Friday, 08 July 2016 13:21

Surf's Up!

Written by 
Published in Microbial Sciences

Blue Tide NoctilucaFigure 1. The beaches are a popular destination for travelers during the summer. Here a bloom of bioluminescent dinoflagellates light up the night waves. Image by Bruce Anderson.

With summer here and students having a break from school, many of us are traveling to take vacations at warm and relaxing locations. Perhaps you’re among them and while enjoying the cool, salty beach breezes, you plan to grab a board and ride the waves. But do you know who’s riding the waves with you?  

Certainly you’re aware of the larger, visible marine life, like fishes and invertebrates. But what about the smaller, nearly invisible marine life, like microalgae? These single-celled, photosynthetic microbes don’t get much play in the news except for when they’re causing a nuisance. However, they’re extremely important and live diverse, fascinating, and even whimsical lives.

What makes these nearly invisible microalgae so notable? For starters, they produce nearly 50% of the oxygen we breathe and serve as the foundation of most aquatic food webs. They are also the drivers of nutrient cycling in the ocean. For example, each year microalgae pump nearly 54 billion tons of carbon and 99-143 million ($) tons of nitrogen through the ocean.  Finally, as if all that isn’t enough, they have a significant impact ($) on global climate by releasing compounds that can stimulate cloud formation. These photosynthetic microbes clearly have a huge effect on the health of our planet. But this is just a small part of why they are so fascinating.  

Collection of microalgae culturesFigure 2. Microalgae (also known as phytoplankton) are photosynthetic, like plants, but can produce a range of pigments other than green-colored chlorophyll. This results in a near rainbow of microalgae, from deep reds and purples to greens, yellows, and browns.Image by CSIRO.

Though microalgae share common roles in our global ecosystem, they represent huge diversity while doing so. Microalgae consist of both eukaryotic and prokaryotic members and come in a variety of shapes, sizes, and colors. To survive, they employ a range of strategies for avoiding predators and finding nutrients. For example, when the coccolithophore Emiliania huxleyi switches from diploid to haploid states, it avoids viral infection. Members of another group, the dinoflagellates, possess flagella that help them swim through the water and capture their food. A personal favorite is the surf diatom. Diatoms are a large group of microalgae, with some of the most notable geometric shapes. These types of microalgae share the common trait of having silicate frustules, or glass shells. As their name suggests, the subset known as surf diatoms occupies the tumultuous surf waters where they attach to air bubbles to travel up and to sediment particles to travel down.

Can you envision that, as you’re surfing the waves this summer, microscopic surf diatoms are doing the same, but on bubbles, not boards? Researchers theorize that surf diatoms use this ability as a way to both find the nutrients they need and avoid predators. Currently, there are nearly 10 confirmed species ($) classified as surf diatoms, representing wide diversity, and found around the world. Mucilaginous secretions composed of different types of polysaccharides facilitate these cells’ attaching ability. While some surf diatoms follow a predictable day-night cycle of rising then falling, others switch between the two without a known pattern, sometimes so quickly (a matter of minutes or less) that it makes them very difficult to study. Attempting to capture surf diatoms without artificially influencing their state has been a challenging task for researchers. Various methods have been tried, such as wading into the water to sample, sampling from a boat, and aerial sampling: each with its pros and cons depending on complexity and degree of interference with the community of interest. Some studies have compared satellite data of the environment with the results of direct samples.

DiatomFigure 3. Diatoms. Image by Wipeter.

Of course, researchers aren’t just focused on the amusing lifestyle of surf diatoms. Because of the critical roles microalgae play, it’s important to understand how the different types influence their local ecosystems and to understand what environmental and biological factors influence their physiology and growth. It’s also critical to understand how these interactions change with the seasons and how they may change as a result of changing climate. Surf diatoms stimulate high productivity in areas otherwise thought to be too nutrient poor for productive food web schemes. This is good not only for the local aquatic life, but also for communities dependent upon productive coastal waters.  

Did you have any idea that you were swimming and surfing with some of the planet’s most important creatures? Thankfully they don’t’ take vacations, but you can enjoy their company while you take yours.

Further Reading:

Odebrecht, C., Du Preez, D. R., Abreu, P. C., & Campbell, E. E. (2014). Surf zone diatoms: A review of the drivers, patterns and role in sandy beaches food chains. Estuarine, Coastal and Shelf Science, 150, 24-35. doi.org/10.1016/j.ecss.2013.07.011.

Seckbach, J. & Kociolek, P. (Eds.). 2011. The Diatom World. In: Cellular Origin, Life in Extreme Habitats and Astrobiology Volume 19.  Springer, Boulder.

Gambino, M. (2014). Secretive Victorian Artists Made These Intricate Patterns Out of Algae. 

 

Last modified on Wednesday, 28 September 2016 15:46
Janet Goins

Dr. Janet Goins is Assistant Director of UCLA's Undergraduate Research Center. She works to provide undergraduate students with research experiences that prepare them for future success in STEM-related careers. Previously, her research focused on the ecological impacts of algal host-virus interactions, the evolution of and molecular steps involved in host cell pathogen defense, and the biological factors that influence harmful algal blooms. She was awarded a 2012-2013 ASM-BWF Science Teaching Fellowship and completed its program. In 2015 she received the ASM Science Communication and Strategic Marketing Fellowship.

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