Blue Planet II returns

Blue Planet returns to our television screens tonight as Blue Planet II, 16 years after the first series aired to great critical acclaim. The series, fronted by Sir David Attenborough, focuses on life beneath the waves, using state-of-the-art technology to bring us closer than ever before to the creatures who call the ocean depths their home. Over the coming weeks, we’re going to be sharing a selection of content from our life science resources, focusing on the theme of that week’s episode of Blue Planet II, over on our Tumblr page.

The topics we’ll be exploring include: ‘the deep’, coral reefs, ‘green seas’, ‘big blue’, coastlines, and the future of our oceans. To kick things off as an introduction, we’re thrilled to share with you a collection of articles and facts all about our wild and wonderful oceans, along with a selection of articles touching on the themes of upcoming episodes to whet your appetite. Be sure to head over to our Tumblr page on the 5th November for the next instalment of our Blue Planet II series!

An overview of our oceans

• “The marine environment is the planet’s largest and most important habitat, and covers 3.6 x 10¹⁴ m², which represents about 71% of the Earth’s surface; contains more than 99 per cent of its habitable living space; represents its largest repository of living matter; produces half its primary production; and supports a remarkably diverse and exquisitely adapted array of life forms, from microscopic viruses, bacteria, and plankton to the largest existing animals.”

• Evidence of ocean exploration comes long before written records, with Homo erectus, an early hominid, mastering crossing the relatively small stretches of water that separated one island from another along the Indonesian archipelago, where they established a presence on the island of Flores. There is then an extensive gap in marine archaeological knowledge, before the first waves of Homo sapiens migration out of Africa around 70,000 years ago.
• China recently began investing in deep-sea research, leading to the launch of its first multidisciplinary deep sea research program, the “South China Sea”, in 2011.
• What are the implications for marine mammals of large-scale changes in the marine acoustic environment? Human sources of sound in the ocean (such as ship traffic, air guns for seismic exploration, and sonar for military and commercial use) can disturb marine mammals, evoking behavioural responses that can be viewed as similar to predation risk, and they can trigger allostatic physiological responses to adapt to the stressor.
• Marine mammals and their environment in the twenty-first century: what are the threats facing our marine environments today?
• Four different phenomena cause the ocean’s circulation: The wind drags surface waters, inducing surface currents. These surface currents, combined with precipitation and evaporation, create “hills” and “valleys” at the ocean surface that induce pressure changes that generate currents over depths of hundreds or even thousands of meters. Density gradients due to differences in temperature and salinity may also cause horizontal and vertical water masses motions, and tidal currents, which are due to the gravitational fields of the Moon and the Sun. Tides play an important role for the deep ocean mixing.
• Marine mammals as ecosystem sentinels: Species dependent on sea ice, such as the polar bear (Ursus maritimus) and the ringed seal (Phoca hispida), provide the clearest examples of sensitivity to climate change.
• Conservation physiology can provide insights into pelagic fish demography and ecology by uniting the complementary expertise and skills of fish physiologists and fisheries scientists, which is crucial for effective management and successful conversation of pelagic fishes.

• Studies in marine science and fisheries experienced a gradual shift from focusing on limited spatial and temporal national and regional issues in the 1960s through 1980s, to more broadly-based ecological goals focused on recovery and sustainability of coastal ocean goods and services from a global perspective today.
• Increasing the size and number of marine protected areas (MPAs) is widely seen as a way to meet ambitious biodiversity and sustainable development goals. Yet, debate still exists on the effectiveness of MPAs in achieving ecological and societal objectives. Although the literature provides significant evidence of the ecological effects of MPAs within their boundaries, much remains to be learned about the ecological and social effects of MPAs on regional and seascape scales. Key to improving the effectiveness of MPAs, and ensuring that they achieve desired outcomes, will be better monitoring that includes ecological and social data collected inside and outside of MPAs.
• Cycling of carbon in the upper ocean remains a key aspect in understanding the ability of the world’s ocean to buffer the atmospheric carbon dioxide (CO₂) increase and control the associated raise of pH. So far, the balance between primary production and ecosystem respiration has been shown to be regulated and balanced mostly by photo- and microbial respiration involving zooplankton communities.

Featured image credit: Jellyfish by Free-Photos. CC0 Public Domain via Pixabay.