Marine- Plankton, corals, currents

describe Eddy

• small temporary loops of swirling water

• can travel long differences before dissipating

• swirling motion causing nutrients normally in cooler, deep water to come to surface

describe ocean gyres

• a large system of spiraling circulations thousands of miles in diameter

• movement of gyres help thermohaline circulation.

describe thermohaline circulation

• deep ocean currents driven by differences in water density

• this is controlled by temperature and salinity

what are the 3 things that effects currents

1. landmass: earths continents and other landmasses influence gyres

2. Coriolis effect: Earth rotates on an axis so air is deflected to the north in northern hemisphere and south in southern hemisphere

3. Eckman spiral: surface molecules move by force of wind and drag deeper layers with it. each layer moves slower than the layer above it which creates a spiral effect.

what are the 2 types of corals

hard coral and soft coral

describe hard corals

• polyps build hard limestone cups around bases

• cups cement together to make coral colony

• reef are made of hundreds of hard coral colonies next to each other and on top of.

describe soft corals

• lack hard skeleton

• protect themselves by releasing chemicals called terpenes (toxic to predators)

• filter feeders

• resemble trees, bushes, fans

what are polyps

• they make up hard corals

• the tentacles release stinging cells when something brushes by them

• polyps make own limestone cups to hide in during the day

• at night polyps come out to catch plankton floating by

• tentacles armed with nematocysts (stinging cells)

• when tentacles encounter animals it shoots nematocyst and kills prey.

• once food is broken down into polyps tissue it passes nutrients to other polyps

• limestone base is added slowly from the polyp absorbing calcium carbonate from the seawater.

what is algae in coral

• inside polyps live algae called zooxanthellae

• give coral its colour

• since alae are plants they use CO2 and sunlight to make its own food through photosynthesis

what is the relationship between coral and zooxanthellae and describe it

• it is a symbiotic relationship

• it is when 2 organisms live together and help each other

• zooxanthellae makes O2, removes polyps waste, and makes food for the polyp from photosynthesis

• coral polyps protect zooxanthellae, release CO2 and provide zooxanthellae with necessary nutrients

what are the growing conditions for coral reefs

• thrive in shallow tropical waters

• temperatures between 20-30 degrees

• not above low tide line

• few reefs grow close to mainland because water quality is too poor from high sediment run off

• they need clear water to get light, low nutrients, stable salinity, hard surface to grow on

how does competition exist with corals

• they compete for space in different ways

• fast growers grow upward and branch out, cutting neighbors off from light

• slower growing corals use filaments. when they come in contact with other coral they extend filaments and digest it

• other use sweeper tentacles with nematocysts to sting

• also compete with sponges, weeds, and invertebrates

• in right conditions seaweed can grow faster than corals

• kept in check with low nutrient loads and predators

what are the ecosystem benefits of coral reefs

• one of the most diverse ecosystems in the world

• about 2.5% of fish depend on ocean reefs

• used for shelter, food, reproduction, and nurseries.

describe the coastal protection benefits of coral reefs

• protect coastlines from storms and erosion

• absorb 97% of wave energy

• reduces wave height by 84%

• prevents loss of life and property damage

• provides flood protection benefits of around $1.8 billion annually

what are the human benefits that come from coral reefs

• about 500 million people rely on reefs for food, protection, and livelihoods

• source of food: locals use reefs to fish for food, developing countries they account for ¼ if total fish caught

• cultural value to indigenous peoples , net value of great barrier reef is $56 billion annually of tourism

• estimated $375 billion/yr around the world in goods and services

• medicine: scientists have extracted chemical s from coral to fight infections, bacteria. coral reefs used in treatment of cancer, HIV, and cardiovascular disease

• source of income: making money from fishing (fisheries about $5.7billion annually), snorkeling, diving, and tourism (53,800 full time jobs from Great barrier reef)

what is coral bleaching

• a stress response that causes coral to expel symbiotic zooxanthellae from temperature which causes coral tissue to turn white.

what cause stress to occur for coral bleaching

• high light or UV

• Cold temperatures

• low salinity and high turbidity from coastal run off/heavy rain

• exposure to air during low tides

• major factor is high water temperatures

describe the thermal stress with coral bleaching

• corals live close to thermal max limit

• is water gets 1-2 degrees higher than summer average, coral gets stressed and bleached

• NOAA satellites measure global ocean temperatures

Do corals recover from bleaching events, and how

• yes they can recover if they don’t stress for to long

• some corals eat more zooplankton to survive lack of zooxanthellae

• some species are more resistant to bleaching and more able to recover

• they eventually regain colour by gaining more zooxanthellae from water column for reproduce from cells tat survived

• can recover after a few weeks

• if stress is sever, polyps in coral colony will die

how does coral bleaching effect corals susceptibility to disease

• high temperatures and bleaching can leave corals more vulnerable to disease

• can quickly kill part or whole coral colony

how does coral bleaching effect bioerosion

• areas of dead coral are more vulnerable to bioerosion

• bioerosion is when animals wear away the coral limestone structure

how to protect coral reefs

• shade reefs

• cool reefs

• improve water quality

• reduce other stresses

• reduce overfishing

what are plankton

• plankton are made up of animals and plants that either float passively in water or very little powers swimming so they are carried places by currents

• they dominate well lit surface layers of ocean

• they range in size from tiny microbes (microscopic) to jellyfish

• apart from bacteria, planktonic organisms are most abundant life form on earth and play vital role in food chain.

describe phytoplankton

• they are microscopic plants

• they are tine photosynthetic organisms

• species are more closely related to protists and bacteria than true plants

• these include diatoms, dinoflagellates, cyanobacteria

• they produce more O2 than all plant life on earth and are vital to maintaining earths atmosphere

• the organism that will be greatest affected by climate change and global warming as sun pass through hole in Ozone and could kill them

describe zooplankton

• floating/weak swimming animals that rely on water currents to move great differences

• larger than phytoplankton from copepods to jellyfish

• there are 2 major types of zooplankton:
  1. holoplankton: spend entire life as part of plankton e.g krill, slugs
  2. Meroplankton: only spend larval or reproductive phase as phytoplankton. most have no resemblance to adult form. they feed from other members of plankton or live off yolk they have retained from hatching. some spend short time in phase while others spend longer.

• they are food source for many marine animals so they can camouflage is main survival strategy

• best solution is to be as transparent as possible

what affects the distribution of plankton

• they are found in oceans, seas and lakes but local abundance depends horizontally, vertically and seasonality

• main source of variability is light, all plankton ecosystems driven by solar input. it confines production to surface water where light is abundant

• second is nutrients

• although large areas of tropical and subtropical have abundant light, they experience low production as low nutrient availability

how are plankton monitored

• SeaWIFS project, and AusCPR

describe SeaWIFS project

• when light hits surface of object, different colours can be absorbed

• most of our world ocean, phytoplankton influence colour

• phytoplankton contain green pigment chlorophyll

• we can measure change of plankton from space

• SeaWIFS stand for Sea-Viewing Wide Field of View Sensor.

• main principle behind remote sensing is the more blue=less phytoplankton, green=more phytoplankton

• satellites orbit Earth every 99minutes, 14 x/day

describe AusCPR

• stands for Australian Continuous Plankton Recorder Survey

• The aim is to map plankton biodiversity and distribution to develop a long term plankton baseline for Australian waters

• occurs in the Great Barrier Reef, EAC, and down to Southern Ocean Time Series Mooring.

• it involves using an instrument called a continuous plankton recorder to monitor plankton communities. It then filters plankton from seawater onto a silk ribbon, which is then preserved and analysed in a lab.

• it provides details on plankton diversity, distribution and changes over time.

what are the differences between SeaWIFS and AusCPR

• AusCPR is the physical sampling method that collects and analyses plankton

• SeaWIFS is the remote sensing technique that uses satellites to measure the colour of the ocean to look at phytoplankton abundance and distribution