Some Intertidal non-crustacean arthropods

By Nicole Webster

The intertidal is a transitional zone, from the water to the air, but also from salt to fresh water. A lot has been said about the ecological consequences of this transition, perhaps idealized by salmon’s migration and how they transfer nutrients from the marine to terrestrial/freshwater ecosystems (Cross-boundary subsidy). I’m not going to say anything in depth about this, and if you are interested, I recommend speaking to Caroline Fox (uvic website), who is in and out of Bamfield semi-regularly and is completing her PhD on this topic.

This post is nothing so ecological or philosophical. This summer I came across a couple arthropods (non-crustacean) that are not commonly mentioned and wanted to expand your view of the intertidal.

This is Diaulota densissma (I believe).


This is a rove beetle (Diaulota densissma) in a petri dish, with possibly a larva. They are not easy to photograph. I could have sedated one for better ID and imaging, but didn’t. Credit: N Webster

I encountered these beetles on the barnacle rocks that I heave to the lab to feed my greedy snails. Quite a few of them I found regularly swimming desperately on the water in my seatable and crawling around on the dry rocks. At first I thought they were unfortunates brought in from a true terrestrial habitat, but there were too many, and too consistent. It was suggested to me to check out Kozloff’s Seashore life of the Northern Pacific coast. It is not a field guide, nor is it like his Key to Marine Invertebrates. It is really a nice introductory book about the seashore, looking from high to low intertidal, from sandy to rocky shores, and describing the types of organisms found there.


This is the beetle on a barnacle rock. Credit: N Webster

Indeed my rove beetle is in the book. It is a small intertidal predator that eats mainly amphipods and other tasty arthropods at low tide. According to Ahn (1996) these beetles live even in the low intertidal, and can spend most of their day submerged. They don’t have gills, they just find an air pocket (barnacle test, under a rock) and wait. Watching them swim, they obviously have a highly hydrophobic coating, probably with lots of hairs to trap air bubbles.


This is Neomolgus littoralis. It is an intertidal mite, known as the red velvet mite.

Red velvet mite on some Ulva, in the high intertidal on Edward King. They are ~3mm in length. Credit: N Webster

Red velvet mite on some Ulva, in the high intertidal on Edward King. They are ~3mm in length. Credit: N Webster

These mites are found in the high intertidal and eat kelp flies (another intertidal insect). They are very easy to spot, as they are shockingly red.



  • Kozloff, E.N. 1993. Seashore life of the Pacific Northwest: an illustrated guide to northern California, Oregon, Washington, and British Columbia. 370 p.
  • Kozloff, E.N. 1974. Keys to the marine invertebrates of Puget Sound, the San Juan Archipelago, and adjacent regions. Seattle, Washington, University of Washington Press, 226 p.
  • Kee-Jeong Ahn. 1996. A Review of Diaulota Casey (Coleoptera: Staphylinidae: Aleocharinae), with Description of a New Species and Known Larvae.The Coleopterists Bulletin Vol. 50:3, pp. 270-290


“Why Bamfield, British Columbia is unique, awesome and you should go there” part III

Bridgette just posted the last of her 3 part series on Why Bamfield, British Columbia is unique, awesome and you should go there. Part 3: Learning.

Do go check it out. I praised her and her blog last week, which you can check out here.

Bracket (shelf) fungus. Why? Because. Credit: N Webster

Bracket (shelf) fungus. Why? Because. Credit: N Webster


“Why Bamfield, BC is unique awesome and you should go there” – Bridgette Clarkson

A friend of mine has a wonderful blog. It is insightful, delightful and full of photos. Bridgette just completed a stint working as a public educator for BMSC, and described herself as a biologist and science education consultant.

Crashing Bull kelp (c) Bridgette Clarkson

In honour of World Oceans day (yesterday), she posted the 2nd part of her 3 part series about her time in Bamfield this year.

I strongly encourage you to check them out, if only for the breathtaking imagery.

Do check out some of her other posts like how to check marine forecasts, or her flickr stream.

Hand-fed Gooseneck barnacle

By Nicole Webster

I have below what we believe to be the first footage of someone hand feeding a Pollicipes polymerusThese gooseneck barnacles are found only in high flow areas, and feed differently than your average acorn barnacles. Rather than swat the water for prey with their legs, they let the water to the work for them, holding out their legs, and let the tide wash in their food. They eat larger pieces (as you can see below), and here appear to actually grab it.

These videos were taken by my lab mate Tomonari Kaji, a postdoc who’s looking at the development and plasticity of barnacle leg segments, and how they change leg length in different environments.

Moving Barnacles

Windy ride

By  Nicole Webster

I want to share this obscure paper with you:

J. E. Moriarty, J. A. Sachs and K. Jones. 2008. Directional Locomotion in a Turtle barnacle, Chelonibia testudinaria, on Green Turtles, Chelonia mydas. Marine Turtle Newsletter 119.

I’m going to give you the punchline first: They found evidence of barnacles moving!

Now that I’ve got your attention, lets start with some basic introduction. Chelonibia testudinaria is a species of barnacle that lives specifically on the backs of sea turtles. It is part of an entire superfamily of barnacles (Coronuloidea) that are obligate epibionts, meaning they only live on other living organisms. Members of this group live on everything from whales, manatees, crabs, molluscs, and turtles. This is how these barnacles get to travel the world!

Chelonibia patula on a Blue crab Credit: Cirriphilia (Wikipedia)

Chelonibia patula on a Blue crab Credit: Cirriphilia (Wikipedia)

To date, no one has shown any significant harm these barnacles do to their hosts (nor benefit), and this is considered a commensal, not parasitic relationship. In contrast, there is evidence that they may preferentially settle in wounds (ouch!). I imagine this might relate to chemosensory settlement cues that would be strongest at an open wound. It is thought the main advantages to the barnacles are dispersal, and predator evasion (what sea star or snail will climb on the turtle just to eat them?)


Moving sessile organisms

In general, sessile organisms (like barnacles), are considered sessile for a reason. They don’t move as adults. The larvae settle out of the plankton based on certain cues (many are poorly understood at best) on what they hope is a good spot, and then metamorphose, binding themselves to a location for their entire life. This extends to coral, barnacles, sponges, mussels, tunicates, tube worms, bryozoans, and anemones.

This isn’t 100%. Life is full of exceptions. A big one is anemones. Some of the swim (Stomphia), but even less spectacular anemones have the ability to crawl slowly.

This would be of great advantage to a sessile organism. I was with a tour group last week, and someone asked why all the anemones were in pits and crevasses. At first I thought it might just be differential survival, but no, I’m pretty sure those anemones would move to the more sheltered locations all by themselves.

I have not heard of coral, sponges, tunicates, or tube worms moving once settled, but mussels (at least when they are small) can move about as well. They use byssal threads to attach to the substrate, and can move by progressively moving where their byssal threads attach. This is separate from their ability to crawl using their foot.

Barnacles is new, and very exciting (to me at least) as an addition to the list of sessile organisms that are not so sessile!

So what about this paper then?

It is known that filter feeding organisms do best in areas of high flow: more units of water pass by, carrying more food. On a turtle, this would be the front edge or dorsal ridge on the shell. It was previously known that barnacles are more common on these regions of a turtle carapace, but this was thought to be due to cyprid (the barnacle larva stage that settles and metamorphoses) movement and differential survival.

This paper was a casual case of observation. The authors were studying Green Turtles, Chelonia mydas in florida, and noticed that the barnacles were in different locations on the same individual. It doesn’t say so in the paper, but I imagine the reaction was more along the lines of: “What? That can’t be right, check again!”, in the paper this is stated as: “Casual inspection of the photographs indicated that the barnacles were moving on the carapace of these turtles over a period of months. To investigate this, we assembled a series of photographs for each of the three turtles.”

All in all they had 8 barnacles on  turtles that moved. Most moved anteriorly and medially (towards the middle and front), as you would expect based on where the highest flow is.

Green turtle bearing the gray locomotion trail of a relocated Chelonibia testudinaria. Moriarty et al 2008.

Green turtle bearing the gray locomotion trail of a relocated Chelonibia testudinaria. Moriarty et al. 2008.

How fast? Average rates varied from 1.4 mm – 0.27 mm/day! Seems kinda slow, I know, but definetly faster than 0. They even leave a trail on the shell, so you could see part of their track.

The authors raise an interesting point: the ideal settling location is in high flow, and its difficult to settle there for the same reason. If you are capable of moving after you have settled, that gets the best of both worlds. A low flow settling location to get properly attached, followed by a migration to an ideal feeding spot.

Unlike many barnacles, C. testudinaria does not have a base plate, making moving a bit easier. The authors suggest they move by creating tension in the leading edge of the shell, causing it to move forward with growth increments of the shell.

To be fair, some barnacles are capable of rotating in place, or getting pushed by growing neighbours, and the settling cyprid larvae can migrate, but this is the first evidence of large scale adult barnacle motion.

Also, there are only three turtles, and less than a dozen barnacles in this study, so some caution is warranted, but I believe the pictures speak for themselves. This paper is available free online here, so take a look for yourself.

Extra bonus paper

I love phylogenies, I admit it. So there’s a cool side note to this story. Zardus et al. 2014 just threw a big wrench into our understanding of these turtle barnacles. Previously there were 5 species of Chelonibia, each with a specific range of hosts (different sea turtle species, as well as some crustaceans and manatees), and associated morphologies. I won’t go into the nitty gritty of this paper, but the conclusion is that there are only two species of Chelonibia, and all that host specific morphology is simply phenotypic plasticity! One is Chelonibia caretta which is specific to a few types of sea turtle, but all the others are being grouped together as morpho-types of C. testudinaria.  (Why can’t I hear you whooping in excitement?).

Putting these papers together, does this mean the barnacles on manatees can move too? What about whale barnacles? The soft tissue embedding seems to me unlikely to allow migration, but who knows? I’m pretty sure there’d be no reason barnacles on crabs couldn’t wander about…

There are so many cool things out there just waiting for you to notice them! Take your time, and don’t brush off anomalies.


J. E. Moriarty, J. A. Sachs and K. Jones. 2008. Directional Locomotion in a Turtle barnacle, Chelonibia testudinaria, on Green Turtles, Chelonia mydasMarine Turtle Newsletter 119:1-4

J. D. Zardus, D. T. Lake, M. G. Frick and P. D. Rawson. 2014. Deconstructing an assemblage of “turtle” barnacles: species assignments and fickle fidelity in Chelonibia. Marine Biology 161:45-59

Climate change and the 5 stages of grief

by Amanda Kahn

In 1969, Dr. Elizabeth Kübler-Ross outlined 5 stages of grief in her book On Death and Dying to help people cope with grief from the loss of a loved one or news of their own terminal illness.  Psychologists later noted “that this emotional cycle was not exclusive just to the terminally ill, but also other people who were affected by bad news, such as losing their jobs or otherwise being negatively affected by change” (

How does this tie in to climate change or other new, major ideas and why might it be helpful to keep these 5 stages in mind?  Well, when I thought about my own thought progression, the changing perspectives of the scientific community, and then how the media and public see climate change, I realized that we’ve been walking through the 5 stages of grief, also called the Kübler-Ross Grief cycle.  Quotations below all come from a great summary of the Kübler-Ross Grief Cycle from

There are 5 major stages that vary between being active or passive (with a few extras sometimes thrown in, as seen in the diagram below).  During active stages, a person is likely to do something/be pushed into action (whether correct or misdirected).  During passive stages, a person usually is stuck/unable to act as needed.  The five stages are: denial, anger, bargaining, depression, and acceptance.

Kubler-Ross grief cycle

The Kubler-Ross extended grief cycle. Credit:


Consensus about climate change

Public perception versus actual consensus in the scientific community regarding climate change. Credit:

The first stage is a transitional stage of shock followed quickly by denial, where people pretend that no news has been given.  “They effectively close their eyes to any evidence and pretend that nothing has happened.”  When I first read about climate change, I thought the projections must be overestimates, and that we wouldn’t allow ourselves to stay on a dangerous trajectory.  Some of the general public and news media seem stuck in this denial phase, preferring to stir up controversy or conflict where there is none in the scientific community.  Take note: this is a brilliant strategy for preventing or avoiding change since denial is one of the passive phases–no one acts if they can find a nugget of doubt that says that they do not have to.  This is why gas companies, for example, might be interested in expressing doubts about climate change.

Contributions to climate change

Bar graph showing % contribution of humans versus natural sources to climate change over the past 50-65 years. Different colors of bars indicate different climate models run. Credit:


Denial eventually transitions to anger and frustration.  A person might try to blame anyone or anything for the change, except for him/herself.  I was frustrated and blamed everything that emitted greenhouse gases–industries, cows, cars, volcanoes–but couldn’t think clearly about how I fit into things.  Interestingly, the anger and denial stages can cycle back and forth, getting stuck in a loop.

Human contributions to climate change

Predicted human contributions to climate change in 2020 and 2100. Credit: NASA/GISS


After getting over anger, a person begins to realize that the inevitable is happening.  They begin “seeking ways to avoid having the bad thing happen. Bargaining is thus a vain expression of hope that the bad news is reversible.”


This phase is easy to get stuck into.  “The inevitability of the news eventually…sinks in and the person reluctantly accepts that it is going to happen…In this deep depression, they see only a horrible end with nothing beyond it. In turning in towards themselves, they turn away from any solution and any help that others can give them.”  “In this phase, the person may now be blaming themselves as they take responsibility for their action where something has gone wrong.”  In 2008, I attended the Monterey Bay National Marine Sanctuary Currents Symposium.  At that time, climate change was just coalescing into a well accepted theory within my field’s small pocket of the scientific community, and the conference was filled with depressing reports and projections of what was to come.  Looking back, I felt that the scientific community was in that state of depression.


“Acceptance is typically visible by people taking ownership both for themselves and their actions. They start to do things and take note of the results, and then changing their actions in response. They will appear increasingly happier and more content as they find their way forward.”  By 2010, the research presented at the same symposium was different.  The focus of the research changed, even though the projections and ideas about climate change had not. Instead of doom-and-gloom predictions, there were people presenting research on carbon-neutral energy, technology to sequester carbon into building materials, and adaptive ways to lessen our contributions to, and the impacts of, climate change.  It was a call to action–research was being done to figure out how to live on our changing planet and to temper human impacts.  This is the most effective, active phase of the grief cycle and is where everyone needs to be: willing to change, find creative ways to lessen our impact, and accept responsibility in a human role in the situation.

My acceptance phase was similar to the views at the symposium.  I was depressed about it until I accepted that it’s inevitable given what we’ve already emitted, but it doesn’t have to be something I can do nothing about.  The climate is changing and carbon emissions from humans are responsible, but it’s possible to change what emissions are being put out. the way we emit, and the research and technological energy we put into dealing with it.  When media and the general public move from the passive phases of denial and depression into the active phase of acceptance, we’ll become the responsive, adaptable, innovative problem-solvers we need to be to live in a changing world.

Where do you fall in this cycle?  Have you experienced this same progression of thoughts, either relating to climate change or some other concept or idea?  Write them in the comments below.

Please remember that this was a thought exercise based on my personal observations and experiences.  This isn’t the post or the place to argue the validity of climate science–it is about the thought progression of people accepting a new idea that was at one time controversial.

Sandy Mussel beds II

Windy ride

By  Nicole Webster
I was back at Ross this Spring, and am here to update you on the state of the mussel bed on the beach. Short form: It’s still there! (last year’s post)

Overview of the bed, facing the point. Credit: N Webster

Overview of the bed, facing the point. Credit: N Webster


Close up of the mussels. They are about 5cm in length. Credit N. Webster

Close up of the mussels. They are about 5cm in length. Credit N. Webster

The mussels are big enough, I could believe they are the same as last year’s, and if so, must have survived the winter storms without a good anchor due to the very protective nature of the beach.