Term 1 2023 Questions Flashcards
why is the new lithosphere isostatically most buoyant
there’s a direct relationship between depth + age (so newest is lightest)
what subsections are marine biology subdivided into
functional biology, ecology and biodiversity
what were the earliest life forms
methane-producing Archea, 4.5 bn years ago
what’s an example of a divergent plate margin
Mid-Atlantic Ridge
what is an example of a convergent plate margin
Mariana Trench or NW Pacific
How do tectonics help reefs develop
through isostasy (gravity+buoyancy act on outers crust)
what features occupies the majority of the ocean floor
continental slope and ocean ridges (33%)
How much of earth is water
97%
What are the main properties of water
its a solvent, it has high covalent (allows things to stick), high thermal inertia (latent heat capacity), high viscosity (requires morphology that increases laminar flow)
What are the 2 properties that determine the physical (+chemical) ocean’s structure
Temperature and salinity (+depth+pressure)
how does ocean depth temperature profiles vary
spatially, temporally and with depth
what factors influence an ocean’s depth temperature profiles
seasonality, sunlight intensity, temperature
what are the 3 distinct zones of the ocean’s temperature
surface zone (mixed 25-500m), thermocline (200-1000m) and deep zone (>1000m)
how is the pycnocline (based on density) made
with the thermocline (temperature) and the halo cline (salinity)
what makes the ocean stratified
the temperature determining the density of the water, splitting it into layers that don’t mix often
why does the mixed layer deepen in winter
due to wind mixing (remove pycnocline)
what are the 3 important nutrients for phytoplankton
nitrogen, phosphorus, silicon
what is the global salinity for seawater
34.7% or 34.7ppm
why is salinity more important in colder areas
salt is key for deep waters and drives circulation
what are the properties of salt
non potable, highly corrosive, harmful to many terrestrial plants
why are the subtropics salty
they’re warmer so there’s more evaporation
why are equatorial waters fresher
more precipitation and stronger hydrometeorlogical cycles
why are the poles fresher
less evaporation, glacial melt and very cold so dense salt sinks
why is the Atlantic salty
the continents shapes limit circulation and lots of mineral deposits from rivers
what are the effects of water when salinity is increased
density increases, boiling point increases and freezing point is lowered
how is salinity measured in the ocean
directly: Niskin bottle samples indirectly: CTD (electronic sensors)
what store has the longest residency times in the global water cycle
the ocean - ~3,000yrs
how are ocean currents driven
by wind currents (surface) or global overturning circulation (density-driven), Coriolis force
What is the only gyre that circumvents the whole earth
Antarctic Circumpolar Current
What current carries warm water to the UK
Gulf Stream
what type of flow is caused in cyclonic wind (low pressure)
divergent flow causing upwelling due to surface divergence
what type of flow is caused in anticyclonic wind (high pressure)
convergent flow causing downwelling due to surface convergence
what is the features of the Pacific Ocean circulation
2 subtropical gyres with dominant equatorial countercurrents
what are the 2 categories to organise pelagic organisms
nekton and plankton
what are the types of phytoplankton
diatoms, dinoflaggelates, coccolithophorids, cyanobacteria
what are the types of zooplankton
viruses + bacteria (pico), ciliatiates, dinoflagellates + metazoan larvae (micro), copepods (meso), and gelatinous (macro)
what are the pelagic reigns of the ocean
epipelagic, mesopelagic, bathypelagic, abyssal pelagic, hadalpelagic
what are the benthic regions of the ocean
littoral, sublittoral, bathyal, abyssal, hadal
how is the pelagic realm defined
based on depth and proximity to land
what is plankton defined by
size and broad ecological role
why do marine systems only have 4/5 levels
inefficient eating (>70% lost as heat), long food chains are unstable, predator design is limited, omnivory popular
what is a good predictor of trophic level in marine organisms
body size (energetic demands increase with size) +PP are very small and numerous
why are marine food webs more complex
low levels of specialism (omnivores), opens of system, large sizes changes along life history, long lifespans (ontogenetic shifts)
what was evidence of top-down control
Overfishing of cod in N.Atlantic, increase in crustacea
evidence of trophic cascades
removal of sea otters= increased sea urchins and kelp decreased
example of mesopredator release
removal of cape fur seals led to large predatory fish dominance, depleting stocks
why does carbon form the backbone of life on earth
has intermediate electronegativity (can form several covalence bonds), it’s less reactive and has 4 valence electrons (form rings + chains)
what is the Redfield ration
106:16:1 (C:N:P)
how do nutrients cycle
remobilising: currents, upwellings, upwards migration of organisms. Sinking and dead o C: marine snow, waste and dead organisms
what do seafloor carbon stocks do
cycle, bury and redistribute nutrients eg. photosysnthesis, trapping sediment
what are human-influenced disruptions to marine nutrient cycles
ocean acidification, hypoxia (Gulf of Mexico dead zone), SST temps increasing
are the root adaptations for mangroves
shallow roots, aerial roots, elongation (<9mm/day), aerenchyma, branching, pneumatophore, roots have negative hyrdostatic pressure
where are mangroves distributed
20C isotherms of sea temp
why are mangroves so important
create coastline stability, nursery grounds + provide source of PP
how much of seagrass biomass is underground
20-60%
why are seagrasses important
reduce turbidity, trap suspended sediments (increasing photosynthetic pot. + carbon sequestration
what are the adaptations of seagrasses due to lower light
have a thin, porous cuticle to absorb CO2 , large gas lacunae, single layer chloroplasts in epidermis, grow >20m generally
ow much carbon burial is seagrass responsible for
10-12% (~0.2% coverage)
what is the seagrass ecosystem threatened by
fungal wasting disease, physical damage, coastal development + reduced water quality
what challenges must seagrass overcome
submergence, CO2 limitations and O2 limitations in sediments
what are the subdivisions of the rocky shore
supra littoral, eulittoral and sublittoral
why is the rocky shore important
high species diversity and habitat complexity, + lots of interspecific competitions
what was a test for interspecific competitions
removal of Balanus that then favorured Chthamalus growth
what are the gradients of the rocky shore
wet-dryness, wave action, particle size + salinity
what conditions allow organisms to live in the upper limit (high intertidal) in the rocky shore
its mobile, has a shell and has high metabolic rates
what pressures influence the lower limit (low intertidal) in the rocky shore
competition and predation
how is wave action determied
fetch + wind that drives period, height + swell
what strategies do species have to overcome wave action
timing, positioning, burrowing, attachment (byssal threads or cementing)
what physical and biological factors drive zonation in the rocky shore
desiccation tolerance + competition, niche partitioning, physical + biological forces
what are ht functional groups of primary producers in the rocky shore
microalgae (biofilms+diatoms), simple algae, complex algae (red, green,brown), encrusting algae (calcifies)
what are the functional groups of the grazers within the rocky shore
sweepers (topshells), rakers (isopods), diggers+abraders (urchins), biters+cutters (fish+crabs)
what are the functional groups of the suspension feeders within the rocky shore
individual - strainers (barnacles), siphonal (musses) and colonial (bryozoans+sponge)
what are the functional groups of the predators within the rocky shore
borers+drillers (whelks), crushers+crackers(non-grapsid crabs), external digesters(starfish), browsers+partial predators(nudibranchs), mobile vertebrates(fish+birds), sit+wait(anenomes+hydroids)
how is the rocky shore defined
by gradients and resource partitioning
why does the rocky shore have a high species diversity
large habitat complexity (niches) and abundance of food
what are basking sharks threatened by
trawling bycatch, line entanglement, propellor strikes + people harassment, plastic ingestion
what are the 8 main marine invertebrates
porifera, cnidaria, Ctenophora, polychaete, Mollusca, echinodermata, crustacea, hemichordata
what roles do marine invertebrates play in ecosystem functioning
secondary production, nutrient recycling, habitat structure, grazing + predation
what are the 2 forms of cnidaria
medusa and polyp
why are detritus-feeding polychaete a keystone species
important food source for flatfish and wading birds + burrow causing bioturbation (increases nutrients)
why are muscles good ecosystem engineers
they provide habitats for cryptic fauna, protected from wave action + thermal stress, trap sediments, stabilising mud + enhance habitat heterogenity+ species diversity (increases ecosystem diversity)
what are the general characteristics of nekton
larger body size, greater swing power, mostly vertebrates, mostly fish
what is the importance of nekton
large influences on marine communities, important in current/historical harvests, + important to world food supply
what is the vertical distribution of ocean zones and which types of species are found
mesopelgaic -epipelagic (countershading present), bathypelagic-holoepipelagic (shark), abyssopelagic-meroepipelagic (herring, salmon)
what are the morphology of mesopelagic fish
<10cm, well developed teeth + large mouths, large, light-sensitive eyes, photophores
hat is the morphology of abyssal pelagic fish
species-specific pattens of photophores, small with flabby, soft transparent flesh supported with weak bones, oversized mouth
what are the sub-classes of cephalopods and the superorders
Natuiloidea, Coleoidea: superorder Decapodiformes (squid+cuttlefish) + Octopodiformes (octopus and vampire squid)
what are the features of elasmobranch (sharks)
dermal denticles, 57 gill cleft openings, small, placid scales, rigid dorsal fins, cartilaginous, highly varied + both benthic and pelagic
unlike all other fish, elasmobranchs don’t have swim bladders, how do they control depth
with pectoral fins, using dynamic lift (like helicopter) and gliding on downward trajectory
what makes seabirds different from terrestrial birds
webbed feet, strong sense of smells, partly-wetable plumage, less colourful, increased melanism in wing tips
differences between dolphins and porpoises
body: more streamlined vs smaller + more stout. Rostrum: longer vs blunt. Dorsal fin: falcate vs triangular+smaller. Teeth: pointy vs blunt
what features make nekton have predictable environments
iteroparous (return to grounds), long-lived, delayed maturity, low-reproductive rates, migratory
which nekton are semelparous
cephalopods
what are the adaptations of deep-water nekton
detrivores/carnivores, bioluminescence (photophores), large sensitive eyes, large sharp teeth, expandable bodies, hinged jaws, counterillumination
what are the features of marine reptiles
ectothermic, covered in scaled, have specialised slat glands (excrete excess salt)
what are the differences in seals and seal lions
seals: lack prominent ear flaps, smaller front flippers, fore flipper claws, different hip structures, wiggle and sea lions waddle
what is the defining feature of Carnivora
prominent canine teeth
what is the defining feature of Sirenia (manntees+dugongs)
herbivores
what are the characteristics of Cetacea
elongated skulls with blowholes, few hairs and fluked tails (horizontal)
what adaptations do Cetacea have
large tails + streamlined body + special skin structure (fast swimming), low O2 use (deep diving), collapsible lungs, store lots of O2
causes for migration
food requirements (patchy resources +long time to learn to hunt)
why is conserving nekton difficult
they travel large migratory routes that requires global efforts “conserving a moving target” and they’re extremely overexploited but have a high longevity (if lost, very slow recovery) + vulnerable to bycatch
why are fisheries not even distributed
high coastal poductivity (upwelling + nutrient flow-ins) + easy access
what are the types of nets for fishing
angling, hand-line, demersal long line, floating longline, set nets, drift nets, purse seine, bottom otter trawl and pelagic trawl
what are examples of artisinal/ small scale fishing
freediving, remonas, fish traps, cycanide fishing, dynamite bombing, lobster pot, cast nets, spear fishing
whats an example of the consequence of overfishing
cod stocks in Newfoundlands, 1960s, dramatically decrease in size, use to be <2m long
what are the 4 reasons overfishing occurs
tradegy of the commons, fishing down the foodweb, shifting baselines, hope spots
what are mechanisms used to improve fish stocks
time-area closures, zoning, quotas, gear modification, MPAs and aquaculture
whart are the different types of aquaculture
whole life (salmon), early juvenile only (scallop/lobster), most of lie (mussel), later juvenile only (tuna), ongoing harvest (algae)
what are the 8 key attributes to aquaculture
desirability/marketability, uncomplicated reproduction, hardiness, high growth rate, readily met food requirements, readily met habitat environments, monoculture/polyculture, minimal ecological impacts (from feed/waste/invasives/pollution)
what are the negative sides of aquaculture
doesn’t meet full demand (still catching in open ocean), need to catch fish for food for managed fish, eutrophication+mangrove removal, bycatch, very complicated to manage eg. if no fishing, bushmeat increases, environmental damage, waste disposal issues
what are the advantages of fisheries
renewable resource, food security, employment, cultural identity
what are the characteristics of turtles
reptiles, long-lived, natal philopatry, site fidelity, migratory?navigate, temperature-dependant sex determination
what turtle eats jellyfish
leatherback, flatback
which turtle eats sponges
hawksbill
what turtles eat crabs
kemp’s ridley
which turtle is herbivorous
green turtles
which turtle is data-deficient
flatback turtle (N.Austrailia)
which turtles are the most endangered
CE: Kemp’s Ridley (only nests in Mexico) and CE: Hawksbill (hunted for shell)
how long do turtles live for
not known ,only can base upon return to nesting sites
how do turtles navigate
hatchlings orient self to moonlight and downward slope + perpendicular to waves (magnetic orientation[learned behaviour])
which turtle is the deepest diver
loggerhead, <10.2hrs (longest), leatherback >1,000m (deepest)
how do turtles reproduce
they store sperm and lay eggs with GSD (female bias)
what are the 3 families of the sub-order Pinnipedia
Odobenidae, Otariidae, Phocidae
what are the differences between phocidae (seals) and otariidae (sea lions)
movement: hindflippers + wiggle vs foreflippers, + can walk. Ear: no external ear vs external ear. Breeding: capital vs income, size: larger vs smaller. Scratch: fore flippers vs hind flippers
what are the characteristics of Pinnipeds
found in all major oceans (+freshwater), have amphibious lifestyle, most numerous marine mammal
what is the life history of pinnipeds
need land to moult, then at sea, then breed + pregnancy (delayed implantation), then return to sea
what are the factors of capital breeders
have single long trips, economic foraging strategy (phocidae) provisioning: short lactation, fasts during it, rapid pup growth
what are the factors of income breeders
multiple short trips, depend high energy to obtain high energy (Otariid) provisioning: long lactation, feeds during it, slow pup growth
what Pinniped has the shortest lactaion period
hooded (4 days 60% fat) and Harp (12 days 48% fat)
what is the general diet of Pinnipeds
fish + squid (exceptions: walrus, crabeater + leopard)
how do walrus feed/prey
bottom feeders, eat benthic prey (>600 clams/day), find with vibrissae, stir up sediment
what are Pinnipeds threatened by
bycatch, climate change, competition, zoonotic events
why are seabird important
ecosystem engineers (bring nutirents to islands + regulate plankton+ guano deposits), ocean sentinels (indicate ocean health)
how many seabirds are there globally
~0.7 bn
what are the characteristics of Bluefin Tuna
large + commercially-exploitable, endothermic, complex spatial dynamics (fishing pressures, climate + recruitment)
what are tunas spawning behaviours
time: 0-sunrise. depth: shallow <25m. temp: warm ~25C (chase + cross thermocline continuously)
why is marine biodiversity important
protect coastal communities from storms + erosion, tourism, commercial fish habitat (estuaries+seagrass), produce 1/2 O2 + carbon sinks, natural filters (saltmarshes+mangroves), provide jobs (at fisheries), new medicine (reefs)
what are the drivers of biodiversity loss
overexploitation, climate change, invasive species, pollution, habitat degradation
why is bycatch difficult to define
there’s multiple defs as some consider only size and age of sqme species as bycatch, others different species and some unused/unmanaged species. and some are unharmed, released or some have injuries or are killed
wat are the physical changes to the marine environment from climate change
ocean acidificaiton, ocean freshening, increasing desertification, increasing air temp, extreme events, slowing thermocline circulation, sea level rise, increasing sea temps, ozone depletion, melting land-ice
what are the challenges of marine conservation
expensive as difficult to access and monitor. difficult to find life history, abundance and distribution + socio-economic drivers fo human behaviours
how can invasive species be introducee
shipping (taking water into hull), aquaculture, canal constructing, aquarium trade, live seafood trade
how many marine species are considered by the ICUN to be data deficient
21%
how do we reduce threats in marine environments through conservation
quantify threats, understand impacts, need data + evidence for conservation
what ways can we reduce bycatch
increase stocks via recruitment (legalise), set limits, good governance, protection+mangament, education+awareness, time area closures, BRT, buy outs (eg nets that allow turtles through)
what are the biodiversity conventions
Kunming-Montreal Global Biodiversity Framework (2022) and Protected PLanet website (UNEP-WCMC)
what is the problem with large-scale MPAs
political (winner in MPA size), don’t consider patchiness and migration corridors or arent target-orientated, takes away areas that are biodiversity hotspots and need to be protected
how are people made aware of MPAs and conservation
work with local educatoras, campaigns, lobbying (blue planet)
what are the main categories of marine pollution
toxic substances, solid waste (plastic debris), sewage+eutrophication, warm water noises, noise, light
what are the 2 types of pollution discharge
acute (oil spill), chronic (year-round sewage)
what are the 2 types of pollution sources
point (discrete entry) and diffuse (variety of entries)
what are the 2 types of marine pollution effects
acute (oiling) and chronic (changes in community structure)
what are the types of toxic substances founding marine pollution
heavy metals, POPs, CO2 and PAHs
what are the effects on heavy metals in the ocean
methyl-mercury bioaccumulation (minimata disease), denatures proteins, binds to blood pigments, effects renal function
what are the effects of POPs on the ocean
slow degradation, biomag+accum, carcinomas, reproductive failure, impacts on immune, endocrine +nervous system functioning
what are the effects of PAHs on the ocean
Oil fouling, cascades, PHAs (cancer), toxic (chemical dispersants)
what are the effects of CO2 on the ocean
decreased seawater pH, reduced CaCO3 for crusteacea, increased sea temps (coral bleaching+glacial melt)
what are the effects of plastics on the ocean
ingestion, chemical contamination, entanglement
what are the effects of nitrogen on the ocean
eutrophication (anoxia), harmful algal blooms (red tides causing poisoning)
what are the effects of noise pollution on the ocean
hearing damage, stress, behavioural changes, distrubance, masking
what are the effects of thermal pollution on the ocean
kills species, replace PP, increase alien species
what are the effects of light pollution on the ocean
disruption o movement patterns, greater exposure to other threats, reduced reproductive success
why is ascension island s focus in terms of MPAs
large sea turtle nesting spot, part of British overseas terretories
How are threats to fish found out in terms of MPA set up
look at fish bycatch, satelite tracking (residency), seamount surveys, BRUVS, look at seabirds
what are the issues to set up MPAs
must be more profitable than other strategies + could be a paper park or “blue belt” for politics.
