The Lemmens Inlet Water Column study (LIWC) is a west coast oceanographic monitoring project. We aim to create a baseline dataset for the area, and provide local stakeholders with information about local oceanographic conditions, and how they change over time.
This pilot study (June 2017 - June 2018) had the goal of better understanding local water conditions. We are most interested in select biotic (living) and abiotic (non-living) features. Specifically, we are looking at plankton abundance and diversity, as well as monitoring the pH, temperature, and salinity of the water column.
We hope to be able to characterize this system and create a baseline data-set for the area. Additionally, we hope to communicate with shellfish farmers and other stakeholders about local conditions, and how they change over time.
Follow along with our project on this page!
Learning from the Pros - June 28th, 2017
We spent our first feild day under the helpful gaze of oceanography expert Dr. Cheryl Greengrove of the University of Washington Tacoma.
Dr. Greengrove and her team offered us sound advice on techniques and field planning, which greatly shaped our project methods. One peice of advice Dr. Greengrove offered was to test as your methods before applying them on a long time scale. On this date, we sampled on both the incoming and outgoing tide to better understand the system we are studying: Lemmen's Inlet near the Tofino harbour.
Out on the water - July & August 2017
Sampling is well under way! We have added additional field days this summer to better refine our methods. It great to have the help of our summer interns! Once the summer is over, we will compare the different conditions and use this information to help select a single, monthly sample day moving forward.
Changing Communities - September 2017
We are noticing the abundance of plankton is dropping as the fall weather sets in.
Here are a few of the species we are commonly seing at this time of year:
Noctiluca scintillans - A dinoflagellate responsible for creating the ocean later light up at night (commonly refered to as bioluminesence):
Coscinodiscus spp. (and a water bubble above it) - A beautiful diatom species:
A copepod (zooplankton):
Sunny days...and plankton blooms? - October 2017
This month has been a bit of an oddity on the West Coast of Vancouver Island. Except for one mid-month storm, we have experienced a series of clear, bright, sunny days, which has made the logisitics of sampling rather easy so far!
On this last sampling session, we found evidence of a small, localized autumn plankton bloom. The water was a murky, reddish colour. Compared to the crystal clear conditions in other parts of Clayoquot Sound, this was surprising to find!
Look at the colour of the top sample, as compared to the other three samples:
Under the microscope, it was evident what was causing the colouring of the water. Look at all of the individual plankton cells!
A plankton "bloom" is the term used to describe a sharp increase in biomass within a given area. A bloom may occur when conditions such as temperature, pH, or salinity, among others, are favourable. In response, spcecies may undergo excellerated cellular division, which increases the total number of cells present in the water column. If the area does not expereince sufficient flushing via currents, wind, or tide, an accumulation of plankton will create a bloom.
In many cases, the species causing a bloom are considered non-harmful, and the bloom provides a beneficial source of nutrients to the local ecological food-web (Smayda, 1997). However, blooms can also be a cause for concern (have you ever heard of "Red Tide?") if the species is considered harmful to other marine organisms, or to humans (Cassis, 2007).
Ongoing monitoring efforts by the Dept. of Fisheries and Oceans work to ensure that commercially grown and harvested shellfish are safe for human comsumption. If you are interested in harvesting wild bivalve species such as mussels, or eating locally harvested shellfish, make sure to check if it's safe first: http://www.pac.dfo-mpo.gc.ca/fm-gp/contamination/biotox/a-s-24-eng.html
Cassis, D. (2007). "Temperature, Harmful Algae, and Summer Shellfish Mortalities in British Columbia." Aquaculture Update, Dept. of Fisheries and Oceans Canada.
Retrieved from: http://www.dfo-mpo.gc.ca/Library/335333.pdf
Smayda, T.J. (1997). "What is a bloom? A commentary." Journal of Limnology and Oceanography 42(5, part 2), pg 1132-1136.
Retrieved from: http://onlinelibrary.wiley.com/doi/10.4319/lo.1997.42.5_part_2.1132/pdf
The expected lull - November and December 2017
There has been a lull in the diversity and abundance of plankton found within the water column during the past two winter months. Despite sunny days, the cold weather and loss of light this late in the year has greatly slowed primary production in the water column. As compared to the summer months, we are generally seeing an order of magnitude of difference between samples (for example, if the summer samples generally conatined 100 plankton cells per 20 units, the Novemeber and December samples contain 100 plankton cells per 200 units*).
Despite the lower numbers of plankton in the water column, we ran two successful educational programs for local youth!
In November, Ms. Morris' grade 6/7 class learned about the project methods by collecting their own water samples at the 4th st dock, and looking at the samples under micrscopes. We also discussed the role of plankton in the ocean, and the changing ocean environment.
Additionally, we partnered with the Tofino Heartwood School in December to discover and learn more about plankton in the water column. The students had so many interesting questions!
We are looking forward to delivery more educational programs to local students in the New Year. And, we are looking forward to observing a rise in plankton abundance in the water column once again!
*the units we are using are squares in a Sedgewick Rafter Slide, which is a small, specialized microscope slide that provides a grid for counting individual plankton cells in a methodical manner, and is of a 1 ml cubic volume, so plankton are able to move freely throughout the sample.
The lull continues.... - January and February 2018
During the lull, it became quickly apparent that the initial method of counting and recording individual plankton cells was WAY too time-consuming for all 8 (4 surface, and 4 net tow) water samples. Therefore, we had to tweak my methods to account for the limited number of plankton in the water column at this time of year.
The initail method (borrowed from Nicky Haigh of Microthalassia Consultants) was to count 100 plankton cells by scanning the Sedgewick Rafter Slide. To produce a comparable ratio across samples, this method givs me [# of plankton cells / # of squares counted]. But in these samples (as in the November and December samples), we were hard pressed to find 100 individual plankton cells without scanning nearly ALL of the 1000 squares on the rafter slide!
Consequently, we adapted our methods by counting either 100 plankton cells, or 20 squares on the rafter slide. Both methods produce the desired [# of plankton cells / # of squares counted] ratio, so that we can continue to comapre our monthly samples.
Lesson learned: adaptation (without compromising results) is key.
The winter and early spring months are often the best time to deal with the comupter work side of a monitoring project. Catching up on data input and interpretation takes many more hours than collecting data in the field, so there is always plenty of work to catch up on back at the office!
We have been able to create some preliminary data on plankton diversity across sample sites (Figure 1). As can be seen in the figure, site 1 (located at the mouth of Lemmens Inlet) diplayed the greatest diversity across sites, and site 4 displayed the least. This leads to interesting questions regarding how currents might influence plankton movement, and thus presence, in the main chanel vs. the side bays of Lemmens Inlet.
We used the Shannon-Weiner index to calculate diversity. Essentailly, the more difference (ie. diversity) there is in a sample, the higher number it will be assigned. For example, a sample with a SW index of 0 would be made up of only one species, whereas the greater number of different species are present in a sample, the higher number will be produced. To be clear, the most diverse sample may not have the most individual plankton cells; a sample with 10 individual plankton cells of 10 different species would be considerd more diverse than a sample with 100 individual plankton cells of only 2 different species (like what can often be the case in a bloom event).
Figure 1. A comparison of plankton diversty across sample sites June - October 2017.