“The big mystery about plankton is what controls its distribution and abundance, and what conditions lead to big plankton blooms,” said Dennis McGillicuddy, Senior Scientist and Department Chair in Applied Ocean Physics and Engineering at the Woods Hole Oceanographic Institution (WHOI).
Two new papers explore this question and provide examples of conditions that lead to massive plankton blooms with vastly different potential impacts on the ecosystem, according to McGillicuddy, co-author of both papers. Both papers also point to importance of using advanced technology—including video plankton recorders, autonomous underwater vehicles, and the Ocean Observatories Initiative’s Coastal Pioneer Array—to find and monitor these blooms.
In one paper, Diatom Hotspots Driven by Western Boundary Current Instability, published in Geophysical Research Letters (GRL), scientists found unexpectedly productive subsurface hotspot blooms of diatom phytoplankton.
In the GRL paper, researchers investigated the dynamics controlling primary productivity in a region of the Mid-Atlantic Bight (MAB), one of the world’s most productive marine ecosystems. In 2019, they observed unexpected diatom hotspots in the slope region of the bight’s euphotic zone, the ocean layer that receives enough light for photosynthesis to occur. Phytoplankton are photosynthetic microorganisms that are the foundation of the aquatic food web.
It was surprising to the researchers that the hotspots occurred in high-salinity water intruding from the Gulf Stream. “While these intrusions of low‐nutrient Gulf Stream water have been thought to potentially diminish biological productivity, we present evidence of an unexpectedly productive subsurface diatom bloom resulting from the direct intrusion of a Gulf Stream meander towards the continental shelf,” the authors note. They hypothesize that the hotspots were not fueled by Gulf Stream surface water, which is typically low in nutrients and chlorophyll, but rather that the hotspots were fueled by nutrients upwelled into the sunlight zone from deeper Gulf Stream water.
With changing stability of the Gulf Stream, intrusions from the Gulf Stream had become more frequent in recent decades, according to the researchers. “These results suggest that changing large‐scale circulation has consequences for regional productivity that are not detectable by satellites by virtue of their occurrence well below the surface,” the authors note.
“In this particular case, changing climate has led to an increase in productivity in this particular region, by virtue of a subtle and somewhat unexpected interaction between the physics and biology of the ocean. That same dynamic may not necessarily hold elsewhere in the ocean, and it’s quite likely that other areas of the ocean will become less productive over time. That’s of great concern,” said McGillicuddy. “There are going to be regional differences in the way the ocean responds to climate change. And society needs to be able to intelligently manage from a regional perspective, not just on a global perspective.”
The research finding demonstrated “a cool, counterintuitive biological impact of this changing large scale circulation,” said the GRL paper’s lead author, Hilde Oliver, a postdoctoral scholar in Applied Ocean Physics and Engineering at WHOI. She recalled watching the instrument data come in. With typical summertime values of about 1-1.5 micrograms of chlorophyll per liter of seawater, researchers recorded “unheard of concentrations for chlorophyll in this region in summer,” as high as 12 or 13 micrograms per liter, Oliver said.
Oliver, whose Ph.D. focused on modeling, said the cruise helped her to look at phytoplankton blooms from more than a theoretical sense. “To go out into the ocean and see how the physics of the ocean can manifest these blooms in the real world was eye opening to me,” she said.
Another paper published in the Journal of Geophysical Research: Oceans (JGR: Oceans), A Regional, Early Spring Bloom of Phaeocystis pouchetii on the New England Continental Shelf, also was eye opening. Researchers investigating the biological dynamics of the New England continental shelf in 2018 discovered a huge bloom of the haptophyte phytoplankton Phaeocystis pouchetii.
However, unlike the diatom hotspots described in the GRL paper, Phaeocystis is “unpalatable to a lot of different organisms and disrupts the entire food web,” said Walker Smith, retired professor at the Virginia Institute of Marine Science William and Mary, who is the lead author on the JGR: Oceans paper. The phytoplankton form gelatinous colonies that are millimeters in diameter.
When Phaeocystis blooms, it utilizes nutrients just like any other form of phytoplankton would. However, unlike the diatoms noted in the GRL paper, Phaeocystis converts biomass into something that doesn’t tend to get passed up the rest of the food chain, said McGillicuddy.
“Understanding the physical-biological interactions in the coastal system provides a basis for predicting these blooms of potentially harmful algae and may lead to a better prediction of their impacts on coastal systems,” the authors stated.
Massive blooms of the colonial stage of this and similar species have been reported in many systems in different parts of the world, which Smith has studied. These types of blooms probably occur about every three years in the New England continental shelf and probably have a fairly strong impact on New England waters, food webs, and fisheries, said Smith. Coastal managers need to know about these blooms because they can have economic impacts on aquaculture in coastal areas, he said.
“Despite the fact that the Mid-Atlantic Bight has been well-studied and extensively sampled, there are things that are going on that we still don’t really appreciate,” said Smith. “One example are these Phaeocystis blooms that are deep in the water and that you are never going to see unless you are there because satellites can’t show them. So, the more we look, the more we find out.”
Both of these studies were carried out as part of the National Science Foundation-funded Shelfbreak Productivity Interdisciplinary Research Operation at the Pioneer Array involving partners at WHOI, University of Massachusetts Dartmouth, Massachusetts Division of Marine Fisheries, Virginia Institute of Marine Science, Wellesley College, and Old Dominion University. Additional support has been provided by the Dalio Explorer Fund.
For more information, see the video “Life at the Edge: Plankton Growth at the Shelf Break Front,” produced by ScienceMedia.nl for WHOI.Read More
OOI’s Principal Investigator John Trowbridge and NERACOOS Executive Director Jake Kritzer have a lively discussion about the value of ocean observing systems on the SeaState podcast sponsored by Ocean News & Technology Magazine. Choose the podcast “Jake Kritzer on Ocean Observations” and listen in here.
The Oregon Coast Beach Connection reports:
(Newport, Oregon) – There’s a whole lotta Sci-Fi-like action taking place off the Washington and Oregon coast, and no one really knows. Think the movie “Sphere” with a touch of “The Abyss,” throw in some X-Files and even a handful of high seas adventures, and you may have what’s going on with the Ocean Observatories Initiative (OOI), its enormous cabled array around the ocean floor, and the occasional research vessel – all studying the Axial Mount undersea volcano and the entirety of that area where the two tectonic plates meet…
Battery longevity and funding are limiting factors for glider deployment at present. OOI Engineer Matt Palanza weighs in on what the future may hold should new power sources prove successful in an article in Wired magazine. Spoiler alert: the future looks bright![threecol_one]
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[media-caption type="image" class="external" path="https://oceanobservatories.org/wp-content/uploads/2020/10/Wiki-Video.png" alt="Video Wiki" link="#"]The OOI is one of five institutions featured in this five-minute wiki. [/media-caption]
The Ocean Observatories Initiative is featured in a new video wiki Leading Institutions In The Field Of Ocean Research. OOI is joined by Texas A&M’s Harte Research Institute for Gulf of Mexico Studies, the Consortium for Ocean Leadership, Saildrone, and the Future Ocean Labs at the Universida de Vigo. The five-minute video, produced by Ezvid Wiki, summarizes the work of each institution and its contribution to understanding of the changing ocean.
Founded in 2011, Ezvid Wiki was the world’s first video wiki, and is now among the top 3,000 websites in the United States. Its YouTube channel has more than 600,000 subscribers and has had more than 350 million views since its founding.[threecol_one]
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ECO Magazine posted an article about Oregon State University’s assumption of OOI’s cyberinfrastructure on 7 October 2020.[threecol_one]
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In the March 2020 issue of Oceanography, a group of authors issued an invitation to undergraduate classroom instructors to integrate OOI data into their classrooms.
There are many benefits to using real data in undergraduate science education, including building analytical and problem-solving skills and visualizing concepts through real-world examples. The Ocean Observatories Initiative (OOI) provides a unique source of continuous, long-term oceanographic data from multiple locations in the world ocean. Each of these arrays hosts a suite of co-located instruments that measure physical, chemical, geological, and biological properties. Existing educational resources derived from OOI data can be leveraged for undergraduate teaching activities in and beyond the classroom. We provide example applications of the use of OOI resources in lesson plans and in research experiences for undergraduates. There are also abundant opportunities for new resources to be developed by the community. Our goal is to guide educators in determining appropriate OOI data sets and applications for their own needs.
Read the complete article Using Authentic Data from NSF’s Ocean Observatories Initiative in Undergraduate Teaching: An Invitation here.Read More
Regional Cabled Array Director Deb Kelley, provides some insights as to what the 13 scientists aboard the R/V Thomas G. Thompson will experience during the month of August while in the northeastern Pacific. The interview was reported by the news staff at the University of Washington, 3 August 2020.
It’s summertime, and that means scientists across the University of Washington College of the Environment are in the field collecting data. Researchers in the School of Oceanography are no different and are working off the Oregon coast on their annual expedition to maintain the long-running cabled ocean observatory. Part of the broader National Science Foundation’s Ocean Observatories Initiative (OOI), UW oversees the Regional Cabled Observatory that spans several sites in Pacific Northwest waters, ranging from shallow coastal locales to deeper waters in the open ocean more than 300 miles offshore. Each site hosts internet-connected scientific instruments that measure physical, chemical, geological and biological properties of the marine environment, providing a 24/7, real-time presence in the ocean. The broad goal is to help scientists answer questions about how our planet works, especially in relation to climate and ecosystem changes, and tectonic and volcanic activity in the sea.
For nearly all of August, 13 scientists and engineers from UW will be at sea collecting data and maintaining infrastructure aboard the UW’s R/V Thomas G Thompson. We caught up with Deb Kelley, director of the Regional Cabled Array at the UW, to see what’s in store.[threecol_one]
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Dr. Jonathan Fram, project manager for the Endurance Array, is quoted in this Eos article about the potential implications of the cancellation of the spring cruise to recover and redeploy equipment at the Endurance Array:
With research cruises postponed, scientists are trying to get home safe, and others worry about the fate of their instruments left at sea.
Past Plans Scrapped…
Scientists around the world are scrambling to adjust to a rapidly changing environment. Researchers are shuttering their labs, switching to remote observing on telescopes, and learning to present their work virtually.
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(From The Economist / Technology Quarterly)
From sharks to ice shelves, monsoons to volcanoes, the scope of ocean monitoring is widening.
IN NOVEMBER 2016 a large crack appeared in the Larsen C ice shelf off Antarctica (pictured). By July 2017 a chunk a quarter of the size of Wales, weighing one trillion tonnes, broke off from the main body of the shelf and started drifting away into the Southern Ocean. The shelf is already floating, so even such a large iceberg detaching itself did not affect sea levels. But Larsen C buttresses a much larger mass of ice that sits upon the Antarctic continent. If it breaks up completely, as its two smaller siblings (Larsens A and B) have done over the past 20 years, that ice on shore could flow much more easily into the ocean. If it did so—and scientists believe it would—that ice alone could account for 10cm of sea-level rise, more than half of the total rise seen in the 20th century.
The dynamics of the process, known as calving, that causes a shelf to break up are obscure. That, however, may soon change. Ocean Infinity, a marine-survey firm based in Texas, is due to send two autonomous drones under the Larsen C shelf in 2019, the first subglacial survey of its kind. “It is probably the least accessible and least explored area on the globe,” says Julian Dowdeswell, a glaciologist at the University of Cambridge who will lead the scientific side of the project.
The drones set to explore Larsen C look like 6-metre orange cigars and are made by Kongsberg—the same Norwegian firm that runs the new open-ocean fish farms. Called Hugin, after one of the ravens who flew around the world gathering information for Odin, a Norse god, the drones are designed to cruise precisely planned routes to investigate specific objects people already know about, such as oil pipelines, or to find things that they care about, such as missing planes. With lithium-ion-battery systems about as big as those found in a Tesla saloon the drones can travel at four knots for 60 hours on a charge, which gives them a range of about 400km. Their sensors will measure how the temperature of the water varies. Their sonar—which in this case, unusually, looks upwards—will measure the roughness of the bottom of the ice. Both variables are crucial in assessing how fast the ice shelf is breaking up, says Dr Dowdeswell.
The ability to see bits of the ocean, and things which it contains, that were previously invisible does not just matter to miners and submariners. It matters to scientists, environmentalists and fisheries managers. It helps them understand the changing Earth, predict the weather—including its dangerous extremes—and maintain fish stocks and protect other wildlife. Drones of all shapes and sizes are hoping to provide far more such information than has ever been available before.
That’s why it’s hotter under the water
To this end Amala Mahadevan of Woods Hole Oceanographic Institute (WHOI) in Massachusetts, has been working with the Indian weather agencies to install a string of sensors hanging down off a buoy in the northern end of the Bay of Bengal.
A large bank of similar buoys called the Pioneer Array has been showing oceanographers things they have not seen before in the two years it has been operating off the coast of New England. The array is part of the Ocean Observatories Initiative (OOI) funded by America’s National Science Foundation. It is providing a three-dimensional picture of changes to the Gulf Stream, which is pushing as much as 100km closer to the shore than it used to. “Fishermen are catching Gulf Stream fish 100km in from the continental shelf,” says Glen Gawarkiewicz of WHOI. These data make local weather forecasting better.
Three other lines of buoys and floats have recently been installed across the Atlantic in order to understand the transfer of deep water from the North Atlantic southwards, a flow which is fundamental to the dynamics of all the world’s oceans, and which may falter in a warmer climate.
Another part of the OOI is the Cabled Array off the coast of Oregon. Its sensors, which span one of the smallest of the world’s tectonic plates, the Juan de Fuca plate, are connected by 900km of fibre-optic cable and powered by electricity cables that run out from the shore. The array is designed to gather data which will help understand the connections between the plate’s volcanic activity and the biological and oceanographic processes above it.
A set of sensors off Japan takes a much more practical interest in plate tectonics. The Dense Oceanfloor Network System for Earthquakes and Tsunamis (DONET) consists of over 50 sea-floor observing stations, each housing pressure sensors which show whether the sea floor is rising or falling, as well as seismometers which measure the direct movement caused by an earthquake. When the plates shift and the sea floor trembles, they can send signals racing back to shore at the speed of light in glass, beating the slower progress of the seismic waves through the Earth’s crust, to give people a few valuable extra seconds of warning. Better measuring of climate can save lives over decades; prompt measurement of earthquakes can save them in an instant.Read More