Marine Flashcards
Five Oceans of the World
Atlantic Ocean Pacific Ocean Indian Ocean Arctic Ocean Antarctic (or Southern) Ocean
Australia is surrounded by 3 oceans
Pacific Ocean
Indian Ocean
Antarctic (or Southern) Ocean
Chemical & Physical Properties of water
- Polarity
- Cohesion
- Adhesion
- High heat capacity
- Universal solvent
- salinity
- Density
- Temperature
- Light penetration
Polarity
Uneven distribution of charges across a molecule making one end positive (H) and the other negative (O)
Cohesion
• Hydrogen bonds hold water molecules together. Cohesion creates surface tension
Adhesion
The tendency of water to stick to other substances
High heat capacity
- Water has the highest specific heat capacity of any liquid. Specific heat is defined as the amount of heat one gram of a substance must absorb or lose to change its temperature by one degree Celsius. For water, this amount is one calorie, or 4.184 Joules.
- Because water absorbs and releases heat at a rate much slower than land, air temperatures in areas near large bodies of water tend to have smaller fluctuations
Universal solvent
• Water can dissolve many substances
-able to separate ionic bond from substances
Dissolved salt (salinity)
• Seawater is 3.2% to 3.7% salt (~35 ppt – parts per thousand or PSU = Practical Salinity Unit)
• 99.6% comprised of: chlorine (Cl), sodium (Na), and magnesium (Mg), sulpher (SO4), calcium (Ca), & potassium (K)
-salt of the water comes from eroding land, reaction from seafloor, volcanic activity, atmospheric depravity
- higher salt concentration occurs at tropical area due to high evaporation and low presentation and vice versa also in land lock and arid region
-melting of ice and connecting to river can also lower salinity
Properties of seawater
• Salt decreases heat capacity (~4%)
• Lowers freezing point (-1.9°C)
• Increases density
Density is a measure of how much mass there is in a given volume or amount of space. The density of any substance is calculated by dividing the mass of the matter by the volume of the matter
-The density of seawater is a function of temperature, salinity, and atmospheric pressure
Temperature
- lower temperature are found in the north poles near antartica.
- high temp are found in the equator
- the cause is due to more sunshine on the equator. the sunlight concentration is less in the poles area
- In australis, the temperature of the north coast is higher than that of the south coast
Light penetration
- Sunlight entering the water may travel about 1,000 meters into the ocean under the right conditions, but there is rarely any significant light beyond 200 meters
- Light with longer wavelengths is absorbed more quickly than that with shorter wavelengths
- The higher energy light with short wavelengths, such as blue, is able to penetrate more deeply
Ocean Currents
Throughout the ocean there is one interconnected circulation system powered by wind, tides, the force of the Earth’s rotation, the sun, and water density differences
Convection cells in the ocean
Cold, dense polar water is drawn down from higher latitudes and sinks to the ocean bottom, pulled down toward the equator as lighter, warmer water rises to the ocean’s surface.
Coriolis effect
The Coriolis effect describes the pattern of deflection taken by objects not firmly connected to the ground as they travel long distances around the Earth
-This is due to the earth revolve faster in the equator area than the pole
Rotating Earth
• North hemisphere deflect to right (clockwise)
• South hemisphere deflect to left (anti-clockwise)
Air movement
- air can also affect the surface water movement as they pull water along
- three cell patterns exist in northern and southern hemispheres due to unequal distribution of land and earths movement
- largest are Hardly cell: at the equator, warmer and less dense air rises up to 18 km and spread out underneath the tropopause while cool air sink down toward the poles end
- smallest are polar cells which acts in a similar way to hardy cells
- in the middle cell are ferral cell, not driven by temperature and flow in the opposite direction compare to the other two. transport heat from the equator to the poles and create area of semi permanent high and low pressure
Major ocean currents
- In the northern hemisphere, predictable wind know as trade wind blow from east to west and pull water with them, create surface current. due to clorioslus effect, it pull current to the right heading north. at 30 nrth lat, another wind cause the current to east , creating a close clockwise loop which is know as a gyre
- the same occur in the souther hemisphere but counter clock wise
Australia’s ocean currents
-Australia’s ocean currents influence pattern of rainfall on land, distribution of marine organisms and productivity of the sea
knowledge of currents useful when designing infrastructure, searcher and rescue
Upwelling
-wind flow parallel to the coast with coast line to the right. this cause water to move offshore allowing colder and nutrient-rich water to rise
most important is bonny upwelling, occur summer to autumn, oct to may
Tides
Tides are the periodic rise and fall of surface water caused by the gravitational force of the moon and the sun and by the rotation of the earth
Biological Oceanography
Biological oceanography is a field of study that seeks to understand what controls the distribution and abundance of different types of marine life, and how living organisms influence and interact with processes in the oceans
Primary Productivity
Marine primary producers use dissolved carbon dioxide, with sunlight and water, to make carbohydrates (~60 gigatons [109] of carbon are fixed each year)
Phytoplankton are free-floating prokaryotic and eukaryotic photosynthetic microbes that live in large bodies of water; they are very abundant (≥103 ml-1) and perform essential ecosystem services to sustain life on Earth
Phytoplankton are highly diverse (morphology, size, taxonomy), occupying different habitats in the global ocean (also exist in freshwater and estuaries)
Primary consumers
Zooplankton
• Copepods: about 7500 species, extremely abundant. Biomass ~0.8 and 2.0 billion tons
• Krill: Shrimp, etc., ~500 million tons in the southern ocean
• Meroplankton: Larval forms of barnacles, molluscs, fish, and jellyfish, all of which grow to be much larger animals
Secondary & tertiary consumers
- Planktivorous fish (sardines, anchovies)
- Baleen Whales
- Cephalopods
- Predatory fish
Higher-level consumers
- Large predatory fish
- Marine mammals
- Birds
- People
What is biodiversity
variety of life in the sea that comprise of variation in level of complexity from within species to across ecosystem
Four components of biodiversity
o Compositional diversity = the number of entities
o Structural diversity = the distribution of abundances of these entities in communities (α-diversity), can take into account relative abundance and evenness (=the extent to which species are equal in number)
o Divergence or disparity = the degree to which the entities differ (β-diversity)
o Functional roles these entities play in ecosystems = e.g., trophic, metabolic, habitat forming
Most commonly used measures of biodiversity
- Genetic diversity
- Species diversity
- Community/Ecosystem diversity
Genetic diversity
Diversity within species: variation within the genome of a species
Contributes to adaptive potential
New genetic variation arises via
o Mutation
o Interbreeding (recombination)
o Migration of individuals
Forces operating on standing genetic variation
o Genetic drift (chance)
o Environmental drivers & natural selection - adaptation
Species diversity
-the abundance and variation of species living in a specific area
• Only ~226,000 multicellular eukaryotic marine species of an estimated total of ~2.2 million have been described (Appletans et al 2012; Mora et al 2011)
• This is 1/5-1/4 of all eukaryotic species on Earth
• Molecular methods will add/are adding tens of thousands of (cryptic) species
Indo-Pacific – Australia is a biodiversity hotspot
Australia is home to ~11% of known multicellular eukaryotic marine species
- 50 thousand marine species (32000 describe)
- 5k fish
- 30% of shark and ray
Community/Ecosystem diversity
-The variety of different habitats, communities and ecological processes
-Six discrete marine regions have been identified under Australia’s marine bioregional
planning in support of the Environment Protection and Biodiversity Conservation Act
-A marine bioregional plan has been developed for each region that describes its marine environment and conservation values, sets out broad biodiversity objectives, identifies regional priorities and outlines strategies and actions to address these priorities.
-North, Coral Sea, Temperate East, South-east, South-west and North-west
• Life originated in the sea
• Oldest known fossils are marine stromatolites, laminar structures produced by the
activity of cyanobacteria, preserved in Australia and dating back 3,500 million
years
• First animals also appeared in the sea, These animals belong to the so-called
“Ediacara” fauna of the Vendian system, a name which recalls the Australian
locality where they were discovered (640 million yr old)
Biodiversity change over evolutionary timescales
General increase over geological timescales, punctuated by declines caused by mass extinctions.
-change slowly over a course of time, this is know as ecological succession. This is caused by a disturbance which lead to increase in biodiversity due to the species themselves. A larger disturbance can reset the diversity. As time pass, the initial increase might decrease.
Drivers of biodiversity
Biodiversity is somewhat predictable:
i) Tropics > temperate
ii) More structural complexity > less complexity (e.g., coral reefs
> open ocean; forests > grasslands)
iii) High productivity > low productivity (e.g., productivity is often
inversely correlated with elevation/depth)
iv) Mainland communities > island communities
v) Larger area > smaller area.
Note that in the marine realm, apparent latitudinal gradients in biodiversity are
not always real and in some groups have been shown to be closely related to
oceanographic covariates, such as water temperature
Intermediate disturbance hypothesis
-diversity in maximise when the disturbance ins not too rare or too frequent, small
Marine biodiversity largely explained
by 3 variable
- Depth
- Temperature
- Light
Long-standing hypotheses behind CIP diversity hotspot
• Centre-of-origin: Centre of diversity is centre of speciation.
• Centre-of-accumulation: Speciation in originated elsewhere and transport
to centre via dispersal on ocean currents.
• Centre-of-overlap: Centre is overlap area of otherwise separate
biogeographic provinces defined by oceanic conditions & past geological
events.
• Centre-of-survival: Lineages in the CIP experienced less extinction than
those in surrounding regions
Porifera: Sponges
Key Characteristics: • Mostly lack symmetry, few tissues, no organs • Skeleton of spicules • All sessile • All filter feeders • Important in nutrient cycling
Cnidaria: corals, hydroids, jellyfish, anemones
Key Characteristics: • Possess nematocysts (stinging cells) • Two body forms: medusa and/or polyp • Radially symmetric • Auto & heterotrophic • Important in forming habitat
Annelida (ringed worms)
- Bilateral, segmented bodies
- Circular and longitudinal muscle layers
- Soft bodied
- High diversity of body shapes
- High diversity of habitats
Arthropoda: Crustacea, e.g. crabs
Key Characteristics: • Hard exoskeletons and jointed limbs • Segmented bodies • Grow by moulting • Key to ocean food webs (e.g., copepods) • Important scavengers and grazers • Important food source for humans
Mollusca: Gastropods, Bivalves
Key Characteristics: • Soft body with (usually) external shell • Ventral foot for locomotion • Mantle tissue for producing the shell • Tongue-like radula • High complexity • Important at many trophic levels • Important food source for humans
Mollusca: Cephalopods, e.g., squid, octopus, etc.
• ‘head footed’ and possess a beak • Found in all oceans at all depths • All carnivorous • Important predators • High intelligence, well-developed sensory systems • Most have chromatophores • Many bioluminesce
Bryozoa (Ectoprocta): Moss animals or lace corals
• “Moss animals” • Majority are colonial • Majority with external mineral ‘house’ • Common fouling organism
Echinodermata: sea cucumbers, urchins, brittle
stars, seastars, feather stars
Key Characteristics: • Pentamerous (five-part radial) symmetry • Water vascular system with tube feet • Calcareous endoskeleton • Grazers or carnivores • Can alter sediments
Urochordata: ascidians (sea squirts , tunicates)
Key Characteristics: • ‘vertebrate predecessor’ with notochord • Simplest of chordates • Colonial or solitary • Possess gelatinous tunic • Important filter feeders • Some invasive
Coral Reefs
-Scleractinian corals deposit calcium carbonate skeletons and form the 3-dimensional structure of the reef, which provides habitat to many other reef-dwelling organisms.
-Reef-building corals are thus both foundation and keystone species
‘Reefs grow when calcium containing sediments are deposited in spaces between coral
-Encrusting coralline algae “glue” the sediments together, new “live rock” is formed
Scleractinian coral colony morphology
Most scleractinians are modular organisms, forming colonies comprised of many identical modules, the coral polyps or it can be an individual polyps Massive • Slow growing, large • Dome-shaped • Reef margins & lagoons Branching • Fast growing • High/mid-wave energy • Fragmentation propagation Encrusting • Lichen-like • Low spreading Foliaceous • Often scroll-like • Fast growing, fragile • Early recruiters Laminar • Table-like (surface) • Plate-like (depth)
The scleractinian coral body plan
Corals are an ancient group having a simple, radially-symmetrical body with a single opening that serves as both a mouth and anus (Coelenteron). The body is made up of two layers of cells(Gastrodermis and mesodermis), separated by a jelly-like layer (Mesoglea) with no internal organs. Corals possess specialised stinging cells called nematocysts on their retractable tentacles that are used to catch food.
The polyps make skeletons (or corallites) of calcium carbonate around themselves
Coral symbiosis
Corals form an obligate symbiosis* with dinoflagellate algae (family Symbiodiniaceae)
-alge provide sugar for coral ( it’s major food source)
Main types of reef structures
Fringing reef
Project seaward directly from the shore, forming borders along the shoreline and surrounding islands
Barrier reef
Barrier reefs also border shorelines, but at a greater distance. They are separated from their adjacent land mass by a lagoon of open, often deep water
Atoll
Atolls are usually circular or oval, with a central lagoon. Parts of the reef platform may emerge as one or more islands, and gaps in the reef provide access to the central lagoon
Fringing reefs
Adjacent, attached, or nearshore
o No/narrow lagoon
o Strong terrestrial influence
o High non-carbonate sediments
Barrier reefs
o Off-shore structures
o Wave-resistant consolidated limestone
o Lagoon separating shoreline
o Oceanic controls
Atolls
o Often ring-shaped
o Central lagoon
o Off-shore
o Channels connect to open ocean
Patch reefs
o Smaller reef structures
o Often in “deep” lagoons (10-15m)
o Often sand hallow
-small patches that are close to each other
Coral reef Modern distribution
- Common in the tropic
- closely associated with land
- not in the pacific due to lack of island, no shallow bottom
Coral Reproduction
Asexual reproduction • Budding of polyps • Fragmentation • Fission • Asexually produced larvae • Polyp bail-out Sexual reproduction • Broadcast spawning • Brooding • Hermaphroditic or gonochoric
Conditions for coral reef growth
Light (algal endosymbionts) Hard substrate Low sediment Marine salinity 35 Limited emersion <1 hr Warm water >18°C (but not too warm)
Climate warming causes mass coral bleaching
- increase in temperature cause the coral to be stress
- alge leaves the stressed corall
- coral die
Reef community
Algae • Crustose coralline algae (CCA) o Important cue for coral recruitment o Suppress macroalgal growth o Solidification of reef framework Macroalgae • Filamentous • Response to nutrients • Compete with corals • ‘Phase-shifts’ Sponges (porifera) • Filter feeders • Nutrient cycling & transfer up food web • Add physical complexity Octocorals • Soft corals, sea fans, sea pens, blue corals • Create complexity (habitat) • Modular cnidarians • Sometimes with algal endosymbionts • Polyps with eight tentacles Molluscs • E.g., nudibranchs, clams, cephalopods, scallops, • Many trophic levels • Giant clams harbour algal symbionts in specialised tubular structures Crustaceans • E.g., prawns, shrimps, crabs, crayfish, barnacles • Scavengers • Symbiosis, eg cleaner shrimps, removal of dead coral tissue by coral-inhabiting crabs Echinoderms • E.g., starfish, crinoids, • Important algal grazers, others predators, planktivores • Can be keystone (Diadema antillarum) Fishes I • Many functional groups: o Corallivores (e.g., butterflyfishes) o Herbivores (e.g., parrotfish, surgeonfish) o Omnivores/planktivores (e.g., damselfishes) predator
Crown-of-Thorns starfish
(Acanthaster sp.)
• A major source of decline of Indo-Pacific coral reefs
Coral competition
• Definition: A contest between
organisms for territory, a
niche, or other resources…
• Sweeper tentacles (attack competitor coral via neumatocis)
• Mesenterial filaments (kill and devour competitor)
Symbiosis on coral reefs
Mutualism • Symbiosis: the long-term, intimate association between two or more species • Microalgae & corals • ‘Cleaner’ crab • Guard crab/shrimp and corals • Cleaner shrimp/fishes • Anemones and anemonefishes Commensalism • a relationship between species in which only one has a benefit, no harm to the other • Coral shrimp and corals • Gall carbs Parasitism • relationship between species, where one organism, the parasite, lives on or inside another organism (the host), causing it some harm • Parasitic nudibranchs, flatworms, copepods, …
mportance of reef ecosystem
Coral reefs provide an estimated US$30 billion each
year in goods and services, including:
• Fisheries
o Nurseries for ~25% of ocean’s fish
o 1 billion people depend on coral reefs for food and income
o Can yield 15 tonnes of seafood per km2 per annum
• Tourism
o GBR generates US$1 billion per year; Florida Keys ~US$3bn
o Alternative income for coastal communities in developing countries
Importance of reef ecosystem
Coral reefs provide an estimated US$30 billion each year in goods and services, including: • Coastal protection o Break wave energy during storms (wave adapted) o Protect coastal erosion • Medical opportunities/prospects o Anti-viral, cancer and HIV • Intrinsic cultural value o Cultural traditions o Biophysical beauty
The reat southern reef versus the GBR
Similarities and Differences
Both provide structure for many species
•Corals are dominant on the GBR, and provide structure for other species
• Kelps /fucoid algae dominate the GSR and provide structure for other organsms.
(‘Structure’ means both places to attach and live, and hiding places)
Both habitats have high diversity (because they provide structure)
•but each coral reef is much more diverse
•GSR reefs have more spatial diversity; they differ more from each other.
Both are powered by algae,
•but the algae are small on the GBR
- Algae are inside corals as symbiotes, and on dead coral as a ‘turf’
•The kelps/fucoids are huge, and other algae of all sizes live on and around them
•GBR reefs have low nutrients, and low productivity
•GSR reefs often have very high nutrients and high productivity
Global Temperate Reef Kelp Forests
Dominant Kelps: L –Laminaria (north) E – Ecklonia (south), M – Macrocystis (both)
Kelp beds elsewhere
Huge kelps – up to 20 m tall, are found on the west coasts of South Africa and North and South America.
These areas are far more productive because of strong upwelling
All one species of giant limpet! Feeding on kelp washed ashore.
Warm currents on our southern coasts
The warm waters of the Leeuwin Current in the west, and the East Australian Current on the NSW coast are nutrient poor.
Also, Australia has much less upwelling than other continents. So our kelp forests are mostly small.
Our Ecklonia especially, has adapted to fairly warm, nutrient poor water
Australia’s Temperate Diversity
Relative to elsewhere, Australia’s temperate marine flora and fauna are very diverse
Why are temperate seas in OZ diverse?
- Keystone predation (on dominant competitors)? • Dominant competitors eliminate others during succession
- Predation removes dominants, and then other species can exist.
- But why would Australian reefs have more predators?
- Australia is Upwelling Poor
- Upwelling provides high nutrients and plankton blooms.
- Large food supply leads to fast growth and dense populations.
- Fast growing dominants exclude other species, so low diversity.
- Thus poor upwelling allows for higher diversity
- Disturbances promote diversity
- gaps are opened that new species can colonise
- In the time between disturbances, dominant species exclude others.
- low nutrients > slow growth and thus slow exclusion by dominants,
- So there is time for more disturbance effects, and thus more diversity
5 Faunal Zones
- solanderian (tropical)
- Damperian (tropical)
- Peronian warm temperate
- Maugean cool temperate
- Flindersian warm temperate
FAUNA OF KELP FORESTS
Kelps make shade for understorey algae
Algae provide hiding places for small shrimps & other crustaceans, plus fish & other animals
Also algae are torn loose – provide drift algae food for herbivores
And algae break down into detritus for filter feeders
Food chains in subtidal Kelp Forests
- Many small crustaceans hide in the algae, and eat algae or detritus, or
plankton. Small fish also hide in the algae and eat plankton.
The crustaceans are eaten by small fish such as the seadragons.
The small fish may be eaten by giant squid and larger fish. - Benthic herbivores like urchins, abalone, elephant and turban snails eat algae,
or fronds of algae that break off and drift.
These are eaten by predators: crabs and leatherjackets eat small
juveniles, while Port Jackson sharks, eagle rays and Rock lobsters eat
larger ones. - Sessile animals like ascidians, sponges, bryozoans and mussels grow on both
rocks and algae, and filter bacteria and small plankton.
These have small predators like sea‐slugs, but also snails and rock
lobsters will eat them. Seastars will eat mussels and other molluscs.
f Temperate Subtidal reefs:
Brown Algae (Kelps/Fucoids) provide structure
• More productivity than Tropical areas.
• Less diverse than coral reefs, but more variation between areas
• More diverse than on other continents
• other algae under the canopy of the Kelps/Fucoids
• Three major food chains, starting from
1. Small crustaceans in the algae
2. Benthic herbivores
3. Sessile animals on rocks and algae
Introduced animals via shipping are a danger
- Temperate fauna often endemic (only in one area)
* New introductions can eliminate species
TEMPERATE ROCKY SHORES
- Characteristic zonation – gradient of dryness
- Splash zone ( Lichens, Littorina grazers)
- Barnacle zone (Barnacles filter wave foam)
- Limpet zone (Galeolaria and Hormosira zones in OZ)
- Sublittoral fringe (large algae, ascidians, sea urchins)
Mollusc in rocky shore
- Molluscs often dominate the intertidal zone
- Retreat into their shell to survive dry low tides
- Radula tongue – rake /scrape /cut algae, bore into prey
Lower shore of rocky reef
Larger animals and more predators lower on shore
• e.g. sea urchins, Thais, sea anenome, octopus
INFAUNA /EPIFAUNA IN/ON SEDIMENTS
- Diverse infaunal animals feed on the rain of detritus that falls down to the seabed.
- Some are suspension feeders filtering the water.
- Others are surface deposit feeders, picking up detritus from the surface.
- Others burrow and swallow buried detritus in the mud (buried deposit feeder).
- Sedentary Annelids are the most common infaunal animals, but bivalves and brittlestars are also common.
- Predators (gastropods, starfish and fish) move over the surface and smell them, then dig down to eat them.
Predators: Thais –a whelk
Whelks are predatory snails.
Thais drills into bivalves such as clams and muscles with a tube-like proboscis. The radula tongue inside it acts as a drill, and an acid gland dissolves the shell
