ESS Term 1

Closed systems

Allow the travel of energy in and out through the boundaries of the system, but only allows matter to enter it and not leave, for example a terrarium (plants stay inside, but heat energy can enter and leave).

Isolated systems (not found in nature)

Allow matter and energy to enter the boundaries of the system but not exchanged, for example a thermos flask (the heat is trapped and so is the liquid).

Open systems

Allow the entering and exiting of matter and energy through the boundaries of the system, for example a pond (gains water from rain and loses it through evaporation and gains energy from sunlight while losing it to the surrounding air).

Arrows

Flows of energy or matter either transformation or transfers

Transformations

Change of state (e.g Water freezing)

Transfers

Change of location or movement of an object (e.g Water currents)

Rectangular Boxes (Systems Diagram)

Living of non-living stores of matter and energy called storages (e.g. Oxygen in our Lungs)

Stratification

When there are two or more distinct layers in a vertical column of water (e.g. salt water or freshwater)

Causes of Ocean Stratification

Temperature Differences (Thermocline), Salinity Gradients (Halocline), Limited Mixing

Consequences of Ocean Stratification

Reduced Nutrient Upwelling, Oxygen Depletion and impacts on Climate systems

Temperature Differences (Thermocline)

Warm, less dense water stays at the surface, while colder, denser water sinks. Further traps heat

Salinity Gradients (Halocline)

Higher salinity (caused by high evaporation rates) increases water density, creating layers as dense water sinks below less dense water, forming distinct layers that further reduces mixing.

Limited Mixing

Reduced vertical mixing due to weak winds, currents, seasonal changes(depth of thermocline changes seasonally) enhance stratification.

Reduced Nutrient Upwelling

Limits nutrient availability for phytoplankton, disrupting marine food chains.

Oxygen Depletion

Deep waters receive less oxygen, potentially creating dead zones.

Impacts on Climate Systems

Weakens thermohaline circulation(affects how much warm water transported down), affecting global climate patterns like ENSO.

La Niña

Cooler-than-average sea surface temperatures in the central/eastern Pacific (RIGHT), strengthening trade winds — causing opposite weather effects to El Niño.

El Niño

Warmer-than-average sea surface temperatures in the central/eastern Pacific, weakening trade winds —> altering global weather patterns.

Neutral Phase

Normal conditions with no significant temperature anomalies.

Impact of increase in ocean temperature

Redistributes heat across planet and disrupts thermohaline circulation (driven by differences in water temperature + salinity).

Warmer oceans

Reduce density (less cold water that sinks), slowing circulation & heat distribution and reducing ocean's ability to absorb heat and CO₂, increasing global warming

What happens when warm ocean currents heat the air above them

Contribute to the formation of low-pressure systems, leading to increased precipitation, storm formations (e.g., monsoons) Cold currents create high-pressure systems, resulting in dry conditions (e.g., deserts like the Atacama).

How increase in ocean temperature impacts ENSO

Moves warm and cold water between oceans. Disruptions intensify El Niño events, causing extreme weather globally. As temperatures rise, ENSO events become more frequent, severe, exacerbating global warming and further disrupting periodic weather systems.

Impact of increased temperature on Ocean currents

Creates differences that influence deep-water currents & more wind (powers gyres & upwelling), as well as earth's rotation (Coriolis effect), tides & gravity that cause vertical & horizontal movement

Increased Atmospheric CO2

Caused primarily from ocean absorption of burning fossil fuels, deforestation, and industrial processes.

CO2 Absorption (and chemical reactions that occur)

Caused when CO2 reacts with seawater to form carbonic acid, which then dissociates into hydrogen ions, lowering pH, making it more acidic.

Reduced Calcium carbonate availability for shell-building organisms

Caused when increased H+ reacts with calcium carbonate ions, creating weaker calcium carbonate shells and organisms struggling to maintain them

Move to zones of physiological stress, behavioural changes

E.g. ability to find food, avoid predators in marine life, making them more susceptible to predation, disease, environmental stressors

Food web disruption

Changes in species abundance & abundance (can't survive in ZOP), reduced stability & resilience

pH changes

Impact coastal estuaries and waterways and then leads to reduced food sources, coastal protection, tourism and climate regulation

Global Warming

Increases atmospheric CO2, driving both ocean acidification and stratification.

Ocean Acidification

Caused by increased CO2 absorption, lowering pH and affecting marine life.

Ocean Stratification

Warmer surface waters and increased freshwater input (from melting ice) reduce mixing, exacerbating acidification by trapping CO2 in surface layers.

Feedback Loop

Stratification weakens thermohaline circulation, further altering climate systems and intensifying global warming.

Marine ecosystems

Oceans are a larger body of open water while seas are a smaller body, usually enclosed by lands with 3.5ppt salt concentration

Intertidal Zone - Rocky Shore Zone

Known as an extreme environment because there is a huge amount of change in the course of a day, Change in temperature (colder with more water/higher tide) Increased salinity, increased evaporation, changes in oxygen level, moisture daily

Freshwater environments

Can be either lentic (still water, e.g. Ponds, Lakes, Wetlands, Aquifers) and Lotic (running water, e.g. Rivers, Streams) with <0.5ppt salt concentration

Lentic

Depends on depth, influenced by light penetration

Lotic

Depends on size, depth and distance from source with two main zones, rapids and pools. Rapids are faster moving water while pools are slower moving water

Issues with still water

Can become stagnant, meaning there is less mixing and there can be less nutrients and oxygen

Mangroves vs Estuaries

Mangroves only occur in tropical and subtropical temperatures and must have mangroves, while Estuaries are all interstitial ecosystems

Brackish

Intertidal transition zone between freshwater and marine (aka where the river meets the sea) that has both water types

Supralittoral (splash) zone

Only occasionally covered by the highest tides. Characterized by presence of lichens, algae, and some invertebrates. Abiotic factors include sunlight, wind, and occasional salt spray.

Upper Intertidal Zone

Regular tidal inundation and exposure. Organisms need adaptations to withstand variations in temperature, salinity and dessication. Example are barnacles, snails and limpets.

Middle Intertidal Zone

This zone is submerged during high tide and exposed during low tide. Abiotic factors include wave action, temperature fluctuations and salinity changes. Organisms like mussels, seas stars and anemones are adapted to survive in these conditions

Lower Intertidal Zone

This zone is mostly covered by water, even during low tide. Abiotic factors include strong wave action and varying levels of light penetration. Organisms include kelp, sea urchins, and certain types of crabs.

High tide

Greatest temperature change, light exposure, salinity and UV, 75% exposed to water,

Mid Tide/Low Tide

Lots of wave action, greatest biotic factors occurring, increase in competition) 50% exposed to water while Low Tide- 25% exposed to water

Niche

Encompasses more than where the animal lives; organism's role and position within its environment (where, when, how organism lives) as well as particular set of abiotic and biotic conditions and resources to which an organism or population responds

An organism's ecological niche

Depends on habitat, activity patterns, resources used, interactions with other organisms

Niche Vs Habitat

Niche is what an organism does, occupation VS habitat is where an organism lives; address

Fundamental niche

describes the full range of conditions and resources in which a species could survive and reproduce

Realised niche

describes the actual conditions and resources in which a species exists due to biotic interactions

Biotic interactions

inter-specific (between members of the same species) and intra-specific (across species); both can influence an individual's realised niche)

Dessication adaptations

Such as hard external coverings (which trap water next to the body of the organism), operculum (which retains water already trapped in the shell), clumping together (traps water between the shells of the individuals of the groups, Shelter - under a ledge finding shade)

Wave action adaptations

Holdfasts, Byssus, Cementing exoskeleton to rock surface, basal disc, muscular feet, tube feet, spines for anchorage

Interactions between Biotic and Abiotic Factors

Abiotic factors like wave action, temperature, and salinity often limit the upper limits of species distribution creating a fundamental niche while biotic interactions like competition and predation shape the lower limits creating a species' realised niche

Adaptations

Inheritable characteristics that increase an organism's ability to survive and reproduce in an environment

How adaptations helpful

Help an organism find food and water, protect itself, or manage in extreme environments

Adaptations may be

Behavioral - runs from prey, attracts mate, Physiological - internal, (e.g. Snake has venom), Structural (morphological) - characteristic (e.g due to water pressure)

Species biodiversity

Allows multiple connections in food web - higher resillience

Genetic biodiversity

Variety, increases chance of survival with diseases and allows for natural selection (evolution for better adaptations)

Ecosystem biodiversity

Provides many niches for organisms to live in (allows for species & genetic biodiversity)

Producers/Autotrophs

take light energy or chemical energy and convert it into organic matter, as the base of the food web

Producers Examples

Phytoplankton, seaweed and seagrasses as well as diatoms, dinoflagellates and cyanobacteria, brown algae, red algae and green algae

Primary consumers

Animals that eat producers or marine herbivores, e.g. Parrotfish (eats algae, Zooplankton (feeds on phytoplankton) and the green sea turtle (eats seagrass)

Apex predators

Predators with no natural enemies in their ecosystem and feed on primary consumers such as the great white shark, the orca and the giant squid

Keystone species

Species that has a significant detrimental impact on an ecosystem when they are removed

How do Keystone Species maintain balance

Consume a diverse range of prey or are essential food sources for many predator, prevents any one species from overpopulating or even modify important habitats.

Disrupts the food chain

If a key species disappears, predators may struggle to find food, and prey species may overpopulate

Loss of biodiversity

Fewer species means less variety in the ecosystem, making it more fragile and less adaptable to changes

Ecosystem collapse

If a keystone species is lost, the entire ecosystem structure can break down

Reduced fisheries and food supply

Many marine species are important for human food, so species loss can harm fishing industries and global food security

Algae blooms and oxygen loss

If predators of certain organisms (like algae-grazing fish) decline, algae can overgrow, depleting oxygen and creating "dead zones"

Weakened climate regulation

Marine ecosystems help absorb carbon and regulate the climate, so species loss can reduce this ability, worsening global warming

Simpson's biodiversity index (BDI)

Quantifies the chance that two randomly selected individuals will belong to the same species (more diversity = higher value)

Species richness

Number of species in a population or community present

Species evenness

How evenly distributed are/relative proportion of individuals of each species

Increases population

Birth rate + Immigration

Decreases population

Death rate + Emigration

Disease, predators and parasitism

Decrease the individuals in a population but increase the deaths, same goes for natural disasters and extreme weather

More people

Less food for others, while good food/nutrient availability results in more births.

Carrying capacity

The maximum population size that the ecosystem and sustain and where the population can be supported indefinitely on the available resources and services of an ecosystem

Limiting factors

Any factor limiting the size of a population that can be density dependent (affect populations based on size and density) or independent (affect populations regardless)

Density-dependent factors

Competition (Food, water, shelter, mates), Predation, Crowding, Parasitism, Infection diseases

Density independent factors

Natural disasters, extreme weather, climate change, pollution

Invasive species

Organisms that has be introduced into ecosystems where they do not historically or naturally occur, spreading rapidly and causing harm hence the term biological pollutant

Endemic species

Organisms that are only found in one country

Native species

Organisms that occur naturally in that environment/country

Introduced species

Non-native species brought to a new area, either intentionally or accidentally without causing significant harm

Impact of Aquatic invasive species

Impacts pre-existing species populations through competition, predation, habitat alteration (e.g. blocking sunlight) and disease transmission (introducing diseases that native populations aren't resistant to)

Prevention, Control and Contain, Eradication

Increase of cost and reduced effectiveness

Natural predator (Why high population of COTS)

Giant Triton snail but it's overfished due its tasty mollusc

Reproduction (Why high population of COTS)

Really fast reproductive rates, Due to the excess nutrient run off from farming, the larvae have the best conditions and sufficient food to survive

Fertilisation (Why high population of COTS)

High, with warm waters encouraging their breeding as well, one female producing 10 million eggs

COTS impact on diversity of coral reefs

High population and preys on all corals, negatively impacting habitats for other species and who rely on coral as well as tourism

Manual Oneshot Injections

Difficult to control a population of millions

Robots using the Oneshot Injections

Can't get into tight places where COTS like to hide, costly

Household Vinegar

Still hard to attack many COTS, ethics (as slowly kills off COTS)

Giant Triton Snail

Eats only one starfish a week, dwindling population