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Humpback Whale Singing at a Norwegian Feeding Ground

Humpback Whales Underwater

Papers: Changes in humpback whale song structure and complexity reveal a rapid evolution on a feeding ground in Northern Norway; Humpback Whale (Megaptera novaeangliae) Song on a Subarctic Feeding Ground

Authors: Saskia C. Tyarks, Ana S. Aniceto, Heidi Ahonen, Geir Pedersen and Ulf Lindstrøm

Featured Image: Humpback whales swimming near Tonga. Photo by Elianne Dipp.

US Navy engineer Frank Watlington was searching for Russian submarines in the 1950s when his underwater microphone picked up some otherworldly noises: humpback whale singing. He was amazed to realize that the whale vocalizations were arranged in an intricate pattern that repeated itself in a song-like manner, with a similar structure to music composed by humans. 

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Soot in the water – Understanding oceans’ carbon cycle

Featuring image: soot produced by incomplete burning by fossil fuels. Picture: Pxhere, Public Domain (C0)

Paper: Hydrothermal-derived black carbon as a source of recalcitrant dissolved organic carbon in the ocean

Authors: Y. Yamashita, Y. Mori, H. Ogawa

Earth’s oceans not only harbour a multitude of organisms, they are also a major carbon sink, compensating the increased production of carbon by humans and thus slowing down climate change. But could hydrothermal vents be another source of carbon in the oceans themselves?

A lot of the carbon that is produced on land by organisms and industry is transported into the oceans by rivers and wind. Black carbon (or soot), which is for example produced by incomplete burning of fossil fuels, can be stored in the oceans and remain inaccessible for long periods of time (several thousand years). But is all the stored black carbon coming from land sources? Although scientists already had some hints that not all dissolved black carbon (DBC) in the oceans comes from the land, a reliable evidence for a DBC source within the oceans remained elusive. The research from a group from Japan was able to shine new light on this question by looking at hydrothermal vents in the Pacific Ocean.

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One Sailors’ Legend Down, Many More To Go – Multiple Milky Sea Events Detected by Satellite

Processed satellite images showing a milky sea event in Java, 2019.

Featured image: Processed satellite images showing a milky sea event and its components in Java, 2019. From Miller et al, 2021 (figure 5).

Paper: Miller, S.D., Haddock, S.H.D., Straka, W.C. et al. Honing in on bioluminescent milky seas from space. Sci Rep 11, 15443 (2021). https://doi.org/10.1038/s41598-021-94823-z

Sailors see a lot of, well, stuff while they’re far from land. And they’re known for telling unbelievable tales, some of which later turn out to be more or less true. Milky seas are one of those: a horizon-to-horizon sea that glows white like the snow in the moonlight. In a 2021 paper, Dr. Steven Miller of Colorado State University and colleagues used satellites to look for these systems in hopes of understanding how and why these glowing patches form.

The first satellite detection of a milky sea event was also the work of Dr. Miller, in a 2005 paper that detected just a single event by combing ships’ logs and satellite archives from the preceding decade. Now, Miller’s research team has refined the algorithm that he’d previously developed for modern satellite records. Today’s satellite technology is better able to ‘see’ these events due to higher resolution of their images and can pick out the bioluminescent glow of microbes in the ocean better than the last generation of satellites.

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Throwing Earth Off Balance: Evidence Grows that Our Planet is Heating Up Faster than in the Past

Feature image: A satellite looks down at the surface of Earth. Image from Unsplash 

Paper: Satellite and Ocean Data Reveal Marked Increase in Earth’s Heating Rate

Authors: N. G. Loeb, G. C. Johnson, T. J. Thorsen, J. M. Lyman, F. G. Rose, and S. Kato

At the most fundamental level, what causes climate change? Simply put, climate change is a symptom of an energy imbalance with more energy coming into Earth’s atmosphere than is able to go out. This imbalance drives changes in our climate system that scientists around the world study, including warming temperatures, rising sea levels, melting glaciers, and coral reef bleaching. Using two different kinds of observational data, a recent study has found evidence that the energy imbalance is increasing, which suggests climate change will only worsen.

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Antarctic krill and their role in ocean carbon cycling

Antarctic Krill under a microscope. Photo courtesy of Uwe Kils, CC-BY-SA 3.0

Paper: Manno et al. (2020)

The transfer of carbon from the surface ocean to the deep ocean, or carbon export, can strongly influence climate. The main pathway of carbon export in the ocean is through sinking particles, also known as the biological carbon pump. These sinking particles can include plankton biomass, aggregates of cells, and zooplankton feces and molts. Understanding what contributes to carbon export is important in understanding how this may change as temperatures warm due to climate change.

A recent study by Manno et al. found that Antarctic krill in the Southern Ocean may play a significant role in transporting carbon to the deep ocean through their carcasses, fecal material, and most notably their molts, or shedding of their shells. Exoskeletons are not only an important vehicle for carbon export but also provide food to animals living on the seafloor. This is the first study to investigate the contribution of krill molts to carbon export in the Southern Ocean.

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Where’s the plastic gone?

Featured image: Plastic pollution in Ghana. Photo courtesy Wikimedia Commons/ Muntaka Chasant, CC BY-SA 4.0 license.

Paper: The global biological microplastic particle sink

Authors: K. Kvale, A. E. F. Prowe, C.-T. Chien, A. Landolvi & A. Oschlies

Scientists estimate that about 4% of the plastic waste generated globally ends up in the ocean, much of it in the form of microplastics. These tiny plastics, smaller than the width of a pencil, are a major pollution problem: because of their small size, they are extremely difficult to remove and can be transferred up the food chain to species that humans eat. Furthermore, harmful chemicals have been shown to adsorb onto microplastics, so consumption of microplastics may have indirect health impacts.  While scientists have put together a “plastic budget” for the ocean by estimating inputs of plastic to the ocean and fragmentation rates of larger plastics into microplastics, models based on observations of the amount of plastic waste in the ocean suggest that there is less plastic in the surface ocean than expected based on these budgets. The authors of this study used a model to test two possible explanations for this ‘missing’ plastic, zooplankton ingestion and sinking to the sea floor with marine particles, and find that these biological pathways can account for 100% of the observed “missing” surface microplastic, even in simulations where these processes are modeled as being inefficient.

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