Micro-Invertebrates Inhabiting the Algae of Zone 5 of the Ala Wai Canal
Team All G
Ayumi Tachida, Janelle Matsumoto, Katie Tom,
Kelsey Kato, Robyn Hamada, Samantha Dacanay
AP Biology
May 22, 2012
Abstract:
The purpose of the lab was to identify and quantify the micro-invertebrates that inhabit the algae
located in Zone 5. The team collected various algae bloom samples in Zone 5: (Algae 1) brown
algae, or diatoms, that were completely submerged in the water, (Algae 2) green algae that was
partially exposed to air, and (Algae 3) green algae that was primarily exposed to air. The team
used an algae rake to collect the brown algae that was at the bottom of the canal; we severed
branches of bushes along the Ala Wai to collect the green algae samples. The original brown
algae we collected during our first two trials became scarce after heavy rains and the winter
season. Because of this, there was a period when we did not collect algae. During our last two
trials, we collected two different types of algaes, but this caused too many variables, perhaps
rendering our results inconclusive. The micro-invertebrates that we discovered included:
diatoms, annelids, copepods, nematodes, and amphipods. Using the data we found, we noted
that the amphipods were most abundant in Algae 1 while copepods were most abundant in Algae
2 and Algae 3.
Purpose: To identify and quantify the micro-invertebrates that inhabit the algae located in Zone
5 of the Ala Wai Canal.
Question: What are the various micro-invertebrates that inhabit the algae located in Zone 5 of
the Ala Wai Canal?
Background:
The Ala Wai Canal contains brown algae. Distribution of brown algae is strongly
seasonal, with peak production typically occurring during summer months when there are more
sunlight hours and temperatures are higher (Treasures of the Sea, 2011). Many species exist in
and around the algae. However there are a plethora of different types of algae that occupy
different niches within the Ala Wai Canal. Other than the brown algae, or diatoms, which were
found during the early fall, but had disappeared later in the fall and winter, there are also red
brush algae, green algae, slime blue-green algae, hair algae, and beard algae.
Diatoms are a group of protists that are unicellular but often exist in colonies. They are
also one of the most common types of phytoplankton (Cooper, 2011). Autotrophic diatoms are
major producers of food for marine and freshwater microorganisms as well as sources of
atmospheric oxygen (About, 2011). Responsive to silica, a salt in which an anion contains both
silicon and oxygen, diatoms grow silica walls. Two silica valves make up the frustules, or the
exoskeleton. When the cells divide, new walls are constructed. Generally found in shallow-water
environments, some diatoms float freely and others cling to the surfaces of other plants or
animals (UCMP, 2011).
An ostracod is a class of small aquatic crustaceans whose bodies are completely covered
by a shell. The shell consists of two valves on its back. Its size ranges from 0.33mm to 5.00
mm. They typically possess eight appendages to help it tow materials, swim, sense its
surroundings, crawl, feed, and mate. They are planktonic creatures who thrive on the benthos
(the top level of the sea floor) and crawl through the sediment. An ostracod’s diet consists of
organic detritus along the floor, algae, plant material, dead snails, worms, and larvae (Smith,
2009).
Nematodes from the phylum Nematoda (Wikipedia, 2011) are the most abundant
multicellular organism on the planet. In nature, nematodes feed on fungi, bacteria, and other
nematodes (Wormgen, 2011). Nematodes are similar to annelids in that they possess elongated
cylindrical bodies; however, annelids’ body segmentation, classified as metameres, is the crucial
differentiating factor between annelids and nematodes (Biology Questions and Answers, 2011).
On average, an adult nematode’s body is composed of approximately 1000 somatic cells, while
hundreds of other cells are dedicated to the reproduction functions of the nematode (Wormgen,
2011). Nematodes can be very long or microscopically tiny, ranging anywhere between 0.3mm
to 8.0m (Wormgen, 2011). Additionally, regarding structure, nematodes lack circulatory and
respiratory systems, but instead have digestive, reproductive, excretory, and nervous systems
which run throughout their bodies. Nematodes have often been referred to as “a tube within a
tube” because of the fact that they possess an alimentary canal that runs from the head of the
nematode to its anus (Wormgen, 2011).
Annelids, also known as the segmented worm, are invertebrates classified in the phylum
Annelida (Encyclopedia Britannica, 2011). Annelids possess a body cavity also known as a
coelom, movable bristles also referred to as setae, and a body divided by rings. There are
various types of annelids which include polychaetes, oligochaetes and leeches. With regards to
reproduction, annelids are very similar to many other microscopic organisms. Annelid’s eggs
and sperm leave their body though gonoducts or tubes of passage for reproductive cells,
excretory or nephridial openings, pores, or ruptures in the body wall.
Isopods (Armadillidium vulgare) are an order of crustaceans that are also known as
“pillbugs” due to their habit of rolling into tight, pill-shaped balls. Their bodies are usually grey,
black, or brown and oval shaped, about half an inch long. Their lifespan is about three to four
years. Isopods possess pereonites, or seven armor plates that protect them. They have seven
pairs of legs. Isopods are crustaceans and thus have gills; for that reason, although they live on
land, isopods must stay in moist places. Although usually nocturnal, isopods sometimes come
out on cloudy days (William, 2011).
Amphipods are an order of crustaceans that lack a carapace, or the hard covering of the
thorax that most crustacea have. Amphipods have seven segments along with seven leg-like
appendages. They bear two pairs of antennae: one small pair and one bigger pair. Their size
ranges from 5 mm to 20 mm and are brownish black in color while alive and red when they are
dead. During reproduction, females deposit eggs into a pouch on their undersides. Eggs hatch
between one to three weeks, and the amphipod will complete its life cycle in one year or less.
Amphipods are scavengers that inhabit decaying vegetation or the undersides of rocks and
usually live on the top layer of moist ground (Fasulo, 2011).
Copepods, or Macrocyclops albidus, like crayfish and water fleas, are tiny crustaceans
found in bodies of water such as ponds, marshes, and streams (Fairfax County Public Schools,
2011). Copepods are generally small thus they range from about 1mm to 2mm. Copepods
generally thrive at the top of bodies of water, though copepods have been found living at the
bottom of streams. Copepods’ bodies are divided into two main parts known as the abdomen
and cephalothorax. The copepod’s small ten legs help to propel it through the water while its
abdomen assists it in steering (Fairfax County Public Schools, 2011). A copepod’s diet consists
of bacteria protozoans, insect larvae, crustaceans, plankton organisms, small fish, plant or animal
matter, and even other copepods; overall, copepods can consume a vast variety of organisms
(Fairfax County Public Schools, 2011). Female copepods are generally much larger than male
copepods. After the copepods copulate, female copepods will carry their unhatched eggs in her
ovisacs which can hatch anywhere between the time from 12 hours to 5 days (Fairfax County
Public Schools, 2011).
Although not commonly observed in algae from the Ala Wai canal, Chironomidae larvae
are often found in aquatic environments, sometimes in degraded ecosystems because many
species have successfully adapted to degraded and hypoxic conditions (Coffman, 1996).
Chironomidae are non-biting midges or flies of the suborder Nematocera, characterized by
elongated bodies and thin, segmented antennae and aquatic larvae. The aquatic larvae of
Chironomidae have distinct heads and are wormlike and segmented, and in most cases it is not
possible to identify larvae to species. Larvae and pupae are often important food sources for fish
and other aquatic organisms, and are also important as indicator organisms because their
presence or absence can indicate the presence of pollutants (Ekrem, 2004).
Materials and Methods:
●Algae rake
●Buckets
●Boat
●Petri dishes
●Glass bowls
●Gloves
●Pipettes
●Light microscopes
●Needle
●Light microscope
●Knife or scissors (to cut branches with algae on them)
The team collected the invertebrates found in algae samples from Zone 5 of the Ala Wai
using the boat, a bucket, and algae rake to collect blooms or shears to collect algae that lived on
roots of plants along the Ala Wai. We then separated the samples among the team members.
Each member diluted their sample and counted the microorganisms under light microscopes.
Internet references and the assistance of our supervisors help us classify the species found in our
samples. The totals of each member are added up to create a percentage makeup of each sample.
Samples are taken every other week or whenever the boat and other materials are
available. It is necessary that we be wary of the tides. Because the experiment involves algae
gathering, ensuring the tides are low is key. High tides hinder algae collection as it becomes
increasingly difficult to distinguish blooms of algae in deep, brackish water. Similarly, the
weather and season affect algae growth and limit the days on which algae collection is possible.
Algae is cyclic and its growth depends on the amount of sunlight available and water
temperature which, if too low, can prevent algae growth or kill existing algae.
We needed to use a knife to collect the other types of green algae, algae 2 and algae 3, as
shown below. These types of algae grew on branches that were either primarily exposed to the
air or intermediary, partially submerged in the water and partially exposed to air. By using a
knife to sever the branch, we were able to collect the specimen with minimal disturbance to the
algae. However, to preserve the microorganisms as well as the macroorgansims that inhabited
the algae we were required to submerge the algae covered branches in a bucket of water. The
buckets ensured that the organisms would neither leave the algae, nor dry out.
To collect reliable data, the process should be repeated several times.
Data
Data from three types of algae were used:
Algae 1: Completely submerged in the canal, zone 5
Algae 2: Located on the branches partially submerged, zone 5
Algae 3: Located on branches primarily exposed to air, little submersion, intermediate of zone 4
and zone 5
Trial 1 (September 24, 2011) 9:00 AM (0.0 in of rain)
Algae 1
Organisms Amphipods Dipthera
Nematode Annelid
Larva
Quantity
20
0
2
1
(71.4%)
(7.1%)
(3.6%)
Copepod
5
(17.9% )
Chironomida
e
0
Trial 2 (November 11, 2011) (0.01 in of rain)
Algae 1
Organisms Amphipods Dipthera
Nematode
Larva
Quantity
73
0
7
(79.3%)
(7.6%)
Annelid
Copepod
0
12
(12.5%)
Chironomida
e
0
(Macroorganisms: 15 unknown slugs)
Trial 3 (several days, spanning from December 2011 to early April 2012)
It was impossible to collect algae in Zone 5 of the Ala Wai Canal during the winter due to
heavy rain (below is the graph of rainfall from December 17, 2011) and the seasonal nature of
the brown algae the team had been collecting. The team looked for algae multiple times during
this period but did not succeed in finding any brown algae.
Trial 4 (April 14, 2012)
Algae 2
Organisms Amphipods
Quantity
27
(61.4%)
Dipthera
Larva
3
(6.8%)
Nematode
Annelid
Copepod
8
(18.2%)
6
(13.6%)
(too many 0
to count)
(Macroorganisms: barnacle larvae, 1 Samoan crab)
Chironomidae
Trial 5 (April 28, 2012)
Algae 2
Organisms Amphipods
Quantity
Algae 3
Organisms
Quantity
5
(14.7%)
Amphipods
Dipthera
Larva
0
Nematode
Annelid
Copepod
24
(70.6%)
4
(11.8%)
(too many 1
to count) (2.9%)
Dipthera
Larva
0
Nematode
Annelid
Copepod
1
0
0
(100%)
(Macroorganisms: barnacle larvae, 2 Samoan crabs)
Organisms
Amphipod:
Copepod:
Annelid:
Chironomidae
Chironomidae
(too many 0
to count)
Chironomidae:
Nematode:
Discussion:
For the first two trials, we found consistent growth of an algae bloom in Zone 5. For
following trials, however, we were unable to attain any data due to heavy rain and the end of the
growing season for brown algae. The heavy rains ultimately washed the algae bloom from the
zones. Although there was minimal algae bloom growth and little organisms recorded in algae
bloom 1, we hypothesized that the algae exhibits a cyclic behavior and will be less abundant
during the fall and winter seasons. During the fall and winter seasons the photoperiods
decreased, thus restricting the algae bloom growth. However, it is evident that there are more
amphipods inhabiting the algae than any other organism.
Although the original algae bloom collected in trial 1 was not found in the following
experiments, other species of algae bloom were found and examined. There were different
microorganisms and macroorganisms located within the second species of algae, used in trials 2
and 3, and in the algae 3, used in the final trial. In algae 1 there were a significant amount of
amphipods quantified, whereas there were not as many other species recorded; however, in algae
2 there were many species in greater quantities. There were many copepods found in algae 2,
quantified as “too many to count,” suggesting that algae 2 provided a more favorable habitat for
the copepods in comparison to algaes 1 and 3.
Algae 3, which was taken from an intermediate region between Zone 4 and Zone 5, had
very few organisms residing within it. There was only an abundance of copepods located in algae
3, with the exception of one amphipod, thereby showing that the algae 3 was an unfavorable
habitat for species other than the copepods. It could be concluded that copepods generally
inhabit algae 2, whereas other microorganisms, such as the annelids, amphipods, nematodes,
chironomidae, and the dipthera larva inhabit a different species of algae. The species of algae
bloom that the microorganisms inhabit can also correlate to the region, the amount of air
exposure, and the amount of water submersion, for each algae differed from the others in these
respects.
In order to get optimal results, the experiment, ideally, would be executed several times
with the same algae bloom, for measurements are taken once during each trial. However, due to
the sensitive seasonal nature of brown algae, there was a period where the team was unable to
collect data. After several trials where we were unable to collect data, the team opted to collect
different types of algae and examine those. This changed one of the constants of the experiment,
which may have affected the results.
Reflection of Process:
The team collected data on a total of four organized work days, although we attended as
many work days as we could: September 24th, November 11th, April 14th, and April 28th. We
consistently took algae blooms from the same zone, Zone 5. We have found that there are the
largest and most consistent amount of algae blooms in this zone. By keeping the zone's location
consistent we were able to compare the amount and types of species under relatively similar
situations.
We have been able to collect and examine algae blooms from the Ala Wai on four work
days, but unfortunately were unable to find algae on the third day, December 17th, and several
trials that followed. The heavy rain caused the algae bloom to be swept out of the zone that we
had previously observed, Zone 5. Heavy rain and high tides make it difficult to collect algae
bloom from the Ala Wai Canal, for high tides make it more difficult to access the algae because
visibility is poor and rain washes blooms down the canal. The lack of algae bloom during the fall
and winter months, such as December 17th, can be because that species of algae bloom grow
cyclically, meaning that it will develop according to the seasons.
Prior to the fourth and fifth trial the group had no knowledge about the different types of
algae and the species that inhabited it. However, upon investigating these different species of
algae bloom the group was able to find different organisms at differing quantities. Although
these results illustrate that a plethora of microorganisms inhabit different niches despite the
proximity of their habitats, the results must be deemed inconclusive because of the numerous
variables that were recorded at the same time. The data collected can not be entirely attributed to
one particular variable, but rather, it is at the current time, impossible to determine which factor
affected the number and types of microorganisms. For example, it is uncertain whether the five
copepods quantified in trial 1 is significantly less than the amount of copepods in trial 5 because
of the species of algae that was examined, the location of the algae or because of the current
season.
Some corrections that can be made to the experiment is to better focus the objective;
rather than examining microorganisms in various algae located in different conditions it would
be more cogent to have only one variable in the experiment. The location of the algae, the
season, and the amount of water submersion are all variables that will greatly affect the types of
microorganisms that are quantified. Perhaps the entire experiment would have ran more
efficiently and effectively if the experiment had a clearer objective and less variables; some
possible purposes include: quantifying the types of microorganisms located in the algae within
the the same exact zone, quantify the types of microorganisms located in various algae during the
same season. The scale by which we quantified the organisms--percentage and the general
amount of organisms we found during each trial--should also be adjusted to ensure more
consistent results. A better method would be calculating how many organisms per mass unit of
algae.
While collecting the algae we may have inadvertently changed the number of
microorganisms within the algae. To collect the brown algae we needed to rake the algae from
the bottom of the canal, possibly shaking out and losing much of the organisms that were
residing within the diatom. On the other hand, when collecting the green algae we had to cut the
entire branch on which the algae was located. Although we tried to cause minimal disturbance to
the algae that was located on the lower portion of the branch, the cutting motion and the removal
of the entire branch as a whole may have caused so microorganisms to leave the algae. In
addition to disturbing the algae during its removal, we may have also impacted the quantities of
microorganisms in our attempt to preserve the algae by placing it in water. When removing both
types of algae from their natural habitat, we placed them in a bucket filled with water from the
Ala Wai Canal. It is possible that we may have introduced foreign microorganisms that may
reside in the nearby waters but not in the algae, thus throwing off the calculations.
Conclusion

The micro-invertebrates found in the algae were annelids, copepods, nematodes, and
amphipods.

In the brown algae bloom 1, amphipods were most abundant.

In the green algae bloom 2, copepods were most abundant.

Due to the seasonal nature of the brown algae, we were forced to collect different types
of algae. This caused too many variables, perhaps making our data unreliable.

For further experimentation, we would also observe the macro-organisms that inhabit the
algae of Zone 5 of the Ala Wai but in an experiment (such as a constant algae type)
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