Microbes and a Changing Environment

Josh Brycki
Bigelow Laboratory for Ocean Sciences in East Boothbay, Maine.

When Bob Dylan released “The Times They Are a-Changin’” in 1964, it was middle of Civil Rights Movement, and social change was a major theme of the album (and song of the same name). The theme of change, more generally, is particularly relevant today due to environmental change.

Scientists have developed methods such as carbon dating and the fossil record for detecting long term environmental change. “Big history” is the use of these methods to discover something about long-ago changes and processes on Earth. Big history also provides necessary background information for understanding current changes and processes. Furthermore, relative to big history, “the times they are a-changin’” very fast.

For example, the human population has multiplied by about fifteen times in just the last 500 years (Roser and Ortiz-Ospina, 2018). Land-use changes and increased pollution associated with increased population size have led to issues such as the loss of biodiversity and human-caused climate change. Vertebrate extinction rates are, conservatively, 100 times that of the predicted normal background rate (Cabellos et. a. 2015). Meanwhile, the climate is warming at a rate that is projected to be, conservatively, about 10 times as fast as the emergence from past ice ages (National Research Council, 2006).

Additionally, atmospheric carbon dioxide (CO2) levels (in parts per million) are over 30 percent higher than any time within the past 400 thousand years, making this unprecedented in the whole period anatomically modern humans have existed (The Relentless Rise of Carbon Dioxide,” 2016). The last time CO2 levels are estimated to have exceeded the current 411 parts per million was 25 million years ago, when it is thought that the Arctic was 15-20°C (59-68°F) warmer than today, and the sea levels were 20 meters (~66 feet) higher (Boweler and Bice).

Predictions of a climate changed future are as follows: an increase of 2.5 to 10 degrees Fahrenheit over the next century, increased ground level ozone and particulate, an additional rise in ocean levels of 1 to 4 feet by 2100, an essentially ice free (summer) arctic, longer growing seasons, changes in precipitation patterns (namely harsher weather like droughts and hurricanes), increased disease transmission, and continued ocean acidification (“National Climate Assessment,” 2014).

The unprecedented nature of current changes in Earth’s biosphere, and the speed at which they are occurring, is a formula for unintended consequences. For example, the change we experience may lead to “winners and losers,” with some species going extinct and others growing in population and distribution. Furthermore, changes can have indirect consequences of their own, including possible feedbacks causing acceleration of climate change, biodiversity loss, ocean acidification, etc..

Take for example the end-Permian mass extinction which took place over 20,000 years, beginning about 252 million years ago. It was the largest scale mass extinction with an estimated 90% of species going extinct. It is thought that this was sparked by volcanic-driven alterations in the carbon cycle. Research shows that the nickel released into oceans by volcanic ash may have led to the excessive growth (i.e. bloom) of methane producing archaea (a type of microbe, i.e. single celled organism) called Methanosarcina (Rothman, Daniel H. et al., 2014). This bloom is then thought to have been the primary driver behind changes in the carbon cycle that caused the end-Permian extinction (Chandler, 2014). Thus, volcanism may have only been the first in a chain reaction with much larger ramifications than otherwise would have occurred. The major issues occurred only when microbes responded to this change. 

The end-Permian extinction serves as a warning that microbes may have profound impacts when they react to changes in the environment. In the case of Methanosarcina, the changes may have led to a mass extinction.

Emphasis has been placed on studying microbes and their response to climate change because of their role in biogeochemical cycling. In fact, Microbe’s effects on climate change are already being observed (Swanson et al., 2016). Take for example the release of methane (a major greenhouse gas, and the same gas produced by Methanosarcina) in permafrost that is being warmed by climate change. This process is mediated by bacteria that otherwise would not be able to function in the frozen permafrost, and this is one process by which climate change has a positive feedback due to the effects of microbes.

On the other hand, microbial activity may lead to resilience. For example, blooms of diatoms serve as a major carbon sink in the oceans and may increase the Earth’s reflection of sunrays.

In my time at Bigelow Laboratory for Ocean Sciences, I am continuing research performed by Dr. Steve Archer and Kevin Posman on halocarbon exchange between marine microbes and the atmosphere. Specifically, I study two diatom species: Porosira glacialis and Ditylum brightwelii. Halocarbons play an important role in the global halogen cycle, and in turn are important due to their role in naturally occurring ozone depletion. This is because halogens in the atmosphere catalyze the destruction of ozone.

My research focuses on the production of halocarbons by diatoms. This is important to understanding why we see various halocarbons abundant in the ocean, and then being released into the atmosphere. Interestingly, we have found unexpected halocarbon production rates in relation to the activity of these diatoms, indicating there is something unknown occurring in the system we study. It is important to elucidate this unknown because production rates by diatoms ultimately have a major impact on global cycles, and understanding production rates is necessary for understanding the cycling of halogens.

At the Air and Sea Interactions Laboratory where I am an intern, research has led to important discoveries on how planktonic microbes currently interact within the biosphere, and how they are reacting within a changing environment.

At Bigelow Laboratory, researchers are at the forefront of basic and applied research into understanding Earth’s changing systems. Bigelow Laboratory is a great place for this research, specifically because it is a large community of diverse researchers. The diversity of research preformed at the Laboratory ultimately leads to unique collaboration that is necessary for solving the large, complex problems in environmental biology.

Science writer Michael Shermer once said, “Science is the best tool ever devised for understanding how the world works.” The importance of building an understanding of how the world works, and microbes role in the world, is increasingly important due to the unprecedented rate of change the Earth is experiencing and the possibility for unintended consequences of change. After all, “the times they are a-changin,” and microbes like Methanosarcina, Porosira, and Ditylum are responding to this change in potentially unexpected ways.

Josh Brycki is a Juniata College student in Bigelow Laboratory for Ocean Science’s Research Experience for Undergraduates program. This intensive experience provides an immersion in ocean research with an emphasis on hands-on, state-of-the-art methods and technologies.

Microbes and a Changing Environment