Science Update | Darienne Dey: Marine Life
Written by Darienne Dey.The sighting of marine organisms can be both exciting and reassuring. Their lively activity stirs our imaginations and comforts us as we wistfully gaze across the seemingly endless expanse of sea and sky. The ocean is truly theirs, and we feel grateful to be guests of their realm.
Since departing Tongan waters, we have been fortunate to encounter and be guided by various marine organisms. During our darkest (i.e., relatively moonless) nights, bioluminescent plankton was observed between 0 to 20 feet below the surface and most often off of our port side. Some showcased their blue brilliance when the water was agitated by our hulls while others glowed when illuminated by bright white light. During the daytime, their larger counterparts shared a similar blue hue and even sported their own sails, harnessing the power of both the wind and current.
As we sailed near the tectonically active Kermadec Trench, we anticipated observing pumice particles as the crew of Hikianalia’s maiden voyage did while traversing this part of the ocean back in October of 2012. As the Pacific plate subducts below the Australian plate, some molten rock escapes, erupting from the trench and rapidly cooling with vesicles of trapped gases that allow it to float to the surface. Appearing as speckled mini soccer balls ranging from thumb- to fist-size, these drifting rocks also carry passengers. Crabs, anemones, and fire worms were the most common riders on these naturally-formed ocean-going vessels.
But the most exciting marine life to observe is our fellow mammals: dolphins and whales. For traditional Pacific navigators, pods of such animals can sometimes serve as “sea marks” that help guide canoes in the absence of other viable navigational information. During this time of year, humpback whales (especially mothers and calves) are known to travel from tropical waters to Antarctica for the southern hemisphere’s summer, tracing a pathway that very nearly aligns with the Kermadec Trench and that includes a pit stop at Rangitahua (Raoul Island), the northernmost of the Kermadec Islands. Thus far dolphins have joined us during the day, and one pod of whales was observed paralleling our course line.
The sighting of marine organisms can be both exciting and reassuring. Their lively activity stirs our imaginations and comforts us as we wistfully gaze across the seemingly endless expanse of sea and sky. The ocean is truly theirs, and we feel grateful to be guests of their realm.
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