of the six species but does show species-specific variation in both the consistency of Mg-calcite distribution along the length of a colony and the relationship between concentration of Mg-calcite in the root and growing tip. Analysis shows a statistically significant trend of increasing Mg-calcite concentration with increasing temperature. This adds further data to a growing body of published evidence for this mineralogy trend. The results of this study suggest that if bryozoan species are to be used as indicators of environmental change then it will be critical to have robust, replicated data of species-specific profiles for Mg-calcite distribution. This data, viewed alongside published mineralogy trends, may allow the use of skeletal mineralogy as a register of environmental effects and may enable monitoring of future impacts of climate change in marine benthic ecosystems.

Seaweed responses to ocean acidification

Ocean acidification (OA) is the decline in seawater pH caused by the sustained absorption by the oceans of anthropogenically produced atmospheric CO₂. The consequences of OA to seaweed-based coastal ecosystems range from organismal to community levels of biological organization. Organismal responses can be species specific, depending on their carbon physiology, mode of calcification, and morphology (functional form). At the community scale, changes in community structure and function can have severe consequences on trophic dynamics. Biologically driven fluctuations in seawater carbonate chemistry are observed from micro- (diffusion boundary layer, DBL) to mesoscales (e.g., within a kelp forest), and such fluctuations may be exacerbated by OA. The synergistic effects of elevated CO₂ with other human-induced environmental stressors (e.g., warming, eutrophication, and UVR) could make the primary producers of coastal ecosystems vulnerable to global climate change; some species may perform better than others under “greenhouse” conditions, leading to community phase shifts.

Sperm motility of the scleractinian coral Acropora digitifera under preindustrial, current, and predicted ocean acidification regimes

Ocean acidification caused by the uptake of anthropogenic CO₂ in the oceans negatively affects the early life stages of corals by reducing their calcification rate. Acidification also inhibits the sperm motility of corals, potentially affecting fertilization success. We investigated the effects of different pCO₂ (partial pressure of CO₂) conditions on the sperm motility of Acropora digitifera. Using a pCO₂-control system, we maintained pCO₂ at concentrations from preindustrial and present-day levels up to the level predicted by the year 2100 (300, 400, and 1000 ppm, respectively). Our results indicated that ocean acidification has the potential to suppress the sperm flagellar motility of A. digitifera. Furthermore, sperm motility will likely decline by ~30%, which may impact fertility, if the sensitivity of sperm motility to decreasing pH cannot adapt over a span of ~90 yr.

Acidification de l’océan (video; in English and French)

Kumiko Azetsu-Scott, Ph. D. étudie l’acidification des océans et explique le prix à payer par les océans pour absorber autant de dioxyde de carbone de l’atmosphère terrestre.

NOAA seminar: coral reef conservation ocean acidification science plan overview

Date and Time: June 13, 2012, 14:00-15:00 Eastern Time Zone [Check U.S. Time clock for your local time]
Location: NOAA SSMC-4, Room 10153 (1305 East-West Highway, Silver Spring, MD, 20910)
Speaker(s): Dwight Gledhill (NOAA Ocean Acidification)
OneNOAA Seminar Sponsor: NOAA Coral Reef Conservation Program
Abstract:

Changes in ocean chemistry in response to rising levels of atmospheric carbon dioxide, termed ocean acidification (OA), has emerged as a topic of considerable concern to scientist, policy makers, and resource managers. Over the next century changes in carbon dioxide could impart significant, albeit poorly understood, impacts to marine resources. The NOAA Coral Reef Conservation Program Ocean Acidification Science Plan is intended to guide NOAA funded coral reef ecosystem OA research for 2012-2016, including research conducted through extramural partners, grants and contracts. The plan covers all shallow coral reef ecosystems under the jurisdiction of the United States and Pacific Freely Associated States, and outlines national research needed to address the many management challenges for reducing threats, reversing declines and promoting the resilience of coral reef ecosystems.