Last week I was able to get down to Key Largo for the American Water Resources Association (AWRA) Florida chapter annual meeting. Like any opportunistic biologist I always take the opportunity to look around.
The first place I went before even checking into my hotel room was John Pennekamp Coral Reef State Park. One of my favorite things to do there is to snorkel around mangrove roots. People familiar with mangroves often know that they harbor a complex root system (especially red mangroves with buttressing roots) that protects and supports many species including juvenile fish. What surprised me on my first visit several years ago to the park, is how many different things live on the roots themselves. These epiphytes (“epi” meaning on, and “phyte” meaning plant) and epizoans (“zoans” refers to animals) are vibrant and diverse. The delicate little tendrils of minute anenomes are littered in among examples of solitary and colonial species of tunicates, little squishy organisms with in-current and ex-current siphons. Clusters of Isognomon alatus, the flat tree oyster, are visible. It’s an amazing brackish little universe.
While they may seem a little frenetic, I captured a couple videos as well. The first is a little tour of the mangrove roots I describe above:
And the next is of a small barracuda I followed for a moment or two:
I later moved my prospecting off shore a couple days later when I donned scuba gear with Rainbow Reef Dive Center. Besides the surprise siting of an interesting shark or notable sea creature, one of the appeals of diving down in the keys is the intricate landscape of benthic creatures including things like corals, sponges, and christmas tree worms.
And while I can always be kept busy watching the variety of oddly colored and shaped fish, the appearance of a rather large green moray eel doesn’t disappoint!:
The following picture is not overly well composed or striking. But it does represent a moment I found particularly exciting – my first cicada!
I’ve had the stray thought several times that it seemed unusual to always hear the constant summer whine of cicadas in Florida without ever seeing any. Finally, I spotted one!
It turns out IDing him is an altogether different task. According to the University of Florida’s entymology and nematology department, Florida supports 19 different species of cicada. They categorize species relative to their size as defined by the length of their forewings. The cicada picture above most squarely fits into the larger species. The coloring indicates what I saw was some species in the genus Tibicen (or Neotibicen according to this site). However, it turns out species in this genus can experience quite a bit of color variation.
This graph, also from the UF site might not entirely narrow things down either:
I took my cicada picture on July 28th, which according to the timing of different species in our county, could suggest five different Tibicen species. This summer appearance also gives this genus it’s more common name of dog-day cicadas in reference to the dog-days of summer. So short of some insight from someone more versed in than I am, he will ever after be referred to as Tibicen spp.
Another detail I found surprising is Florida has no periodical species of cicada, which refers to 13 and 17 year cicadas that emerge all at once in some regions of the country. Instead our summer denizens will be present every year.
To listen to some of our local cicada songs, visit the website here.
Full disclosure, I was once not the oyster devotee I am now. As a proper native New Englander and marine biologist, I of course was acquainted with them. But it wasn’t until I trekked across the eastern coast of the United States and wound my way down to start a PhD program at the University of Florida with molluscan biologist Shirley Baker, that I began to suspect there was something more salient about my study organism.
In the great assemblage of all the graduate students that ever were, many a person has chosen a dissertation topic out of convenience and as a means to an end. Things may have started out in a similar vein for my own research. Currently it seems oysters are a sexy topic, and ecosystem services – the benefits of nature that directly influence human wellbeing, an even sexier one. But as I began to work on my research I began to realize the uniqueness and gravity of Crassostrea virginica, the American Oyster.
Like most people with a glancing familiarity with oysters, I knew they were filter feeders, making them unknowing proponents of positive water quality in many an estuarine region. Under this premise, I started field research at the Guana Tolomato Matanzas National Estuarine Research Reserve (which we call the GTM NERR for brevity’s sake) in the St. Augustine region of Florida to examine clearance rates of oysters within the system. So far I’m learning interesting lessons that I continue to explore. While the Nature Conservancy posts the following graphic about the filtration capacity of a single oyster, I’d like to provide the caveat that this indicates what an oyster could do, not necessarily what it does do:
Within the reserve, oyster clearance rates are often lower than lab studies might estimate. But this can often be attributed to the complexities of the natural environment and their influence on the biological processes of organisms. Oysters feeding rates can be influenced by qualities like temperature, salinity, and the nature of the particles in the water they are feeding on. Within the GTM NERR, we’ve also found evidence that tidal cycles may be hugely influential in how much time certain parts of reefs have available to feed.
But while I continue to reveal information on oyster filter feeding within the reserve, I had less initial insight about the full worth of the expansive reefs I was seeing. I did not know how much of a refuge oysters provide until I started to find the squidgy, pinchy little creatures while working on reefs. If you grab a cluster of oysters and rotate it in your hand, you’ll see the craggy irregular patches of barnacles interspersed with often minuscule ribbed mussels hanging on dearly by their byssal threads. Porcelain crabs will flatten themselves against shell in a desperate effort to avoid detection. While collecting oysters, you may also spot sea cucumbers and oyster toadfish while sheepshead and blue crab loiter nearby.
I also didn’t fully appreciate the bastion of strength reefs are against the storms that regularly visit Florida coastlines. It’s suggested oyster reefs have the ability to pace themselves with sea level rise, making them a common and ideal constituent of living shoreline designs which are meant to function as hardier and more effective alternatives to grey infrastructure historically used for shoreline armoring.
The title of my post then refers to the measure of what oysters can teach us about the sometimes unexpected ways we are tied to our environment. But if we attune ourselves to what oysters have to say about the health of our coastlines, we should also listen to one another about the values and concerns we imbue these natural resources with.
In St. Augustine, oysters also provide a source of harvest both directly for oystermen and for fishermen who recognize reefs’ ability to foster good fishing grounds. However, ability to access reefs and to harvest oysters depends on regulation especially in relation to water quality; oysters need to be gathered in locations where they are deemed safe enough to eat. Resource managers are often trying to balance providing positive harvest experiences with optimizing the other services oysters provide.
Information on how fishermen and oystermen currently use reefs, how they would like to use reefs, and how things have changed can then be crucial for the decision making process around managing oysters. We can try and gather those details indirectly or we can talk to these groups directly – a route I am currently tapping into. Through one-on-one interviews, people are telling their stories, revealing vital information about oyster use in the area, and teaching me about the fascinating culture and relevance of oysters within their coastal experiences. I hope study results will lead to more targeted management recommendations and provide opportunities for public outreach, education, and local engagement. Simultaneously, I am quickly learning to embrace my burgeoning love for human dimensions and social science research. All because of oysters. Who would have thought?
If this research interests you, especially my current study on the perception around and use of oyster reefs by oystermen and fishermen, consider donating to my crowdfunding campaign. My friend Natelle, of Natelle Draws Stuff, has designed these amazing postcards and stickers for those who would like some oyster swag:
Yet again drones have proved an invaluable instrument for new discoveries, especially when it comes to observing marine mammal behavior (see my past post: Whale Tales – Current Cetacean Communiqués). The subject in question this time is the strange and elusive Narwhal.
The edited footage above conveniently highlights moments where individual narwhals stun passing cod with a solid tap of their tusk. It’s an interesting hunting method, but one that is rivaled by other examples in the marine world. Many species immobilize their prey; some, like sailfish, use similar techniques, while others may use contrasting tools. Electric Rays and eels shock their quarry, while pistol shrimp usehigh-speed cavitation bubblesto daze their targets. Archer fish knock their dinner out of overlying branches by spitting a stream of water at them.
The purpose of the narwhal’s tusk likely doesn’t stop at clubbing unwitting prey. The absence of an enamel coating on their tusk supports the idea that these animals might be using them in a sensory capacity, allowing the specialized tooth to come into contact with surrounding water masses to detect environmental changes such as salinity and temperature, as well as chemical cues in the water associated with food and mates. Pairing this awareness of their surroundings with highly directional echolocation also allows them to find sometime slim openings in Arctic ice coverage where they can surface and breath as needed.
However, these animals may still suffer catastrophic events living in the extremes they do. Pods of narwhals occasionally suffer entrapments when rapidly shifting weather conditions cause unexpected freezing over potential air holes leading to open water. Kristin Laidre, a researcher at University of Washington’s Polar Science Center, noticed the frequency and timing of those events may be changing with recent shifts in Arctic climate. This, paired with a variety of additional stressors to the whales’ habitat, is the focus of one her current research projects examining the behavioral ecology of narwhals in a changing Arctic. She and other researchers have tagged the animals on multiple occasions in Canada’s Baffin Bay to track their movement, the depth of their dives, and associated water temperatures. As it turns out the temperature data has proved useful to other scientists interested in climatology data. Laidre is soon hoping to once again utilize the oceanographic power of narwhals, this time in Greenland.
A week and half ago multiple science news outlets reported on the publication of a study that described a new species of Geckolepis geckos, a bizarre genus that goes by the more common moniker of “fish-scale” geckos. They appear to be relatively unique to the Comoros Islands and Madagascar, locations that harbor other fascinating endemic species (restricted to a certain region), a fact which can largely be attributed to island isolation.
These lizards are sheathed in a layer of vibrant scales that they jettison quickly in response to perceived predatory threats. Mark Scherz, the PhD candidate who lead-authors the study, experienced significant challenges trying to collect fully-covered specimens of what would later be identified as Geckolepis megalepis. The gecko loses skin with scales, and much resembles a naked baby mouse after the process. As the study notes, “The new species has the largest known body scales of any gecko (both relatively and absolutely), which come off with exceptional ease.”
This quality of Genus Geckolepis to lose then regenerate scales is suggested to have applications in human medicine with regards to tissue recovery. In addition, geckos have been studied for other enviable qualities including their ability to adhere to vertical surfaces with ease.
There is currently a great deal of collective breath-holding surrounding the fate of a portion of the Larsen C ice shelf. Reports since December have been narrating the changes in a widening crack along its face, as the rift has increased in length by 20 miles. Only a 12 mile stretch of intact ice keeps the shelf tenuously anchored. As USA Today notes, you can literally bet on when it will give way.
The Larsen ice shelf is a region of chaos along the Antarctic Peninsula which curves towards the toe of Chile. The region is named after whaling captain and explorer Carl Anton Larsen, who experienced an Antarctic winter stranding with his men, not unlike that of Ernest Shackleton. Much of the shelf has already been lost previously due to catastrophic collapse events. 1995 saw the crumbling of Larsen A. Seven years later, Larsen B disintegrated over the course of 2-3 months. Its epic demise was cataloged by watching satellites.
The sheering off of these massive stretches of ice are not without effect. Ice shelves are comparable to sea ice, and their liberation does not directly contribute to changes in sea level. However, they often fortify nearby glaciers, and once absent, glacial movement can speed up significantly. Glacial ice, in contrast, can contribute to changing sea levels. It is thought that global warming trends have contributed to many ice sheet de-stabilization events around Greenland and Antarctica. Because ice is a cooling influence on climate due to its reflective nature (called albedo), ice loss is part of a positive feedback loop. Warming trends reduce both ice cover and albedo which leads to further warming.
On perhaps a lighter note however, the calving of ice also has also led to unexpected discoveries. After the break up of Larsen B, scientists discovered an intricate chemotrophic ecosystem a half mile below the ocean’s surface. Chemotrophic organisms create their own energy through chemical pathways rather than relying on photosynthesis. The system below Larsen B was populated by cold seep clams and mats of microbes, examples of tenacious organisms that have adapted to get by with little access to sunlight or the growth of the phytoplankton food source it supports. This along with findings like vast microbial communities found within subglacial lakes in Antarctica adds to our collective evidence that life finds ways to subsist in the most extreme of environments.
A new species of Bonnethead has been described in Belize by FIU researcher Demian Chapman, thus the scenario of a single widespread species in that region now becomes the story of one or more species with overlapping ranges. The discovery was made after analyzing a snippet of the shark’s genome.
DNA analysis has allowed a much more nuanced perspective on species-level differences beyond the physical characteristics that were once the focus of classically-trained taxonomists. Now scientists are able to classify variance on a genetic level and have refined the technique. Now researchers use a method called DNA barcoding, which needs to examine just a small portion of an animal’s genomic sequence, and is often compared to scanning groceries at your supermarket’s checkout line. Large-scale efforts to catalog and archive these genetic identifiers, such as Barcode of Life, make this data widely accessible.
In addition, this finding was part of a larger initiative, called Finprint, focused on filling in data gaps concerning sharks, fins, and rays – all of which constitute a group of cartilaginous fish known as elasmobranchs. Finprint uses baited remote underwater video (BRUV) as one of their primary tools for studying these creatures. Much of their work appears to be focused on their spatial distribution, identifying regions that could lead to conflict with other uses such as fishing or areas that can be marked as candidates for protection.