WEEK 1-6 2204

What percentage of the Earth's surface is covered by the ocean?

71%

How much more space for life do oceans provide compared to land and freshwater?

300 times more space

When did oceans form?

4400 - 3500 million years ago

What limits plant growth in aquatic environments?

Light penetration and essential nutrients

What are the three ecological zones defined by light penetration?

Euphotic zone, Diphotic zone, Aphotic zone

What is the Euphotic zone?

The zone with sufficient light to support plant life

What is the Diphotic zone?

The zone where fish and some invertebrates can see, but there's not enough light for positive net photosynthesis

What is the Aphotic zone?

The zone where sunlight is not detected by any biological system, with no plant life

What is light attenuation?

The reduction of light intensity as it travels through a medium, caused by absorption and scattering

What abiotic factors affect aquatic life?

Light, Temperature, Salinity, Water movement

How does temperature affect biological processes in water?

It controls the rate of chemical reactions and biological processes

What is the Coriolis force?

A force that causes wind and currents to appear to move on a curve due to the Earth's rotation

What causes tides in the ocean?

The gravitational pull of the moon

What is the significance of hydrostatic pressure in the ocean?

It increases with depth and limits biological processes, causing physical hazards

What are isotherms?

Lines of equal temperatures that set distribution boundaries for species and communities

How does water movement affect nutrient availability in the ocean?

Water movement can return essential nutrients to the upper waters where plant growth occurs

What is the role of temperature and salinity in water density?

They determine the density of water, affecting buoyancy and aquatic life distribution

What limits the depth distribution of plants in the ocean?

Light penetration

What is the impact of decaying matter in aquatic environments?

It sinks to the seafloor and can only be returned to the upper waters by water movement

What is the primary energy source for ocean currents?

Energy from the sun

What are the three main types of marine organisms based on their habitat?

Plankton, Nekton, and Benthos.

What are plankton?

Organisms that live in the water column and cannot swim against currents; also known as drifters.

What is an example of plankton?

Phytoplankton.

What are nekton?

Organisms that can swim freely in the water column and are capable of swimming faster than currents.

Name the three main groups of nekton.

Arthropods (e.g., shrimps), Molluscs (e.g., shellfish), and Chordates (e.g., sharks, whales).

What are benthos?

Organisms that spend most of their time in, on, or above the bottom of the ocean.

What are phytoplankton?

Microscopic algae that float on the ocean's surface and are the food base for the open sea.

What percentage of the world's net primary productivity is attributed to phytoplankton?

More than 45%.

What characterizes the shelf environment?

It is dynamic and heterogeneous, with shallow waters and strong tidal currents.

What types of substrata are found on the continental shelf?

Soft bottoms (sand, mud) and hard or rocky bottoms (granite, limestone).

What is infauna?

Organisms living within the substrata (sand, mud).

What is epifauna?

Organisms living on top of the substrata (sand/mud/rock).

What is the primary source of food in soft bottom habitats?

Dead matter (detritus) from rivers, estuaries, and decomposing organisms.

What are the dominant feeding types in soft bottom habitats?

Deposit feeders and suspension/filter feeders.

What are the characteristics of hard bottom habitats?

Provide areas for sessile organisms, dominated by seaweeds, and have high competition for space.

What defines the deep sea benthic environment?

A dark, stable environment with homogeneous physical and chemical conditions.

What drives thermohaline circulation?

Density differences between cold, salty water and warm, fresher water.

What are the two main zones of the ocean?

Benthic zone (seafloor) and Pelagic zone (open ocean).

What are the general characteristics of fish?

Ectothermic vertebrates with scales and fins, primarily aquatic.

How many vertebrate species on Earth are fish?

Half of the 60,000 vertebrates.

What are the three classes of fish?

Agnatha (jawless), Chondrichthyes (cartilaginous), and Osteichthyes (bony).

What is the mesopelagic zone?

A mid-water zone that supports a rich community of animals but has limited food availability.

What adaptations do mesopelagic fish have?

Well-developed lateral lines, small size, needle-like teeth, and photophores.

What is the deep scattering layer?

An apparent false ocean floor created by clusters of small organisms that move towards the surface at night.

What factors affect the distribution of organisms?

Environment (light, nutrients, temperature, waves) and biological interactions (predation, competition, facilitation).

What is the sequence of ecological processes involving organisms?

Reproduction (proliferation) -> Dispersal (movement) -> Recruitment (establishment).

What is the ecological role of reproduction, dispersal, and recruitment?

They exchange genes, maintain existing populations, and colonize new ground.

What are the two main types of reproduction in organisms?

Sexual reproduction and vegetative reproduction.

How does coral reproduce asexually?

Through budding of polyps within a colony or fragmentation.

What is sexual reproduction in corals?

Gametes mix to form planulae that disperse via currents to establish new colonies.

What is the difference between internal brooders and external broadcast in coral reproduction?

Internal brooders release sperm into the water to swim to female colonies, while external broadcast involves mass release of eggs and sperm for long-distance dispersal.

What are propagules in the context of dispersal?

Gametes, spores, zygotes, seeds, and fragments that enable movement away from an existing population.

What factors influence dispersal distances of propagules?

Longevity of propagule, release height, size, buoyancy, motility, taxis, and environmental conditions like waves and currents.

What is recruitment in ecological terms?

The establishment of juvenile organisms within a population, often influenced by environmental conditions.

What environmental factors control recruitment?

Light, waves, cracks and crevices, and sensitivity to pollution and sedimentation.

How is recruitment often measured?

Using quadrat counts or settlement plates.

What is the relationship between reproduction, dispersal, and recruitment?

They are distinct but interconnected processes that can be difficult to separate.

What influences the dispersal outcomes of different reproductive strategies?

The traits of propagules and the environments in which they are dispersed.

How does recruitment vary in space and time?

It is often patchy and can be influenced by local environmental conditions and biotic interactions.

What is the significance of genetic mixing in populations?

It strengthens fitness and serves as a basis for evolution.

What role does facilitation play in recruitment?

Facilitation can enhance the establishment of juvenile organisms by improving conditions.

What are the potential risks of external broadcast reproduction in corals?

Gametes may wash away, making timing critical for successful reproduction.

What is the impact of disturbance regimes on recruitment?

They create opportunities for recruitment by releasing space and altering the environment.

What is the role of biological interactions in recruitment?

Interactions such as grazing and facilitation can limit or enhance recruitment success.

What does the term 'patchy' refer to in the context of recruitment?

It refers to the uneven distribution of juvenile organisms in space and time.

What is phylogeny

Species that share the same evolutionary path

What is geography

A collection of species in the same place at the same time

What is species richness

Number of different species

What is species evenness

Abundance of individuals within each species

What are functional groups

It is the range of ecological functions

What is apatiotemporal structure

The distribution of populations and individuals in space and time

What is physical structure

3D (structural species/foundation species)

Measuring community structure

Quantify the identity and abundance of biota

What is competition

Where two species share a need for a limited resource, which reduces the fitness of one or both species

What is Interference competition

Direct antagonistic behaviour

What is resource competition

Indirect interaction through the exploitation of shared resource

What is predation

Where one species feeds on another

What is commensalism

Where one species receives a benefit from another species

What is mutualism

Where two species provide resources or services to each other

What is a keystone species

A species that affect community structure disproportionately to their abundance

What is a foundation species

A species that affect communities by their presence not their actions

What is perturbation

Pressure/effect on ecosystem

What is stress

Persistent sub lethal pressure that causes suboptimal performance and slow attrition

What is disturbance

An event caused by perturbation

What is resilience

The capacity to withstand perturbation resistance and recovery

What is recovery

The capacity to return to initial pre-disturbance state

What is elasticity

The speed of recovery to its original state

What is amplitude

The maximum disturbance the community can recover from

What are the most widely traded food commodities in the world?

Fisheries products

What is the biggest human impact factor on marine ecosystems?

Fisheries

What are two major environmental issues affecting fisheries?

Climate change and plastic pollution

How many people are involved with fisheries globally?

A very large fraction of humanity

At what two levels does fisheries science operate?

Tactical level and strategic level

What does the tactical level of fisheries science focus on?

Local scale, single species level, and basic fish biology

What is involved in stock assessments?

Determining biomass and sustainable catch levels

What is the strategic level of fisheries science concerned with?

Global interconnectedness and bigger picture science

What does FAO stand for?

Food and Agriculture Organisation of the United Nations

When was the FAO created?

In the late 1940s

What type of data does the FAO report on?

Fisheries data provided voluntarily by individual countries

What is the definition of fish in fisheries science?

Finfish and aquatic invertebrates