Marine ecology Flashcards

Question

What are the advantages and disadvantages of lecithotrophic larvae?

Answer 1

Advantages: *Own food supply (egg sack/yolk) *Less time for predation *Close to suitable habitat Disadvantages: * Fewer larvae produced *Lower dispersal distances

Answer 2

Advantages: * Large numbers are produced *Long time in water column, increasing dispersal distances, creating high geographical species areas Disadvantages: * Unpredictable food sources *Long exposure to predators *.Last development stage needs to be timed when suitable habitat is found for settlement – high probability of missing the mark!

Answer 3

It is a period of time during the life cycle spent floating freely in the water column. It means the larvae have a different food source to the parent reducing competition. It also means it can disperse long distance and means there is not a threat of benthic predators (but increased exposure to pelagic predators).

Answer 4

*Exploitative – ability to harvest limiting food resources *Pre-emptive – competitor recruits to and dominates space *Interference – competitors physically contest resources

Answer 5

Intraspecific competition is within species whereas inter specific variation is between different species

Answer 6

The geographic location where a species is no longer present. Can be affected by habitat availability, genetics, oceanographic and atmospheric factors.

Answer 7

The largest regions of sandy habitat occur within the tropics. Species in the tropics usually have a planktonic larval stage due to big segmentation between beaches and larger dispersal stage. Soft shores are inhabited by mobile epifauna and infauna.

Answer 8

The volume of pore space in between particles. * Small particles fill up spaces and reduce porosity. *Large particles = more empty space, increase porosity

Answer 9

The rate of percolation of water through the sediment. *Low porosity leads to low permeability. *High porosity leads to high permeability

Answer 10

(Normal sand) When pressure applied, the sand becomes dry and hard packed as water driven out of the interstices. This sand is difficult to burrow into. Few organisms live on them. Lots of wave action, so a harsh environment. Common on exposed beaches.

Answer 11

(Quick sands) Sands with high clay content become wetter and more easily penetrated when agitated. This sand is easier to burrow into.

Answer 12

Do not drain and are saturated with water. These are soft and easy to burrow into.

Answer 13

* Aerobic bacteria decompose organic material at the surface where oxygen is abundant *Oxygen consumption at the surface deprives deeper layers of oxygen, so sediments below the surface are anaerobic * The depth of the oxygenated layer varies according to the grain size of the shore – which determines its permeability

Answer 14

As oxygen concentrations diminish with depth, anaerobic bacteria start to dominate. The transition layer between oxygen-rich and oxygen-poor layers is the redox discontinuity layer. This varies due to porosity and exposure.

Answer 15

Some animals extend a long siphon into the oxygenated waters so they can respire and feed while sheltered from predation deeper in the sediment

Answer 16

* Generally no macroalgae, but sometimes see blooms of sea lettuce on mudflats *Brown seaweeds present if attached to pebbles *Benthic diatoms form biofilms and live at surface for photosynthesis

Answer 17

Organisms that are bigger than 1mm

Answer 18

*deposit and filter feeders are common but the distribution depends on exposure and wave action. E.g.more filter feeders when wave flow is high. * Predators e.g. shore crabs, birds

Answer 19

*Lots of nematodes, which are more common in sandy than muddy shores (80% of animals are nematodes)

Answer 20

Species richness, abundance and total biomass increase with increasing sediment stability (decreased wave exposure).Highest in muddy/sheltered habitats

Answer 21

Tidal height does not cause much zonation in muddy and sandy shores as the sediment allows for burrowing away from physical stressors.

Answer 22

* Some sediment depth is due to siphon length, to allow for oxygen * Sediment depth can also be due to competition with different species

Answer 23

*Increase cohesiveness (stickiness) *Make sediment surface smoother *Form protective layer over sediment surface

Answer 24

*Make sediment surface rougher *Regrade the sediment particle structure *Reduce sediment strength *Oxygenate sediment

Answer 25

An extended interface between a marine and flowing freshwater (lotic) system

Answer 26

There is a big mixture of organisms due to the mixing of fresh and salty water *Invertebrates dominate both epifauna and infauna. E.g. crabs and shrimps *Fish use estuaries as nursery grounds or move in with tides / migration. E.g. salmon *Birds migrate E.g. geese *Plankton are mainly diatoms and dinoflagellates

Answer 27

A balance between volume of river flow and strength of tide – water density. There is both vertical and horizontal variation.

Answer 28

The osmotic pressure within animal’s cells are equal to the surrounding water

Answer 29

Active regulation of osmotic pressure within cells

Answer 30

Tolerates large salinity range (many estuarine species)

Answer 31

Tolerates only a narrow salinity range

Answer 32

*Some species move in and out of the estuary with the tide *Some bury their head in the sand to reduce fluctuations in interstitial fluids in sediments

Answer 33

The deep sea is beyond 200 metres water depth ( most of the ocean is deep sea environments)

Answer 34

The dysphotic zone, also known as the twighlight zone occurs at mid-water depths between 200-1000m. There is still some photosynthesis but there is not enough sunlight for net primary production. 90% of animals are bioluminescent

Answer 35

Bioluminescence is created by the oxidation of a luciferin substrate via a luciferase enzyme. Most bioluminescence in the deep sea is blue wavelength as it attenuates less quickly and matches down-welling light.

Answer 36

*Signalling to conspecifics (members of the same species) *Catching prey *Evading predators *Counter-illumination

Answer 37

Counter-illumination only occours in the dysphotic zone. As there is still some downwelling irradiance (sunlight), animals cast a "shadow" beneath them. Many dysphotic zone animals have sensitive upward-looking eyes to detect these shadows so animals can use their bioluminescence to mask their silhouettes.

Answer 38

Either by using bioluminescent lures (to attract prey) or by illuminating prey during hunting *Dragon fish use red light that is invisible to most deep-sea animals (which stops the prey from detecting being targeted and taking defensive action)

Answer 39

*To confuse predators (e.g. expelling bioluminescent fluid). *To discourage predation according to the "burglar alarm" hypothesis - making a display attracts potential predators of the predator that threatens them

Answer 40

The aphotic zone, also known as the midnight zone, is deeper than 1000m where there is no more down-welling sunlight. Prey can be increasingly scarce therefore adaptations for predation, & predator evasion, are increasingly apparent.

Answer 41

It reduces reflectance of bioluminescence to less than 0.5%

Answer 42

Continental slopes are inclines which begin at 200m of off continents towards the ocean basin.

Answer 43

Deep water corals are scleractinians (stony corals) but do not have photosynthetic zooxanthellae. This means they have a slow growth rate which makes them particularly vulnerable to damage by bottom-trawling of deep-water fisheries

Answer 44

Flat regions of the ocean floor with gradients less than 1:10000. There is high species richness of macrofauna living in sediment (e.g. molluscs) and can have high species richness of meiofauna. A lot of the organisms burrow into mud

Answer 45

Active or extinct undersea volcanoes rising more than 1000 m above the surrounding seafloor. Steep slopes provide bare rock surfaces for attachment of suspension feeders Enhanced flow around seamounts provides increased food

Answer 46

Formed from moving tectonic plates. They are similar to seamount habitat

Answer 47

Ocean trenches normally start at 6000m depth. Oceanic trenches are prominent, long, narrow topographic depressions of the ocean floor. They funnel organic input such as marine snow, reducing the rate of decline in food availability with depth

Answer 48

Pressure increases by ~1 atmosphere per 10 m depth - at 5000 m, ambient pressure is >50,600 kPa

Answer 49

As depth increases internal and external pressures are equalised in most organism tissues but pressure can trap water on surfaces of unfolded proteins inside cells, preventing them from folding into the necessary shape for correct enzyme function. Chaperone molecules remove water molecules from unfolded proteins & promote correct folding

Answer 50

TMAO is a chaperone molecule used by fish and decapod crustaceans. As depth increases TMAO levels also increase

Answer 51

A species of snail foist found at 8178m in Mariana Trench

Answer 52

Exoskeletons of trench-living amphipods are coated by an aluminium hydroxide gel that protects their calcite mineral content from dissolving under pressure

Answer 53

*predation *Suspension-feeding *Deposit-feeding *scavenging *exploiting larger organic falls

Answer 54

*Common in the aphotic & dysphotic * Many deep-sea predators have adaptations to tackle large prey relative to their own body size - flexible jaws, expandable stomachs, additional neck joints

Answer 55

Suspension feeding is the capture and ingestion of food particles that are suspended in water. There are two challenges: * Need to escape boundary layer where seabed friction reduces flow. To overcome this many species have evolved stalks or colinise upstanding features *Need to anchor if stalked

Answer 56

Deposit-feeders extract organic matter from sediment. There are 3 types: *Batch reactor - with one entrance/exit *Continous-flow stirred tank reactor - with separate entrance and exit *Plug-flow reactor - with separate entrance and exit but a continuous input and output

Answer 57

Many benthic deep-sea scavenger species have olfactory and other sensory adaptations to detect food-falls

Answer 58

Some organic input to the deep-sea benthos is much larger than particulates in size (e.g. larger animal carcasses & “wood-falls”) Some taxa are specialists in exploiting these resources, often through partnerships with symbiotic bacteria

Answer 59

*pairing behaviour *accessory dwarf males *opportunistic mating behaviour *aggregation of broadcast spawners

Answer 60

Most deep-sea species are smaller than their shallow water relatives. Normally due to less food availability than upper ocean

Answer 61

Deep-sea body sizes being much larger than their shallow-water relatives

Answer 62

Fixation of inorganic carbon using chemical energy. Reduced chemical compounds provide a source of electrons

Answer 63

*2-stage process very similar to photosynthesis: (1) production of “reducing power” (2) fixation of inorganic carbon (e.g. CBB cycle) *Process requires a terminal electron acceptor (e.g. oxygen, in AEROBIC chemosynthesis)

Answer 64

Prokaryotic microbes E.g. Archaea and bacteria

Answer 65

H2S, CH4, H2, iron Fe(II), manganese Mn(II)

Answer 66

O2, NO3 - , SO4 2- , iron Fe(III), S

Answer 67

* availability of electron donors *availability of electron acceptors *energy yield of the reaction

Answer 68

They occur where reduced chemicals are available at the ocean floor: *hydrothermal vents *cold seeps *whale falls *wood falls

Answer 69

Entire global ocean volume passes through hydrothermal circulation every ~104years Removes Mg and SO4 from seawater (which helps to maintain the salinity of the oceans)

Answer 70

Hydrothermal vents at high temperatures (over 350’C) which erupt at high flow rates. Iron and other metals in the fluid precipitate as they mix with seawater, forming ‘black smoke”

Answer 71

Hydrothermal vents at lower temperatures (below 200’C) which seep through small cracks. Lower metal concentrations and particles of anhydrite, barite, or talc forming “white smoke”

Answer 72

Highest temperatures only occur in primary vent fluid at the throat of the vent chimney. There are very sharp gradients. 360 ºC to 2 ºC over 10s of cms

Answer 73

Sulfide oxidation is the mains form of chemosynthesis in terms of carbon fixation. Hydrogen sulfide (H₂S) is readily available in vent fluids and oxygen is readily available from background deep-sea water

Answer 74

*endosymbiotic relationships *microbial epibionts (an organism that lives on the surface of another) *by grazing or suspension feeding of free-living microbes *by predation / scavenging on primary consumer animals

Answer 75

These tubeworms don’t have mouths, anus or guts so don’t have a digestive system. Instead they have a trophosome which contains lots of chemosynthetic bacteria (they’re endosymbionts). This bacteria creates energy for the tube worm by chemosynthesis

Answer 76

For chemosynthesis they need inorganic carbon (to turn into sugars), oxygen (as the terminal electron acceptor) and hydrogen sulfide (as the energy source). The worm acquires these from its environment and transfers it to the bacteria inside.

Answer 77

It can be obtained from either: *Heterotrophic CO2 from Riftia tissues (by the worms respiration) *Vent fluids or deep-sea water DIC transported in blood as HCO3 - and CO2

Answer 78

PROBLEM: hydrogen sulfide is highly toxic to animal tissue *it poisons cytochrome c oxidase electron transport enzyme *usually replaces oxygen at binding site on haemoglobin Riftia take up HS- (less toxic form for cytochrome c oxidase)

Answer 79

Riftia haemoglobin has high affinity for O2. Can have environmental temperature gradient along worm body (warmer at trophosome than worm plume) may aid unloading of O2 at trophosome

Answer 80

They can host dual symbioses inside their gill cells. Both sulfide-oxidising and methanotrophic bacteria.

Answer 81

Some animals at vents have epibiotic bacteria (lives on their surface). Roles may include nutrition and detoxification. The animals may have an increased surface area to allow for their epibionts.

Answer 82

They graze on bacteria present either as biofilms or mats of filamentous bacteria. Grazers include limpets and polychaetes

Answer 83

They filter-feed on organic matter at vents - e.g. Eolepadid stalked barnacles

Answer 84

Steep physical-chemical gradients at vents on similar scale to rocky intertidal environment, gradients include temperature, sulfide & O2 concentration.

Answer 85

Closest zone to active vents is often dominated by species that can feed on e-proteobacteria. The next zone is often dominated by species that show trophic relationships with g-proteobacteria. Filter-feeding species then extend further away from vents and then a “halo” of non-vent animals possibly 100s of metres from vent

Answer 86

e bacteria can respire using S as an electron acceptor therefore it can thrive closer to vents where there is a greater diversity of electron donors and less O2 whereas g bacteria require O2 for their two S-oxidising metabolic pathways, so are restricted to zones with greater mixing with seawater

Answer 87

Hydrothermal vents occur in “fields” (clusters of vent chimneys) depending on the underlying geology: the availability of heat source and pathways for circulation. On a fast-spreading mid-ocean ridge (e.g. East Pacific Rise), vent fields may be 10s of km apart. On a slow-spreading mid-ocean ridge (e.g. Mid-Atlantic Ridge), vent fields may be 100s of km apart

Answer 88

Vents don't last forever. Volcanic eruptions or tectonic activity can disrupt the “plumbing” of the vents. How long a vent field lasts depends on how frequently these types of disturbance occur. Vent fields on a fast-spreading mid-ocean ridge (e.g. East Pacific Rise) may only last for 10s of years. Vent fields on a slow-spreading mid-ocean ridge (e.g. Mid-Atlantic Ridge) may last for 1000s of years

Answer 89

Environments where non-volcanic geological processes generate reduced chemicals at the seafloor to support chemosynthesis

Answer 90

*salt diapir system *mud volcanoes *asphalt seeps *methane hydrate beds

Answer 91

Typically found on continental margins but can also occur in ocean trenches. Generally found in soft-sediment seafloor settings

Answer 92

Geological process forces organic compounds from deep reservoir up through seafloor sediments. Hydrocarbon sediments are buried which degrade to produce methane. Anaerobic subsurface microbes oxidise methane using SO4- to produce HS- + HCO3- +H2O. This sulfide provides an energy source for chemosynthesis.

Answer 93

A salt flat is buried as sea levels change. There are now new sediment laying on top however the rocks salt below is more buoyant so is trying to crack its way up to the surface. This vertical movement of salt up through the seafloor sediment is salt diapirism

Answer 94

The brine pool is anoxic and hypersaline surrounded by bed of mussels. There are also grazers like gastropods and polychaetes and scavengers like shrimp and lobsters. Species zonation occurs following gradients in sulfide flux and oxygen conditions

Answer 95

Seep tubeworms acquire sulfide via their roots, not their plumes.

Answer 96

They don't last forever because reactions such as methane oxidation happening under the sediments produce bicarbonate which causes biogenic carbonate rock to form in the sediment under the seep site. This carbonate rock eventually blocks seeping of methane at the site

Answer 97

The delivery of reduced chemicals is slower, thus primary production is lower, and the environments are more stable

Answer 98

Degradation of whale carcasses on the ocean floor can result in a partially chemosynthetic environment, there are still heterotrophs present. Non-chemosynthetic scavengers remove flesh from skeleton & bone. Whale bones are very rich in lipids & anaerobic bacteria then break down these lipids, reducing seawater sulfate to sulfide in the process, resulting in a sulfide flux which can support chemosynthetic primary production by other microbes

Answer 99

Whale skeleton lipids are eventually depleted after decades

Answer 100

The whale carcasses from little islands with distances typically around 10s of km

Answer 101

Large amounts of wood are swept out to sea from rivers creating a partially chemosynthetic environment. some species exploit wood falls heterotrophically but microbes digesting cellulose in wood can also release sulfide which can support other chemosythetic microbes.

Answer 102

They interrupt gene flow between populations by: *geographical isolation by movements of plates and ridges *changes in ocean currents Dispersal of fauna is usually achieved by larval stages

Answer 103

*Major global wind patterns due uneven heating of the earth by the sun due to its angle *Latitudinal variation in the coriolis force (deflection of winds to the right in the Northern Hemisphere and deflection to the left in the Southern Hemisphere.)

Answer 104

Surface currents are at a 45 degree angle to the wind. Right in Northern hemisphere and Left in southern. As we go deeper in depth the angle increases, known as the Ekman spiral. This means currents move at 90 degrees to the wind, known as Ekman transport.

Answer 105

*north pacific *north atlantic *south pacific *south atlantic *indian ocean

Answer 106

Huge circular moving current systems which dominate the surfaces of the oceans. Because of coriolis and Ekman spiral they turn clockwise in northern hemisphere and anti-clockwise in southern hemisphere.

Answer 107

Sea surface temperatures are high in the mid latitude due to high levels of irradiance in comparison to low latitudes and polar regions

Answer 108

Driven by evaporation and precipitation. High evaporation = high salinity. Inter tropical convergence zone creates a lot of precipitation so not as simple as temperature map with poles to equator difference

Answer 109

Low concentrations of essential nutrients for algal growth. They generally support low levels of primary production.

Answer 110

High concentrations of essential nutrients for algal growth. They generally support high levels of primary production.

Answer 111

Nitrate levels are generally low but there are higher levels in the southern ocean

Answer 112

A warm current flowing along the the eastern coast of North American content north. It helps form the Sargasso Sea gyre

Answer 113

*nutrients *sea surface temperature *physical factors that can cause upwelling

Answer 114

Meso-scale eddies are approximately 100km and 1 month. They pump nutrient-rich waters from depth and can be described as the weather of the ocean

Answer 115

They pump nutrient-rich waters from depth stimulating new phytoplankton which zooplankton can graze on

Answer 116

New nutrients enter the euphotic zone from an outside system e.g. the atmosphere, deep waters and rivers

Answer 117

The ratio of nitrate (NO3) uptake by phytoplankton to total inorganic (NO3, NO2, NH4) and organic (e.g. urea) uptake by phytoplankton.

Answer 118

The old view said the overall biomass and production was very low and they where inefficient ecosystems with nutrient-limited growth. The new view agrees that production is low but there are seasonal varitions which allows for blooms of organisms.

Answer 119

They have episodic mixing events which are important for annual production. 65% of annual production occur in 2 weeks

Answer 120

Picoplankton

Answer 121

*Fresh supply of new nutrients *Larger species - diatom blooms

Answer 122

Regions where nutrient levels are low, regeneration

Answer 123

Regions with high levels of nutrients - no need of regenerated nutrients.

Answer 124

The enzyme responsible for N-fixation (nitrogenase) requires high amounts of iron.

Answer 125

When there are no other inputs of nitrogen. Trichodesmium is the dominant N2-fixing organism in the ocean

Answer 126

They vertically move nitrate (NO3) up from depths when levels are depleted

Answer 127

It dominates when there is nutrient-limitation. Dissolved organic materials such as carbon is returned to higher trophic levels via its incorporation into bacterial biomass, and then coupled with the classic food chain formed by phytoplankton and zooplankton.

Answer 128

Lower trophic levels are the limiting factor, it relys heavily on how much phytoplankton are growing

Answer 129

Predators and higher trophic level control the food web by removing lower levels.

Answer 130

The continental shelf is part of the continental land mass however is submerged under water. It ends at 200m depth where there is then a steep decline gradient

Answer 131

They drift within ocean currents and photosynthesise to produce their own food

Answer 132

*Eukaryotic cells contain a nucleus and organelles bound by plasma membranes *Prokaryotic cells don’t have a membrane-bound nucleus or organelles

Answer 133

*Cyanobacteria *Dinoflagellates *Diatoms *Coccolithophores

Answer 134

They are prokaryotes and have the highest diversity in tropical zones. They have symbiotic asscociations for example with sponges. They are a single long filament

Answer 135

They are the 2nd most abundant phytoplankton group. They can be autotrophic, heterotrophic or mixotrophic. They are motile as have 2 flagella. Their blooms form red tides and some species are toxic

Answer 136

They are found in all aquatic environments and are the most abundant phytoplankton group. They have a silica frustle skeleton and are non-motile.

Answer 137

They reflect sunlight and heat back out of the water. They are formed from CaCO3

Answer 138

*Light (energy source) *CO2 (carbon source) *O2 (for respiration) *Nutrients (to make cell structures)

Answer 139

Si (silicon)

Answer 140

C:N:P = 106:16:1

Answer 141

NO3, NO2, NH3, N2

Answer 142

HPO4^2-, PO4^3-, H2PO4^-

Answer 143

S04^2-, H2S

Answer 144

CO2, HCO^3-, CO2^3-, H2CO3

Answer 145

*Euphotic zone - the sunlight zone where photosynthesis can occour *Dysphotic zone - the twighlight zone where sunlight decreases rapidly with depth and photosynthesis is not possible *Aphotic zone - where sunlight cannot penetrate

Answer 146

It measures the depth light can penetrate and depends on wavelength, dissolved material and particles.

Answer 147

Sunlight penetrates ocean waters further than coastal waters as it contains less output from the shore

Answer 148

Photosynthetically Active Radiation. Phytoplankton can only use certain colours of radiation, between 400-750 nm

Answer 149

It compares the rate of photosynthesis to the level of light. X axis = irradiance, y axis = photosynthetic rate

Answer 150

Radiant flux per unit area received by a surface

Answer 151

Photoinhibition is when photosynthesis starts to decrease - perhaps due to physical damage from too much light or the cell shutting down to stop any possible damage

Answer 152

It compares respiration and photosynthesis rate. When respiration = photosynthesis there is just enough sunlight for organisms to photosynthesise and survive.

Answer 153

In wintertime the thermocline is none existent so has little to no impact. This means there is a lot of nutrients as there is a lack of sunlight so they are not being uses up. Then in spring there is a good balance of nutrients and sunlight for optimum photosynthesis In summer zooplankton levels rise as there is big blooms of phytoplankton however the zooplankton then eat the phytoplankton so levels drop.

Answer 154

*They have little ability to swim against major water currents. * They play key roles in pelagic food webs and biogeochemical cycling. *Most are heterotrophs but some are mixotrophs *Patchy distribution is a very common feature of zooplankton, occurring at a variety of spatio-temporal scales. It is partly due to the fact they are motionless so move due to physical processes such as gyres, eddies and tidal mixing

Answer 155

They are a powerful mechanism of vertical mixing in natural bodies of water, driven by wind and waves. They are a series of shallow, slow, counter-rotating vortices at the ocean's surface .

Answer 156

Zooplankton moving up and down the water column each day due to light variations. Preferred depth ranges vary with life stage, weather, season and latitude.

Answer 157

They lay their eggs at depth Dec-April. The population matures at surface when primary productivity is high. By June, storage lipids are accumulated and they migrate to deeper waters in autumn. The causes are temperature and food availability

Answer 158

Short food chains deplete less energy prior to consumption, compared to long food chains. At each step energy and heat is lost through processes such as metabolism. Nutrients are also lost e.g. feces

Answer 159

For trophic level 1, the average transfer efficiency is 2% (98% loss); all other trophic levels average 10% efficiency (90% loss)

Answer 160

Growth/Growth + Respiration or Growth/Food intake

Answer 161

*Type of organism *Level of complexity *Swimming ability *Life-history stage

Answer 162

Growth at trophic level t+1/Growth at trophic level t

Answer 163

Energy transferred between trophic levels

Answer 164

Food chains are linear. Food webs take into account complex systems with interconnected food chains

Answer 165

Non-living hard substrates that are usually found along continental shelves in temperate and subtropical areas

Answer 166

A rocky reef with canopy forming kelps that reach sea surface. They are highly productive and add structural vertical complexity allowing for the survival of more species. Kelp forests can refer to any type of brown seaweed that can form a canopy

Answer 167

*Significant primary production and carbon sequestration *Regulate the recruitment of coastal species by providing food and shelter *Important habitat for a number of juvenile fish - they can hide within the forest *Provide buffering and protection against the effects of waves and storms

Answer 168

6CO2+6H2O→C6H12O6+6O2.

Answer 169

It makes up the order Laminariales. They are are large brown subtidal seaweeds with very strong holdfasts to stay attached to rocks.

Answer 170

*Flat blades - with high SA:V ratio for nutrient absorption *Air filled pneumatocysts - allow blades to float close to the surface for photosynthesis *Stipe - which link blades to holdfasts and are used for shock absorption from wave impact *Holdfasts - which ancghor kelp seaweeds to the bottom

Answer 171

*Canopy *Understory *Algal turf

Answer 172

Fronds lying on surface or midwater. It has the most light and wave action

Answer 173

Fronds erect or close to bottom. They have the highest diversity of marine life in the kelp forest and are the area of stipes.

Answer 174

Short clumps, filaments and encrusting algae. Area of holdfasts of larger kelp, invertebrates, and red algae

Answer 175

They where found in the northern pacific and grazed almost exclusively on kelp in the canopy. They had no teeth just broad bony pads to chew kepl. They where hunted to extinction approximately 250 years ago. This was influenced by only a few offspring produced every year and long generation times.

Answer 176

Small invertebrates, adult rockfishes, kelp bass, sheaphead and abalone

Answer 177

They are found in areas with high nutrients, often this is due to high upwelling. The tropics are too hot and nutrient poor

Answer 178

*Substrates *Light *Nutrients

Answer 179

*Environmental reasons such as El Nino , where there is less upwelling so warmers water temperatures and less nutrients *Biological reasons such as hunting of predators of kelp predators *Storms

Answer 180

Upwelling is important for kelp beds because it brings cold nutrient rich waters to the surface. Upwellings are seasonal, but they also vary among years (e.g. El-Nino events). Kelp forest abundance follows the pattern of El Niño / La Niña years

Answer 181

Sea urchins are herbivores and potentially destructive to kelp. Urchins normally passively feed on drift kelp (free-floating kelp detritus). When drift kelp is limited, and urchins start to experience food limitation, their feeding behaviour changes to live kelp. When urchins get out of control, they initiate a “phase shift” in kelp bed ecosystems to urchin barrens.

Answer 182

When an ecosystem changes from one stable state to another due to perturbations. E.g. kelp forest to urchin barren

Answer 183

A chain-reaction within food webs that results from changing population densities at higher trophic levels, shifting the dominance and impact of consumers in lower levels

Answer 184

The frozen ocean. It is an ice-covered ocean surrounding the North pole land. It is a 14.5 million km2 ocean basin

Answer 185

It used to be divided into two basins. The Eurasian Basin formed during the Cenozoic era and the Amerasian Basin formed earlier during the Mesozoic era. Opening of Fram Strait 17.5 Mya - changed the arctic from an oxygen poor lake stage to an estuarine sea with more oxygen.

Answer 186

The frozen continent which is 14 million km2 and mountainous

Answer 187

The breakup of the supercontinent Gondwana 180 mya slowly lead to the oceanographic isolation of antarctica 40 mya

Answer 188

*Both high latitude and polar *Both cold water systems with very low sea surface temperatures *Arctic continental shelf = 200m deep, Antarctica continetal shelf = 500 m deep (due to the continent pushing it down) *Arctic = North pole, Antarctic = South pole

Answer 189

*Both areas have very cold air and water temperatures due to low solar angles in high latitude areas and albedo of ice *Both continents are very dry as colder air can't hold as much moisture as warm air *Arctic wintertime = -40C summer 0C, Antarctic wintertime = -60C summer = -28.32C

Answer 190

The main reason the antarctic is slightly colder than the arctic is because it is a huge land mass so receives very little heat from the ocean whereas as the antarctic is heated by the ocean.

Answer 191

*Glacier ice (glaciers & icebergs) *Sea ice (pack ice & multiyear ice)

Answer 192

*Both the Arctic and Antarctic have both kinds of ice *There is a lot of annual ice in the Antarctic due to advance and retreat of the sea ice *There is a lot of multiyear ice in the Arctic as the centre of the arctic melts completely every year

Answer 193

Glacier ice is compacted snow. It is made entirely of freshwater. Where glaciers meet the sea, they can carve and form icebergs which can float out to sea

Answer 194

Sea ice is formed from freezing seawater. The density of seawater increases as it cools, it freezes at about - 2C. Annual ice is sea ice which forms every year and melts again.

Answer 195

1. Bering Strait - cold and less salty water enters the arctic ocean 2. Chukchi Sea - very cold winds coming from land masses surrounding the arctic blow onto the sea water and start the freezing process. As seawater freezes it rejects salt so surface seawater is a lot fresher. Dense salty seawater sinks into the western arctic ocean. 3. Beaufort Gyre - Once the water is fully in the Arctic ocean it is circulated around the gyre 4. Transpolar Current - wind shifts (the transpolar current) in direction and the Beaufort gyre weakens 5. Various exit gateways - weakened gyre allows very big volumes of freshwater to leak outside the Arctic. 6. North Atlantic current - warm salty water enters the Arctic and cools the further it goes in flowing anti-clockwise

Answer 196

Antarctic Circumpolar Current (ACC). It flows West -East (clockwise) and is the largest wind-driven current. There is convergence where cold antarctic waters meet warmer sub-antarctic waters, because they are more cold at the convergence the antarctic waters sink under the sub-antarctic waters

Answer 197

Arctic - tundra Antarctic - two flowering plant species

Answer 198

Arctic - Many terrestrial mammals (e.g. reindeer) Antarctic - No terrestrial mammals Both have many marine mammals e.g. seals and whales

Answer 199

*The arctic has a government and there are more than 4 million people lving there. *The Antarctic has no government and nor permanent residents, just scientists

Answer 200

All water south of the polar front so is oceanographically isolated. It has low stable temperatures and a deep continental shelf.

Answer 201

Cooling 40Mya and the opening of the Drake passage established the polar front and antarctic circumpolar current (ACC) which creates the isolation and a glaciated environment. The isolation allows for evolution of diverse fauna in the Antarctic

Answer 202

*Stenotherms (-1.85 to +2 deg C) *Slow physiological rates

Answer 203

Warming of air and sea surface temperatures are now starting to impact all of the Antarctic and not just the North. Glaciers are retreating at a higher rate to the rate of glaciers advancing, there ae increases in precipitation and sea ice seasons are shortening

Answer 204

Antarctic benthos are extremely vulnerable to climate warming sue to their strict physiological limits (e.g. stenothermy) and slow physiological relates. Antarctic benthos are a useful barometer for climate change and other species in different areas

Answer 205

Benthic organisms may be impacted by an increase in icebergs which scour the seafloor

Answer 206

How/why do interactions between organisms and their biotic and abiotic environments affect the genetic composition of marine populations?

Answer 207

The formation of one or more species from an ancestral species. Speciation occurs when populations of the ancestral species become reproductively isolated from each other.

Answer 208

*Population with a common gene pool - the ancestral species *Populations become reproductively separated *Genetic differences (e.g. mutations) build up between the populations, creating morphological variation *Natural selection *After a long time, if the two populations come into contact, they can no longer interbreed

Answer 209

The differential survival and reproduction of individuals due to differences in phenotype.

Answer 210

*Allopatric *Peripatric *Paripatric *Sympatric

Answer 211

When two or more populations become completely geographically (and hence, reproductively) isolated. Over time, genetic and morphological differences accumulate, causing the formation of new species.

Answer 212

When small groups of individuals break off from the rest of the geographic range of a species. Over time, genetic and morphological differences accumulate, causing the formation of new species.

Answer 213

When populations do not become separated by a geographic barrier, but by a colonization of a new habitat type/niche. Individuals then only mate with those in their same habitat/niche type. Over time, genetic and morphological differences accumulate, causing the formation of new species.

Answer 214

When there is no geographic or habitat barrier to gene flow between populations. But still over time, genetic and morphological differences accumulate, causing the formation of new species.

Answer 215

Cryptic species. They are morphologically similar but genetically distinct

Answer 216

Phylogenetic trees

Answer 217

*Morphological characters *Genetic characters *Characters shared between the MRCA and all its descendants are synapomorphies (similar morphologies)

Answer 218

Most Recent Common Ancestor

Answer 219

A group of organisms comprising all the descendants of the MRCA

Answer 220

The study of historical processes influencing the modern distribution of a species using molecular tools. It can also be used to understand genetic population divergence and speciation

Answer 221

When a single genome can produce more than one phenotype (e.g. morphology, life history) when exposed to different environments

Answer 222

They can be caused by sea-level changes caused by glacial/interglacial cycles. They can contain shell fossils, which are data points for deciphering geographic ranges due to their occurence witin the terrace

Answer 223

The centre population as there is often higher gene flow between populations in the range centre

Answer 224

By examining closely related species that live in the same region (i.e. they broadly experience the same oceanographic conditions) but differ in their habitat preference, abundance, and distribution

Answer 225

Life history refers to the age and/or stage specific patterns in the timing of events in an organisms life

Answer 226

How fast an organism grows and rate of change over its life cycle

Answer 227

*Determinate - stop growing at a certain age (e.g. humans) *Indeterminate - grow throughout whole life

Answer 228

*Growth rate *Age/size of first reproduction *Age/size of sex change *Reproductive output and timing *Sex ratio *life span

Answer 229

*Grow and mature fast *Make lots of babies *Leave them to defend themselves after they hatch *Very few survive to adulthood *Die young, ~4 year life span *Reproduce once (as mother dies as soon as eggs hatch due to lack of food whilst protecting the eggs) *Mothers lay tens of thousands of eggs

Answer 230

*Grow and mature slowly (~10-15 years old) *Make few babies (~1 every 5 years) *Protect them until they are fully grown *Die of old age (>50 years old) *Many other marine mammals have a similar life history strategy This means they are very vulnerable to poaching and fishing pressure as they don’t recover as quickly

Answer 231

*All individuals start their lives as female *Females reach maturity at ~ 4 years *Sex change occurs at ~ 8 years old *Age span varies by location, upwards of 50 years

Answer 232

*Social factors (e.g. territoriality) *Size-advantage hypothesis: reproductive potential (i.e. chance of successful reproduction can change with size, for this species, it is more advantageous to be male when large)

Answer 233

*Protrandrous - male to female *Protogynous - female to male

Answer 234

*All individuals start their lives as male *Grow quickly and males mature at ~2 years *Broadcast spawning once a year (winter) *Size/age of sex change varies by location (and harvest pressure) *Sex change occurs when territory is acquired (size-advantage hypothesis) *Life span ~ 10-15 years

Answer 235

Mortality increases with age so not all live to switch gender (⅔ first sex, ⅓ second sex)

Answer 236

Size selective harvesting. Species that grow slowly and have low reproductive output are more vulnerable to human impacts

Answer 237

It does not impact determinate growing species. However can impact indeterminate species as older/larger mothers produce higher quality oil globules for their larvae – which enhances their growth and survival. Older/larger mothers also produce larger, higher quality egg

Answer 238

Reefs are rocky marine habitats that rise from the sea bed. They are generally subtidal but may extend as an unbroken transition to the intertidal zone.

Answer 239

The cover 0.2% of the ocean but support at least 25% of all marine species. They also help provide food for humans and support the tourist industry. They can also be used as coastal buffers against storms, and the weathering of coral supplies sand to beaches.

Answer 240

They are Cnidaria and are stony/hard corals that help build hermatypic corals

Answer 241

*Reef building *Contain endosymbiosis algae *Limited to the photic zone *Mostly found in tropical latitudes

Answer 242

*Non-reef building *No endosymbiosis algae *Deep and cold water

Answer 243

Made of a stomach with tentacles at the top, making polyps. Each polyp is connected by tissues and are genetically identical

Answer 244

It is coral-algal symbiosis. The algae consume wate products produced by the coral host and uptake nutrients from seawater. They then photosynthesise to produce food and energy for the coral.

Answer 245

*Access to sunlight *Stable and protected environment *Coral metabolic waste

Answer 246

There is a hotspot in the ENSO-pacific region and tropics Less diversity closer to the poles

Answer 247

*Temp = 18-36 degrees Celsius *Latitude = 30 degrees N - 30 degrees S *Depth = 0-30m for sunlight *Salinity = 33-35 psu *Wave action = high wave energy (but this has risk of storms)

Answer 248

*Fringing reefs *Barrier reefs *Atolls *Patch reefs

Answer 249

Volcano erupts - lava piles up on seafloor and creates a seamount which breaks the surface of the water and becomes an oceanic island. Hermatypic corals settle and begin to grow around the island = Fringing reef and grows directly out from the island

Answer 250

Over millions of years, volcanic island erodes and sinks (subsidence) - fringing reef turns into barrier reef - farther from shore and with a deeper lagoon.

Answer 251

Ocean waves erode the reef and the sand piles up on the reef as island continues to sink - creates atolls = ring shaped islands.

Answer 252

Fringing reef - barrier reef - atolls

Answer 253

They generally pop up in lagoons as hermatypic coral settles on any available substrate

Answer 254

It has very high coral diversity with other 75% of all known species. Bird’s head peninsula has 72%.

Answer 255

There is limited space on reefs, and so this leads to competition over space, as well as light. There is exploitative competition over shading and interference competition with tentacles.

Answer 256

*Predatory pressure is mainly chronic with sharks at the top *There are 39 species of obligate corallivores *The starfish Acanthaster Planck can destroy coral colonies

Answer 257

*Invertebrate herbivores: Sea urchin *Vertebrate herbivores: Fishes, sea turtles, dugongs. *Parrot fish (detritivores) produce coral sand

Answer 258

It refers to the phenomenon of coral reefs shifting to unusually low levels of coral cover, associated with persistent states of high cover of fleshy macroalgae. This results in reduced biodiversity

Answer 259

Diversity of coral in tropical reefs is a nonequilibrium state, if it is not disturbed further it may lead towards a low-diversity equilibrium community

Answer 260

*Pollution *Temperature *Hypoxia *Ocean acidification

Answer 261

*Prey abundance *Predator threats *Parasites *Disease

Answer 262

Increasing sea surface temperature. Endosymbiotic algae is ejected from the polyp resulting in decreased growth and reproduction. This is increasing in frequency due to ENSO events and climate change

Answer 263

The edges of the tropics are where the geographic ranges of species found primarily within low latitudes (e.g. 0 - 25 º) come into contact with those primarily found within higher latitudes (25 º+)

Answer 264

*Tropical species are warm adapted and there is little seasonality *Temperate species are adapted to high seasonality

Marine ecology Flashcards

(291 cards)