PLANKTON & KRILL LEVELS RAPIDLY DECREASING SeaKeeper 1000™ can provide important data

The projected global collapse of ocean fish stocks by the year 2048 grabbed headlines in November when Science magazine published the alarming findings of an international panel of scientists.  While that report focused on the larger, fishing species that we typically eat, equally important is the bottom of the complex ocean food chain.  As with any structure, its stability and strength are based on its foundation. Plankton and krill are the small animals and plant-life that make up the base of the ocean food chain.

Plankton are extremely small, free-swimming organisms that can be single- or multi-celled.  There are two major plankton categories: phytoplankton and zooplankton.  As the names suggest, phytoplankton are tiny algae or plants, and zooplankton are the animal counterparts.  Krill consist of a group of about 85 separate species of shrimp-like animals up to two inches in length; the Antarctic Krill (Euphausia superba) is one of the most significant. 

By far, plankton and krill collectively are the largest biomass on the planet, with an estimated 150 million tons of krill alone spawned in the oceans annually. In comparison, the total world consumption of fish and shellfish is approximately 100 million tons a year.

Plankton are a key component of the marine ecosystem and are sensitive to environmental change. Many natural resources directly depend on plankton as a food source. Not only is plankton is the diet of small krill, but of the largest animal on earth – the blue whale. Plankton provide the link between the atmosphere and the ocean as they pass the energy of sunlight and nutrients the food web to fish, bird, and mammal populations.

Scientists have now correlated the increase in ocean temperatures with a decrease in phytoplankton production.  As documented in the recent Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), the oceans are warming.  In fact 80 percent of the heat that is being trapped by greenhouse gases is absorbed by the ocean.

In some areas of the ocean, there has been a 30 percent decrease in phytoplankton production between 1999 and 2004 alone.  These small algae convert or sequester a tremendous quantity of carbon, consumed in the form of the greenhouse gas carbon dioxide. The 30% reduction in phytoplankton would equate to about 190 million tons of unabsorbed carbon per year – a significant quantity in the global carbon equation.

Krill feed on phytoplankton near the ocean surface at night, but sink deeper in the water column during the day to hide from predators. New research shows the importance of these small animals in balancing greenhouse gases.  It was recently discovered that Antarctic krill absorb substantial amounts of carbon; when they sink they then carry it down and bury it in the deep ocean. 

In a recent issue of the journal Current Biology, scientists from the British Antarctic Survey (BAS) and the Scarborough Centre of Coastal Studies at the University of Hull discovered that Antarctic krill 'parachute' from the ocean surface to deeper layers several times during the night.

Lead author Dr. Geraint Tarling from the BAS said, "We've known for a long time that krill are the main food source for whales, penguins and seals, but we had no idea that their tactics to avoid being eaten could have such added benefits to the environment. By parachuting down they transport carbon, which sinks ultimately to the ocean floor – an amount equivalent to the annual emissions of 35 million cars – and this makes these tiny animals much more important than we thought." 

But understanding the correlations between global warming and marine ecosystems is complex; there are still anomalies and much more relevant, accurate information is needed.  Collecting large amounts of quantifiable data, such as ocean temperature, pH, dissolved oxygen, chlorophyll, and nutrients, is crucial in order to refine our understanding of what is happening to the krill and plankton.

The International SeaKeepers Society’s automated SeaKeeper 1000™ monitoring system is one of the innovative systems providing this suite of data to scientists. But because of these small plants and animals’ importance on such a massive level, monitoring plankton and krill distributions is crucial to understanding how marine ecosystems are responding both positively and negatively to climate change.

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Global chlorophyll patterns tell scientists where phytoplankton, or ocean surface plants at the base of the food chain, are growing, which is an indicator of the health and diversity of the sea. Such global maps also allow scientists to estimate how much carbon the plants are absorbing as they soak up sunlight and carbon dioxide and convert them into food. Bright greens, yellows, and reds on this chart compiled in the spring of 2006 indicate that the northern oceans were alive with plant life. While the global data for this image comes from NASA satellites, data from SeaKeeper 1000™ installations provides important verification of satellite data and critical supporting information in the form of simultaneous measurements of salinity, pH, and nutrients that cannot be accurately measured by satellite. (Image: NASA)

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