Archive for the 'Science' Category

Climate change projections for the surface ocean around New Zealand

The future status of the surface ocean around New Zealand was projected using two Earth System Models and four emission scenarios. By 2100 mean changes are largest under Representative Concentration Pathway 8.5 (RCP8.5), with a +2.5°C increase in sea surface temperature, and decreases in surface mixed layer depth (15%), macronutrients (7.5–20%), primary production (4.5%) and particle flux (12%). Largest macronutrient declines occur in the eastern Chatham Rise and subantarctic waters to the south, whereas dissolved iron increases in subtropical waters. Surface pH projections, validated against subantarctic time-series data, indicate a 0.335 decline to ∼7.77 by 2100. However, projected pH is sensitive to future CO2 emissions, remaining within the current range under RCP2.6, but decreasing below it by 2040 with all other scenarios. Sub-regions vulnerable to climate change include the Chatham Rise, polar waters south of 50°S, and subtropical waters north of New Zealand, whereas the central Tasman Sea is least affected.

Continue reading ‘Climate change projections for the surface ocean around New Zealand’

BIOACID Science Portrait: Felix Ekardt (video, in German; English subtitles)

The jurist, philosopher and sociologist Prof. Felix Ekardt is founder and director of the Research Unit Sustainability and Climate Policy and external professor for public law and legal philosophy at Rostock University.

Continue reading ‘BIOACID Science Portrait: Felix Ekardt (video, in German; English subtitles)’

Digital technologies as support for learning about the marine environment: steps toward ocean literacy

Over the last century the ocean has been negatively impacted by human activities. In order to continue benefitting from marine services and goods, and the qualities afforded to human life through the ocean, citizens need to be informed about their relationship to the ocean and their own impact on it, that is they need to be ocean literate. Marine education is challenging, as most of the ocean is invisible to the human eye and marine processes are spread over large temporal and spatial scales. Digital technologies have the potential to support learning about the ocean as, virtually, they can take learners into the depths of the ocean and help them visualise complex interactions between different factors over time and space. This thesis consists of four studies scrutinising the role of different digital technologies for learning about marine environmental issues with an emphasis on communicative aspects, with two of the studies having a specific focus on ocean literacy. Study I is a literature review of the use of digital technologies in environmental education. Study II investigates the use of a marine research institute’s Facebook page aimed at supporting communication and learning about marine topics. Study III addresses the use of a carbon footprint calculator as an opportunity for students to reason about their greenhouse gas emissions. Finally, Study IV analyses the questions asked by students on an online platform where they engage in an asynchronous discussion with a scientist around the issues of ocean acidification. The four studies show how the use of digital technologies in environmental education can make the invisible visible, allowing engagement with and manipulation of the abstract features of the ocean. As demonstrated in my studies and as is evident from previous research in the multidisciplinary field of environmental science, digital technologies offer new means to make sense of and engage with global environmental issues. These technologies provide a field of action where users can experiment, make mistakes, get feedback and try again in ways that are different from paper-based learning activities. The findings from Studies II, III and IV also illustrate the challenges associated with these technologies, and it becomes obvious that the technical features of a tool do not determine the kind of interactions that will evolve from its use. The contexts in which a tool is used, and what the features mean to the users in situ, are key, and demonstrate the importance of studying not only the outcome of a learning practice but also the ongoing interaction between the users and the tool in a specific context. In conclusion, this thesis offers an overview of the range of impacts that digital technologies can have on the development of ocean literacy, as well as illustrating how technologies open up new ways of learning about marine environmental issues both inside and outside of school. It also provides an account of why ocean literacy is such an important skill for 21st-century citizens living in a rapidly changing world with significant challenges to the environment and our own habitats.

Continue reading ‘Digital technologies as support for learning about the marine environment: steps toward ocean literacy’

Ocean acidification increases the toxic effects of TiO2 nanoparticles on the marine microalga Chlorella vulgaris

Highlights

  • Ocean acidification enhanced growth inhibition of algal cells caused by TiO2 NPs.
  • Ocean acidification increased oxidative damage of TiO2 NPs on Chlorella vulgaris.
  • Elevated internalization of NPs contributed to enhanced toxicity of TiO2 NPs.
  • Slighter aggregation and more suspended NPs in acidified seawater were detected.

Abstract

Concerns about the environmental effects of engineered nanoparticles (NPs) on marine ecosystems are increasing. Meanwhile, ocean acidification (OA) has become a global environmental problem. However, the combined effects of NPs and OA on marine organisms are still not well understood. In this study, we investigated the effects of OA (pH values of 7.77 and 7.47) on the bioavailability and toxicity of TiO2 NPs to the marine microalga Chlorella vulgaris. The results showed that OA enhanced the growth inhibition of algal cells caused by TiO2 NPs. We observed synergistic interactive effects of pH and TiO2 NPs on oxidative stress, indicating that OA significantly increased the oxidative damage of TiO2 NPs on the algal cells. Importantly, the elevated toxicity of TiO2 NPs associated with OA could be explained by the enhanced internalization of NPs in algal cells, which was attributed to the slighter aggregation and more suspended particles in acidified seawater. Overall, these findings provide useful information on marine environmental risk assessments of NPs under near future OA conditions.

Continue reading ‘Ocean acidification increases the toxic effects of TiO2 nanoparticles on the marine microalga Chlorella vulgaris’

Calcification in Caribbean reef-building corals at high pCO2 levels in a recirculating ocean acidification exposure system

Highlights

  • A recirculating OA system can be utilized as long as off-gassing measures are taken.
  • Aeration, water retention and algal scrubbing are effecting off-gassing measures.
  • Elevated pCO2 did not affect coral calcification rate or tissue growth.

Abstract

Projected increases in ocean pCO2 levels are anticipated to affect calcifying organisms more rapidly and to a greater extent than other marine organisms. The effects of ocean acidification (OA) have been documented in numerous species of corals in laboratory studies, largely tested using flow-through exposure systems. We developed a recirculating ocean acidification exposure system that allows precise pCO2 control using a combination of off-gassing measures including aeration, water retention devices, venturi injectors, and CO2 scrubbing. We evaluated the recirculating system performance in off-gassing effectiveness and maintenance of target pCO2 levels over an 84-day experiment. The system was used to identify changes in calcification and tissue growth in response to elevated pCO2 (1000 μatm) in three reef-building corals of the Caribbean: Pseudodiploria clivosa, Montastraea cavernosa, and Orbicella faveolata. All three species displayed an overall increase in net calcification over the 84-day exposure period regardless of pCO2 level (control + 0.28–1.12 g, elevated pCO2 + 0.18–1.16 g), and the system was effective at both off-gassing acidified water to ambient pCO2 levels, and maintaining target elevated pCO2 levels over the 3-month experiment.

Continue reading ‘Calcification in Caribbean reef-building corals at high pCO2 levels in a recirculating ocean acidification exposure system’

Carbon dioxide, climate change, and ocean acidification

Chapter 13: Carbon dioxide, Climate Change, and Ocean Acidification

A natural blanket of greenhouse gases surrounds the Earth and has made it far more livable than it would be otherwise. The average surface temperature of the planet is a reasonably comforable 60° F rather than the 0° F it would be without our unique atmosphere. Carbon dioxide, methane, nitrous oxide, and fluorinated gases are the four major greenhouse gases, and each one is present in a different concentration. Each gas also has its own natural concentration, but these have now been significantly increased by human activities. Water vapor is also a greenhouse gas, but its concentration in the atmosphere is not affected by human activities.

Continue reading ‘Carbon dioxide, climate change, and ocean acidification’

Auckland Region climate change projections and impacts

Auckland Council and Council Controlled Organisations commissioned NIWA to analyse projected climate changes for the Auckland region and potential impacts of climate change on some of Auckland’s environments and sectors. This report addresses expected changes for 21 different climate variables out to 2120, and draws heavily on climate model simulations from the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report. Potential climate change impacts on important environments and sectors in the Auckland region are discussed.

Chapter 8 addresses ocean acidification.

Continue reading ‘Auckland Region climate change projections and impacts’


Subscribe to the RSS feed

Powered by FeedBurner

Follow AnneMarin on Twitter

Blog Stats

  • 1,045,897 hits

OA-ICC HIGHLIGHTS

Ocean acidification in the IPCC AR5 WG II

OUP book