PUPCYCLE Day 4 – Express Yourself, Bacteria!

Monday, May 27, 2019 – Incubation Site #1

PUPCYCLE 2019 – Express Yourself, Bacteria!

Bacteria were the first forms of life on Earth, dating back to 3.8 billion years ago during the Archaean Eon. These single-celled prokaryotes (containing no nucleus) have thrived in some of the harshest conditions and survived the 5 mass extinctions recorded in Earth’s past. Bacteria, like many other microbes, have a bad reputation as pathogens, or disease-causing agents. In

Figure 9 – Nataly Guevara places her sealed samples inside the Incubation system. [Photo Credit: Miriam Sutton]
reality, 90% of bacteria are helpful and most other species, including humans, could not survive without these microscopic workhorses. Their short life span is filled to capacity with tasks ranging from the decomposition of decayed matter to the “fixation” of nitrogen for plant absorption to the production of 50% of the oxygen for our atmosphere. “We just learned the importance of these marine bacteria  some decades ago,” said Nataly Guevara, a researcher onboard the R/V Oceanus who is keeping an eye on these fundamental contributors during PUPCYCLE 2019. She added, “While most people relate to the importance of monitoring the many species of plants and animals visible to the naked eye, many of the microbial communities are overlooked.” Out of sight, out of mind.

Nataly designed 2 sets of experiments to analyze the responses of these deep microbial communities and how their carbon-processing abilities are altered once they are upwelled and exposed to surface conditions. Her investigation began with the collection of bacteria from the deep-water samples brought up at midnight Monday morning. Some of her samples were sealed in dark containers to simulate the environment in which they were found while others were sealed in containers where diffused light (similar to the light found in surface water) could interact with the bacteria. In addition to controlling the bacteria’s exposure to light, Nataly is also controlling the temperature to simulate either colder deep water or warmer surface water. Controlling these variables will allow Nataly to isolate the response of the bacterial communities over the next 4 days. The second phase of Nataly’s investigation will use samples collected during an active upwelling cycle the PUPCYCLE team plans to follow in the next few days. Being able to control variables with Incubation experiments will be compared to observations from bacterial communities that are exposed to all variables found in an active upwelling event.

Nataly will be using bioinformatics technology to identify the bacteria; analyzing their genes to identify different types of bacteria found within the community; recognizing “who” is actually in the water sample and in what abundance (e.g.,decomposers, nitrogen fixers). Her next objective is to analyze the bacterial degradation (or decomposition) of Dissolved Organic Carbon (DOC) found throughout the water column.

Figure 10 – A simplified version of the Microbial Food Web illustrates the cycling of Dissolved Organic Matter/Carbon through the various trophic levels. [Image credit: Modified from http://www.ucl.ac.uk/~ucbt212/chapter5.htm]
DOCs comprise one of the largest carbon pools in the ocean and it is the bacteria that degrade DOC into useable energy that supplies all the trophic levels, from the Chlorophytes, Haptophytes, Dinoflagellates, and Diatoms all the way up to the mighty Blue Whale. This latter analysis will allow Nataly to observe which genes the bacteria are expressing under various environmental conditions; those she is controlling with the Incubation experiments and the conditions experienced by the bacteria during natural upwelling conditions.

Nataly Guevara, was born in Ecuador and completed her undergraduate degree in Biotechnology and Biology at the University of San Francisco at Quito (Ecuador). She then moved to Bremen, Germany for her Master’s degree in Marine Microbiology at Max Planck Institute and is now a doctoral candidate at the University of North Carolina – Chapel Hill.

Today’s Certificate Challenge: Bacteria, Diatoms, and many other microscopic organisms have the ability to select and change their expression of _____ based on environmental conditions.