New report shows ocean pastures bloom with the seasons and enrich the ocean with oxygen to far greater depths than formerly believed.

Satellite view in false color showing spring blooms with Iceland visible in the top right of the image — click to enlarge

The spring blooms in the North Atlantic are especially vital and beautiful though you might need to be in orbit to see it.

Tragically the blooms are diminishing.

At the same time that we are enjoying the blossoms in our parks and pastures on land that signals the start of a warmer season, a similar “greening” is taking place at sea. Massive spring blooms of phytoplankton (plant plankton) are happening in the Atlantic Ocean from Bermuda to the Arctic. The plankton blooms are converting hundreds of millions of tonnes of deadly ocean acidifying CO2 into ocean life and oxygen.

In the North Atlantic Bloom, countless trillions of microscopic plants, phytoplankton, use sunlight to capture carbon dioxide (CO2) that they use to grow more of themselves in the surface ocean. These short-lived ocean pasture plants have life cycles of hours to days during which they are heavily grazed by tiny zooplankton. Like most animal life on earth only a portion of the plant life consumed becomes part of the animal most of it becomes poop and in the ocean all animal life poop sinks.

click to enlarge

This potent biological system transfers most of the pastures organic matter to the deep ocean, removing it from the atmosphere for millenia. This ‘biological pump’ working to sink carbon makes the North Atlantic Ocean highly efficient at soaking up CO2 from the air. In fact, the North Atlantic is responsible for absorbing more than 20 percent of the entire ocean’s many billions of tonnes of annual uptake of human-generated CO2, making it a crucial factor affecting our climate.

“Much of this particulate organic carbon, especially the larger, heavier particles, sink. But we wanted to find out what is happening to the smaller, non-sinking phytoplankton cells from the bloom. Understanding the dynamics of the bloom and what happens to the carbon produced by it is important, especially for being able to predict how the oceans will affect atmospheric CO2 and climate,” says Melissa Omand, who did this study as a postdoctoral investigator in Amala Mahadevan’s lab at the Woods Hole Oceanographic Institution (WHOI).

Research vessel Bjarni Saemundsson off the coast of Iceland

During fieldwork from the research vessels Bjarni Saemundsson and Knorr in 2008, the researchers used an ocean science instrument float to follow a patch of seawater off Iceland and observe the progression of the bloom by making measurements from multiple platforms in a way that hadn’t been done before. A suite of autonomous gliders outfitted with sensors were used to gather data, such as temperature, salinity and information about the chemistry and biology of the bloom itself —oxygen, nitrate, chlorophyll and the optical signatures of the particulate matter.

Yes ocean science seems to take forever to be revealed in publication as the 7 year-long drawn out process in this papers publication reveals as being very typical, even speedy, for the field. The large oceanographic institutions have become cash cows, or perhaps dinosaurs, that feed at the public research troughs and the longer they can keep the research strung out the more feeding they can do. Ed

Beginning just around the time of onset of the bloom and following its development over a month, the four seagliders gathered 774 profiles to depths of up to 1,000 meters (3281 feet). Analysis of the profiles showed that about 10 percent showed unusually high concentrations of phytoplankton bloom properties at depth, as well as high oxygen concentrations typically found at the surface.

“These profiles were showing what we initially described as ‘bumps’ at depths much deeper than where phytoplankton can grow,” says Omand. “That was the first indicator we had that something interesting was going on, in terms of what was moving this carbon around.”

Mahadevan, an oceanographer at Woods Hole Oceanographic Institution, uses three-dimensional computer modeling to look at the dynamics of ocean eddies. Using information collected at sea by Perry, D’Asaro and Lee, she modeled the ocean currents and eddies, and their effect on the spring bloom and the phytoplankton it produced.

Hemholz ocean eddy structure

“What we were seeing was surface water, rich with phytoplankton carbon, being down-welled or transported downward by the currents in filament like features on the edges of eddies,” Mahadevan says. “That was somewhat surprising since eddies were not previously thought of as a significant way that organic matter is moved into the deeper ocean. But we’ve shown through both observations and modeling, that this type of eddy-driven subduction could account for a significant downward movement of small, phytoplankton carbon from the bloom. Furthermore, we have a way to quantify this transport, which can be applied to other regions.”

“It’s been a challenge to estimate carbon export from the ocean’s surface waters to its depths based on measurements of properties such as phytoplankton carbon,” says David Garrison, program director in NSF’s Division of Ocean Sciences. “This paper describes a mechanism for doing that.”

In related work published in 2012 in Science, the research team found that eddies act as early trigger of the North Atlantic bloom. Before the sun begins to warm the ocean, eddies help keep phytoplankton in shallower water where they can get plenty of sunlight to fuel photosynthesis and growth, which contributes to the oceanic uptake of carbon dioxide.

In future work, the scientists hope to better quantify the transport of organic matter from the surface to depth in other regions and times, and to relate this to variables that can be measured, including the physical attributes and the productivity of the phytoplankton.

The researchers say that learning more about eddies and the underlying physical mechanisms of the annual blooms will allow these to be represented more accurately in global models of the oceanic carbon cycle and improve the models’ predictive capability.

Decline of North Atlantic Blooms

North Atlantic primary productivity, that which is supplied by ocean pasture blooms, is in dramatic decline as seen in this chart of satellite data beginning in the early 1980’s

The paper neglect to report on the cataclysmic decline in primary ocean productivity both globally and in the N. Atlantic study region where even though the spring blooms of plankton continue they are reduced by nearly 20% since satellite records began being collected in the early 1980’s. This collapse of ocean pasture productivity is surely a primary cause of the collapse of fish populations in the North Atlantic especially that of the Atlantic Cod.

We have the means to replenish and restore vital ocean pastures and bring their spring blooms and fish back to levels of historic health and abundance.

PS. The authors of this recent paper ocean science institutions however are openly hostile and facilitate the use of their public monies to political ends to oppose mitigation methods to help prevent further ocean pasture collapse. One possible explanation of this bizzare behavious is that they may fear that actually delivering timely solutions to ocean problems would result in a slowing of their endless flow of “research” dollars into their feeding troughs.