Marine Ecology Flashcards

Question

Lampreys

Answer 1

Mainly freshwater or costal - Some migrate to the ocean to mature and bread in freshwater  Have unpaired fins  Redemptory vertebra  Most species are not parasitic! - sea and river lamprey attach to fish, rasp a hole into the victim, and feed on fluids and tissues

Answer 2

Cartilage skeleton - lighter and more flexible than bone  Placoid scales - tough sandpaper like skin  Moveable hinged jaws  Ventral mouth with well developed teeth  Maintain buoyancy through a oil-rich liver  Can detect weak electric field to locate prey - ampullae of Lorenzini

Answer 3

Fusiform shape (tapered at both ends) - aids movement through water  Strong caudal (tail) fin for propulsion  Two dorsal fins and paired pectoral fins  5-7 gill slits on each side of body behind the head  Most are carnivorous  Largest sharks are filter feeders (whale shark - Rhincodon typus)

Answer 4

Sensing organ that uses electroreceptors to detect the weak electrical currents emitted by living organisms. • For example fish hiding under sand. • Consists of pores connected to gel filled tubes. • Also found in other chondrichthyes (e.g. rays)

Answer 5

``` Dominant vertebrates in the sea  More taxonomically diverse than rays & sharks  Wide range of shape, size, color, swimming ability, feeding habits, reproduction and behavior ``` Skeleton made of bone  Anterior, midline mouth  Swim bladder to provide buoyancy  Scales made of bone, covered by skin and mucus  Gills protected by a flap of bony plates (operculum)

Answer 6

``` Swim bladder (5% of animal’s volume).  Two gas filled sacs – fish achieve neutral buoyancy by changing the volume/pressure of the bladder. ``` Only in bony fish - so what about sharks?  Altered salt content of cellular fluids (low salt) relative to seawater.  High lipid content - liver may occupy up to 25% of volume of a shark  Also “flying” using fins for lift

Answer 7

Gelatin-filled tunnel - runs beneath skin along each side from tail to head - contains clusters of nerve cells for detecting vibration - detects reflections of bow waves off nearby objects, including other fishes Allows rapid movement near solid surfaces and tight schooling

Answer 8

Rover predators (tuna, marlin, blue shark) long torpedo shaped = efficient swimmers  Lie-in-wait (ambush) predators (barracuda) – Body does not taper. Acceleration from strong powerful tail, (caudle peduncle is wide).  Flatfish (flounder and plaice - bottom dwelling  Deep-bodied (butterfly fish) – lots of contact with water = manoeuvrable, tight turns  Eel-like (moray eel) fishes are adapted for moving through crevices

Answer 9

Anadromous: Feed and grow at sea - Reproduce in freshwaters • Salmon Catadromous: Feed and grow in freshwaters  Reproduce at sea  European and American Eels

Answer 10

``` Topmost zone, light is abundant ▪ This is where photosynthesis takes place = lots of food ▪ You need to see your lunch before it sees you – or you become lunch! ▪ Speed is king – escape or catch Adaptations: - Large eyes - Strong muscles, fast swimming - Counter shading - Streamlined ```

Answer 11

``` Sufficient sunlight for vision, but not photosynthesis ▪ Energy comes from sinking organic material - ≈20% of primary production sinks out of the epipelagic - <5% of primary production reaches 1000 m Depends on the surface layers for O2 Natural thermocline ``` Short on food: Most adaptations are concerned with finding food, or conserving energy They also have to stay afloat, within these constraints Vision is still a key sense: Seeing in the dark, and not being seen is key. Despite the lack of food, as much as 95% of fish biomass may be in the mesopelagic!

Answer 12

Common adaptations: ``` ▪ Small size – don’t waste energy Make the most of every meal ▪ Large mouths ▪ Hinged extendible jaws ▪ Needle-like teeth ▪ Unspecialised diets ```

Answer 13

Common adaptations: ``` ▪ Small size – don’t waste energy Make the most of every meal ▪ Large mouths ▪ Hinged extendible jaws ▪ Needle-like teeth ▪ Unspecialised diets ``` Carnivores have: ▪ large mouth ▪ extendible jaws & needle-like teeth (e.g. viperfish & rattrap fish) Zooplanktivores have: ▪ smaller mouths to rapidly ingest small prey ▪ upward facing eyes to spot zooplankton in the downwelling light (e.g. lanten fish)

Answer 14

Stay put, sit and wait 2. Go find food Many mesopelagic fish undergo a diel vertical migration, moving up to the surface at night (when they are safer from predators) to find food. This is the biggest migration on earth.

Answer 15

Following food source (e.g. zooplankton) ‘Safer’ from predators at night Vertical migrators possess - well developed muscles - swim bladder (often filled with lipid rather than gas) Migrators contribute to the deep-scattering layer Migrators bring surface production down with them - enriching food in the mesopelagic - non-migratory predators feed on them

Answer 16

``` non-migrators cope with the reduced food supply (relative to migrators) by reducing energy demand ▪ near neutral buoyancy ▪ lack swim bladders ▪ less muscle ▪ watery flesh ▪ soft weak bones Sit and wait predators - lurk in the dark and wait for a meal (use of lures) ```

Answer 17

``` Look up ▪ Large, often tubular, eyes ▪ Upward orientation ▪ Main retina for upward field ▪ Secondary retina for lateral vision ``` Vision is still important in the mesopelagic, but counter shading is less effective with less light. Most fish are looking up at you so common adaptations are: • Transparency • Lateral compression of body to reduce silhouette Counter illumination Counter illumination - - photophores (light emitting organs) on underside (ventral) - bioluminescence - blue light to match spectrum of downwelling light Countershading - using coloration (silver sides and black backs) to blend in.

Answer 18

We see many adaptations that we saw in the mesopelagic to deal with lack of food: ▪ Week flabby muscles (don’t waste energy) ▪ Large mouth/teeth ▪ Generally slow metabolisms ▪ Reduced or no swim bladder ▪ Bioluminescence ``` Adaptations seen in mesopelagic fish to low food are generally exaggerated. Don’t miss a meal: ▪ large mouth ▪ hinged extendible jaws ▪ long sharp teeth ▪ bioluminescent lure Don’t waste energy: ▪ sluggish ▪ flabby watery muscles ▪ weak skeletons ▪ poorly developed respiratory and circulatory systems ▪ poorly developed nervous system ▪ lack swim bladders ```

Answer 19

Hard to find a mate in a sparsely populated sea. Especially when you don’t move much. ▪ Some species are simultaneous hermaphrodites ▪ Some use pheromones to find each other ▪ Angler fish have dwarf males that attach to females (can't waste an opportunity to mate)

Answer 20

No natural light here and very little food. Very little food reaches the bottom - Food falls (whale carcasses etc) - Marine snow and fecal pellets (POM) Covered in a fine muddy sediment. - bacteria and meiofaunna degrade POM/DOM and make it available to the food chain - Fish also scavenge larger food fall directly

Answer 21

Scavengers with strong muscles to move to food falls ▪ Relatively large and slow growing ▪ Often elongated (eel-like) ▪ Strong muscles (will swim a long way to find food). ▪ Small or no eyes (few are bioluminescent) ▪ Black/brown in color

Answer 22

unicellular protist about 40-50% of marine primary productivity silica cell wall called a frustule single cells or long chains ``` capable of rapid growth tolerant of low light temperate and polar regions bloom forming (spring bloom, upwelling) adequate light high nutrient concentrations subject to intense grazing pressure from zooplankton cysts (dormant stage) survive for years (e.g. in sediments) seed for new population growth ```

Answer 23

Coccosphere Cell wall composed of calcium carbonate (CaCO3) plates Complex, and still poorly understood, life cycle Often important in tropical waters Capable of forming large blooms, usually following the diatom bloom Major source of CaCO3 to the sea floor. Responsible for extensive CaCO3 rock formations (e.g. White Cliffs of Dover). Upon dying, coccolithophores produce large amounts of dimethyl sulfide (DMS), a gas that escapes to the atmosphere. DMS may aid cloud formation and allows sulfur to be transported from the ocean to the land.

Answer 24

``` Dinoflagellates motile using two flagella longitudinal (trailing behind the cell) transverse (around the cell's middle) cell wall (theca) consists of cellulose ``` Capable of vertical migration in stratified waters Slow growing, requiring high light Form cysts that can persist in sediments for years seed for new population growth when environmental conditions are favourable Red tides, not due to rapid growth, but rather due to persistence and accumulation of toxins associated with defences against grazers Small contribution to marine primary productivity None-the-less, ecologically and economically important Includes about 100 toxic species, producing a variety of effects in man and fish.

Answer 25

prokaryotic blue-green to pink in colour phycobiliproteins (phycocyanin, phycoerythrin) are major light-harvesting pigments includes the smallest and some of the largest phytoplankton Trichodesmium is capable nitrogen fixation - transforming N2 gas into ammonium Synechococcus accounts for about 20-30% of total ocean primary productivity Prochlorococcus is the smallest photosynthetic cell (<1 µm diameter)

Answer 26

heterotrophic protists and animals rely directly, or indirectly, on phytoplankton for food largest biomass in surface waters (epipelagic) ``` metazoan zooplankton Crustacean zooplankton Chaetognaths (arrow worms) Pteropods (molluscs) Gelantinuos zooplankton (coelenterates, ctenophores, salps) ``` protozooplankton ciliates, flagellates, amoeboids ``` Single-celled animals that are grouped based on motility into flagellates ciliates amoeboids: foraminifera radiolaria ``` consume bacteria, phytoplankton and other protozooplankton fed upon by larger zooplankton mixotrophic protists are both photosynthetic and phagotrophic

Answer 27

Radiolaria silicate test feed using long, thin, retractable pseudopodia planktonic species may contain symbiotic algae (zooxanthellae) many benthic species

Answer 28

The term bacterioplankton refers only to heterotrophic prokaryotic organisms in the plankton. excludes cyanobacteria, which are autotrophic. includes archaea, which are not bacteria. Bacterioplankton consume organic matter consuming O2 and releasing CO2. Bacterioplankton also play important roles in the nitrogen cycle. Virioplankton are viruses that infect bacteria, phytoplankton, protozoa and other organisms.

Answer 29

``` Meroplankton = zooplankton that spend part of their life in the plankton and the remainder in the benthos Holoplankton = planktonic organisms that spend their entire life in the plankton Ichtyoplankton = planktonic developmental stages of fish Neuston = organisms associated with the sea surface Pleuston = organisms that protrude into the air (Portuguese man-of-war) ```

Answer 30

Autotroph = an organism that manufactures its own organic carbon using energy from the sun or other sources. photosynthesis uses light energy (photoautotrophy) chemosynthesis uses chemical energy (chemoautotrophy) Primary production = the conversion of inorganic carbon into organic compounds by autotrophs.

Answer 31

availability and uptake of nutrients temperature affects the rate of metabolic reactions specific temperature optima and tolerance ranges intensity and quality of light net primary production is confined to relatively shallow water depths due to the high attenuation of light in water the relationship between photosynthesis and light intensity Limiting Factors: Nutrients Nitrogen is the principal limiting nutrient for many pelagic marine ecosystems. Iron is a limiting factor in the Southern Ocean and other ‘high nitrate/low chlorophyll’ (HNLC) regions. Diatoms require silicate. Phosphorus can limit growth of N2-fixing cyanobacteria.

Answer 32

nutrients in high concentrations near the sea surface sufficient light throughout the surface wind-mixed layer to allow net phytoplankton growth, and the growing phytoplankton population must also escape from the high mortality imposed by zooplankton grazers

Answer 33

diatoms tolerate low light, mixing keeps these non-motile cells in suspension, silica cell wall and large cell size provides protection from many protozoan grazers

Answer 34

phytoplankton growth rate increases due to the increased availability of solar radiation, and shallower mixed layer depth diatoms are poised to take advantage of these favourable conditions because of their ability to grow rapidly, and to avoid being eaten by protozoa

Answer 35

diatoms provide an excellent food source for crustacean zooplankton calanoid copepods are the principal grazers of diatoms adult female copepods may lay up to 50 eggs a day comb jellies, tunicates and arrow worms become abundant, grazing on the copepods zooplanktivorous fish become abundant in the declining phase of the spring bloom

Answer 36

protozoan zooplankton become increasingly important as the water column remains stratified protozoa regenerate nutrients in summer most of the primary productivity depends on recycling of nutrients between protozooplankton, bacterioplankton and phytoplankton with little export in sinking particles

Answer 37

picophytoplankton have high surface area-to-volume ratios and high nutrient affinities N2-fixing cyanobacteria can tap the atmospheric N2 source vertically migrating dinoflagellates, because they can migrate to nutrient rich deep waters.

Answer 38

Regulated by the same environmental factors and ecological interactions as the seasonal cycle. Typically nutrient-limited in tropical seas. Little seasonal variability. Typically light-limited in polar seas. Summer bloom.

Answer 39

One of the major differences between the pelagic and most other environments is that there is virtually no place to hide in the open water. Exceptional, are clumps of the floating plant Sargassum and other floating debris. These ‘islands’ often attract animals.

Answer 40

``` Body armour (Chitin, CaCO3, SiO2, Cellulose) Chemical warfare (toxic dinoflagellates) Camouflage transparency colour/shading counter illumination Diel vertical migration ```

Answer 41

There are two broad classes of vertical migration. Ontogenetic - associated with different developmental stages in an organism’s life history (seasonal). Diel - a behavioural response that involves a trade-off between: maximising feeding and avoiding being eaten. Diel Vertical Migrations (DVM) often involve upward migration at or after dusk (following isolumes) and downward migration prior to dawn (endogenous biorhythm)

Answer 42

Accumulation of buoyant cells in sinking regions of Langmuir circulation, or accumulation of sinking cells in rising regions of Langmuir circulation.

Answer 43

Order Cetacea Odontoceti: Toothed whales: dolphins & porpoises Mysticeti: Baleen whales: the great whales streamlined, elongate body to reduce drag forelimbs reduced to stabilising paddles hind limbs completely reduced (vestigial bones) highly muscular posterior ending in a horizontal tail for propulsion - fluke nearly hairless body thick subdermal fat layer (blubber) insulation streamlining energy reserve ``` blow-hole (nostrils) located on back of head expel CO2 upon reaching the surface Mysteceti – two Odontoceti – one storage of O2 haemoglobin in blood myoglobin in muscle hearing is the most important sense sound travels faster and further in water than in air light is attenuated rapidly some river dolphins are blind ```

Answer 44

``` sperm & killer whales, dolphins & porpoises active hunters of large prey sonic and subsonic clicking signals echolocation communication social animals ``` killer whales travel in small pods dominant female, several females and subordinate males subordinate males remain with mother’s pod but mate with females from other pods

Answer 45

Clicks are generated by moving air between internal cavities (air sacs) and are focused using a fatty structure (melon) Incoming sound is perceived by lower jaw, and transmitted to the inner ear

Answer 46

filter feeders having baleen plates instead of teeth right whales swim slowly = current = zooplankton (<3 mm length) strained on baleen plates rorqual whales intermittent suspension feeders -expandable pleats of elastic tissue in throat and thorax -enclose swarms of zooplankton in mouths and use tongue to force water through baleen plates to strain prey

Answer 47

most toothed whales do not migrate, but do travel to search for food many baleen whales - feed in polar regions on abundant plankton in summer - migrate to warmer regions to breed in winter still uncertain how whales navigate - visual clues when close to shore - earth's magnetic field

Answer 48

large eyes for vision in low light hearing most important sense whiskers are tactile organs used in detecting prey moult annually feed on fish, cephalopods, krill, other seals some bottom feeders (crabs and shellfish) prey to sharks, killer whales migrate between feeding ground and haul out sites mate and rear young on rocky shore areas suitable beaches are limited in extent, hence large colonies and competition for space large males arrive first and establish territories, and maintain them by display and combat dominant males maintain harems subordinate males at the fringes of the territories of the dominant males

Answer 49

Adaptations to prevent the bends -formation of N2 bubbles in blood and joints during rising from depth collapse lungs before diving -limits the amount of N2 that can dissolve in blood under high pressure experienced at depth Adaptations to reduce O2 demand Heart rate slows (in northern elephant seal, for example, from 85 to 12 beats per minute) Blood supply to vital organs (brain, heart) is maintained Blood supply to extremities and intestine is reduced

Answer 50

``` Trophic interactions (i.e. predation) lead to flow of energy Not all consumers eat all prey Not all consumers eat producers Energy flow through steps – “Food-Chain” Each step = Trophic level Many chains in every web! ```

Answer 51

tides alternatively submerge and expose intertidal plants and animals affecting - physical stress (heat and water stress) - food supply - susceptibility to predation tides drive water circulation in bays tides trigger spawning in some species

Answer 52

Two forces cause the tides - gravitational forces exerted by moon and sun, and - centrifugal force due to rotating earth. Result is the equilibrium tide -two bulges on opposite sides of the earth.

Answer 53

Spring tides = greatest tidal range (highest high and lowest low) occur during new and full moon Neap tides have the lowest tidal range (lower high and higher low) occur when sun and moon are at 90o.

Answer 54

The tidal range in the ocean varies from 0 (Caribbean) to 15 m (Bay of Fundy, Canada) Macrotidal = large tidal range > 4 m range British Isles tidal currents are important in sediment transport Microtidal = small tidal range <2 m Mediterranean sea waves are important to sedimentary processes

Answer 55

Waves begin to form as soon as the wind starts to blow Size of wave depends on speed and duration of wind fetch = span of water over which the wind blows Waves break when their orbital motion feels the friction of the sea bed

Answer 56

Vertical zonation - dominant species occur in distinct horizontal bands - along a gradient from fully terrestrial to fully marine. Zones are compressed in protected areas with low tidal range. On open coasts, the zones are extended by wave splash.

Answer 57

Lichens (Verrucaria) -black blotches cyanobacteria (Calothrix) -dark green mats Tufts of algae - algae (Ulothrix) - brown (Pelvetia) - red (Porphyra) Periwinkles (Littorina) and Limpets (Patella) graze on algae Top predators include terrestrial animals (e.g., birds, rats) and marine predatory snails

Answer 58

Acorn barnacles form bands at upper end (Chthamalus, Balanus & Semibalanus) Lower in the mid-intertidal are - mussels (Mytilus) - gooseneck barnacles (Pollicipes) - rockweed (Fucus & Pelvetia)

Answer 59

Mussels & barnacles are rare due to high predation pressure Zone is dominated by seaweeds Sea urchins are common grazers

Answer 60

Four major factors involved in zonation are larval settlement (dispersal & colonisation) physiological tolerance of stress Predation (e.g. by seastars, birds etc) competition for space

Answer 61

``` Epifauna = live on the surface Some animals avoid being dislodged by seeking shelter in cervices behavioural response Adaptations to hold on holdfasts in seaweeds mussels glue themselves on using byssal threads limpets and chitons (right) cling on using a muscular foot ```

Answer 62

extremes of temperature during periods of emergence sea has more stable temperature than air due to high heat capacity of water adaptations include: ability to tolerate high temperature range use of light colours to reflect sunlight sheltering in moist places to allow evaporative cooling (under rocks… like the below)

Answer 63

Drowned river valley (= coastal plain estaury) formed when sea level rose at end of last ice age Examples include Thames Estuary Delaware Bay Chesapeake Bay Fjords are estuaries in deep valleys cut by glaciers formed when sea level rose at end of last ice age high latitudes including Norway, Southwestern Chile Bar built estuaries: sediments build up to form barrier sand bars & islands North Carolina Bays behind protection given by Cape Hatteras North Sea coast of the Netherlands & Germany Tectonic estuaries are formed by subsidence

Answer 64

Freshwater flows out near the surface Saline water flows in near the bottom Salt wedge = a layer of denser, saltier seawater that flows along the bottom of the estuary There is mixing at the interface between salt and fresh waters due to wind, tides and river flow Tidal prism = the volume of water that is moved in and out of an estuary with the change in the tides

Answer 65

Mid-salinity zones of estuaries are often regions of low taxonomic diversity Estuarine species must be able to tolerate salinity fluctuations Stenohaline species tolerate low salinity range Euryhaline species tolerate a high salinity range Osmoconformers allow the salinity of their body fluids to change with external salinity Osmoregulators keep the salt content of their body fluids constant

Answer 66

Diatoms (Bacillariophyceace) Cyanobacteria (Cyanophyceace) 3. Euglenoids e.g. Euglena 4. Macroalgae e.g. Ulva, Enteromorpha 5. Angiophyceace e.g. Zostera (eel grass) 6. Chemoautotrophs e.g. Sulphur oxidising bacteria

Answer 67

Salt marshes are intertidal habitats dominated by cord grasses (Spartina spp.) Spartina typically spreads by vegetative growth of rhizomes (root networks within sediments) Often a marsh consists of one or a few clones Roots and rhizomes trap & stabilise sediment, leading to build-up of the marsh and infilling of estuaries Spartina blades contain siliceous deposits that deter grazing Typically, <10% of blade growth is consumed by grazers; the remainder fuels detritus food chains Salt marsh creeks are often productive nurseries for marine fish species.

Answer 68

Spartina anglica originated in southern England in about 1870 when the European cordgrass S. maritima hybridized with the introduced American S. alterniflora more vigorous than either native species -rapid rate of growth, high fecundity and aggressive colonisation planted for coastal erosion control - rhizome systems bind coastal mud - stems increase silt deposition, thereby assisting in land reclamation from the sea

Answer 69

mangroves are salt tolerant tropical and subtropical trees salt is secreted from leaves by salt glands mangrove forests (mangal) support detritus-based food webs root systems are adapted to anoxic, waterlogged conditions oxygen is transported to below ground tissue by upward facing pneumatophores allowing aerobic metabolism in an anoxic sediment fine roots take up nutrients prop roots support the body of the tree

Answer 70

Like cord grass (Spartina), these grasses have extensive rhizome systems Reduced turbulence traps fine sediments Roots extract nutrients from sediments Shoots obtain CO2 from the water column Beds expand largely by vegetative growth of shoots from the rhizomes

Answer 71

Kelp are macroalgae (brown seaweeds) a holdfast attaches the kelp to hard bottoms the stipe provides support allowing the blades to reach the sea surface buoyancy is provided by pneumatocysts

Answer 72

Alternation between large sporophyte (diploid, spore-producing) and microscopic gametophyte (haploid, gamete producing) stages Spores settle on bottom, develop into male or female gametophytes Sperm produced by male gametophyte fertilize eggs produced by female gametophytes to produce diploid sporophytes

Answer 73

Kelp growth off California depends on upwelling of cold nutrient rich waters Upwelling, in turn, varies with large scale patterns in the winds and ocean circulation Coastal upwelling is associated with along shore winds that blow towards the equator on the west coast of continents

Answer 74

occurs as a result of Ekman transport of surface waters the Coriolis force causes surface water movement to be deflected to the right of the direction of the wind in the N. hemisphere (to the left in the S. hemisphere) thus, when winds blow from the N to S off California (or S to N off Peru), the surface layer flows off shore

Answer 75

El Ni~no Southern Oscillation (ENSO) The term El Ni~no was coined in 1891 to describe an event that devastated the Peruvian fishery - warm surface current flowed over the coastal waters off South America near Christmas 1891 - thus associated with Christmas (hence El Ni~no, the (Christ) child) It is a short-term weather disturbance that influences wind patterns, sea surface height and precipitation, and affects marine and terrestrial plant and animal populations

Answer 76

a change in atmospheric pressure distributions that accompany El Ni~no normally, atmospheric pressure is - high over the eastern Pacific and - low over the Indian Ocean - prevailing winds blow from east to west

Answer 77

central Pacific trade winds increase in intensity the South Equatorial current speeds up upwelling of cold, nutrient rich water increases surface waters off Peru & California cool down

Answer 78

Soft bottoms are those into which organisms can burrow sand, silt, and/or clay depending on how much water motion there is and the source material for the sediment Exposed places with strong waves have course sand or gravel bottoms Calm, sheltered areas with little wave action often have muddy bottoms Soft bottoms are unstable and shift in response to waves tides currents Sediments may be vegetated (e.g., sea grass beds) or unvegetated (e.g., sands, muds)

Answer 79

Sediment is a mixture of inorganic particles decomposing organic mater labile = readily degradable carbohydrates, lipids and proteins, with high extractable energy content (freshly produced) refractory = what is left over after labile material has been extracted - decomposition products including cellulose, chitin microorganisms bacteria, algae, protozoa

Answer 80

course sediments are well drained and can dry out fine sediments retain water poorly sorted sediments can become water logged O2 (oxygen) content is determined by -the microbial activity (respiration) in the sediment -which consumes O2 and by the extent of mixing which introduces O2 Anoxia develops where -the rate of O2 consumption by respiration exceeds the supply of O2 by percolation of water through the sediment mixing of the sediment by waves or currents Anaerobic bacteria break down organic matter using - sulphate (SO4) instead of O2, - produce hydrogen sulphide (H2S)

Answer 81

``` Meiofauna live in the interstitial spaces between sediment grains Macrofauna Where they live: Epifauna live on the sediment surface. Infauna burrow within the sediment How they feed: Predators & scavengers Deposit feeders: Surface feeders Head-down (in sediment) feeders Filter feeders ```

Answer 82

faecal pellets, chitinous exoskeletons, and marine snow are produced by plankton in the epipelagic much is remineralized (broken down) along the way by bacteria and meso- and bathypelagic organisms sediment traps (cylinders placed at different depths in the water column) are used to sample this material there is a pulse following the spring bloom in temperate waters it can take months for this material to reach the bottom

Answer 83

Food falls of dead fish and sea mammals provide "hot spots" of activity on the deep-sea bed. Deep-sea fishes and invertebrates can home in on these food falls.

Answer 84

high biomass of clams, crabs, mussels, limpets and tube worms most feed on mats and suspensions of free-living sulphide oxidising bacteria dissolved H2S from the vents provides energy that supports these communities chemosynthesis uses the energy from oxidation of H2S to fix CO2 into organic matter

Answer 85

(zooxanthellae) are essential for reef-building by hermatypic corals corals that lack zooxanthellae are ahermatypic and generally do not form reefs zooxanthellae contribute to success of hermatypic corals by removing CO2 which promotes CaCO3 precipitation providing organic matter to the host zooxanthellae benefit from stable environment freedom from predators nutrients supplied by host

Answer 86

high calcification only occurs in warm water zooxanthellae require light rapid growth is limited to depths <50 m tidal exchange and coastal currents bring nutrients and zooplankton to the reef suspended solids (turbidity) reduce light and smother coral polyps strong waves can damage corals role of tropical storms parrot fish and burrowing/boring invertebrates attack living corals creating rubble

Answer 87

Fringing reefs develop near shore, throughout the tropics, where there is a hard surface for larval settlement. Barrier reefs are separated from the shore by a lagoon. The lagoon is protected from the waves, and has a soft bottom. An atoll is a ring of reef, sand bars and islands surrounding a central lagoon.

Answer 88

``` susceptible to damage by sedimentation, pollution and freshwater runoff. reef flat is sand, mud and coral rubble. living hard corals seaweeds, seagrasses and soft corals. ``` reef crest is subject to intense wave action reef slope is steep with dense coral cover

Answer 89

``` Example: Great Barrier Reef (Australia) consists of back-reef slope, reef flat, reef crest and fore reef slope separated from shore by a lagoon ``` fore reef slope is steep with dense coral cover

Answer 90

Fast-growing corals grow up and branch out to collect sunlight also shade their neighbours. Other species attack their neighbours with mesenterial filaments (used for digeston and absorption of prey) or sweeper tentacles that are loaded with nematocysts. The most aggressive species are slow-growing massive corals.

Answer 91

the steps of energy transfer from primary producers through consumers. Energy is lost at each step in a food chain. The longer the food chain, the lower the biomass and productivity of the top carnivores.

Answer 92

low primary productivity long food chains to the commercially important top carnivores (sharks, tuna, salmon) Temperate and Equatorial open ocean regions Southern Ocean

Answer 93

Managing effort limiting catch per boat limiting total catch (close fishery once limit is reached) Restrictions on access number of boats length of season size of fish that are allowed to be caught Restrictions on gear power of boats mesh size prohibition of some types of gear

Answer 94

The introduction by human activity of substances that decrease the quality of the marine environment An oil spill is pollution, a natural oil seep is not. Humans have affected the entire marine environment from beaches to the deepest oceans.

Answer 95

Sources: - Nitrogen oxide from burning fossil fuel - Volatilisation of nitrogen from fertilizer and animal waste - Biomass burning Input via wet (rain) and dry (dust) deposition. This is the primary source of anthropogenic nitrogen into the open ocean

Answer 96

Fertilizers washed off from agricultural land into rivers High in nitrogen and phosphorus Also toxicants such as pesticides and pesticides Increase in extreme weather events means this is likely to get worse. (Christensen & Christensen, 2003) The primary input into costal systems

Answer 97

Sewage is the wastewater generated by domestic and industrial activity. ``` Contains high amounts of organic nutrients (N and P) and chemical toxicants: Drugs (pharmaceutical & illicit) Cleaning products Heavy metals Pathogens ``` During heavy rain untreated sewage is directly discharged into rivers, and untimely into the marine environment.

Answer 98

Shift in the balance of an ecosystem from slow growing corals or seagrass to fast growing macro- or microalgae. ``` Algal blooms Increased phytoplankton Increased benthic and epiphytic algae Oxygen depletion Turbid water Decreased biodiversity ```

Answer 99

Harmful algal blooms Toxic algae Shellfish poisoning Anoxic (no O2) or hypoxic conditions (low O2) Fish kills (suffocation) Loss of harvestable shellfish/fish Odour & loss of cultural value H2S is produced when SO42- replaces O2 in the decomposition of organic matter

Answer 100

In extreme cases eutrophication can lead to permanent or seasonal hypoxic zones. This occurs when large amount of phytoplankton sink and are decomposed by bacteria, depleting oxygen Animals either leave the area or die, undermining ecosystems and fisheries Hypoxic zones are a natural phenomenon but are increasing in size and number

Answer 101

Plastics break down (e.g. exposure to UV) and enter the food chain when consumed by filter feeders such as jellyfish and mussels. Negatively impact fitness due to lack of energy pay off. Toxic additives used in the manufacture of plastics can affect endocrine, reproductive and/or immune systems. They also for agglomerations with other organic pollutants (Pesticides, PCBs) facilitating bioaccumulation in fatty tissues. Plastic pollution has potential to impact biogeochemical cycles such as the biological pump

Answer 102

Organic pollutants such as: chlorinated hydrocarbons (many pesticides) polychlorinated biphenyls (PCBs) manufacture of plastics dioxins and furans As they can dissolve in fat they are very persistent once ingested, and are then accumulate up the food web. Due to biomagnification can reach high concentrations in top predators.

Answer 103

bioaccumulation is a build up of a given toxin over time due to PROLONGED exposure Biomagnification increases in concentration UP the food web BOTH are dangers to Human Health and Marine Life

Answer 104

Direct mortality/toxicity (e.g. copper) Effect sense organs in fish (smell), impacting: -predator avoidance -foraging -schooling -navigation (delayed migration in salmon) -Breeding (finding mates/delayed spawning salmon) Slow growth Increased disease Antibiotic resistance via co-selection

Answer 105

Propeller driven ships Oil, & gas uses seismic surveys that create pulses of intense noise. Anti-submarine measures and sonar generate very loud short pulses of sound that may damage the brain and other organs. Offshore construction (e.g. wind farms) requires prolonged pile-driving and underwater use of explosives.

Answer 106

Seawater is used as a coolant in power plants, oil refineries etc. – leading to elevated temperature around discharges. Fish may be attracted to these areas In tropics, most organisms live in waters that are close to their upper temperature tolerance limit. Fish that should migrate don’t, but are venerable to cold shock if the hot water is disrupted Reduces dissolved oxygen levels Localized change in plant communities as macroalgae/seagrass are replaced with phytoplankton

Answer 107

Low level radioactive wastes are discharged to environment, and high levels of radioactivity may be released during accidents. Low-level radioactive waste has been discharged into the Irish Sea from Sellafield since 1952. Greenpeace described the Irish Sea as the most radioactively contaminated sea in the world.

Answer 108

Inhibit growth of phytoplankton/primary producers kill invertebrates and fish Increase susceptibility of fish to disease Cause hypoxia and anoxia as oil is degraded (what is this similar too?) Destruction of habitats Bioaccumulation of toxic components from water, sediments, or food. lose their insulating ability, leading to death of mammal and birds due to exposure.

Answer 109

Marine phytoplankton perform 50% of global photosynthetic CO2 fixation They also release CO2! Nutrient re-cycling, underpinning food webs. They are venerable to change: Microorganisms have fast turnover rate, for example compared with trees (days versus decades). how microbial communities have/will respond to change is uncertain

Answer 110

The balance between marine microbial autotrophy and heterotrophy will be of key importance with a changing climate - (Sarmento, Philos Trans R Soc B Biol Sci . 2010). There is evidence that the balance may shift towards heterotrophic processes as the climate warms - (Vaqué, Environ Res Lett 2015; 10) This could result in a feedback loop between CO2 production and microbial heterotrophic activity!

Answer 111

Lower pH of fish blood (acidosis). This costs energy to correct and reduces fitness. Changes in behavior e.g. reduced predator avoidance and have trouble navigating. (See Moodle for the debate) corrosion of placoid scales in sharks

Answer 112

Tropical seeps dead reef substratum (yellow) is eroded structural complexity of living corals declines algae proliferate sub-tropics loss of hard coral/coralline algal cover diverse macroalgal communities replaced by turf algae. temperate coasts loss of brown algal canopy cover. coralline algae decline as turf algae proliferate In each case, calcified invertebrates (sea urchins) become fewer and smaller

Answer 113

Difficult to assess stock size because of patchiness in distribution differences in efficiency of capture methods intermixing of stocks on feeding grounds Usually assessed by landings divided by effort (Catch per Unit Effort = CPUE) which reflects population size spatial distribution of the population intensity of fishing effort number of fishing boats, their size and fishing hours However, fishing is not random Effort and catch are self-reported by fishers verified (sometimes) by inspectors

Marine Ecology Flashcards

(137 cards)