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Zooplankton Flashcards

1
Q

What is autotrophy?

A

Nutrition involving the synthesis of organic substances using photosynthesis (phototrophy) or chemosynthesis. Typically associated with the use of inorganic nutrients

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2
Q

What is bacterioplankton?

A

Bacterial (prokaryote) plankton acquiring nourishment via osmo(hetero)trophy, and some also via chemo (auto)trophy

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3
Q

What is consittutive mixoplankton (CMs)?

A

protist plankton with an inherent capacity for phototrophy that can also exhibit phagotrophy

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4
Q

What is Cyanobacteria?

A

Bacterioplankton (prokaryote) members of the phytoplankton

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5
Q

What is generalists non-constitutive mixoplankton (GNCMs)?

A

NCMs that acquire their capacity for phototrophy from general (i.e. non-specific) phototrophic prey

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6
Q

What is heterotrophy?

A

nutrition by obtaining nutrients from other plants or animals for energy and organic carbon

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7
Q

What is metazooplankton?

A

multicellular (non-protist) zooplankton

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8
Q

What is mixoplankton?

A

Plankton protists capable of obtaining nourishment via photo(auto)trophy and phago(hetero)trophy, as well as via osmo(hetero)trophy.

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9
Q

What is mixotrophy?

A

Nutrition involving both autotrophy and heterotrophy

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10
Q

What is non-constitutive mixoplankton (NCMs)?

A

Protist plankton that acquire the capability for phototrophy from consumption (via phagotrophy) of phototrophic prey

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11
Q

What is osmotrophy?

A

A mode of heterotrophy (i.e. osmo(hetero)trophy) involving the uptake of dissolved organic compounds

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12
Q

What is phagotrophy?

A

A mode of heterotrophy (i.e. phago(hetero)trophy) involving the engulfment of particles (often whole organisms) into a phagocytic vacuole in which digestion occurs

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13
Q

What is photoptrophy?

A

A mode of autotrophy (i.e. photo(auto)trophy) involving the fixation of CO2 using energy derived from light.

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14
Q

What is phytoplankton?

A

Plankton obtaining nourishment via photo(auto) trophy and osmo(hetero)trophy. They are incapable of phagotrophy

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15
Q

What is plankton?

A

Organisms that cannot maintain a fixed location in the water column, and are thus moved by the tides and currents

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16
Q

What is a protist?

A

single-celled eukaryote organism

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17
Q

What are protophytoplankton?

A

Protist phytoplankton

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18
Q

What are protozooplankton?

A

Protist zooplankton

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19
Q

What are specialist non-constitutive mixoplankton (SNCMs)?

A

NCMs that acquire their capacity for phototrophy from specific phototrophic prey

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20
Q

What are zooplankton?

A

Plankton obtaining nourishment via heterotrophy. They are incapable of phototrophy

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21
Q

What are planktotrophic organisms?

A

meroplankton that feed in the plankton stage

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22
Q

What are lecithotrophic organisms?

A

meroplankton that don’t feed in the plankton stage

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23
Q

What is the most common plankton class?

A

metazooplankton

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24
Q

Where is plankton found?

A

Plankton are found everywhere in the water column, from coastal to open ocean water

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25
Q

Why are zooplankton important?

A

*At some stage in their life cycle at least 95% of marine animals spend time in the water column as zooplankton.
*They provide the energetic link between primary producers, microheterotrophs and higher trophic levels, as well as facilitate the flux of organic matter to the deep sea floor.
*They are key indicators of climate change and anthropogenic inputs to the ocean.

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26
Q

What is holoplankton?

A

They spend their entire life cycle as plankton.

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27
Q

What is the species that plays a major contribution to the global biomass of mesezooplankton?

A

Copepods

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28
Q

What are the two main groups of holoplankton?

A

*Protists
*Metazoans

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29
Q

What are the main groups of protist holoplankton? (Protozooplankton)

A

*Heterotrophic flagellates
*Ciliata
*Radiolaria
*Foraminifera

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30
Q

What are the main groups of metazoan holoplankton? (Metazooplankton)

A
  • Cnidaria
    *Ctenophora
    *Mollusca
    *Chaetognatha
    *Tunicata
    *Crustacea
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31
Q

What are heterotrophic flagellates?

A

*Protozooplankton
*2-5um
*Dominate biomass and grazing of oligotrophic systems

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32
Q

What 3 methods of feeding do heterotrophic flagellates use?

A

*Palluim feeding
*tube feeding
*direct engulfment

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33
Q

What is pallium feeding?

A

Membrane is extended out, releasing enzymes and they digest prey extractracellularly and then the membrane retracts

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34
Q

What are ciliates?

A

*protozooplankton
*Can be loricate (shelled) or aloricate (without shell)
*They feed on small prey items using ciliary currents

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35
Q

What are foraminiferans?

A

*Protozooplankton
*Cell surrounded by a calcium carbonate (CaCO3) many-chambered shell pierced with pores
*Network of needle-like pseudopodia
*Omnivores, moving and capturing plankton food using network of reticulopodia (like pseudopodia)

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36
Q

What are the 4 groups of holoplankton Cnidaria?

A
  • coronatae
    *trachymedusae
    *narcomedusae
    *siphonophorae
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37
Q

What are coronatae?

A

*Order of mainly Scyphozoa
*Contains the species periphylla periphylla and atolla sp.
*Mesopleagic features include red colour, direct development and bioluminesecence
*Undertake diel vertical migration From 50-5000m
*feed on copepods and ostracods

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38
Q

What is direct development?

A

fertilised egg develops directly to medusa

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39
Q

Why do animals use bioluminescence?

A

*Feeding - to attract prey towards them
*Attracting mates - identify between males and females and to communicate to potential mates
*Self defence - startle and distract peredators and camouflage by counter illumination

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40
Q

What are the 3 taxonomic groups of siphonophores?

A
  • Physonect
    *Cystonect
    *Calycophoran
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41
Q

How do you identify the 3 taxonomic groups of Siphonophores?

A
  • Physonect - has a bit of everything
    *Cystonect - has no swimming units
    *Calycophoran - swimming units but no float
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42
Q

What are the characteristic features of ctenophores?

A
  • Globally distributed, including the deep sea
    Carnivorous
    -    Swim using fused ciliary plates - comb plates
    -*Bloom-forming - reproduce and grow quickly
    *have sticky colloblasts (no stinging cells) to catch prey
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43
Q

What are the classes of ctenophores?

A

*class Nuda (without tentacles)
*class Tentaculata (with tenticles)

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44
Q

What are the 2 groups of holoplankton molluscs?

A
  • Thecosomata (heteropods) *Gymnosomata (pteropods)
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45
Q

What are thecosomata?

A

*mollusc
* Sea butterflies - opisthobranch gastropod molluscs
*Most have thin calcified shells
*Foot has developed into 2 wing-like lobes (parapodia) used to swim
*Distributed in upper open ocean

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46
Q

What are gymnosomata?

A

*mollusc
* Sea angels (sea slugs) without shell – opisthobranch gastropod molluscs
*Foot is broad wing-like, flapping parapodia
*Gelatinous, transparent, <5cm
*Carnivores, feeding on heteropods

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47
Q

What are chaetognatha?

A

*Arrow worms
*2-12cm long
*Transparent body
* Bilaterally symmetrical
*Head, trunk and tail sections
*Lateral and caudal fins
*No circulatory or excretory system
*Hermaphrodites
*strong muscularly swimmers

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48
Q

Which factors determine the size and type of prey a
chaetognath can eat?

A

*External factors - light, prey size
*swimming speed
size of grasping spines and mouth

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49
Q

What are the 2 classes of tunicata?

A

*Thaliacea
*Appendicularia

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50
Q

What are thaliacea?

A

*Pelagic tunicates
*Transparent ‘barrels’; solitary or colonial
*Highly efficient filter feeders of phytoplankton
*Hermaphrodites with complex metagenic life cycles: asexual and sexual phases

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51
Q

What are the 3 orders of thaliacea (tunicates)?

A

*salps
*doliolids
*pyrosomes

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52
Q

What are salpida?

A

*class thaliacea, phylum tunicates
*2 distinct body forms: solitary asexual oozoid and colonial sexual blastozooid
*Stolon emerges from oozoid to produce chain of aggregated blastozooids
*Muscle bands incomplete

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53
Q

What are doliolida?

A

*class thaliacea, phylum tunicates
*Complex life cycle involving alternating solitary and colonial zooids, including ‘nurses’ produce trophozooids
*Typically smaller than salps
*Muscle bands complete ring
*Cilia inside body create feeding currents

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54
Q

What are appendicularia?

A

*class of tunicates
*Small trunk with long tail
*Secrete mucous ‘house’ every ~3 hours to filter feed on nanoplankton
*Protandrous hermaphrodite
*Direct development

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55
Q

What are the body characteristics of crustacea?

A

*segmented body divided into three
main parts - head, thorax, abdomen
*two pairs of antennae
*hard chitin exoskeleton

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56
Q

What are ostracoda?

A

*class of crustaceans
*Herbivorous filter feeders
*Carapace bivalved with adductor muscle; all body can be retracted in
*Antennae and anntenules large for swimming

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57
Q

What is parthenogenetic reproduction?

A

A type of asexual reproduction which produces gametes but they are not fertilised

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58
Q

What are amphipoda?

A

*Order of crusaceans
*Open water, surface to deep ocean, particular abundance in twilight zone
*Generally have 2 pairs of compound eyes
*Carnivorous, especially on gelatinous zooplankton

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59
Q

What are mysidacea?

A

*Order of crustaceans
*Moveable eyes on peduncle
*Omnivorous, cosmopolitan feeders
*thoracic limbs for swimming

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60
Q

What are euphausiacea?

A

*Known as krill
*Order of crustaceans
*Mostly herbivorous filter feeders, but also omnivorous
*Significant member of ecosystems, particularly at high latitudes

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61
Q

Why are krill considered to be ‘significant’ members of
ecosystems in high latitudes?

A

*Always lose energy in trophic levels, they allow for a shorter food chain as they eat diatoms, and then large organisms such as whales directly eat them so reduces trophic levels

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62
Q

what are copepoda?

A

*Class of crustacenas
*Dominate most zooplankton samples, often 60-90% of abundance
*10 orders: Calanoida, Cyclopoida and Harpacticoida most abundant and important
*Herbivorous, omnivorous and carnivorous species

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63
Q

What is the anatomy of copepods?

A

*No carapace, but clear divisions between head, thorax and abdomen
*Cephalosome and metasome together are called the prosome
*Compound eye absent

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64
Q

What is the life cycle of copepods?

A

*Eggs spawned or brooded in egg sac
*Egg hatches into a nauplius
*Then 6 naupliar stages and 6 copepodite stages
*Then C VI adult stage with seperate sexes

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65
Q

What are the 3 orders of copeopods?

A

*Calanoid
*Cyclopoid
*Harpacicoid

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66
Q

What are calanoids?

A

*Long 1st antennae (length of body)
*Single egg sac
*Joint is between 5th + 6th segment

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67
Q

What are cyclopoids?

A

*Shorter 1st antennae
*Two egg sacs
*Joint is between 4th + 5th segment

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68
Q

What are harpacticoids?

A

*Very short 1st antennae
*Wide abdomen - looks
worm-like
*No visual egg sack

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69
Q

What makes up meroplankton?

A

*Larvae of most benthic species (polychaetes, molluscs, crustaceans, echinoderms, bryozoans)
*Eggs and larvae of nekton (most fish)
*Cnidarian eggs and planula larvae
*Cnidarian medusae

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70
Q

What is the lifecycle of barnacles?

A

*larvae is released
*6 Nauplii stages
*Then there is the cyprid stage where there is settlement to the seabed and metamorphosis where they turn into adults

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71
Q

What is the nauplii stage?

A

The feeding stage

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72
Q

What is the life cycle off true jellyfish?

A

*sexual reproduction to produce planula
*asexual reproduction produces the ephyra from strobila

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73
Q

What are the different meroplankton nutritional classes?

A

*Lecithotrophs
*Planktotrophs

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74
Q

What are lecithootrophic organisms in detail?

A

*Non-feeding larvae
*They possess a yolk reserve
*Remain in plankton for only a few days
*e.g. cnidarian planulae, barnacle cyprids

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75
Q

What are planktotrophioc organisms in detail?

A

*Feeding larvae in the water column

*Remain in plankton for several weeks as not reliant on a limited internal source
*e.g. crustacean zoea, bivalve veligers, echinoid plutei

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76
Q

What are ciliates larvae?

A

They have hair

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77
Q

What are the 2 types of ciliates larvae?

A

*Downstream
*Upstream

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78
Q

What are downstream larvae?

A

*mouth located behind the principal ciliary band
*Locomotory and feeding currents coincide, so larvae can feed as they swim.
*e.g. trochophore larva

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79
Q

What are upstream larvae?

A
  • Mouth is infront of the main locomotory ciliary bands,
  • Water currents generated during locomotion cannot then be used directly for food capture.
    *Indirect means of concentrating food. *e.g. pluteus larva
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80
Q

What are the 3 classifications of planktonic larvae?

A

*Teleplanic
*Actaeplanic
*Anchiplanic

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81
Q

What are teleplanic larvae?

A

*Planktonic period >2 months, possibly 1 year
*Probably polar region as things develop less fast
*e.g.lobster phylosoma larvae

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82
Q

What are actaeplanic larvae?

A

*Coastal plankton 1 week to <2 months
*70% of temperate sublittoral benthic species
*Feeding (as food reserve wouldn’t last that long)

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83
Q

What are anchiplanic larvae?

A
  • Planktonic for few hours to few days
    *e.g. many sponge and bryozoan larvae
    *Can be non-feeding
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84
Q

What are the rewards of having planktonic larvae?

A

*Increased gene flow
*Dispersal of population (preventing overcrowding)
*Reduced predation from adults
*Reduced competition for space

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85
Q

What are the risks of having planktonic larvae?

A
  • High mortality from:
    *Surviving critical release and return phases
    *Predation in the water column (other zooplankton and fish)
    *Transport away from suitable site
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86
Q

What factors influence the benthic recruitment of planktonic larvae?

A
  • time
    *space
    *abundance
    *larval pool
    *physical transport processes
    *biological interactions, disturbances, physiological stresses, flow rates
    *micro-hydrodynamic, behavioural, and substrate availability processes
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87
Q

What is the role of planktonic larevae in island populations?

A
  • allows spread of species between hydrothermal vents 100s of kilometres away
    *carried by bottoms currents, ridge-controlled currents, and ocean currents
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88
Q

Are there mor meroplankton or heleoplankton cnidarians?

A

meroplankton

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89
Q

What are the characteristics of cnidarian larvae?

A

*Larvae is planula
*Planula forms either forms fertilised egg of medusa or polyp
*Medusa planulae are unable to feed, polyp (Anthozoa) can feed

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90
Q

What are Scyphozoa?

A

*Class of cnidarians
* Female gonads you can see the individual eggs
*Male gonads are more opaque
*e.g. Aurelia aurita

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91
Q

What is the life cycle of a Scyphozoa?

A
  • Fertilised eggs develop in the brood sac
    *It is then releasd to water column
    *It then settles onto seabed and we have an asuxuslly reproducing polyp
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92
Q

What is special about class Hydrozoa polyps?

A

They have polys for feeding and different ones for reproducing

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93
Q

What are the characteristics of polychaete larvae?

A

*Larvae is called trochophore
*Downstream larvae

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94
Q

What is the life cycle of polychaete larvae

A

Trochophore - metatrochophore larvae - pre-settlement post -larval stage

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95
Q

What are the characteristics of mollusc larvae?

A

*Typically hatch as trochophore then develop into veliger
*Veliger has adult organs and enlarged ciliated lobe , the velum for swimming, feeding, gas exchange
* Late veliger stage prior to settlement is a pediveliger, when velum is resorbed

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96
Q

What is the life cycle of molluscs?

A

egg and sperm released to water column
fertilisation and division
trochophore
veliger
pediveliger
juvenile clam
adult

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97
Q

What are the characteristics of lophophorate larvae?

A

*bryozoan minor-phyla
*Larvae called cyphonaute
*Triangular shaped, bivalves and distinct bilateral symmetry

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98
Q

What are the characteristics of echinoderm larvae?

A

*each taxonomic group has its own larvae name
* 2 forms - pluteus and auricularia
*upstream larvae

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99
Q

What is the larvae name of Echinoidea?

A

Echinopluteus (sea urchins)

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100
Q

What is the larvae name of Holothuroidea?

A

Auricularia and doliolaroia (sea cucumbers)

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101
Q

What is the larvae name ophiuroidea?

A

ophiopluteus and vitellaria (brittle star)

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102
Q

What are the larvae name asteroidea?

A

Auricularia, bipinnaria and brachiolaria (sea star)

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103
Q

What are the characteristics of crustacean nauplius larvae

A

*1st larval stage in many crustaceans
*middle naupliar eye

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104
Q

What is the difference between Copepoda and Cirripedia (barnacle) nauplius?

A

*copepoda has no spines
*Cirripedia has 2 Rostand and 1 caudal spine

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105
Q

What is the life cycle and characteristics of Decapoda?

A

*order of Crustacea
* nauplius - zoea - megalopa larval stages - adult

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106
Q

Why do porcelain crab zoea have such long spines?

A
  • Predator deterrence by increasing size relative to predator gape
    *Increases surface area to aid flotation
    *Helps the individual to swim laterally
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107
Q

What are the stages of fish larval development?

A
  • newly hatched larvae feed on yolk supply
    *larvae and late-larvae feed on plankton
    *pre-flexion - mouth starts to open, eyes become pigmented
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108
Q

What physical processes impact spatial distribution patterns and at what scale?

A

1,000km+ - gyres, water mass boundaries
100 km - eddies, tidal fronts, seasonal upwelling
10 km - turbulence
0.01 km - Langmuir circulation, wave action

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109
Q

How does the temperature of the ocean affect zooplankton disribution?

A

Zooplankton are poikilotherms so their body temp is effected by their surroundings

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110
Q

How does salinity impact zooplankton distribution?

A

Zooplankton are mainly osmoconformers so are impacted by surrounding water salinity

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111
Q

What are marine biogeochemical provinces (BGCPs)?

A

*Global classification of regions with similar physicochemical & biological characteristics
*Longhurst (1995) produced subjective system of 4 Biomes split into 56 Provinces
*Updated dynamic versions modelled using depth, Chl a, SST, SSS data

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112
Q

How do latitudinal trends impact number of species?

A

*High latitudes (poles) = small number of spp dominate assemblage
*Low latitudes (tropics) = large number of spp in assemblage

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113
Q

How do latitudinal trends impact individual size?

A

Tendency for zooplankters in low latitudes to have smaller body size than those at higher latitudes

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114
Q

How do latitudinal trends impact overall biomass?

A

*High latitudes = high population / community biomass
*Low latitudes = low overall biomass

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115
Q

What is latitudinal diversity gradient (LDG) explained by?

A

by species-energy hypothesis - i.e. role of energy in regulating diversity

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116
Q

What are the 2 best predictors of LDG?

A

*‘more individuals’ hypothesis
*‘evolutionary speed’ hypothesis

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117
Q

What is the more individuals hypothesis?

A

higher primary production can support more individuals

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118
Q

What is the evolutionary speed hypothesis?

A

In warmer conditions, metabolic rate is higher so reproductive rate is higher causing a higher probability for mutations, increasing diversity

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119
Q

Why is there a dip in salinity at the euqator?

A

The (intertropical convergence zone where rain exceeds evaporation so salinity drops

120
Q

Why is there less data colleced -45 degrees?

A

The southern ocean being less surveyed (due to more oceans and just less scientific interest)

121
Q

What is the biggest driver of zooplankton spatial diversity?

A

*Sea surface temp (SST)
*Oceans warming away from equator is going to cause greater diversity in temperate regions

122
Q

What can organisms be larger in colder waters?

A

t*Metabolic rate is higher at elevated temperatures (IR = R > G)​
*IR=ingested ration​
*R=respiration ​
G=Growth
​Buoyancy versus relative density of seawater (increase lipid and SA)​
*Less phytoplankton biomass in oligotrophic warm waters​

123
Q

What are biomass trends influenced by?

A

Body size and productivity​

124
Q

How does latitude influence diet?

A

*Diet changes with latitude due to food web structure
*Longer food chain in oligotrophic (warm) waters so more carnivores​
*Less carnivores in low latitudes due to less species before them, so eat more phytoplankton

125
Q

How do warm core eddies (WCE) impact zooplankton?

A

less stratification and nitrate at lower levels so less productive and smaller species​

126
Q

How do cold core eddies (CCE) impact zooplankton?

A

pumps lost of nitrate to surface, causing larger species due to increased productivity​

127
Q

What is a patchy distribution?

A

Small scale, short term patterns, which are classified by their primary biotic and abiotic factors.

128
Q

What are the 5 types of patchiness?

A

*Vectorial – regular and vertical​
*Stochastic vectorial – non-regular and horizontal​
*Social – swarming behaviour, predator avoidance​
*Co-active – trophic interactions​
*Reproductive and Ontogenetic – life histories

129
Q

How does the oxycline influence patchiness?

A

*Vectorial patchiness
*Most species want to live near oxycline (805ml/L)​
*Species with low-oxygen tolerance will have higher food availability as less species can survive there​

130
Q

How doe langmuir circulation influence patchiness?

A

*Stochastic patchiness
Light steady wind blowing across surface creating alternate eddies / vortexes either side​
*Parallel vortices create regions of up- & down-welling that concentrate particles

131
Q

How do trophic interactions influence patchiness?

A

*Co-active patchiness
*Trophic interactions lead to horizontal and vertical patchiness​
*Phytoplankton distribution initially related to nutrients and water column stratification (bottom-up control)​
*Zooplankton graze down phytoplankton (top down control)​
*Switch between ‘inverse’ and ‘coincidence’ patterns
​

132
Q

What are the primary driving factors of vertical distribution?

A

Temperature and food availability

133
Q

How does latitude and depth impact physio-chemical conditions

A

High latitudes, no change in temp with depth in comparison to a major change in the tropics with the thermocline​

134
Q

Why is chlorophyll maximum not at the surface?

A

Nutrient limitation in upper water column, so chlorophyll maximum is at about 100m depth as altough in upper ocean light levels are good, nutrient levels are poor​

135
Q

How is abundance impacted by depth?

A

80+% of abundance is in the food-rich upper 200m (epipelagic)​

136
Q

How is no.species impacted by depth?

A

Total species no. greatest in epipelagic (0-200m) to mesopelagic (500-1000m) layers ​

137
Q

How is species diversity impacted by depth?

A

With depth proportion of carnivores increases and herbivores decreases as there is less phytoplankt

138
Q

How does depth impact copepod diversity?

A

Copepods dominate zooplankton through out the water column no matter the depth, however the copepod species dominating does change with depth

139
Q

How might tides and salinity affect zooplankton ​distributions in estuaries?

A

*Salinity tolerance can be wide (euryhaline) or narrow (stenohaline)​
*Utilise behaviour (e.g. D-TVM) to maintain position within estuary
*During daytime at depth to avoid predation
*At night with an ebb tide euryhaline species stay at depth to not be moved out to sea however stenohaline ones migrate up – Opposite pattern on a night flood tide​

140
Q

What impacts the depth movement during DVM?

A

*life stage, season, latitude, water conditions​
*Bigger organisms tend to move more distance

141
Q

What are the major temporal trends of distribution?

A

Long-term climate related trends

142
Q

How does jellyfish abundance impact zooplankton?

A

More jellies = Less zooplankton​

143
Q

How doe NAO impact jellyfish?

A

High NAOI = less jellyfish

144
Q

What percentage of zooplankton are copepods?

145
Q

What does sampling (experimental) design depend on?

A

The purpose of the study - what is the question

146
Q

Why are sampling strategies needed?

A

no one procedure or sampling device will monitor all the community to the same degree

147
Q

What is sampling strategy?

A

The question being asked will dictate the choice of sampling gear and how/when/where it is deployed

148
Q

What are 3 examples of sampling programmes?

A

*Western channel observatory
*CMarZ (census of marine zooplankton)
*Atlantic zone monitoring programme

149
Q

What is the purpose of the Atlantic Meridional transect (AMT) cruise?

A

*AMT 8 - Compare productivity in upwellings and highly productive systems
*AMT 15 - Compare upwelling waters off N Africa with less productive waters of South Atlantic gyre
*AMT 16 - Compare north and south subtropical gyres along 25oW meridian

150
Q

what are 2 types of water bottle samplers?

A

Niskin, go-flow

151
Q

What are the positives of water bottle samplers?

A

*Get fixed volume from known depth
*Useful for microzooplankton spectrum

152
Q

What are the negatives of water bottle samplers?

A

*Not representative of larger sizes of zooplankton
*Very susceptible to patchiness errors

153
Q

What are the negatives of plankton pumps?

A

*Good representation, but active swimmers can avoid low-suction pumps
*Larger gelatinous species may get damaged

154
Q

What are the benefits of in-situ plankton pumps?

A

*Autonomous time-series sampling designs in shallow and deep sea
*Used in hydrothermal vent larval dispersal studies

155
Q

What are the negatives of in-situ plankton pumps?

A

Good for short-term time series studies (battery limited)

156
Q

What collection method is most commonly used?

A

Conventional net hauls

157
Q

What is filtration efficiency (FE) in nets?

A

Filtration efficiency (FE) measures the volume of water passing through the net compared to the theoretical volume passing through the net mouth ring in the absence of the net - i.e. resistance to water flow of the mesh itself

158
Q

What factors affect the FE of nets?

A

*Filtering area (open area ratio)
*Mesh size
*Towing speed

159
Q

What is the open area ratio (OAR) of nets?

A

*Ratio of the total ‘open area’ of net (the mesh openings through which water is filtered) to area of the net mouth
*Ratio = (axB/A)
*a=total area of the net
*B=mesh porosity
*A=mouth area of net

160
Q

What OAR values of nets mean?

A

*If the OAR is <3 efficiency progressively declines to 30%
*OAR > 3 ~ 85% efficiency
*OAR > 5 ~ 95% efficiency

161
Q

Why is mesh size / porosity of nets important?

A

*Determines the size spectrum of sample
*Fine mesh clogs more easily by particulate material

162
Q

Why is tow speed of nets important?

A

If net speed is too high it causes water to form static body in the net. Larger mesh size = faster speed

163
Q

What is being done to increase tow speed?

A

Mouth reduction cone, reduces turbulence at mouth

164
Q

What are bongo nets?

A

*Each net has different mesh sizes
*Designed for vertical or oblique hauls
*Can have a closing mechanism

165
Q

What are Nansen closing nets?

A

Messenger sent down
cable to trigger the
closing mechanism

166
Q

What are MOCNESS nets?

A

Multiple opening closing net environment systems sampler
*Used to assess vertical distribution in
the open ocean – to depths of 5000m

167
Q

What are the positives of nets?

A

*Very efficient at sampling water column if used optimally
*Can be used with ancillary sensors
*Discrete sample that can be identified and quantified

168
Q

What are the negatives of nets?

A

*Can only sample size spectrum determined by mesh size
*Can only sample discrete sector of water column
*Long-term sampling procedure - time required to identify community structure & abundance

169
Q

What are the basic principles of acoustic sampling?

A

*Acoustic signal (sound wave) sent out by transducer
*On encountering an object denser than surrounding water, sound energy reflected / scattered back toward source - a receiver on echo sounder
*Nature of return signal informs on depth, ‘size’ and ‘type’ of objects
*Calibrated using object of known acoustic properties (target strength)

170
Q

What are the technical issues with acoustics?

A

*Target strength (TS) depends on species
*Behaviour of organism (e.g. swimming) also affects signal return
*Echo from organisms living near bottom ‘lost’ in the large seabed echo

171
Q

How can a specific species be identified by acoustics?

A

*Measure TS of individual spp.
*Ground-truth with net hauls
*Use different frequencies

172
Q

What applications do acoustics have?

A

*Monitoring of large-scale distribution and biomass
*Observing behaviour – e.g. diel vertical migration
*Species interactions – e.g. whale / krill feeding

173
Q

What are different optical methods?

A

*Video Plankton Recorder
*Optical plankton counters
*Flow cytometers
*Image analysis of samples

174
Q

What are the pros and cons of a video plankton recorder?

A

*Pros: High-resolution; rapid; semi-automatic; concurrent environmental data
*Cons: Identification to spp. level; under-represent rare taxa (<50 ind. m-3)

175
Q

What are optical plankton counters?

A

*Detects, sizes, and counts individual particles by measuring attenuance of a light beam intercepted by transiting particles.
*Generates silhouette image – can identify larger spp only, such as krill

176
Q

What are flow cytomemeters?

A

Automated ID and enumeration
E.g.FLOWCAM

177
Q

What are image alnalysis of samplers?

A

Zooplankton samples digitised by the ZooScan, processed by ZooProcess
and PkID to detect, enumerate, measure and classify the digitized objects

178
Q

What are the positives if optical methods?

A

*Efficient strategy - good correspondence between net haul samples and optical definition of community assemblage
*Relatively wide size-spectrum identified
*Can use ancillary sensors
*Short-term sampling procedure - details of community assemblage available immediately and sampling programme can be modified

179
Q

What are the negatives of optical methods?

A

*Size definition of target organism significantly influenced by orientation through light beam
*Can only sample discrete sector of water column
*No discrete sample for further analysis unless attached to a multi-sampler

180
Q

What is ash-free dry weight analysis of biomass?

A

*After dry weighing, place in muffle furnace at ~5500C to constant weight (~ 24 hr). This is the ash weight (AW).
*AFDW = DW - AW
*> 5700C results in organics being burnt off and sample is destroyed

181
Q

How are immediate samples preserved?

A

*4-8% seawater Formalin
*Or 70% ethanol

182
Q

How are samples preserved for long term preservation?

A

*formalin/distilled water with CaCO3 to maintain pH at 6 - 7.5 *ethanol/glacial acetic acid in case sample dries out
*store at 5 - 200C in dark *ratio of zooplankton : medium ~1: 9

183
Q

What are the negatives of volumetric analysis of biomass?

A

prone to error associated with interstitial spaces between the organisms and just give rapid estimate of biomass

184
Q

What is wet weigh gravimetric analysis of biomass?

A

*Remove excess water from sample by blotting or filtering, and weigh
*Limited value as measure varies with procedure to remove excess water and type of animal - e.g. water content of crustacean (70%) vs gelatinous (95%) plankton

185
Q

What id dry weight analysis of biomass?

A

*Filter sample, wash in distilled water to remove ‘salts’
*Oven dry at 55 - 600C to constant weight (~24 hr), then weigh
*>70C results in volatilisation of lipids, loss of cellular water and denaturing of proteins

186
Q

What is the elemental approach to analysis of biomass?

A

*All organic compounds contain carbon in similar proportions
*Nitrogen mainly in proteins; Phosphorous mainly in lipids
*C:N:P ratios give hints on physiological condition

187
Q

What are the big questions in plankton research?

A

*Ocean productivity (eutrophication, stratification)
*Redistribution of species related to warming
*Introduced and invasive species
*Ocean acidification
*Match-mismatch and fisheries
*Changes to biodiversity and ecosystem function
*Deoxygenation (spreading OMZs)

188
Q

How do we answer the questions in plankton research?

A

*Identify trends in the field
*Hypothesis-testing experiments

189
Q

How do we identify trends in the field?

A

*Long-term datasets of distribution and abundance
*Identify potential abiotic and biotic drivers of trends

190
Q

What are the hypothesis-testing experiments?

A

Test causation using controlled experiments

191
Q

Why do zooplankton cover a lot of the foodweb?

A

Zooplankton occupy niches spanning a big area of the trophic food web, from phytoplankton up to fish/seabirds as they are herbivores, carnivores and cannibals

192
Q

How are suspended particles collected during suspension feeding?

A

*Creation of a feeding current
*Trapping of particles on a filter or membrane
*Removal of particles from filtering apparatus to mouth

193
Q

How are suspend particles filtered during suspension feeding?

A

*Mucous mesh (gelatinous plankton)
*Setae (crustaceans)
*Cilia (echinoderms)

194
Q

What are the different types of mucous filtration systems in mucous mesh?

A

*muscular pumping e.g. salp
*muco-ciliary e.g. doloilid, pyrosome
*sedimentation e.g. thecosomes

195
Q

How do thecosome pteropods use sedimentation feeding?

A

*Parapodia wings produce mucous web in <5 sec
*Hang motionless and trap phytoplankton and small motile prey
*Animal consumes entire mucous structure and attached particles
- then produces another web
*This is energetically efficient

196
Q

How do Appendicularians filter feed?

A

Beats its tail, water flows in across inlet filters (keeping out big stuff), the food then passes along food concentrating filter and the rest of water leaves through exit spout

197
Q

How do salps filter feed?

A

*Salps rhythmically pump water into oral siphon, through pharyngeal chamber, and out atrial siphon
*Pumping action generated by circular muscle bands creates jet propulsion for locomotion
*Food particles entering pharyngeal chamber strained through mucous mesh

198
Q

what is the advantage of salps capturing tiny tiny particles?

A

means salps do very well in oligotrophic zones where the primary producers are tiny tiny like cyanobacteria

199
Q

How might mucous mesh feeders feeding rates vary with size?

A

*Mucous mesh feeders feed on particles very small relative to their size
*Non-mucous grazers feed in bigger things, there clearance rate is less efficient

200
Q

what are setae?

A

Filtering parts around the mouth
- found in crustacea / copepods

201
Q

How does copepod anatomy produce feeding currents?

A

Feeding currents created by 1st antennae, mouth appendages and periopods during swimming

202
Q

What sensors do copepods have to detect prey by detecing pressure changes?

A

*hemosensory sensillar
*mechanosensory setae
*sometimes bimodal sensillae

203
Q

What are mechanoreceptors in copepods?

A

*Detection by pressure receptors in the 1st antennae and body that identify disturbance in particle flow field
*Particles detected in sensory layer surrounding viscous core re-routed from original pathway to capture area by re-orientation of the copepod.

204
Q

What are chemoreceptors in copepods?

A

Can detect quality of food (e.g.chlorophyll per cell, or if its poisonous) in the
solute cloud surrounding individual algal cells

205
Q

Which characteristics of prey items consumed by copepods
might influence whether they are detected or not?

A

*Presence of toxins
*Presence of other organic compounds
*C:N and Chl a content per cell
*Swimming motion
*Swimming speed
*Distance from prey

206
Q

Why are there multiple copeopd mouthpart shapes?

A

Different copepods and at different life stages have different diets, which causes variations in mouth shapes/morphology

207
Q

Wha determines copepod setae size?

A

The setae depicts the size of particles collected

208
Q

How do mixed diets impact copepods?

A

Growth rate is higher when fed mixed diets

209
Q

Which zooplankton taxa have cilia?

A

*Molluscs
*Polycheates
*echinoderms

210
Q

What are different predation strategies?

A

*Cruise feeding – for slow-moving prey
*Ambush (passive and active) feeding – for active prey

211
Q

What are different methods of detection?

A

*Mechanical
*Tactile
*Chemical
*Visual

212
Q

What are different capture methods?

A

*Entangling – with tentacles
*Raptorial – with mouth

213
Q

What are the preffered diet of copepods?

A

Ciliates and dinoflagellates when diverse foods offered as they have higher nutritional quality (rich in polyunsaturated fatty acids)

214
Q

Where in the world’s oceans are carnivorous copepods
most prevalent, and why?

A

Tropical and subtropical regions are characterised by low nutrients (oligotrophic) and so the primary grazers are protozooplankton, with copepods being higher up the food chain as omnivores and carnivores feeding on protozooplankton

215
Q

How do foraging startegies vary with feeding modes?

A

Diet changes how an organism will swim and scavenge for food. Carnivores are more moving where as herbivores are more stagnant

216
Q

What are different types of foraging movements?

A

*Stationary, suspension-feeding
herbivore or omnivore
*Cruise-and-sink switching
omnivore
*Cruising, raptorial predatory
carnivore

217
Q

How does cruise and sink foraging work?

A

shows it searching a bigger area as it is searching for motile organisms

218
Q

What kind of predators are chaetognaths?

A

Raptorial ambush predators that detct prey with mechanoreceptors

219
Q

What kind of predator are fish?

A

Raptorial visual predators that rely on light and swim speed to search effectively

220
Q

What adaptations do chaetognaths have as a predator?

A

*Large head; grasping spines; anterior and posterior teeth cusped at tips
*Transparent to avoid visual detection
*Strong swimmers; long muscular trunk for strong darting mode
*Regular and short bursts of directional swimming followed by passive sinking

221
Q

What is the chetognath diet?

A

*50-90% copepod
*Small amounts of cannibalism

222
Q

What does fish larvae prey capture ability depend on?

A

*Jaw gape
*Age (size)
*Hydrodynamics

223
Q

How do ambush entangling predators catch prey?

A

*Stationary in water and wait for fast swimmers (copepods) to contact tentacles
*To increase encounter probability, have many & long tentacles to increase SA

224
Q

What are some cruising entangling predators?

A

Scyphozoans such as aurilia aurita

225
Q

What are the two types of medusa jellyfish bell shapes?

A

prolate (tall and narrow) and oblate (large bell diameter)

226
Q

How do prolate medusa forage?

A

*Jet propulsion
*Ambush foraging by drifting and waiting for motile prey

227
Q

How do oblate medusa forage?

A

*Rowing propulsion
*Cruising predators whcih swim more rapidly than their prey

228
Q

Why doe medusae occupy a wide range of trophic roles?

A

Broad morphological and functional diversity

229
Q

How do medusae capture prey?

A

*They have cnidocytes which discharge toxins.
*Once inside bell, medusae use tentacles, mucous & cilia to transfer prey to mouth

230
Q

What are different cnidocyst types?

A

*Nematocyst
*Spirocyst
*Ptychocyst

231
Q

Why are gelatinous zooplankton effective predators?

A

*Large body size - low carbon / high water
*Type I feeding functional response
*Cosmopolitan diet (in most taxa)

232
Q

What are the only raptorial ctenophore species?

A

Beroe spp.
They exclusively eat other ctenophores

233
Q

How do ctenophores capture prey?

A

Fishing tentacles have colloblasts which are sticky and then the tentacles rapidly contract

234
Q

how has the understanding of the microbial food web changed?

A

Recent evidence shows that the microbial food web is a fundamental and almost permanent feature of oligotrophic AND eutrophic coastal upwelling areas

235
Q

How do zooplankton contribute to the biological carbon pump (BCP)?

A

*Sloppy feeding
*Excretion
*Egestion
*Mucous production
*Migration
*Death

236
Q

How can we quantify carbon or energy flowing through food webs? What methods are there?

A

*Bioenergetics
*Fatty acid stable isotope analysis
*Measuring primary and secondary production
*Ecosystem-based modelling

237
Q

What are the bioenergetic equations for net growth and production?

A

net growth or productivity (G) = Ingestion (R) - Faeces (E) - Excretion (U) - Respiration (T)
or
Net growth or production (G) = assimilated food (AR) - Respiration (T)

238
Q

What are the bioenergetic growth yield equations?

A

Growth yield = growth / growth + respitation
Or
Growth yield = growth / food intake

239
Q

What is the typical growth field rate?

240
Q

What does growth yield depend on?

A

*Type of organism
*Level of complexity
*Swimming ability
*Stage of life

241
Q

What is the bioenergetic trophic yield equation?

A

trophic yield (Yt) = production (growth) at trophic level t+1 / production (growth) at trophic level t

242
Q

What is the equation for total efficiency?

A

(Trophic yield)n
*n = no. trophic levels

243
Q

What % of energy within a trophic level is available for the next?

244
Q

What drives trophic structure?

A

The amount of primary production at the base of the pyramid

245
Q

How do nutrients impact food web size?

A

*low nutrients have longer food webs
*nutrient-rich have short food webs as large phytoplankton are more likely to be eaten by large zooplankton

246
Q

How many trophic levels do different ecosystems have?

A

oligotrophic -> 6
moderate -> 4
nutrient rich -> 3

247
Q

How do zooplankton impact fisheries?

A

higher amount of food = better cod recruitment

248
Q

What is the temporal match-mismatch hypothesis?

A

*larvae and food must occur at the same time for the recruitment to be successful
*when colder → the timing of the two peaks is shorter, so more of a match
*when warmer → timing of the peaks is longer

249
Q

What is the spatial mismatch hypothesis?

A

*warm climate conditions - reduced spatial overlap results in lower overwinter survival and recruitment success of juveniles fish to age-1
*colder climate conditions - increased spatial overlap results in higher growth, overwinter survival and recruitment success of juvenile to age-1

250
Q

What is special about the eastern-boundary upwelling system (EBUS)?

A

It covers <1% of the ocean surface but provide up to 20% of the world’s capture fisheries due to their high levels of production fueled by nutrient-rich, cold deep water.

251
Q

How does oceanography impact EBUS?

A

*Wind blowing pushes warm surface water away from the coast
*Displaced water replaced by deep, cold, nutrient-rich water rising to surface
*Nutrient-rich water fertilizes surface waters → high primary production

252
Q

What kind of food chain is EBUS?

A

Short efficient food chains so lots of fish

253
Q

What effects do El Niño
and La Niña in the Pacific have on the oceanographic conditions of upwelling systems?

A

*Normal - Low pressure W. Pacific and high pressure E. Pacific cause trade winds to move surface water to west → upwelling and shallow thermocline.
*El Niño - High pressure system weakens and trade winds reduce. Warm surface water flows east → deepens the thermocline and prevents upwelling.
*La Niña - Unusually strong trade winds bringing deep cold water to the surface resulting in colder water than usual

254
Q

what species is most important for energy transfer pathways in the california current system?

A

euphausiids -> lots of each bc lots of things eat krill

255
Q

what 4 zones is the Benguela Upwelling system split into?

A

*Angola Front
*Northern Benguela
*Southern Benguela
*Agulhas Bank

256
Q

what caused the collapse of the fisheries in northern benguela?

A

*Overfishing of small pelagic
fish triggered chain of events
resulting in rise of jellyfish
and the bearded goby.
*Energy flow is diverted away
from the higher-trophic-level
(HTL) production towards
the benthos and detritus.

257
Q

What are nutrient concentrations in oligotrophic areas?

A

*Episodic mixing events increase NO3 input, and annual production
*Deep waters: blooms in winter due to mixing and NO3 inputs
*Upper waters: blooms in late summer based on N-fixing organisms & eddies

258
Q

what kind of phytoplankton are seen in oligotrophic regions?

A

picoplankton - 60-90% of chl a biomass and 60-80% of C -fixation

259
Q

What zooplankton are present in oligotropic regions?

A

*microheterotrophs
*cyclopoids and carnivorous copepods
*gelatinous zooplankton -> ctenophores, siphonophores, chaetognaths (predators), salps and doliolids (grazers)

260
Q

what food webs are present in oligrotrophic systems and when?

A

*Both pathways co-exist
*nutrient- limitation = microbial loop dominates
*Nutrient (NO3) inputs = classical food web briefly dominates new

261
Q

What is export production?

A

the amount of organic matter produced by primary production that is not recycled (remineralized) before it sinks into the aphotic zone.

262
Q

What is in export production?

A

faecal pellets, exudates, cells from messy feeding, mucous. POC may aggregate
to form ‘marine snow’.

263
Q

What has less export production, the microbial or classical foodhchain/loop?

A

Microbial loop as lots of recycling occours

264
Q

what 3 key biological parameters determine the survival of larval cod?

A

*mean size of prey
*seasonal timing
*abundance

265
Q

What is the plankton index?

A

reflects quality and quantity of plankton food available to larval cod

266
Q

What are the mai variables in 1st plankton index (PC)

A

*Mean abundance of Calanus finmarchicus
*Mean size of calanoid copepod
*Calanus helgolandicus
*Calanoid copepod biomass
*Pseudo-calanus spp.

267
Q

why was Mnemiopsis a good invader in the black sea?

A

*Flexible physiology and lobate – easily pumped & transportable
*Self-fertilising simultaneous hermaphrodite
*High fecundity – 23,000 eggs in 10 days
*Resists starvation by temporary de-growth (shrinking)
*Cosmopolitan diet
*Black Sea a sensitive ecosystem (eutrophication) susceptible to invasion

268
Q

how were Mnemiopsis brought under control?

A

introduction of Beroe sp. which only grazed on them

269
Q

what ecological change has happened in Limfjorden since the 1960s?

A

increased eutrophication -> oxygen depletion near bottom waters -> 40% anoxic

270
Q

What are the physical effectts of global warming on oceans?

A

*Warming, including marine heatwaves
*Deoxygenation
*Melting ice caps
*Sea-level rise
*Increased storminess and extreme weather
*Ocean acidification

271
Q

which parts of the ocean are warming faster?

A

above north America in the arctic and in the area around the Antarctic peninsula

272
Q

What trends in temperature in the Southern Ocean?

A

Air temperatures rising more rapidly than anywhere else in the world, > 5˚C in winter since 1955

273
Q

how does nutrients and oxygen differ in the Atlantic and the Pacific?

A

Atlantic is more oxygenated but has lower nutrients (NO3) than the Pacific due to the age of the water and how it is used by the primary producers.

274
Q

What are the impacts of eutrophication?

A

*hypoxia / anoxia
*switch to gelatinous zooplankton with low requirements for oxygen -> *impacts fisheries

275
Q

how does increased CO2 affect the oceans?

A

*increased acidification -> lower pH -> less CO3 2-
*CO3 2- is required for shell growth -> shells start to dissolve, become less solid

276
Q

Why are zooplankton good indicators of climate change?

A

*Poikilothermic - physiological processes sensitive to temperature
*Short-lived - mostly <1 year (often 2-4 months)
*Not commercially exploited (except krill, some jellyfish)
*Planktonic - most for their whole life
*Most marine animals have planktonic life-stage

277
Q

What is the thermal window?

A

The upper and lower temperature ectotherms thrive for different physiological processes

278
Q

how does the amplitude of the thermal window relate to animal complexity?

A

inversely related to complexity of the animal and physiological process

279
Q

What is the thermal window for short term tolerance vs long term maintenance?

A

short term tolerance has a greater thermal window than the long term maintenance

280
Q

What is organism fitness governed by?

A

Eg = Ei -Er
growth = input - respiration

281
Q

What is the difference between the thermal window in stenotherms and eurytherms?

A

Stenothermal (narrow) and Eurythermal (wide) acclimatized windows

282
Q

how does warming affect TWs and species interactions?

A

warming leads to mismatch between seasonal cues (temperature) and constant cues (light)

283
Q

how might rising sea temperatures affect zooplankton?

A

*Species distributions (biogeographic range shifts)
*Biodiversity
*Body size
*Phenology
*Abundance

284
Q

How can temperature changes be seen from a continuous plankton recorder?

A

Changes in abundance of warm water and cold water species

285
Q

What are the negatives of warmer water species?

A

They are smaller, less biomass, lower oil content and so less nutritious

286
Q

What calanus species are warm water and cold water?

A

*Calanus finmarchicus = col
*Calanus helgolandicus = warm

287
Q

How does northen hemisphere temperature (NHT) impact alien species?

A

Positive correlation of alien/non-native species

288
Q

How are increasing temperatures changing diversity?

A

There is greater species diversity, especially northward

289
Q

What is the relationship between diversity and size?

A

Significant inverse relationship between biodiversity & mean community body
size both spatially and temporally due to changing metabolic rates and food availability

290
Q

What is the temperature-size rule?

A

*Increase temperature = decreased development time and final adult size
*In copepods (reproductive) development rate increases > growth rate
*Adult stage reached before largest potential size achieved

291
Q

How is temperature influencing copepod size?

A

More smaller species

292
Q

What is a regime shift?

A

sudden, dramatic and long-lasting shifts in ecosystem structure and function

293
Q

Where is temperature rising fastest?

A

The poles at the arctic and antarctic

294
Q

How is climate change impacting weather?

A

Increased frequency of extreme short duration storms which impacts the mixing of the water column which impacts productivity and the time of blooms

295
Q

What is ecosystem structure?

A

includes all living organism and their non-living environment. They are maintained by the flow of energy from primary producers through to top predators and then back again through decomposition and detrital pathways

296
Q

What are marine communities?

A

biological networks in which the success of species is linked directly or indirectly through various biological interactions (e.g., predator-prey relationships, mutualism) to the performance of other species in the community.

297
Q

What is ecosystem function?

A

The mix of ecosytem structure and marine communities (e.g., nutrient cycling, primary & secondary productivity), through which ocean and coastal ecosystems provide a wealth of free natural benefits that society depends upon: fisheries and aquaculture,

Y2 S2 (3 decks)

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