News

Photosynthesis by marine algae produces sound, contributing to the daytime soundscape on coral reefs

Abstract.

"We have observed that marine macroalgae produce sound during photosynthesis. The resultant soundscapes correlate with benthic macroalgal cover across shallow Hawaiian coral reefs during the day, despite the presence of other biological noise. Likely ubiquitous but previously overlooked, this source of ambient biological noise in the coastal ocean is driven by local supersaturation of oxygen near the surface of macroalgal filaments, and the resultant formation and release of oxygen-containing bubbles into the water column. During release, relaxation of the bubble to a spherical shape creates a monopole sound source that ‘rings’ at the Minnaert frequency. [...]"

Source: PLOS ONE
Authors: Simon E. Freeman et al.
DOI: 10.1371/journal.pone.0201766

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Decomposing the effects of ocean environments on predator–prey body-size relationships in food webs

Abstract.

"Body-size relationships between predators and their prey are important in ecological studies because they reflect the structure and function of food webs. Inspired by studies on the impact of global warming on food webs, the effects of temperature on body-size relationships have been widely investigated; however, the impact of environmental factors on body-size relationships has not been fully evaluated because climate warming affects various ocean environments. Thus, here, we comprehensively investigated the effects of ocean environments and predator–prey body-size relationships by integrating a large-scale dataset of predator–prey body-size relationships in marine food webs with global oceanographic data. We showed that various oceanographic parameters influence prey size selection. [...]"

Source: Royal Society Open Science
Authors: Tomoya Dobashi, Midori Iida, Kazuhiro Takemoto
DOI: 10.1098/rsos.180707

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Oxygen Saturation Surrounding Deep Water Formation Events in the Labrador Sea From Argo‐O2 Data

Abstract.

"Deep water formation supplies oxygen‐rich water to the deep sea, spreading throughout the ocean by means of the global thermohaline circulation. Models suggest that dissolved gases in newly formed deep water do not come to equilibrium with the atmosphere. However, direct measurements during wintertime convection are scarce, and the controls over the extent of these disequilibria are poorly quantified [...]"

Source: Global Biogeochemical Cycles
Authors: Mitchell K. Wolf et al.
DOI: 10.1002/2017GB005829

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