Chlorophyll and Phytoplankton Flourishing in Natural Hydrocarbon Seeps

Summary: Research at Columbia University, Florida State University and Georgia Institute of Technology finds chlorophyll from microbes in natural hydrocarbon seeps.

Bubbling nutrients ~ Tiny bubbles of oil and gas rising from mile-deep vents on seafloor burst at surface; oil spreads into dinner plate-size patches of rainbow sheen; researchers at Columbia University's Lamont-Doherty Earth Observatory, Georgia Institute of Technology, and Florida State University share findings that microbes near the surface benefit from turbulence that accompanies the rising bubbles: Ajit Subramaniam/Columbia University via EurekAlert!

Natural hydrocarbon seeps in water surfaces along the continental margins of the Gulf of Mexico are supporting micro-organisms, according to a study published online Jan. 25, 2016, in the journal Nature Geoscience.

The ten co-researchers and co-writers base their findings upon chlorophyll concentrations obtained through fluorescence measurements from 2012 and ocean-color satellite image analyses from 1997 to 2007. On-site measurements, satellite images and shipboard flow-through measurements combine to indicate overlaps of elevated chlorophyll concentrations with Gulf of Mexico waters where natural hydrocarbon seeps occur. Research team members from Columbia University, Florida State University and Georgia Institute of Technology describe nutrient and temperature profiles indicative of nutrient-rich upwells from sea floors.

Proper nutrient and temperature levels encourage phytoplankton growth in natural hydrocarbon seep-filled surface waters, where chlorophyll then concentrates.

Research published in 2003 and referenced by the co-authors found that natural hydrocarbon seeps account for 47 percent of oil releases detected in the world’s oceans. A more recent study released in 2012 and targeted in the 2016 study gives data on the support of natural hydrocarbon seeps to benthic (seabed-area) productivity.

One co-researcher in Tallahassee, three co-researchers in Atlanta and seven co-researchers in New York hold that supportive interactions occur in overlying water columns at surface levels. Their data-gathering from 1997 to 2007 and from May to July 2012 indicated that natural hydrocarbon seeps do not hinder healthy growth of surface-level photosynthetic organisms.

The surface waters along the northern Gulf of Mexico join the seabed in hosting healthy benthic and photosynthetic organism growth.

Natural oil slicks as viewed from airplane flying about 1,000 feet above one of the studied regions in Gulf of Mexico: Ian R. MacDonald/Florida State University via EurekAlert!

The collaborative research team members knew of overlapping occurrences at surface levels of ocean waters throughout the world of natural hydrocarbon seeps and nutrient-rich water upwells. That knowledge led the research team to conclude that natural hydrocarbon seeps occupy important marine habitat niches by interacting supportively with organisms at different aquatic layers. It means that overlying water column impacts may hold for other deep ocean seeps and vents at depths of more than 3,280.84 feet (1,000 meters) down. Interactions between natural hydrocarbon seeps, nutrient-rich upwells and photosynthetic organisms need to be prioritized since long-term exposure to oil is less tolerable than low, short-term concentrations.

Andrew Juhl, Biology and Paleo Environment Professor at Columbia’s Lamont-Doherty Earth Observatory and study co-author, observed short-term dominance for nutrients.

Natural hydrocarbon seeps prove conducive to the formation of bubbles whose abundant nutrients from the sea floor attract and support the proliferation of the algae-like phytoplankton. The nutrients qualify as sufficient providers of life-sustaining protection against low concentrations of oil as to encourage phytoplankton to develop, engage in photosynthesis and manufacture chlorophyll.

Ajit Subramaniam, Biology and Paleo Environment Professor at Columbia’s Lamont-Doherty Earth Observatory and study co-author, reveals that a micro-organism’s internal processes may overcome seemingly hostile environments. He states: “This is the beginning of evidence that some microbes in the Gulf may be preconditioned to survive with oil, at least at lower concentrations.”

It turns out that some natural hydrocarbon seeps have twice the microbial density of some of the Gulf’s seep-free areas.

Oil slicks in northwestern Gulf of Mexico appear as white features in image derived from NASA's MODIS Aqua sensor; Mississippi River's Bird's Foot Delta and Louisiana are at top right: Norman Kuring/NASA GSFC via EurekAlert!

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

aerial view of natural oil slicks: Ian R. MacDonald/Florida State University, usage restrictions: credit must be given, via EurekAlert! @ http://www.eurekalert.org/multimedia/pub/107268.php?from=316954

bubbling nutrients: Ajit Subramaniam/Columbia University, usage restrictions: credit must be given, via EurekAlert! @ http://www.eurekalert.org/multimedia/pub/107266.php

oil slicks from space: Norman Kuring/NASA GSFC, usage restrictions: credit must be given, via EurekAlert! @ http://www.eurekalert.org/multimedia/pub/107267.php?from=316954

For further information:

D’souza, N.A.; A. Subramaniam; A.R. Juhl; M. Hafez; A. Chekalyuk; S. Phan; B. Yan; I.R. MacDonald; S.C. Weber; and J.P. Montoya. 25 January 2016. “Elevated Surface Chlorophyll Associated with Natural Oil Seeps in the Gulf of Mexico.” Nature Geoscience, vol. 9: 215-218.
Available @ http://www.nature.com/ngeo/journal/v9/n3/full/ngeo2631.html

LDEO @LamontEarth. 25 January 2016. "New study finds microbes thriving above tiny Gulf of Mexico oil seep. It isn't the oil." Twitter.
Available @ https://twitter.com/LamontEarth/status/691661959561887745

Ranosa, Ted. 26 January 2016. “Biological Phenomenon: Natural Oil Seeps Cause Microbial Life to Thrive in Gulf of Mexico.” Tech Times > Science > Environment.
Available @ http://www.techtimes.com/articles/127749/20160126/biological-phenomenon-natural-oil-seeps-cause-microbial-life-to-thrive-in-gulf-of-mexico.htm