The effects of Daphnia magna on harmful algae bloom Microcystis

Catherine Veseth Author

04/05/2021 Added

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The ability of Daphnia magna to control toxic Microcystis through their microbiome.

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[00:00:00.900]Hello everyone. My name is Catherine Veseth,
[00:00:02.820]and I'll be going over the effects of Daphnia Magna on harmful algae blooms.
[00:00:06.930]Microcysts harmful algal blooms are becoming a growing problem in
[00:00:11.820]lakes, ponds, and other water sources.
[00:00:13.890]These harmful algal blooms are the product of cyanobacteria,
[00:00:17.700]a common one being Microsystems.
[00:00:19.920]The main concern was cyanobacteria is its ability to produce toxins that lead to
[00:00:23.910]problems and the Hep pancreatic,
[00:00:25.920]digestive endocrine dermal and nervous system of animals.
[00:00:29.550]There is little agreement on the cause of these toxic effects and therefore
[00:00:32.910]there are many arguments on how to control cyanobacteria.
[00:00:36.120]Many researchers have suggested a biotic interactions.
[00:00:39.420]There have been theories of changing the temperature pH or nutrient availability
[00:00:43.320]of aquatic habitats to rid of the cyanobacteria changing.
[00:00:47.100]These factors could lead to their own challenges and consequences.
[00:00:50.310]There has also been the suggestion of biotic factors to combat cyanobacteria,
[00:00:55.050]multiple different types of aquatic.
[00:00:56.670]Grazing animals also show a strong indication of providing an effective and
[00:01:00.540]natural treatment to the cyanobacteria.
[00:01:02.850]One of these grazers is Daphnia Daphnia. Magna is an aquatic animal.
[00:01:07.290]Most commonly known as a waterfally.
[00:01:09.480]They are dominantly heart herbivores and are found in aquatic systems around the
[00:01:13.200]world.
[00:01:13.920]Daphne are known as an unimportant Keystone species or that the ecosystem is
[00:01:17.820]dependent on the function of the Daphnia Daphne Daphne,
[00:01:21.540]to create the common link in food webs between producers and secondary
[00:01:25.110]consumers.
[00:01:26.280]They reproduce asexually and have large number of offspring at once. Overall,
[00:01:30.930]this makes them a very promising organism for this study.
[00:01:34.230]Some reach search has suggested that the composition of the microbiome might
[00:01:37.920]play a role in allowing Daphnia to tolerate ingestion of cyanobacteria.
[00:01:42.840]The microbiome is defined as the community of bacteria living in and on
[00:01:46.680]everything. Daphnia, Magna has multiple genotypes,
[00:01:49.920]meaning each Daphnia has slight variances and their genetic makeup there for
[00:01:54.570]each type of genotype has a distinctive microbiome biome and can digest
[00:01:59.430]or not digest specific nutrients found in the environment.
[00:02:04.530]The overall objective of the experiment was to target toxic cyanobacteria
[00:02:08.610]through the use of Daphnia.
[00:02:10.350]The 20 2021 academic year provided the time to run trials on 11 different
[00:02:15.000]Daphnia Magna Chino types,
[00:02:16.530]in order to determine which had the best tolerance in the digestion of
[00:02:19.980]Microsystems through the preparation of this experiment,
[00:02:23.910]multiple hypotheses presented themselves for evaluation.
[00:02:27.450]The first hypothesis being that there is a variation in the microbiome per each
[00:02:31.470]genotype of Daphnia.
[00:02:33.180]This would be the reason that some Daphne genotypes are more naturally occurring
[00:02:36.720]than others. And in a variety of locations,
[00:02:39.300]the second hypothesis being that each genotype will have a variation and
[00:02:43.140]tolerance to Microsystems the variants and Microsystems can be contributed to
[00:02:47.370]different genotypes and microbiomes.
[00:02:49.710]The final hypothesis is that there is a cross-link between the tolerance of
[00:02:53.310]Microsystems and each genotypes microbiome.
[00:02:57.960]All three of these were tested and experiment that was conducted over four
[00:03:02.170]weeks.
[00:03:03.010]Each of the 11 Daphnia genotypes were collected and then separated an individual
[00:03:07.210]files. Initial photos were then taken of each Daphnia and their body length was
[00:03:11.560]measured. Two main groups were formed per each genotype.
[00:03:15.190]The first grade group was made of 50% Microsystems,
[00:03:18.310]which is the cyanobacteria and 50% ANCA distress, which is algae.
[00:03:22.540]That is their regular food.
[00:03:24.070]The second group was composed of 20% Microsystems and 75% ANCA destress.
[00:03:29.440]Each Daphnia was fed per their corresponding group every day.
[00:03:32.560]And their water was changed every other day. Numbers such as fatalities.
[00:03:36.700]Number of offspring and the dates of these events were recorded.
[00:03:39.940]The Daphnia were then photographed and measured for their final measurements.
[00:03:44.410]There were then sent to the third party for microbiome testing.
[00:03:48.670]It is important to note that this is an experiment.
[00:03:51.250]The Daphnia microbiome was analyzed under the presence of ANCA destress or good
[00:03:56.200]food conditions rather than pure cyanobacteria.
[00:04:01.270]These are pictures of Daphnia Magna under a microscope.
[00:04:04.180]Each Daphnia was measured from their eye to the stars with their tail on their
[00:04:07.810]back. These two photos are actually the same Daphnia.
[00:04:10.990]The one on the left is before starting the experiment and it was born from a
[00:04:14.440]healthy mother and a good food environment.
[00:04:17.530]The right photo is the same Daphnia after the treatment.
[00:04:20.710]The Daphne on the right is so much thinner because it's a lack of nutrients.
[00:04:24.310]They become even more translucent and fragile.
[00:04:27.250]She was able to establish some eggs that we can see on her back in the brood
[00:04:31.000]chamber through data analysis, overall trends can be seen in the data.
[00:04:36.580]This first graph is a comparison of each genotypes, cumulative reproduction,
[00:04:40.390]separated by their feeding group as expected and overall drop of fecundity
[00:04:44.740]happens when more Microsystems is used,
[00:04:47.650]this isn't the same for all genotypes genotype.
[00:04:50.260]AA has the highest fecundity average and the twenty-five seventy-five group.
[00:04:55.240]When compared its average in the 50 50 group, there is not much change.
[00:04:59.470]This shows that genotype eight a has a higher tolerance to Microsystems and
[00:05:04.030]higher cumulative reproduction in comparison with the other genotypes,
[00:05:08.320]other genotypes experience, unexpected drop like genotype 12,
[00:05:12.730]a and 32 K a large drop in their average for Kennedy happened when
[00:05:17.470]comparing the 25 to 75 group to the 50 50 group.
[00:05:21.490]These genotypes did not reproduce as much in the higher Microsystems
[00:05:24.970]concentrations showing that they had very low tolerance,
[00:05:28.540]genotype six a was like that of eight eight,
[00:05:31.470]because it had great tolerance when comparing our 50 50 to the 25
[00:05:35.800]75. The average reproduction is very similar showing it had great tolerance,
[00:05:41.050]six, eight just didn't have a large number of offspring in either group.
[00:05:46.780]This image shows a relative abundance of each genre of bacteria and the
[00:05:50.860]microbiome.
[00:05:52.060]We used analysis of bacterial DNA to determine that identity and relative
[00:05:56.200]abundance of different bacteria groups and the Daphnia Magna microbiome.
[00:06:00.410]We amplified a high variable region of bacterial DNA by comparing the amplified
[00:06:05.270]sequence to a database.
[00:06:06.860]We were able to determine the identities of the bacteria in the microbiome,
[00:06:11.180]by counting the total number of sequences assigned to each bacteria genus,
[00:06:14.630]we were able to determine relative abundances.
[00:06:17.780]The DNA was then organized by genre by the bacteria and everything present under
[00:06:22.160]less than five present was condensed together.
[00:06:25.040]We see this at the very top with a light blue color.
[00:06:28.760]This way only the bacteria that is heavily present can be reviewed between each
[00:06:32.270]genotype. Overall,
[00:06:33.920]we can see that each genotype had relatively the same type of bacteria in their
[00:06:37.790]microbiome.
[00:06:38.990]There's not a specific genotype that has a very different microbiome or
[00:06:42.260]presenting completely different bacteria. This being said,
[00:06:45.380]there are noticeable differences between the bacterial abundances per each
[00:06:48.800]genotype and genotypes [inaudible].
[00:06:52.340]There is a similar abundances of the same bacteria,
[00:06:55.610]especially the bacteria limbo habitats,
[00:06:58.070]which is that dark Navy blue color in the center.
[00:07:01.160]This could have possibly contributed to their higher tolerance to Microsystems.
[00:07:05.390]They also have smaller diversity of bacteria.
[00:07:07.670]This can be seen because not as many reads of bacteria, genus are represented,
[00:07:12.020]are present in their columns compared to other genotypes genotypes that did not
[00:07:16.910]do as well,
[00:07:17.540]or had a lower tolerance like 12 [inaudible] and 32 K showed that they have
[00:07:22.040]higher microbiome diversity because they have more genus of bacteria present in
[00:07:26.150]their microbiome. They also have a very different abundance in the bacteria,
[00:07:30.680]pseudomonas pseudomonas,
[00:07:32.600]which is that blue color on the very bottom and a flavor bacterium in
[00:07:37.460]that is that light orange color. At the very top.
[00:07:42.460]These can also be especially seen between genotypes AA and six.
[00:07:46.840]A there are large differences in each microbiome,
[00:07:49.630]makeup and abundance per each genotype.
[00:07:52.090]Overall trends can be studied more to show a possible correlation between a
[00:07:55.960]specific bacterium and cyanobacteria tolerance
[00:08:00.940]in conclusion. Yeah,
[00:08:01.630]it was found that each genotype did have a varying microbiome and each genotype
[00:08:05.530]responded differently and their tolerance to Microsystems connections can also
[00:08:09.790]be made of the cross-link between tolerance and Microsystems in each genotypes
[00:08:13.660]microbiome. These are very strong correlations,
[00:08:16.240]but more specific research must be done to con come to a conclusion.
[00:08:20.440]This research will continue to progress in the academic year of 2021 through
[00:08:24.370]2022,
[00:08:25.690]a more definitive answer to the possible cross-linking of the microbiome to
[00:08:29.290]Microsystems tolerance will be investigated along with the introduction of the
[00:08:33.520]cyanobacteria and Abena real-world application will then take place with a
[00:08:37.810]fluctuation of temperatures and they use a specific genotype of Daphnia to
[00:08:41.770]control the toxic cyanobacteria.
[00:08:45.820]I would like to offer a thank you to the undergraduate creative activity and
[00:08:49.840]research experience,
[00:08:50.950]or you care for providing the financial support to this experiment.
[00:08:54.430]Thank you also to my advisor, Dr.
[00:08:56.140]Kressler and to Riley Cooper for providing the guidance to conduct this
[00:08:59.590]experiment. Lastly,
[00:09:00.910]thank you to Kevin Rice for helping gather data and manage Daphnia.

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The effects of Daphnia magna on harmful algae bloom Microcystis

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