Henry Bryant Bigelow's century-old data compared with current conditions
Dr. William "Barney" Balch's team at Bigelow Laboratory for Ocean Sciences has been sampling the waters of the Gulf of Maine regularly over the same transect for the last 18 years as part of a NASA-funded study. Working with scientists from the U.S. Geological Survey, Dr. Thomas Huntington and Dr. George Aiken, Balch reported in a recent paper an overall reduction in productivity in the Gulf of Maine.
The researchers found that the amount of dissolved organic carbon from rivers emptying into the Gulf of Maine has increased over the last 80 years, a trend they predict will continue through 2100 if annual precipitation continues to increase. The adjacent Gulf of St. Lawrence also was found to supply a significant amount of organic material into the Gulf of Maine via the Scotia Shelf Current. Collectively, these conditions appear to be contributing to the decline in the Gulf's primary productivity, as reported in the American Geophysical Union's journal, Global Biogeochemical Cycles, Volume 30, Issue 2, February 2016, pages 268-292.
Balch explained the significance of this finding: "As increasing amounts of dissolved organic matter leaches from the soil into rivers after rains, these materials ultimately flow directly into the Gulf of Maine or indirectly from the Gulf of St. Lawrence via the Scotian Shelf Current. This organic matter is rich in colored humic materials that impart a brown color to the rivers in Maine--think of a dark "tea" steeped from dead leaves and soil. This input actually changes the color of the seawater and appears to be reducing the light available to phytoplankton for photosynthesis and growth, causing a decline in overall productivity."
"Ocean color serves as a useful proxy for understanding some of the changes in fundamental processes that are happening in the sea as the climate changes. Normally the ocean is blue with little light absorption. When there is a lot of chlorophyll-containing phytoplankton (microscopic plants) in the water, the water has a greenish color, just like plants do on land. However, the dissolved organic matter delivered to the Gulf of Maine by rivers, has a yellowish-brown "tea" color which gives the normally blue ocean a yellow tint. This organic matter also absorbs light necessary for photosynthetic organisms, and can thereby influence the ecology of the Gulf of Maine. Our data suggest that increases in precipitation and runoff during the last 80 years result in more of this organic, dark-colored "tea" being delivered to the Gulf of Maine which could be affecting how marine plants are able to photosynthesize and grow." added Aiken.
Because ocean color is one of the best indicators of what is happening in ocean waters, Balch and his team compared their color measurements of the Gulf of Maine with 1912-1913 color data recorded by Henry Bryant Bigelow, considered the founder of modern oceanography and for whom Bigelow Laboratory was named. In 1912, Henry Bigelow had the foresight to make manual ocean color measurements as he plied the Gulf of Maine aboard his schooner, Grampus. Bigelow used a simple technique published in 1890 by François-Alphonse Forel, a Swiss lake scientist. Balch's team compared Bigelow's original color data with current water color measurements to document color change over a century time scale. The conclusion is that the Gulf has yellowed over the last century, particularly in coastal Maine waters.
Climate and hydrologic models predict increasing precipitation and runoff in the Gulf of Maine watershed in the 21st century. Based on these projections, Balch, Huntington, and Aiken predict that river discharge of soil-derived dissolved organic carbon into the Gulf of Maine could increase close to 30% over the next 80 years, potentially contributing to a continued decline in the productivity of this coastal marine food web.
Today scientists use NASA's Earth-observing satellites and sophisticated shipboard optical measurements to document ocean color. The Bigelow Laboratory-USGS research team also showed a direct link for the first time between satellite-derived measurements of dissolved organic carbon across the Gulf of Maine with dissolved organic carbon discharged in rivers as estimated by the USGS, which go far to validate the satellite-derived measurements as an important predictive tool. With this solid foundation of data and collaboration, the research team expects to continue to mine the data to advance understanding of ongoing changes in the Gulf of Maine.
Bigelow Laboratory for Ocean Sciences, an independent not-for-profit research institution on the coast of Maine, conducts research ranging from microbial oceanography to large-scale ocean processes that affect the global environment. Recognized as a leader in Maine's emerging innovation economy, the Laboratory's research, education, and technology transfer programs are spurring significant economic growth in the state. For more information, http://www.
The U.S. Geological Survey provides science for a changing world. Visit USGS.gov, and follow us on Twitter @USGS and our other social media channels. Subscribe to our news releases via e-mail, RSS or Twitter.
Darlene Trew Crist | EurekAlert!
Water - as the underlying driver of the Earth’s carbon cycle
17.01.2017 | Max-Planck-Institut für Biogeochemie
Modeling magma to find copper
13.01.2017 | Université de Genève
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
17.01.2017 | Earth Sciences
17.01.2017 | Materials Sciences
17.01.2017 | Architecture and Construction