Ocean optimism is a movement I learned about this semester that I think is worth sharing. Centered on the twitter hashtag #OceanOptimism and the accompanying website, it has a clear and simple mission: “Tracking the spread of positive and solutions-focused marine stories on social media.”
We introduced this concept to our students this semester in Marine Ecosystem Sustainability, a course for Cornell undergraduates taught by Professors Drew Harvell and Charles Greene. The course consists of advanced students who want to learn about the ecological underpinnings of coral reefs, the rocky intertidal and pelagic ecosystems, for example. In one lecture, Drew had the idea to ask each student to come in with an example of Ocean Optimism. This moment of focusing on success stories changed the tune of the course to one of leveraging scientific knowledge for positive change.
I usually think of my own role in positive change as being defined primarily by my research, but teaching has started to become a big part of this role. In Marine Ecosystem Sustainability, I got to know the students through small group discussions and the final project. This semester we ran the second generation of a research proposal final project in which the students develop and pitch a study to a hypothetical granting agency. The student’s research proposals were inspiring and thought provoking, giving me my own dose of ocean optimism!
In this post, I want to share a few of their proposals to spread the #OceanOptimism. We have highly intelligent and driven students who understand the ecological, economic and cultural value of marine ecosystems. The following three proposals focus on an interesting mix of ecosystem services, anthropogenic activity and ecological relationships.
A damselfish on a coral reef in Puerto Rico
“Impacts of Nutrient Fertilization in Mangrove Forests on Adult Reef Fish Populations in the Florida Keys National Marine Sanctuary”
Question: What are the ecological connections between mangroves and coral reefs, and how does anthropogenic nutrient pollution affect this?
Method: Fish surveys and environmental DNA (eDNA) to assess the impacts of experimental nutrient fertilization
In their own words: “With this research, we plan to expand the existing knowledge of anthropogenic stressors that occur in one ecosystem but also impact associated ecosystems. We will do this specifically by looking at how nutrient runoff affects mangrove forests’ ability to serve as a crucial nursery habitat for juvenile reef fish, and in turn affects their relationship with coral reefs.”
Crown of Thorns Starfish (Credit: Johan J.Ingles-Le Nobel)
“The Co-Effects of Eutrophication and Ocean Acidification on Acanthaster planci (Crown of Thorns Starfish) on the Great Barrier Reef”
Question: What are the separate and combined effects of nutrients and OA on larval recruitment in the destructive Crown of Thorns Starfish?
Method: Field surveys and a controlled laboratory experiment
In their own words: “In order to protect the reefs, both as a source of biodiversity and a source of ecotourism, research needs to be continued to help our understanding of COTS and the other reef stressors. This will allow for us to create the most effective plan to reduce environmental damage and help us preserve the marine ecosystems that we have put at risk.”
Coral reefs and mangroves in Puerto Rico
“Carbon Sequestration in Restored and Undisturbed Rhizophora mangle”
Question: Do disturbance and restoration affect carbon sequestration in mangroves?
Method: Measuring accretion rates and organic carbon content in a series of mangrove sites around Tampa Bay
In their own words: “Mangroves have never faced the threat they face today… While many mangrove stands are being cut down to provide room for agriculture and aquaculture, others are being replanted as people begin to acknowledge positive effects mangroves have on both marine and terrestrial ecosystems… Testing for sequestration in restored mangrove systems as compared to natural will provide information that will be vital to future mangrove restoration plans.”
Lessons learned for students and teachers
The students learned several key skills in this process, including:
As an instructor, I learned a lot as well. Certainly one of the best parts of this project was that in many cases the students knew more about their topic than I did by the end! I also came away with more ideas on how to teach writing and the scientific method, and I have a renewed sense of optimism for ocean health in a quickly changing world.
Miranda Winningham and Grace Revello, the undergraduate TAs, helped make this all possible.
Thanks also to the students who agreed to have their proposals featured:
We’ve got some marauding diseases on the loose in the U.S. and in oceans around the world. Many of them leave a path of destruction in their wake. Some are heading for the border…
I was writing down my own “most wanted” list in preparation for a lecture the other day when I realized I could crowd-source the list from the audience of undergraduates. While there are marine diseases that maintain a low profile despite wreaking havoc on wildlife populations, the worst ones should be notorious.
So what do Cornell undergraduates think of when they hear the phrase “marine disease”?
1. Sea Star Wasting Disease
This was not a shock. SSWD is unprecedented in scale, affecting around 20 species of asteroids and causing mass mortality. The sea star pictured below, Pisaster ochraceus, is just one of these species. Sick sea stars display twisting, white lesions, and even arms that walk away from their bodies.
Given the role that sea stars play in the ocean, many ecologists worry that removing sea stars via this mass mortality event will have rippling effects throughout the ecosystem. Cornell microbiologist Ian Hewson has linked the disease to densovirus and is posting updates on his experiments on his blog. I recently worked with other graduate students to study the immune response to SSWD. Resistance may be the last resort.
Sea star wasting affects many species of asteroids, including the iconic Pisaster ochraceus of the Pacific NW.
2. Oyster Dermo and MSX
The student who volunteered this answer astutely named both diseases together. Both Dermo and MSX affect oysters in the U.S., sometimes simultaneously. This is of interest to me given my own work on coral coinfection. Additionally, Dermo and MSX are some of the most commercially important marine diseases in the U.S. Both are caused by protists and have been linked to salinity and temperature conditions. Luckily, there is evidence that oysters are developing resistance to disease.
3. Eelgrass Wasting Disease
This was a great answer, but was likely influenced by the fact that students know more about work by Cornell researchers. Still, this might be one of the most important emerging epizootics for U.S. marine ecosystems and resources. Eelgrass beds provide habitat, prevent erosion, and filter runoff. Historically, wasting disease has affected eelgrass in the North Atlantic, Mediterranean, and the Pacific NW. It is caused by the spindle-shaped protist, Labyrinthula zosterae, a relative of the the labyrinthulid protist I study in sea fans.
4. Coral Bleaching
This is not a disease, but it presents a “teachable moment”. Bleaching is not a disease to me because it’s usually not caused by a pathogen. However, it’s certainly very damaging - and this was a very timely answer given the unseasonably warm waters in the Pacific. NOAA has recently declared the 3rd global coral bleaching event and expects widespread damage to coral reefs.
This list is diverse, but it leaves out some major players. I’ve included a few in the table below.
I mostly agree with the undergraduates and I think they’ve pointed out well-known, notorious marine diseases. However, it’s hard to say which are the most important. Even a few years ago, no one would have put sea star wasting disease on this list and now it’s one of the worst we’ve ever seen…
What would you include? Feel free to add a comment to enhance this crowd-sourced “most wanted” list.
Keeping corals alive in the lab requires a simulation of nature, which is a lot like trying to recreate a famous watercolor with your at-home paint set. You can get some of the basic elements, people can see what you were going for, but the original is expert territory.
I’m certainly willing to admit that nature is the expert and we are not. That is one of my biggest take-aways from keeping pieces of sea fans alive in the laboratory.
When I first attempted this feat last year, I learned a lot about the corals just from the process of keeping them alive during pilot experiments. They like light, but not too much. They like salt, but not too much. They do not like touching each other. They do not like stagnant water. They do not like green eggs and ham.
Last week, we collected small pieces of corals from the field, put them in tanks under high-powered lights, and kept them happy for about a week by providing circulation and fresh saltwater (pictured on the left, above). It’s like a weird hotel, but at the end of their stay, we hope that our guests can help us answer the questions we set out to address.
1) How do corals respond when they’re infected with two pathogens instead of one?
2) How do the two pathogens respond to this arrangement? Is one of them just along for the ride?
3) Do the answers to questions #1 and #2 change if we look at one colony vs. another colony?
4) Are there differences in examining this relationship soon after it begins vs. 2 days later?
These are questions we need to go into the laboratory to answer. The controlled conditions in the laboratory allow us to keep all else constant while we change the number of pathogens and measure the response of the corals and the pathogens. The experiment compares what happens when the coral host is infected with the purple spots disease (pictured above on the right), the Aspergillus fungal pathogen of sea fans, and both together.
The motivation for this experiment is the reality that life is not as simple as one pathogen infecting one host. Even though the classic disease ecology Venn diagram, shown below, portrays the relationship between one host, one pathogen, and the “environment” (as a blanket term), disease ecologists of course know that it’s more complicated. Indeed, my laboratory experiment in 2014 delved deeper into the “environment” component of this Venn diagram by exploring the effects of combined stressors. This year, I’m switching gear to further explore the “pathogen” component.
While the field of disease ecology has primarily focused on single infections up to this point, recent studies have been adding to this foundation one step at a time. Research in other plants and animals, though very few marine organisms, has begun to investigate the multiple-pathogen scenario we call “co-infection”. Co-infections in African buffalo, for example, affect mortality rates and disease transmission. Especially interesting is the finding that treating the worm infections may actually exacerbate bovine tuberculosis, a bacterial infection! In the case of Lyme disease, the co-infection of the tick vectors with the pathogens for anaplasmosis and babesiosis has important public health implications: being bit by a co-infected tick matters.
As with buffalo and ticks, co-infections may be very important for corals and coral reefs. Imagine that a coral is infected with one pathogen, and then suddenly beset by a second invader! Will it be better equipped to fight off that second pathogen since it was already in the midst of fighting off the first one? Or will its immune resources be stretched too thin, leading to heavily reduced reproduction, or even death? In either case, there may be a turn in the tide of the battle between the pathogens and the corals.
The results of our laboratory experiment will give us a glimpse of this battle, and we can hope the coral wins. The outcome of coral diseases, including co-infections, determines the health of reef ecosystems. After spending a week in the laboratory doing my best to mimic reef conditions, I appreciate the many moving pieces even more. There’s nothing quite like trying to recreate nature in a box that makes you realize how cool it is.
The ocean is a web of interactions – who eats whom, who is friends with whom, who acquires infection from whom (WAIFW – a real live acronym). It’s a whole community of relationships that’s almost as complicated as a single middle school.
A disease ecologist wants to consider the importance of all the relationships between organisms. But you must start at the very beginning to figure out where the infection is coming from. That includes:
Step #1) What is causing the infection? Is it a bacterium, a virus, a fungus…?
Step #2) What is the mode of transmission?
Transmission! In some ways it’s the holy grail of disease ecology. Research on coral diseases has yielded some information on transmission, but in most cases coral biologists are still on step #1. We do know the etiology of some diseases, such as the bacterium that causes bleaching in Oculina patagonica and the fungus associated with sea fan Aspergillosis.
As for step #2, there are several ways for diseases to be transmitted from a sick host to a healthy host and more than one can be happening at the same time. Here are the possible modes of transmission put in terms of of human disease:
1) Contact – Ex) You come in direct contact with someone with a virus or their possessions
2) Airborne/ waterborne – Ex) Flu particles float through the air and you inhale them
3) Vectored – Ex) A mosquito bites you and transmits the malaria parasite from its salivary glands
We think about all these possibilities when we’re doing our disease surveys of sea fans in Puerto Rico. Sea fans may be in direct contact with each other, but pathogens may also be drifting through the seawater or traveling in biting organisms. Today I’ll focus on vectored diseases.
Disease vectors play an important role in both terrestrial and aquatic outbreaks. Some of the classic examples are mosquito-borne diseases like West Nile virus, malaria, and dengue fever. Some vectored diseases infect multiple host species, like Lyme disease. One of the reasons that disease ecologists find Lyme disease so fascinating is because it involves so many members of the biological community – the ticks, the bacterium (Borrelia burgdorferi), the humans, the mice, the deer… many organisms influence the disease dynamics!
In corals, research on disease vectors has linked sea snails to brown band disease and white band disease. Fish have also been raised as suspects in some disease mysteries. In sea fans specifically, research by past Harvell lab members suggests that flamingo tongue snails contribute to transmission of a fungal pathogen. Of course, organisms found on corals aren’t necessarily transmitting diseases to the corals, and in fact they may be lessening the impact of disease.
Knowing this, how could we not look for other organisms in our disease surveys of sea fans? No matter what they’re doing, our goal is to closely monitor each colony for signs of interactions, such as predation.
In some cases we’re lucky enough to catch the culprits in the act! I excitedly snapped each of the photos above in just such a moment. The first photo is of a group of crinoids nestled in a pocket they’ve formed out of the flexible sea fan. Are they passing through or making a more permanent home? Are they eating sea fan tissue, or eating organisms off the surface that might otherwise be detrimental to these corals? The second photo captures two flamingo tongue snails that are most certainly in the midst of a sea fan feast.
We’re currently more than half way done with the field surveys. In the past two weeks, we’ve recorded data on 11 different sites! Each of the sites requires a long dive full of methodical planning and rapid underwater writing. But the reason for all this scribbling – even in the midst of being tossed into stinging fire coral by waves – is that we want to be able to ask questions about the role of environmental factors and the other organisms on the reef. We want to collect data on many different puzzle pieces to further our understanding of how coral diseases play out in natural populations.
With that perspective, the crinoids, fireworms, and snails are not simply interesting behavioral observations, but key contributors to the reality of coral diseases. No sea fan is an island.
With special thanks to my funding sources for this project:
National Geographic Young Explorers, Young Explorers Grant
American Academy of Underwater Sciences, Kathy Johnston
Betty Miller Francis ’47 Fund
Cornell Graduate School, Research Travel Grant
Atkinson Center for a Sustainable Future, Sustainable Biodiversity
Paul P. Feeny Graduate Research Fund
Sigma Xi, Cornell chapter
Which one of these things is still alive? You may not know it from the haggard state of the sea fan coral on the left, but it’s not dead yet! The lobster, however, is belly-up.
This difference matters because the sea fan may make a comeback. And because corals are so integral for marine ecosystems, it matters to biologists like me trying to study ocean health. It also matters for the people who like to swim on reefs, drive boats, and eat seafood. Given the size of the crowds visiting the local reefs on the weekend, that’s a lot of people.
I took these photos on our first dive last week – kicking off the 2015 field season! I’m focusing on these two photos for the inaugural blog post because these types of images are where it all starts – sick oysters, a die-off of sea stars, declining coral on the Great Barrier Reef. Thus begins a marine mystery. In each of these examples, the ailing animals turned out to be in the midst of a marine disease mystery. That’s right in my wheelhouse as a disease ecologist. Of course, there are other causes of poor health and death. At the beginning, we don’t know what we’re looking at- and that brings us back to the uncertainty depicted in the photos above. Is this a disease outbreak or not?
We’re beyond this early questioning phase in research on Caribbean sea fans. In fact, some of the diseases I study have clear signs, like the purple pox on the sea fans. But there’s a lot more to find out! For the third year now, I’m basing my research out of the University of Puerto Rico’s marine station. I’ll be working with Dr. Ernesto Weil (UPRM), Phillip Fargo (Cornell), and others to survey 15 reefs and run a lab experiment.
As a result of my research in 2013 and 2014 (see previous blog posts), we now know that the purple pox appear on many of the sea fans. We also know more about how the disease works. These findings are critical since the pathogen showed up in Puerto Rico relatively recently and was certainly a marine mystery of its own. I’ve also found that interactions between environmental stressors affect sea fan disease and immunity, which underscores that single stressors cannot be considered in isolation.
This year, we’ll repeat the surveys at the same 15 sites in order to compare disease prevalence and immune function between years. I’m excited to look at coinfection in the laboratory experiment by testing how two different sea fan pathogens affect each other and the host’s immune response.
We have an important job to do here, BUT we see so many cool things in the midst of a project that it’s a shame not to share them. This is the motivation behind the “Dose of Disease” series I’ll be posting this summer. In addition to some updates on our research, I’ll talk about the ideas that pop into our heads when we catch something out of the corner of our eye, the weird things we want to know more about, …
…. the little questions that may actually be the BIG questions.
Re-posted from 2014
I began posting about my field work on coral disease and immunity in Puerto Rico in June of 2013 during my first field season as a graduate student. Please see this and the following posts from 2013 and 2014 (re-posted from the Harvell Lab Blogspot).