Final Flashcards
(315 cards)
1
Q
Describe the “Plankton” community
A
Includes phytoplankton, zooplankton. or it can be subdivided into micro and nano plankton.
These organisms are found in the water column
2
Q
Describe the “Nekton” community
A
Animals larger than plankton that actively swim. Includes fish, larger mobile invertebrates
3
Q
Describe the “Littoral” community
A
Area close to shore. Includes macrophytes growing on bottom, herbivores, decomposers, carnivores.
Typically the littoral zone coincides with the photic zone
4
Q
Describe the “Benthic” community
A
The “benthos” is the bottom layer of a lake. The organisms found there survive on bottom sediments or detritus. May be filter feeders
5
Q
Describe the “Periphyton” community
A
Organisms living on submerged surfaces like rocks
6
Q
Describe the “Neuston” community
A
Associated with surface film of water (surface tension)
7
Q
Describe the “Pleuston” community
A
Float near surface, not attached to bottom.
8
Q
All of the stuff suspended in the water column is referred to as?
A
seston
9
Q
Non-living particles suspended in the water column are referred to as _____
A
Tripton
10
Q
______ is the area of the lake where energy is created (usually photic)
A
Trophogenic zone
11
Q
_______ is the area of the lake where there is an energy defecit and very few or no plants
A
Tropholytic zone
12
Q
The zooplankton are…?
A
Heterotrophic floating organisms, usually detritovores or carnivores
13
Q
Nitrogen fixing bacteria usually have structures called ______. What are they?
A
HEterocyst. Anaerobic environments for fixing nitrogen
14
Q
_____ cells are dormant cells produced when environmental conditions are poor in Cyanobacteria
A
Akinete cells.
15
Q
How do cyanobacteria deter predators?
A
Have a mucous layer on the outside
16
Q
What are the defining features of the cyanobacteria?
A
Can be unicellular, filamentous or colonial.
Compete with eukaryotic algae and often outcompete them in eutrophic water bodies. Can be planktonic or periphytic. Highly resilient and can secrete toxins to destroy competition and predators.
17
Q
What are the three main cyanobacteria genus in Manitoba?
A
Anabaena, Aphanizomenon, Microcystis
18
Q
List some cyanobacteria genus
A
Anabaena, Aphanizomenon, Microcystis, Oscillatoria, Nostoc
19
Q
____% - ____% of cyanobacteria are known to produce
A
50% - 70%
20
Q
What anatomical features make it possible for cyanobacteria to choke out other organisms?
A
They have a gas vacuole and are extremely tolerant to light, so they can stay on the surface and block the light from reaching plants and algae below
21
Q
Describe the effects of cyanobacteria toxins
A
Include neurotoxins, hepatotoxins (affect liver)
Neurotoxins can cause very quick death. Hepatotoxins take a few days to work, as the capillaries of the liver expand.
22
Q
What are saxitoxins?
A
The best known toxin involved in shellfish poisoning. Produced by dinoflagellates and cyanobacteria
23
Q
______ is the only cyanobacteria toxin for which there are water quality guidelines. The maximum is ____.
A
Mycrocystins.
1microgram/L
24
Q
Dynophyta are the _____
A
Dinoflagellates
25
Some dinoflagellates are described as being "naked". Describe this
Under a microscope you cannot see the armour but it is still there
26
Describe the phylum Dinoflagellata
Flagellated protists with uneven flagella. Unicellular, some diploid. Usually have armour. Typically mixotrophic, usually planktonic.
27
Are members of the phylum Dinoflagellata often photosynthetic?
Most can also be heterotrophic, and chloroplasts are optional and can fade away with time. The majority of dinoflagellates are classified as mixotrophic
28
What chlorophylls do Dinoflagellates have?
Chlorophyll a and b, and beta carotin. There are also some groups containing pigments unique to Dinoflagellates, such as peridinin and dinoxanthin, providing the golden-brown colour of most Dinoflagellates
29
The armour surrounding Dinoflagellates is called _____. Describe it
The "Theca". It is made of cellulose plates and lies INSIDE the cell membrane
30
Describe the light-sensing structures of dinoflagellates
Stigma/eyespot - simply senses light
| Ocellus - eyespot similar to primitive invertebrate eyes, has a lens and a retinoid
31
______ are dinoflagellate structures that release mucous in response to threats
Mucocysts
32
What makes cell division of dinoflagellates unique?
Chromosomes are permanently condensed, nuclear envelope does not degrade during division. The theca is often divided in half between the two daughters, who then form their own second half.
33
______ are dinoflagellate structures that are released from the theca to "harpoon" prey
Trichocysts
34
The groove between the plates of the theca in dinoflagellates is called the _______
Sulcus
35
How do dinoflagellates locomote?
The lateral flagellum vibrates extremely quickly
36
Some dinoflagellates are bioluminescent. Describe how this occurs
Light production requires a lot of ATP and "luciferin". It is often done by structures called scintillons
37
Describe how dinoflagellate toxins can affect other organisms
Toxins accumulate in gills of fish, can cause dementia, memory loss, or shellfish intoxication in humans. Dinoflagellates can infect seaweed, which infects fish, which infect us. It is also possible for dinoflagellates to eat fish
38
Where do dinoflagellates often bloom?
Polluted areas likewater near hog barns.
39
How is the Puffer fish related to dinoflagellates?
Dinoflagellates are what give the Puffer fish its toxicity. It consumes them during blooms
40
Dinoflagellates can be linked to the death of which major aquatic animal?
WHALES
41
Briefly describe the group "Euglenophyta"
Facultative heterotrophs, are flagellated, have no cell wall but instead have a "pellicle" under cell membrane. Most are nicellular. They are considered the most ancient eukaryotic algae and some are parasitic. They grow well in high nutrient density, polluted environments, or acidic environments.
42
Describe the protective surfaces on Euglenophyta
Pellicle rests under the cell membrane and is made of spiraled proteins.
Some can have a shell called a lorica, which is made of manganese compounds or ferric hydroxide. This can be outside the plasma membrane and exist in addition to the pellicle
43
Euglenophyta do not have a cell wall. What challenges does this present and how do they get around them?
Water is very easily brought into the cell so they must possess a system of contractile vacuoles to to empty out the incoming water.
44
Where is the second flagellum located in euglenophyta?
Inside the body. Referred to as a "non-emergent" flagellum
45
Euglenid chloroplasts have _____ membranes
3
46
______ is an extremely large euglenid
Phacus
47
how do euglenophyta sense light?
Pyrinoid and eyespot work together to sense light. They like to stay in medium-light environments
48
______ is a red colour produced by euglena, occurs in stagnant, nutrient rich environments
Hematochrome
49
Briefly describe phylum cryptophyta
Golden algae. Have 2 emergent flagella and a system of periplast plates just under the plasma membrane (very similar to pellicle). Have extremely large chloroplasts with a nucleus-like structure and their own endoplasmic reticulum.
50
Briefly describe phylum Xanthophyta
Yellow-green algae. Have beta-caroetene and chlorophyll a. Cell wall is mostly cellulose. Some have two overlapping cell walls like diatoms
51
Bacillariophyta is more commonly known as _____
diatoms
52
Briefly describe phylum Bacillariophyta
Unicellular, colonial, or filamentous. Cell wall is 95% silica. Autotrophic with clorophyll a and c, beta carotenes. Can adopt a cessile benthic lifestyle. Readily absorb sjlica, and can bloom early in spring. Need a constant silica source.
53
_______ are considered to be one of the word's most important primary produces
Diatoms
54
Describe the cell walls of Bacillariophyta
Called frustule. Comes in two halves, overlapping. The overlapping half is called the epitheca and the other half is called the hypotheca. The zone of overlap is referred to as the "girdle".
55
Describe the difference between "girdle view" and "valve view"
When viewing a Diatom, it is possible to view it in "girdle view" from the side or "valve view" from the top.
56
Describe the difference between bilateral and radial symmetry
Bilateral - Symmetry down the middle
| Radial - Symmetry down multiple planes, must be circular
57
Describe the group of diatoms called the "centrales"
Radially symmetrical, centric diatoms
58
Describe the group of diatoms called the "pennales"
Bilaterally symmetrical, pennate (flattened) diatoms
59
Diatoms have one _____ploid nucleus
DIPLOID
60
Describe diatom cell division
Cell walls split and one daughter gets hypotheca and one gets epitheca. This means that after each division, one daughter is smaller than the original parent. This means that over a season diatom populations get smaller and smaller on average.
61
What is the Mcdonald Pfitzer rule
As diatoms divide over a season, the average population size gets smaller and smaller.Once the small diatoms reach 1/3 of maximum diatom size, diatoms switch to sexual reproduction. However, if environmental conditions are poor, the population system dies off
62
Describe sexual reproduction in diatoms
2 cells fuse to form diploid auxospore, which producesa new frustule and restores max size for species.
63
Do diatom blooms occur?
It is possible but they are not super noticeable since they disperse through the water column.
64
Many pennate diatoms have a line or groove down the center called a _____. What is it's function?
Raphe. Secretes muselage which can aid in movement. Diatoms move super quickly.
65
Storage reserves in diatoms are in the form of _____. How does this relate to fish?
Lipids, which add to buyancy. Fish obtain their oil from diatoms
66
Petroleum is thought to have come from ______ earth
Diatomaceous Earth
67
Are diatoms toxic?
They secrete stuff in the water but it is usually non toxic to humans. They can kill fish by irritating the gills.
68
Briefly describe phylum Chrysophytes
Golden-brown algae. Mixotrophic. Uninucleated, solitary/colonial. Like colder temperatures. Have two flagella of equal length.
69
List Manitoban Crysophytes
Synura - Usually in precambrian shield lakes
Dinobryon - Very unique, usually an indicator of lake health.
Malommonas - covered in fine scales
70
Briefly describe phylum Chlorophyta
Unicellular, colonial, multicellular or mulinucleate. Thought to be the precursor to plants. Can be freshwater, marine, or intracellular parasites. Have a cellulose wall, and are so common that they can be found in dust.
71
List and describe some Chlorophyte species/genus
Chlorella - Circular, small, no locomotion
Oedogonium - Long filaments that form mats
Hydrodictyon - Network of interlocking filaments,can trap plankton
Scenedesmus - arranged as series of cells with spikes to prevent them from falling down the water column
72
Describe a Volvox colony. To what phylum does it belong?
Volvox colonies - Blob of a colony with vegetative cells on the surface and daughter cells inside. Eventually bursts forth. The individuals are Chlamydomonas algae, from the Chlorophytes.
73
What condition is often the case if an organism is non-motile?
Has a large cell wall
74
Some Chlorophytes are are composed of two "semi-cells" which are connected at a narrow _____
isthmus
75
List some factors influencing phytoplankton community composition
Light, temperature, buoyancy regulation, inorganic nutrients, organic nutrients, biological factors such as predation
76
Algae can take up _____ (less/more) light in warmer water
more
77
how do algae keep their photosynthetic rate stable?
Adjusting the amount of chlorophyll in chloroplasts in relation to light intensity
78
Why do cyanobacteria have to live close to the water surface?
They need warm temperatures
79
Why is it that algae die if they lose buoyancy regulation?
The light reactions of the chloroplast are not effected by temperature but the dark reactions are (enzymes)
80
What is Stoke's Law? Describe it
A frictional force law dictating the sinking of organisms in the water column.
Organisms are assumed to be spherical and if they are more than 1/2 they will fall according to Stoke's Law. Rate of sinking inverse to viscosity (denser particles fall faster).
81
How to algae mitigate sinking?
Change surface area:volume ratio.
Spines and other projections prevent falling
Mucilage - density less than cell, increases surface area
Gas vacuoles - allows adjustment of level in water column
Lipids - Makes them buoyant
Iron regulation - Change ion concentrations to become a bit motile
Flagella - self explanatory
82
________ occurs when an organism looks different at different times of the season
Cyclomophosis
83
What are the majour limiting macronutrients in algae?
Phosphorous and Nitrogen
84
Liebig's Law of the ______ tells us that whatever nutrient is least available is what limits population growth
Minimum
85
_______ organisms cannot synthesize one or more essential compounds
Auxotrophic
86
Why do algae need micronutrients?
Used mostly as catalysts
87
______ often outcompete algae for nutrients and vitamins
Bacteria
88
When are algae most likely to resort to heterotrophy?
In polluted environments or where there is no light
89
What biological factors can affect phytoplankton communities?
Parasitism - May be fungi, bacteria, viruses
Grazers - zooplankton like rotifers, protozoa and microcrustacans, mussels, fish
Interspecific competition - Some species can secrete toxins against others
90
Give a short breakdown of how phytoplankton composition can change over a year in a lake
Winter - small, flagellated algae, often have ability to become heterotrophic.
February-ish - Diatoms begin to grow, hit max right after spring circulation
Spring warming - Green algae build up as diatoms decline
Summer - Oligotrophic: Diatoms deeper down, Eutrophic: blue-greens
91
What occurs to a lake if left without human inerference
Seasonal periodicity of biomass is consistent, no new nutrients added to system. Fluctuations season to season are much more significant in temperate waters.
Biomass max and minimum will no longer be related to highest photosynthetic rate.
Species composition fluctuates similarly year to year.
Vertical distribution of plankton.
92
What happens to the photic zone of a eutrophic lake?
Collapses. As cyanobacteria build up they block out light
93
Distinguish between Holoplankton and Meroplankton
Holoplankton - Species that are fully planktonic
| Meroplankton - Planktonic for only part of life cycle
94
_____mg/L of chlorophyll "a" is the maximum for algae with no nutrient limitations
1
95
What are some ways that cyanobacteria exclude others?
Collapse photic zone, release toxins, perform so much photosynthesis that carbon is excluded. Also release siderochromes to catch iron which can limit others
96
What are the protozoa?
Most heterotrophic, like calm waters, don't like bright ight. Seen more in early spring/summer. Peaks in algae usually followed by peaks in protozoa
97
Describe Amoeba/Rhizopoda
Usually multinucleate, create branching pseudopodia for locomotion and engulf food. May have a loose-fitting shell or half-shell called a "test". Pseudopodia can emerge from openings in test
98
Describe the ciliates
Covered in cilia used for motility, and two nuclei (macro and micro nuclei) may have harpoon-like trichocysts. Cilia can also pull food into food vacuole and a contractile vacuole expels water.
99
Describe the phylum Gastrotricha
Microscopic worm like animals. They are mostly benthic and live within periphyton. Freshwater species are parthenogenic and they adhere themselves to a substrate using adhesive glands.
100
Describe phyum tardigrada
They feed on detritus and plants, are usually found in habitats rich in organic matter. Some appear as females only and reproduce via parthenogenesis. Males are much smaller than females.
Tardigrades can withstand super extreme environments by becoming a "tun".
101
Describe phylum rotifera
Most species are found in fresh water. Live as zooplankton, attached to submerged surfaces, or on the bottom. Have corona of cilia around mouth. Feeding habits are extremely varied - can eat algae, be carnivorous or detritovores. Most are females, as males only show up at some times of the year (and exist solely for sex). Males are extremely small and may not even have a functional digestive tract.
Rotifers have a stiff shell called a lorica surrounding their body
102
Describe the cladocerans
Body covered by a transparent, chitin, bi-valve carapace. 2 pairs of antennae used for motility. Juveniles molt several times. Do not survive as long in warm water.
103
Describe how Daphnia changes shape throughout the year in response to seasonal variation
The heads of daphnia change in shape and size depending on the temperature of the water. In cooler water, the head is more compact. In warmer water, the head forms a sort of spike at the top
104
Describe the copepoda
Crustaceans that actively pursue prey, kill fly larvae, macerate prey bigger than themselves. Some feed on algae. Most have a single eye on the top of their head.
105
Describe the vertical migration of copepods
At night most species move up in water column and move down by dawn.
106
What is the purpose of migrating vertically as a non-photosynthetic organism (ex. copepods)?
Avoidance of predation - less likely to be seen by predators
Food quality - algae very nutritious and plentiful at the surface at night
Growth better at ow temperatures, good idea to spend most of the day at low temps
Feeding rates greater at high temperatures, may want to go to warmer surface to feed
107
What is one reason why copepods may avoid the shore?
Harmful waves
108
Briefly describe the nektonic community
Cover large distances, eat a lot, often vectors for parasites and ecto-symbionts, eat plants or animals,
109
Why is it that fish are killed in hydro dams?
Anaerobic environment - they suffocate
110
Distinguish between fish growth in tropical and temperate waters
Tropical - Fish grow all year
| Temperate - fish grow half the year
111
Fish are limited to areas near _______ during stratification
the thermocline
112
Why is it harder for fish tosurvive in warm water?
Often warm = polluted. also, less O2 can be dissolved
113
How is it that Dallia Pectoralis can stay alive for weeks frozen solid in ice?
Lowers metabolic rate significantly
114
How is it that Mud minnows can stay alive in ice?
Have oily skin that acts as an antifreeze
115
Why are Tilapia so commmercially useful?
Can live in high-temp, environments because they breathe at the surface. Can live in and feed off of highly polluted water.
116
Fish are _____thermic, tolerate a narrow range of temperatures. making them very vulnerable
stenothermic
117
Fishes prefer ____ (cold/warm) temperatures
cold
118
Why are carp a problem?
Known as the "vacuums" of the lake. Eat all the pollutants and poop and exclude other organisms. They suck.
119
What's interesting about silver carp?
Considered a pest because they jump out of the water and hit people.
120
Describe sturgeon
Live for over 100 years to over 140kg. Are bottom feeders found all over central canada. overfished for their eggs, used in cavier
121
What is freshwater "ick"?
An infection occurring in many fish caused by a ciliate. It forms cysts filled with thousands of daughter cells. It chokes fish by suffocating gills
122
What are the trematodes?
```
A class within the Platyhelminthes. Otherwise known as the FLUKES.
They can only reproduce in adult stages, usually have t go through several very specific hosts first (each called an intermediate host). They live on the bodily fluids of their hosts.
```
123
Describe the typical trematode life cycle in Manitoban flukess
Include definitive host in which they reproduce > egg > miracidium > snail species > cercariae > metacercaria > definitive host.
Must find definitive host quickly because they do not have much bodily function outside of reproduction
124
What causes Swimmer's Itch?
A trematode in the cercarian stage, burrowing into the skin and causing black dots and swelling
125
Cesstoda are the ____
tapeworms
126
Describe the fish tapeworm lifestyle
Definitive host is a mammal, and eggs are passed in feces. It hatches in the water, grows into coracidium larva, then the copepod eats it and it grows into a procercoid larva. then the procercoid larva is released from the crustacean, a fish eats it, a bigger fish eats that, and a mammal eats uncooked or undercooked fish
127
To what depth do vascular macrophytes often grow
approx. 14m maximum - the max. recorded depth of photic zone
128
To what depth can non-vascular macrophytes grow?
Max 50m, because they don't need rootable bottom substrate
129
Macrophytes ______ the water
aerate
130
Briefly describe the non-vascular macrophytes
Submerged mosses, which are large and non-vascular. Nothing eats them, they are long lived, and produce allelopathic compounds
131
What are some non-vascular macropythes in MB?
Chara
| Nitella
132
Vascular plants have air canals called ______ that can take O2 from the water
Lacunae
133
______ plants produce more than one kind of a leaf
Heterophyllic
134
Describe submerged leaves
Do not touch the air, have almost no cuticle, vascular tissue, or stomata
135
Describe the general life cycle of partially submerged plants
Produce submerged leaves first, the grow upward and produce floating leaves, then grow further upward and produce more productive aerial leaves. Most are perennial and have large amounts of underground rhizomes. They are very vulnerable in their submerged stages
136
What is the disadvantage of having only floating leaves?
Have to grow to the surface extremely quickly
137
________ plants have no underground structures
Annuals
138
Often floating-leaved plants have ______ rhizomes
GIGANTIC
139
Describe the floating-leaved plant "Potamogeton"
Wind pollenated, needs very low total dissolved solids in water. Have long, strap-like submerged leaves and oval, leathery floating leaves
140
_______ is the group containing the water lilies. Describe them.
Nymphaea. Water lilies like acidic water and low total dissolved solids
141
The cattail is in the genus _____
Typha
142
How are submerged macrophytes pollinated?
Most flower above the surface, with pollen moved by water surface tension
143
________ macrophytes are fully underwater but may need to flower at the surface
Submerged
144
What are some Manitoban submerged macrophytes?
Myrophyllum, potamogeton
145
Which freshwater macrophyte flowers underwater?
Vallisneria americana
146
What do the leaves of submerged plants look like?
Fine, feathery
147
What are some free-floating macrophytes that float on the surface?
Lemna minor (duckweed), spirodela
148
What are some free-floating macrophytes that float under the surface?
Lemna trisulca, utricularia. All only grow in low nitrogen environments
149
What is unique about utricularia vulgaris?
Has buds called bladders to catch zooplankton
150
Some freshwater macrophytes used a _____ to overwinter. Describe it
Turion. Basically a condensed version of the plant. Resistant to frost.
151
How do the bladders of utricularia capture zooplankton?
Cilia on the outside of the bladder detect and pull in zooplankton, trigger the "door" closing.
152
A eutrophic water body may only have ___-____ kinds of macrophytes
1-2
153
How do rooted plants affect lake recovery
Can stop nutrients like nitrogen and phosphorus from reaching the benthos - stay dissolved
154
How can plants adapt to decreases in light
increase chorophyll in leaves or increase surface area of the leaves for light absorption, OR, most importantly, grow rapidly toward the surface
155
How does pressure affect macrophytes?
Can limit depth of vascular macrophytes due to pressure on the lacunae.
156
Which factor affects freshwater macrophytes more significantly: temperature or pressure?
In labs vascular plants can grow in warm water with high pressure, but in the field cannot grow below the thermocline. Chances are that temperature is the primary limiting factor.
157
Most freshwater macrophytes are ______
Perennial
158
Many freshwater macrophytes grow in groups called _______
cohorts
159
How is plant biomass lost in lakes?
Storms, grazing, human activity
160
What are the main macrophyte grazers?
Gastropods, juvenile insects, herbivorous fish, birds, mammals
161
Grazing loss can range up to ___% of biomass
10%
162
Heterophylls have ____ biomass underground
Lots of
163
Do living or non-living substrates hold better periphyton communities? Compare and contrast them
Non-living, because they are more permanent.
Living: Non-permanent, more competition, needs quickly growing forms
Non-living: Permanent, more productive
164
over ____% of algal species grow attached to a substrate, and many species can grow as plankton or periphyton
90%
165
What does the algal periphyton community consist of?
Mostly pennate diatoms, alot of centric. Many blue-green algae and filamentous green algae
166
_______ plankton live on rock
Epilithic
167
______ plankton live on mud
Epipelic
168
______ plankton live on sand
Epipsommic
169
______ plankton live on macrophytes
Epiphytic
170
______ plankton live on animals
Epizoic
171
The more eutrophic a water body the _____ (less/more) periphyton will be present
More
172
Epileptic and epipelic periphyton will be brown if composed mostly of _______ or green if composed mostly of _____
Diatoms, blue-greens
173
Mud is a viscous liquid. What ratios does an epipelic periphyton community have to have?
Most mis the motile, and able to sense light so they can migrate in accordance to that
174
Sand is composed of hundreds of little grains. What characteristics must an epipsammic periphyton community have?
Must be small enough to fit in the depressions of sand grains. May need something to adhere them to sand grains
175
How can periphyton communities affect freshwater macrophytes
On macrophytes, higher periphyton covering their leaves can block out light. Under eutrophic conditions it is possible for periphyton to kill plants
176
Why is it that periphyton numbers do not really affect emergent-leaved plants?
Because the periphyton cannot grow above the surface, so they can grow all over the submerged parts of the plant without ever touching a leaf
177
In a hypertrophic lake, all but the _______ macrophytes are killed
Emergent
178
How can epizoic periphyton be beneficial?
Can provide camouflage
179
______ and ______ numbers rapidly go up in the periphyton community when organisms in a lake start to die off
Fungi and bacteria
180
Briefly describe how nutrients cycle from bottom sediments to lake body
N and P are moved back and forth from the benthos to the lake body. Sometimes, internal cycling exceeds external input
181
What is the primary role of organisms in the bottoms sediments?
To decompose! Shit falls down and they try to decompose it. Some things decompose quickly, some don't
182
The bottom sediments are made of....
Living organisms, clay, sand, other inorganic particles
183
________ inorganic particles come from organisms that use them, such as Diatoms with silica
Biogenic
184
Why is it that scientists do particle size analysis when studying bottom sediments?
It is a good way to guess which organisms are present, since many organisms are picky about what sediments they will live in
185
______ are sediments that are less than 50% organic and are aerobic
Gyttja
186
_____ are bottom sediments that are more than 50% organic content and are anaerobic and alkaline
dy
187
______ are bottom sediments that are over 50% organic! acidic! have low N2 content and lots of sphagnum moss
Peat
188
______ are bottom sediments that are anaerobic, have a large amount of organic content
Sapropel
189
Sediments with high organic content are usually found in what types of lakes?
Lakes with high primary productivity - organic sediments can build up so that productivity goes down if there is no further external input
190
Sediments are always decomposing. List what is decomposed first to last
1. Carbs
2. Amino acids
3. Sugars
4. Humic acids
5. Lipids
6. Things like lignin and shit
191
If something doesn't decompose it is referred to as ______
Refractory
192
Refractory organic matter includes....?
Phenolic compounds, tonins, cutins, lygnins
193
Why are beaches the cleanest places to swim?
There are far fewer bacteria in sandy, wave-swept littoral areas than quieter, deeper ones. Bacteria are often just swept away
194
_______ take the longest to decompose
Emergent macrophytes
195
______ decompose most quickly
Algae
196
What factors influence decomposition rate?
Initial N2 content (high N2 content means the organism will decompose quickly), high sulfur content means organisms will decompose slowly.
Dissolved O2 (for decomposers to breathe)
Temperature
Micronutrients required BY decomposers
Particle size
197
What conditions bring Protozoa to the bottom sediments? Describe benthic Protozoa
Sewage, eutrophication, high bacterial content. Protozoa can feed on detritus, suspended molecules, or bacteria/algae. They have a short generation time and appear and disappear quickly. Some have chlorophyll to supplement diet
198
What conditions bring Ciliates and amoebae to the bottom sediments? Describe benthic ciliates and amoebae
They usually appear when other major Protozoa are present. Live in the top 1cm of benthos, can have over a hundred species in one lake. Ciliates and amoebae can migrate slowly through the bottom sediments closer to shore with the season to obtain the best temperatures and food
199
Describe benthic Porifera
Most freshwater sponges are small acne inconspicuous. They have internal chambers lined by flagellated cells that create a water current for filtration. Food particles are taken up and digested intracellularly. Some algae may just grow on the sponge (can form symbiosis).
Sponges provide habitats for nematodes, rotifers, crustaceans, baby snails, larval insects (ex. Spongeflies).
Sponges gradually spread over substrate. They produce a gemmule of densely packed spicules when environmental conditions are rough. This is how the sponge survives the winter.
Sponges can do sexual reproduction, alternate sex year to year.
200
Give some examples of Manitoban coelenterata. Describe the phylum
Coelenterata alternate between free swimming Medusa stage and polyp stage. They sting with nematocysts and feed on zooplankton. Usually budding or sexual reproduction. They develop rapidly in spring
Hydra have no polyp stage
201
A ______ occurs when animals suddenly appear on the scene
Irruption
202
Describe the lifestyle of freshwater jellyfish in MB
They live for a long time, alternating between sexual "medusa" stage (which we know and love) and asexual polyp stage. In MB, it can take like 10 years to reach medusa stage
203
Briefly describe the planarians
```
Within phylum Platyhelminthes, class Turbellaria.
Have cilia on their bodies so they can glide along substrate. Primarily eat detritus but can eat small arthropods.Use sexual reproduction when conditions are poor, and go into a torpid state to survive harsh weather.
```
204
Briefly describe phylum nematoda
Roundworms. Usually make up a lot of the benthos. Can be found in most freshwater habitats. Nematodes in MB are usually microscopic and can be parasitic or free living. There are thousands of species, and they all have a non-cellular coating called a cuticle, allowing them to withstand harsh environments. They molt their cuticle.
More common in oligotrophic lakes because the sediments are aerated. They always concentrated below the surface to eat undecomposed organic matter. They like fine sediments
205
How do you determine whether a nematode is male or female? Describe nematode sex
Males have a curly tail for sex.
The body is mostly gonads.
Females are larger than males, and males have sex with a copulatory spicule. Some undergo parthenogenesis
206
Describe nematode feeding habits
Can feed on detritus or macrophytes. Mouths can pierce or chew.
207
What are the adaptations that phylum nematoda have to withstand harsh conditions?
Have a non-cellular coating called a cuticle, allowing them to withstand harsh environments. They molt their cuticle.IN poor conditions, they form a dormant "cyst"
208
Phylum nematomorpha is more commonly known as _____. Why are they named so similar to nematoda?
Commonly known as horsehair worms. They are similar to nematoda in morphology
209
Briefly describe phylum nematomorpha
Look like string/fishing line, can be 50cm - 2m long. Have a cuticle but no cilia on the outside. Adults have no digestive, excretory, respiratory or circulatory system - they exist solely for sex. Larval stages are parasitic in insects.
210
Describe the life cycle of nematomorpha
Larva born > burrows into gut of insect > Survive insect metamorphosis > Insect eaten by beetle or other larger insect > adult emerges
211
Briefly describe phylum bryozoa
Kind of look like coral, rapidly form large colonies attached to substrates. Composed of individual "zoids". Have cilia on the outside for catching food, and chironomids and protozoa may live inside of them
212
Phylum annelida consists of....
Oligochaeta - Earthworms, etc.
| Hirudinia - leeches
213
Briefly describe the freshwater oligochaeta
Look just like terrestrial earthworms. Eat sediments, cycle nutrients. Mix sediments in a process called bioturbation. Covered in bristles called setae. In poor environments, reproduction is mostly sexual.
Need O2 in sediments, and very particular about sediment size. More abundant in the shallows.Their numbers go up rapidly when waters are polluted but still oxygenated.
In poor conditions, they create cysts.
214
Describe asexual reproduction in the oligochaeta
Posterior end grows into a new individual.
215
Oligochaeta cannot survive in bottom sediments with less than ___%-____% O2 concentration
10%-15%
216
_______ are the major predator on oligochaetes
Chironomid larvae
217
How long to oligochaetes often live?
Can live over 5 years but totally depends on when they have the sex
218
What is the diet of class Hirudinea?
Ectoparasites, consume blood and body fluids of vertebrates (and, in MB, snails). They don't have to do this often, they can last 3 months to 200 days without a meal
219
How do members of class Hirudinea go so long without eating?
Store blood in cecae of the digestive tract
220
How do Hirudinea eat?
Have two suckers, one posterior (bigger) and one anterior (small) sucker. They pierce a host and produce a blood anti-coagulant called "hirudin"
221
Leeches are more active at what time of day?
Night
222
Why can't you feel leeches on you?
They produce a local anaesthetic
223
More eutrophic = ______ (more/less) leeches
More
224
Leeches remain longer on ____ blooded hosts
cold
225
The biggest leeches in Canada can be (or COULD be) found in _____ Lake, MB
Sewell
226
Many species of leeches in MB breed at _____ years old and then die
1
227
What are the two freshwater classes in phylum mollusca?
Gastropoda - snails and shit
| Pelecypoda - mussels and shit
228
Briefly describe the gastropods
Use a foot to glide, have antennae and eyes. Herbivorous (minimize competition by occupying different macrophytes). Shell made of calcium carbonate covered by organic periostracum.
They eat with a radula, which is basically a little ribbon with teeth on it (teeth can be either calcium carbonate or iron).
229
Briefly describe the pulmonates
Have a lung, can live in O2 poor environments, have to go to surface to breathe (therefore must live in littoral zone). Can breathe little O2 bubbles underwater
230
Briefly describe the prosobranchs
Have gills, limited to O2 rich lakes or lotic waters
231
What the heck are limpets?
Snails with weird conical shells that look like stuck on rocks
232
How long do gastropods typically live?
Less than a year
233
_____ is the gastropod organ that secretes the shell
mantle
234
What helpful feature do many prosobranchs have for protection?
A "trapdoor" called an operculum on their shell that closes over the body when resting
235
Briefly describe class pelecypoda
Includes mussels, fingernail and pea clams.
236
How do mussels dig?
With a "foot"
237
Describe freshwater mussels
Many are endemic. Almost 1/5 are extinct because they require a specific fish host for larval "glochidia".
Very vulnerable to pollution.
238
The valves of freshwashwater mussels connect at the ________
Hinge line
239
How do pearls form?
When a sand grain gets stuck between the mantle and the sell, the mantle secretes irridescent "nacre", laid in thin layers to make the particle smooth. forming a sphere.
240
Lake Winnipeg used to have more than ____ species of freshwater mussels. Now has only ___, and two make up more than ____% of remaining species
11, 5, 90%
241
how does the reproductive cycle of clams differ from mussels?
Don't have a larval stage, and are viviparous
242
What is the latin name of Zebra mussels?
Dreissena polymorpha
243
Briefly describe zebra mussel morphology
Function similarly to ocean mussels, have a telltale triangular shape and black and white stripes. Shells are super hard and crack like glass. Super strong threads called Byssus attach the mussels to each other and the bottom substrate.
244
Why are zebra mussel larvae unique?
Called "veligers", don't need a fish host and can get into little cracks in boats - this is how they get into water they don't belong in
245
Why are zebra mussels a huge problem in North america?
On top of having no natural predators, they have crazy filtration rates, eat tons of plankton, and destroy ecosystems. They literally suffocate freshwater mussels.
246
The ______ mussel is an invasive species slightly larger than the zebra mussel found in the United States
Quagga mussel
247
Ostracodes are members of the phylum ______
Arthropoda
248
How can one differentiate freshwater molluscs and ostracodes
Molluscs have teeth on the ridge between the pieces
249
What do ostracods look like? What are their shells made of? How do they get around?
Look like little seeds. Shells bi-valved and made of chitin. They get around by sticking their legs/antennae out of the shell and hopping
250
Briefly describe the ostracoda
Omnibores (eat bacteria, algae, detritus) with a bi-valve carapace. Larvae called "nauplius".
251
Ostracods fossilize well. Why is this helpful to scientists?
Can help to determine previous lake composition
252
What are the freshwater malacostracans?
A group of arthropods containing isopods, mysids, decapods, and amphipods
253
Describe freshwater mycids
They look alot like shrimp and carry their young in a brood pouch. They creep around the bottom sediments. Often are bottom-dwelling filter feeders or omnivores.
254
Describe freshwater isopods
Have two pairs of antennae and 7 jointed limb pairs. Use appendages for respiration. Eat detritus and plants
255
The only freshwater decapods are ____
Crayfish
256
Describe crayfish
Look like lobsters. Breathe using gills, and can live in lotic or lentic bodies. Scavengers, will eat isopods and plants
257
Most crayfish cannot tolerate polluted water, but the invasive species _____ can
Rusty crayfish
258
Describe freshwater amphipods
Amphipods have no carapace. most are detritovores or scavengers
259
Class _____ is the largest group of animals in the world
Insecta
260
Which insects complete their whole life cycle in water
Beetles and some hemiptera
261
The dragonflies are known as the _____
Odonata
262
How does one distinguish dragonflies and damselflies?
Damselfly wings are upright when resting. Dragonfly wings are not
263
Describe the odonatan life history
Adults terrestrial, eggs laid on plants, eggs depend on temperature to hatch. Hatch after 2-5 weeks. Molt 10-20 times before becoming adults.
Live in littoral sediments with macrophytes, mature in 5 weeks-5 years.
Take several days to achieve full adult colour.
Camouflage well.
264
What do odonatans eat>
Prey on other insects, other odonata, small fish, nymphs.
265
What are the chironomids?
Dipterans resembling mosquitos (do not bite). Larvae are found in the benthos (bright red - called blood worms). Adults known as midges.
Typically they attack prey much larger than them and they decrease with eutrophic status
266
Order Hemiptera is the _____
true bugs
267
Ephemeroptera are referred to as the ________
Mayflies
268
The presence of ephemeropterans indicates what in a water body?
High dissolved O2 content
269
Briefly outline the life history and traits of ephemeropterans
At rest wings are vertical, adults live 3-4 days and emerge in large mating swarms (are terrestrial). Eggs can take hours-days to hatch. Can molt 4-40 times, Nymphs benthic, like flowing water.
Have 2 winged stages and molt twice then become adults.
270
What are the plecoptera?
Stone flies, live 1-3 years, small numbers, nasty carnivores
271
The Hemipterans in the red river can beover ___ inches long
4
272
Lethocerus grandis is otherwise known as ____
The giant water bug
273
Describe freshwater Hemipterans
Mouth used for sucking and piercing, only eat liquids (body fluids). Overwinter as adults in moist sediments, eggs laid near the water, take weeks to hatch.
Molt 5 times, mature in 1-5 months. They can grow to tremendous sizes and stay near the water as adults (can live up to 5 years).
274
The Dipterans include...
Mosquitos, chironomids, non-biting midges, horseflies, deerflies
275
Briefly describe freshwater dipterans
Many have aquatic larvae, undergo 3-4 molts. Stay larval for several weeks - 2 years (overwinter in sediments). Adults terrestrial
276
Why are chironomid larvae red?
Have lots of hemoglobin to hold O2
277
Describe chironomid adult life
Don't feed, just mate in large swarms. Partition mating times and days by species
278
The Culicidae are more commonly known as ______
Mosquitos
279
Describe the basic features of the Culicidae - particularly the unique larval stage
Do better in areas with more water (eggs laid on water), larvae are aquatic, suspended under the water surface using a siphon to get air. Can grow in small areas (even water-filled pop cans). Some species get air from macrophyte lacunae.
Some are host-specific, undergo 4 molts before they turn into motile pupae
280
Tabanidae are commonly known as the _____. Briefly describe them
Horse/deer flies. Lay eggs in water, larvae carnivorous (tear up prey)
281
Describe the water mites
Not insects. Have 8 legs, attach eggs to stones, carnivorous (eat body fluids), larvae parasitic in hemiptera, become free-swimming adults
282
The trichoptera are otherwise known as ______
Caddisflies
283
Briefly describe the trichoptera
All larvae aquatic, live in a protective case intricately constructed by themselves. Cases vary species-to-species. Some Manitoban species construct cases to look like snail shells.
Remain as larvae for ~1 year, pupate for a few weeks then emerge as adults
284
The Neuroptera are commonly known as ______
Spongeflies
285
Briefly describe the neutroptera
Lay eggs above water, which hatch then drop into the water. They parasitize sponges and use them for camouflage. Adults are terrestrial.
Not commonly found, simply because sponges are not commonly found
286
The Coleoptera are otherwise known as _____
Beetles
287
Briefly describe the coleoptera
Forewings (called elytra) form a hard case over hindwings. larvae and adults can be aquatic, come to the surface to breath. They can also trap air bubbles under the elytra. Some larvae breath via macrophyte lacunae.
Eggs laid on sediments, develop for 1-8 months. Larvae look like mealworms, molt 2-8 times.
Adults are predators that easily attack small fish.
288
The diversity of the benthos _______ with rising trophic status
decreases
289
~____% of benthic fauna is carnivorous
10%
290
What insect is most commonly known for living on the epineuston (upper surface of water film)? What do they eat?
Water strider (hemiptera). Eat floating detritus
291
The ______neuston is the upper surface of the water film
| The ______neuston is the lower surface of the water film
Epineuston, hyponeuston
292
how is it that things can float on the epineuston?
Very thin layer of lipoproteins on water surface
293
List some organisms living on the HYPOneuston
Algae, protozoa, top minnows, ostracods, cladocerans, many arthropods walk upside-down on the film
294
The most famous cladoceran is _____
Daphnia
295
Briefly describe what detritus is
Dead material containing lots of nutrients. Without decomposers there would be no nutrient cycling in detritus.
296
Compare and contrast autochthonous and allochthonous detritus
Autochthonous detritus - Generated within the system (things that died in the water body)
Allochthonous detritus - Comes from outside the system (ex. watershed, runoff, or falling tree leaves)
297
What kind of organisms consume detritus?
Algae, fungi, detritovores (ex. tardigrades)
298
How are refractory particles digested?
Some are eaten several times to be digested
299
Does detritus itself provide much sustenance?
No, detritovores get most of their energy from bacteria and fungi ON detritus
300
What kinds of organisms often eat detritovores?
Copepods, gastropods
301
What are the two types of detritovores?
Shredders - Bite/chew material. These are usually insects
| Collectors- Filter/benthic feeders, eat fine particles
302
Another word for "bog" is ____
Muskeg
303
Bogs are _____trophic
Dystrophic
304
What factors influence bog production?
Wet/moist conditions, high relative humidity, primary production rate exceeding decomposition rate, sphagnum moss present
305
Where are bogs found?
Permafrost basin, springs, moist slopes
306
Describe the production of a bog
Basin fills with undecomposed organic matter. Sphagnum moss "mat" grows over water surface and can cover the lake. Mat gets colonized by plants and trees.
Sphagnum can overtake the basin.
As pH drops in the basin, specialized sphagnums called "hillocks" can form a uneven surface. Eventually they can unite to form a dome with a moat around it.
In the end, only acidophilic plants can grow on it and the surrounding water is dystrophic and full of humic acids
307
A ______ bog looks terrestrial, but still has a water pocket underneath. Moss can break and people/animals can drown
Quaking
308
When sphagnum moss covers a lake it is known as ____ of the lake
Extinction
309
In MB, bogs usually form on ______ lakes
Precambrian shield lakes and humic acid lakes
310
How does sphagnum moss stay so moist?
Has hyaline cells to hold water
311
How do bogs become so acidic?
Peat colloids set acids free as H+ ions
312
If a bog basin fills in completely it is known as a ____ bog with pH of approximately ____
Flat bog, pH of6
313
What kinds of organisms can live in a bog?
Desmids, carnivorous eutrichularia (because they have turions), cyanobacteria, few diatoms, protozoa, cladocerans, potomageton, pitcher plants, turtles!
VERY rarely there will be molluscs, oligochaetes, fish, other insects
314
The bog end product has a pH of ~___-____
3-4.5
315
Describe the low-pH water of a bog
High humic acids (turn water brown), low calcium, supersaturated with CO2.
