IB exam 2018 and a plankton swarm

Second year Marine Science students wrote the second of two papers this morning to complete their IB exam. It has been a wonderful two years – thank you!

At the same time the students were writing their exam, there was a swarm of plankton around the Pearson College dock:

I think that the zooplankton were here to wish the students well!

Many Dungeness crab megalopae have been hanging out around the dock for the past few days (helping the students revise?!).

To the Year 43 Marine Science students: I wish you all the best as you drift on out of Pedder Bay and I hope that the winds and currents are favourable so that you can drift back again some time!

By the wind sailors (Vellela vellela) at Witty’s

While F block was getting ready to do their transect study at Witty’s Lagoon – Tower Point yesterday, Mara found the first of many ‘by the wind sailors’ (Vellela vellela) that we would see in the afternoon.

These are planktonic cnidarians (related to jellyfish, anemones and corals) which float at the surface of the ocean and are usually found in the open ocean. Sometimes though, when the winds are blowing onshore, they arrive at beaches, usually in great numbers.

The one in the photo above is upside down (or perhaps I should say ‘sail-side’ down) in a tidepool with some very photosynthetically active green tangle weed (Acrosiphonia coalita) and some tentacles are visible.

Plankton light traps

At 5:45 pm on 2 November, 8 light traps designed to capture plankton were suspended off the Pearson College dock.

Marine Science students retrieved the traps the next day and examined the plankton that were captured.

We saw some very cool critters including many copepods with egg masses:

And a polychaete worm and a crab megalopa larva:

Plankton sampling and examining

For the past week or so, first year Marine Science students have been learning about plankton. After collecting plankton of the Pearson College dock, students examined the samples using microscopes.

 

Some of the species in the sample included a cross jellyfish (Mitrocoma cellularia):

A sea gooseberry / comb jelly / ctenophore (Pleurobrachia bachei):

A sea cucumber auricularia larva:

More images and videos to follow…

A preponderance of plankton

As I was leaving the floating building at 12:15 pm yesterday (1 October 2014), I noticed a golf ball-sized green blob floating past the Pearson College dock. It turned out to be this red-eye jellyfish (Polyorchis penicillatus) and right next to it was a sea gooseberry or ctenophore (Pleurobrachia bachei) and a barnacle moult.

The bell of the jellyfish is covered in a green algae and the red eyespots are visible around the margin of the bell and there is a red amphipod living in association with the jellyfish too (see it peeking out from the margin of the jelly in the two photos below).

And here is a better view of the comb jelly / ctenophore Pleurobrachia bachei which we rarely see around the Pearson College dock, but is periodically very common at the Race Rocks jetty.

Simon and I also met several students at the dock last night at 8:30 pm to observe bioluminescence. It was magical! While moving our hands through the water we saw a line of bioluminescence about 6 cm long which turned out to be a cross jellyfish (Mitrocoma cellularia) which “luminesces if disturbed in the dark, especially in a band along the margin of the bell” according to Cowles (2009).

Mesodinium rubrum bloom in Pedder Bay

The margins of Pedder Bay have been quite red recently…

This is due to a bloom of Mesodinium rubrum, a little red-coloured ciliate.

Kyle collected a bucket of water off the dock on 7 March 2013 which had some Mesodinium rubrum and looked like this:

And then again today (11 March), which looked like this:

Compared to tap water:

This is not a harmful species, but it does colour the water as a ‘red tide’.

For more information see the UBC Phytopedia entry for Myrionecta rubra.  (I love the lifestyle description of ‘kleptochloroplastidic’ which means stealing chloroplasts!)  It’s also worth doing a Google image search for Mesodinium rubrum to see images of individual ciliates and of other water coloured by blooms of Mesodinium rubrum.

Plankton diversity in Pedder Bay

On Friday 16 November, Mariana (PC38, Mexico) collected plankton samples for her independent research project. She sampled at four locations within Pedder Bay and one location at Race Rocks.

The photo below is of the sample from Race Rocks – lots of copepods and chaetognaths!

Mariana is currently in the process of analyzing her samples – more details later…

A preponderance of plankton

A plankton sample collected from the mouth of Pedder Bay (near the Navy buoy) on Monday 24 September had an incredible diversity and abundance of both phytoplankton and zooplankton.  Species lists and selected photos are below.

Phytoplankton species list:

Diatoms: Thalassiosira sp., Asterionellopsis glacialis, Eucampia zodiacus, Coscinodiscus spp., Ditylum brightwellii, Chaetoceros spp., Thalassionema sp., Thalassiothrix sp., Stephanopyxis sp., Skeletonema sp., Pseudo-nitzschia sp., Cylindrotheca closterium

Dinoflagellates: Noctiluca scintillans, Ceratium sp.

 

 

 

Zooplankton species list:

juvenile bay pipefish (Sygnathus leptorhynchus), barnacle nauplius larva, other crustacean nauplius larvae, crab zoea larva, shrimp larva, snail veliger larva, sea urchin pluteus larva, orange-red eggs (possibly sea star eggs), sea star brachiolaria larva, sea cucumber auricularia larva, nemertean pilidium larva, polychaete worm larvae.

copepods, ostracods, cladocerans (Podon and Evadne), siphonophores (possibly Muggiaea), tintinnids, larvaceans (Oikopleura dioica), Obelia jellyfish

 

 

 

 

 

 

Pedder Bay water has turned to chocolate (& jelly)!

For the past several days the water in Pedder Bay has been the colour of milk chocolate:

The visibility is very poor as seen in the photos above and below.

Brown, brown water!

In the photos below, the jar on the left contains tap water while the jar on the right contains water collected off the Pearson College docks at 12:30 pm today by filling the jar from the surface water.

The brown colour of the water is actually not chocolate, but is in fact due to an abundance of  an as yet unidentified plankton species. Below are photos taken through a compound microscope:

Amongst the many, many little ciliates that were zipping around the field of view, there were a few Parafavella sp. (the little champagne glasses), a dinoflagellate species (Peridinium perhaps?) and the occasional rotifer (one even had eggs).  The sample was clearly dominated by the brown coloured ciliate, however.  If you have any idea about the species (based on these terrible photos or from experience with the ciliates of Pedder Bay), please help with the identification!!

In addition to the microscopic organisms, there has been an abundance of small (1-1.5 cm) Polyorchis penicillatus jellies around the Pearson College docks.

Sorry about the terrible quality of the photos!  For more information on Polyorchis penicillatus (and a much better photo!) see the page from the Monterey Bay Aquarium.

Biodiversity and diverse footwear

This morning first year marine scientists ventured out to collect data that they used to compare the biodiversity of two areas that they selected.

Ela (in the yellow boots above) compared the diversity of organisms in two areas of the rocky intertidal – one that is regularly exposed to freshwater from a drain pipe and one that is not near the drain pipe outlet (in the very upper left of the photo above).

Angela and Jessica (both close to the water level in the photo above) each investigated the effect of height in the intertidal on diversity.

Angela (above) again identifying and counting organisms in the low intertidal.

Miguel (blue fins) and Mariana (yellow fins) chose to focus only on sea star diversity.  They got into their wetsuits at 7 am! and jumped into the water to compare the diversity of sea stars near the Pearson College docks and a short distance away from the docks.

Jon elected to sample plankton at the mouth of Pedder Bay and near the Pearson College docks. While there is no photographic evidence of his work he learned that there is a great deal of diversity in the plankton sampled at both locations!