A research team at UCSB, led by marine ecologist Dana Morton, has spent the past eight years mapping out organism interactions within the Santa Barbara Channel kelp forests to develop a detailed food web. Food webs typically illustrate any consumer-resource relationships and how biomass is transferred through a particular system.

While the kelp ecosystem is known for being rich in species, many people don’t recognize the full extent of its biodiversity. Courtesy of Wikimedia Commons

Their recent publication illuminates the complex connections between organisms in the kelp forest ecosystems by including more parasites and small invertebrates. This also created a higher resolution of species interactions than past webs. 

Their research also extends to more indirect relationships between organisms that are further apart in the food web. “Often we know what the direct interactions would be with a species but we don’t know all the rippling effects,” Morton explained. “If I eat this one species that could affect the predators of that species or that species’ prey, those are all the indirect effects.” 

Morton said these indirect interactions shed light on the large-scale ecological shifts for the kelp forests. The relatively long eight-year length of the project was partially due to the high volume of data being compiled. Morton said they drew some data from past webs while also filling in the gaps through field sampling. For the field samples, they collected fish and invertebrates to study their tissues under microscopes and search for parasites. Once the parasites were found, they created a photographic record of each one. They were then able to piece together more parts of the web with the more detailed record of parasites and small free-living invertebrates. 

According to Morton, one of the main challenges they encountered was mapping precise connections between organisms while not getting swept away in the minute details of the cycle. Morton explained how she would sometimes spend copious amounts of time trying to find one specific record or piece of data. She described this process as “tracing these little trails in the literature.” The immensity of information they needed to compile made it difficult to stay focused on the big picture while also maintaining accuracy. 

“I have to be focused on the details but not so focused on the details that I never get it done,” Morton explained. While they weren’t able to focus on too many small details for this project, it opened up new questions that could inspire future research. 

A graph of a kelp forest food web with parasites (a) and without (b). Courtesy of Dana Morton

One of the new questions came from an undergraduate on her team. Christiana Antonino noticed a marine isopod that acts similarly to a termite within the kelp. This isopod, also known as kelp gribble (Limnoria algarum), burrows tunnels through the kelp which then house their colonies of offspring. According to Morton, these isopods have been observed in different species of algae but never in kelp before. A better understanding of these small invertebrates could provide more information on how they affect kelp ecosystems. Morton described this as “an example of a rabbit hole where you find something cool but it takes you on a tangent from the overall project.” 

Morton hopes that the higher resolution of this food web will aid in efficiency and clarity for future research. “One of the big unknowns when you are looking at how a species is going to interact in the system is what [the] indirect effects will be,” she explained. Morton emphasized that it will now be easier to see how each organism is indirectly affecting the community as a whole. 

She further explained that indirect relationships “can be kind of overwhelming to study, but now that we have the food web, you could look to see what all those potential interactions might be.”

Morton said this food web will also help exemplify the immense diversity found in kelp forests. While the kelp ecosystem is known for being rich in species, many people don’t recognize the full extent of it. A visual representation of these species and systems will expand upon previous understanding of the ecological diversity.