Mari112 -> lecture 21

What is sediment?

Mineral or organic matter that us deposited by water, air or ice

describe the rock cycle

The rock cycle is a continuous process that describes how rocks are formed, transformed, and recycled over time. It involves three main types of rocks: igneous, sedimentary, and metamorphic. The cycle begins with the formation of igneous rocks through the cooling and solidification of molten magma or lava. These rocks can then be weathered and eroded into sediments, which are then compacted and cemented to form sedimentary rocks. Under intense heat and pressure, these sedimentary rocks can undergo metamorphism and transform into metamorphic rocks. Through processes like melting and uplift, these rocks can be remelted and recycled back into the magma, restarting the cycle.

how is sediment classified

Sediment can be classifies using both its texture and composition first, texture uses the wentworth scale to classify sediment based on the size and shape of the grains, compositions uses the colour, minerals present and other materials present to help classify the sediment. Its provenance and transport history is then considered second.

what is provenance

Provenance refers to the origin or source of something.

how are different sources of marine sediment classified

Different sources of marine sediment can be classified based on their origin and composition. Here are some common classifications:

1. Terrigenous Sediment: Derived from land sources such as rivers, glaciers, and wind-blown dust.

2. Biogenic Sediment: Composed of the remains of marine organisms, such as shells, coral reefs, and microorganisms.

3. Hydrogenous Sediment: Formed through chemical processes in the water column, including precipitation of minerals from seawater.

4. Volcanogenic Sediment: Produced by volcanic activity, including ash, lava fragments, and volcaniclastic deposits.

5. Cosmogenic Sediment: Derived from extraterrestrial sources, such as meteorites and cosmic dust.

These classifications help scientists understand the origin and processes involved in the formation of marine sediments.

Allochthonous

Allochthonous refers to geological or biological materials that are formed or originated in a different location from where they are currently found. These materials are typically transported by natural processes such as erosion, weathering, or tectonic movements. Allochthonous materials can include sedimentary rocks, fossils, or even plant and animal species that have been introduced to a new habitat.

autochthonous

Refers to sediments that were formed in place and stayed there

how do terrigenous sediments get to the ocean

Terrigenous sediments are transported to the ocean through various processes. The primary mechanisms include:

1. Rivers (fluvial activity): Sediments eroded from land are carried by rivers and deposited into the ocean. This is the most significant pathway for terrigenous sediment transport.

2. Wind (Aeolian activity): Fine-grained sediments, such as dust and sand, can be transported by wind over long distances and eventually reach the ocean.

3. Glacial activity: Glaciers can transport sediments from land to the ocean when they melt or calve icebergs.

4. Mass wasting: Gravity-driven processes like landslides, rockfalls, and slumps, also known as coastal erosion, can transport sediments from coastal areas to the ocean.

Once in the ocean, these sediments can be further transported by currents, waves, and tides, eventually settling on the seafloor.

what are the main types of biogenic sediment?

Biogenic sediment can be either mainly carbonate (CaCO3) or silicate (SiO2).

• carbonate sediments are usually made up of:

  • shelf/shore invertebrates, in warm areas these will be corals and algae and in cool areas these will be molluscs bryozoans and barnacles

  • Deep sea calcareous microfossils like coccolithophores and foraminifera

• Silicate sediments are usually made up of:

  • Deep sea silicate microfossils such a s radiolaria and diatoms

These sediments are brought to the sea floor via the bio-pump

how do sedimentation rates vary with different sediment types

Flashcard: Sedimentation rates vary with sediment types. Coarser sediments settle faster due to their larger size and higher density. Finer sediments settle slower as they have smaller particles and lower density. The composition and shape of sediments can also influence settling rates.

describe the distributions of calcareous and siliceous sediments

A= pelagic clays

B= siliceous radiolarian oozes

C= calcareous oozes

D= siliceous diatom oozes

E= glacial-marine sediments

F= continental margin sediments

what are some controlling factors in marine sedimentary environments

Some controlling factors in marine sedimentary environments include:

1. Water depth: Determines the type of sediment that can accumulate.

2. Energy of the water: Influences the size and sorting of sediment particles.

3. Climate: Affects the rate of sediment supply and preservation.

4. Proximity to land: Determines the type and amount of terrigenous sediment input.

5. Ocean currents: Influence sediment transport and deposition patterns.

6. Biological activity: Organisms can influence sediment composition and structure.

7. Tectonic activity: Controls basin formation and sedimentary processes.

8. Sea level changes: Impact sedimentation rates and distribution.

9. Salinity and temperature: Affect the types of organisms and sediment characteristics.

10. Substrate composition: Influences the nature of sediment deposition.

These factors interact to shape the characteristics of marine sedimentary environments.

What is the fate of marine sediments?

• breakdown

  • Dissolution

  • Abrasion

  • Ingestion

• Transport

• Stabilisation

  • Encrusted or agglutinated

• Lithification

Agglutinated

Agglutinated refers to the process of particles or materials sticking together to form a larger mass or structure. This term is commonly used in geology and sedimentology to describe sediment particles that are bound together by a cementing agent or by physical forces. Agglutinated sediments can be found in various environments, such as marine, lacustrine, or terrestrial, and their composition and characteristics can provide valuable information about past environmental conditions and geological processes.

What is a microbe

Microbes are anything that is smaller that about 100micrometers. They are a highly diverse group of organisms that are represented across all three domains of life.

what is a photoautotroph

A photoautotroph is an organism that uses sunlight as a source of energy to convert carbon dioxide into organic compounds through the process of photosynthesis. Examples of photoautotrophs include plants, algae, and some bacteria.

what is a photoheterotroph

A photoheterotroph is an organism that obtains energy from sunlight (like a photoautotroph) but relies on organic compounds as a carbon source (like a heterotroph). It combines photosynthesis with the consumption of organic matter for growth and metabolism. Examples include certain bacteria and protists.

what is a chemoautotroph

A chemoautotroph is an organism that obtains energy by oxidizing inorganic compounds, such as hydrogen sulfide or ammonia, and uses this energy to synthesize organic molecules. They are capable of sustaining their own growth and metabolism without relying on sunlight or organic sources of carbon, they gain their carbon from CO2.

what is a chemoheterotroph

A chemoheterotroph is an organism that obtains energy by breaking down inorganic compounds through chemical reactions. It relies on external sources of organic molecules for both energy and carbon. Examples of chemoheterotrophs include animals, fungi, and most bacteria.

what are some points about Pelagibacter ubique, SAR11

• The most abundant free living organism on earth

• < 1 micrometer

• Rod or crescent shaped

• A prokaryotic obligate heterotroph

• Consumes dissolved organic matter and is an important component of the decomposer/microbial food web

What are some points about Prochlorococcus spp.

• one of the most abundant photosynthetic organisms on earth

• <1 micrometer

• Non nitrogen fixing Cyanobacteria

• A prokaryotic obligate photoautotroph

• Can adapt to a wide range of light intensities through the use of different pigments

What are some points about Trichodesmium spp.

• a filament out bloom-forming nitrogen fixing Cyanobacteria

• Does not form heterocysts (visible colonies)

• A prokaryotic nitrogen fixing obligate photoautotroph

What are some points about Nitrobacter spp.

• one of the many important nitrifying bacteria

• Oxidises nitrite to nitrate

  • 2NO2(-) + H2O → NO3(-) +2H(+) + 2e(-)

• A prokaryotic obligate chemoautotroph

What are some points about Rhodobacter sphaeroides

• a physiologically plastic bacteria found on black smokers

• Can be:

  • Anaerobically photoautotrophic

  • Anaerobically anaerobic

  • Aerobically heterotrophic

• Purple and green Sulfur bacteria have bacteriochlorophyll which absorbs light energy between 700-1000nm

• A prokaryotic facultative heterotroph

What are some points about protists

• most other single celled eukaryotic microbes

• Eukaryotic heterotrophs

  • Some dinoflagellates, ciliates and amoeba

  • Important consumers of other microbes

  • Can be either obligate or facultative heterotrophs

What are some points on eukaryotic photoautotrophs

• taxonomically and morphologically diverse

• Many are small enough to be considered microbes

• Absorb photosynthetically active radiation and undertake oxygenic photosynthesis

• Classic example of obligate photoautotrophs

What are some points on viruses

• the most abundant biological entities on earth

• 20-200nm

• Important in remineralisation of inorganic nutrients

• Responsible for the viral shunt

Why is it important to study marine microbes?

1. Microbes cause diseases of macroscopic organisms

2. They provide examples of early life on earth

3. They are model systems for general principles in ecology

4. They mediate many biogeochemical processes that affect the climate

what is the microbial loop

1. Phytoplankton fix carbon during photosynthesis, converting inorganic C and nutrients into organic matter (dissolved or particulate)

2. Phytoplankton biomass is then consumed by zooplankton grazers

3. Heterotrophic bacteria then consume the DOM and POM released by the phytoplankton, converting it into biomass, respiring, and remineralising inorganic nutrients

4. Protists and zooplankton the graze on the bacteria

5. The heterotrophic bacteria transform DOM from a labile (usable) form to a recalcitrant (unusable) form, this then leads to long term carbon storage

6. The POM the sinks to the ocean floor as marine snow.

Why is the growth rates of bacteria in nature lower than what can be achieved in lab cultures

There are a lot of different factors that can affect this:

• temperature differences

• Organic carbon concentrations are very low in nature

• Predation and viral lysis

what is the viral shunt

The viral shunt is the production of dissolved organic matter through the viral lysis of bacteria, which is then reutilised by other microbes.

What are some biotic factors that limit bacterial production?

• Viral lysis

• Predation from protists

What are some abiotic factors that limit bacterial production?

• temperature

• Organic carbon concentrations

what are phytoplankton

Phytoplankton are eukaryotes, they are single cellular, photosynthetic and have membrane bound organelles.

Why are phytoplankton important?

• they photosynthesise and so they are primary producers

• The fix inorganic carbon (CO2) into organic carbon

• They are the base of marine food webs

• They release oxygen

• They produce 50% of the oxygen we breathe

Why are phytoplankton important?

• they photosynthesise

• They fix inorganic carbon into organic carbon, then feeds everything else in the food chain

• They are the base of marine food webs

• They release oxygen, producing almost 50% of the air we breathe

What are some facts about picoplankton/ cyanobacteria

• 0.2 -2 micrometers

• 80% of the photosynthetic activity in some ocean regions

• 5% of global photosynthesis isattributed to prochlorococcus

What are some facts about diatoms

• 2-200 micrometers

• More than 5600 known species

• Very efficient at photosynthesis

• 55% of energy from sunlight converted of carbohydrate chemical bonds

What is a diatom frustule

• made of silica

• Optical properties of glass

• Two halves

• Either centric or pennate

What is a centric diatom

A centric diatom has a petri dish/hat box shape that is radially symmetrical surrounding a central areola. they can float solitary or in chains using fatty acids, oils, their structure and their chains to stay floating.

What is a pennate diatom

Pennate diatoms are linear or an elongated oval in shape and they are bilaterally symmetrical. They can float in solitary or chains and some have a raphe slit to allow a gliding movement. Pennate diatoms usually live in the benthic regions.

how do diatoms reproduce

Diatoms reproduce using asexual binary fission, which is when the cell just splits directly in half, this means the cell will get continually smaller until it can no longer divide. When the call becomes too small to divide it will split open, releasing gametes that will fuse with a gamete from another cell, forming a zygote which will then become a new cell.

What are some facts on dinoflagellates

• 2-200 micrometers

• Flagella for mobility

• They are free living and can be symbiotic, for example the zooxanthellae in coral

• Contain a range of pigments including chlorophyll a

• Not all are autotrophic

What is the difference between autotrophy, heterotrophy and mixotrophy

Autotrophic organisms use inorganic molecules to make their own nutritional organic molecules.

Heterotrophic organisms obtain food from other organisms

Mixotrophic organisms do a bit of both

What are some facts about coccolithophores

• 5-100 micrometers

• Covered in little plates of calcium carbonate (coccoliths)

• Coccoliths offer sunshade and grazing protection

• Contribute up to 10% of primary production

what is the great calcite belt

The Great Calcite Belt is a region in the Southern Ocean where high concentrations of calcite are found in the surface waters. It is formed by the growth of coccolithophores, microscopic marine algae that produce calcite plates. The calcite reflects sunlight, leading to a decrease in carbon dioxide levels in the atmosphere. This belt plays a significant role in the global carbon cycle and has implications for climate change.

What is liebigs law of the minimum

Liebig's Law of the Minimum states that the growth and development of a plant is determined by the nutrient that is in the shortest supply. This means that even if all other nutrients are abundant, the plant's growth will be limited by the nutrient that is most scarce.

What are some things that phytoplankton growth is dependent on

• light

• Uv

• Macro + micro nutrients

• Temperature

• Ph

what are the stages of bacterial growth

The stages of bacterial growth are as follows:

1. Lag phase: Bacteria adjust to their environment, synthesizing necessary enzymes and preparing for growth.

2. Log phase: Bacteria experience exponential growth, with a rapid increase in population size.

3. Stationary phase: The growth rate slows down as the number of new cells being produced equals the number of cells dying.

4. Death phase: The number of dying cells exceeds the number of new cells being produced, leading to a decline in population size.

Note: It's important to mention that these stages can vary depending on the specific bacterial species and environmental conditions.

what is PAR

Photosynthetically active radiation

What can determine light penetration

• weather

• Latitude

• Season

• Time of day

• Turbidity, because the particles scatter and absorb light

• There is also greater light penetration in the open ocean

What is the photic zone

The photic zone is the upper layer of a body of water where sunlight can penetrate and support photosynthesis.

what is the aphotic zone.

The aphotic zone is the portion of a body of water where sunlight cannot penetrate, resulting in complete darkness. It is typically found in the deeper parts of oceans, lakes, and other bodies of water.

What are the main macronutrients?

• N, proteins and amino acids

• P, nuclei acids and ATP / ADp

• Si, cell structure

The macronutrients support energy and growth, they are present in the environment and they required in higher amounts. Macronutrients are usually found in macromolar (ppm 10-6) concentrations in the ocean.

What are the main micronutrients?

• Fe, electron transport and enzymes

• Zn, nucleic acids

• Vitamins, enzyme co-factors

• Trace metals

The micronutrients play biochemical and physiological roles in cell processes and they are generally needed in smaller amounts. Micronutrients are usually found in nanomolar (ppb 10-9) concentrations in the ocean.

what is the extended redfield ratio

The extended redfield ratio includes one extra macronutrient and one micronutrient, Si and Fe respectively. This changes it from:

C:N:P - 106:16:1

to

C:N:P:Si:Fe - 106: 16: 1:15: 0.1 → 0.001

Variability in this ratio can indicate nutrient limitation

What is the nutrient concentration profile and why?

The nutrient concentration is lower at the surface as nutrients are consumed by phytoplankton, the concentration then increases as depth increases due to remineralisation by bacteria. The surface nutrients are then replenished by ocean mixing and upwelling.

What is the phytoplankton centric food web?

How will climate change affect phytoplankton in the future?

• ocean warming may cause cells to move to waters in the higher latitudes, in order to stay in optimal temperatures

• warmer waters will also increase stratification, decreasing ocean mixing, therefore decreasing the nutrients available to phytoplankton and causing phytoplankton to be smaller

• Ocean acidification may also cause a decrease of phytoplankton that use calcium carbonate.

What is primary productivity?

Primary productivity is the synthesis of organic materials from inorganic substances by photosynthesis or chemosynthesis. Primary producers are often called autotrophs, but they are also called lithotrophs.

Where are waters generally more productive

Coastal waters are generally more productive.

What are accessory pigments?

Accessory pigments aid chlorophyll a and give photo- autotrophs access to a larger range of light. The green pigment is chlorophyll b, which gives marine organisms access further into the spectrum. The red and brown pigments allow marine organisms access to the green window.

What are the brown pigments?

• fucoxanthin

• The carotenoids; chlorophyll C1 and c2

What are the red pigments?

• phycoerythrin

• Phycocyanin

• Also known as the phycobillins

What is chemosynthesis?

Chemosynthetic organisms convert one or more carbon molecules (usually carbon dioxide or methane) into organic matter using the oxidation of inorganic compounds (eg sulphide) or methane as a source of energy. Chemosynthesisers often live in the deeper oceans particularly around hydrothermal vents and cold seeps.

How does chemosynthesis support fisheries?

• spiny lobsters get 20% of their diet from chemosynthetic food sources

• Seagrass habitats also provide chemosynthesis based ecosystem services

What are the units used for primary productivity

Primary productivity is measured in grams of carbon bound into organic material per square metre of ocean surface area per year or:

C/m2/ yr or cm-2 y -1

How does marine primary production differ from terrestrial primary production?

Why is primary productivity important?

• it fixes carbon and is the base of marine food webs

• Provides oxygen for not just us but other marine organisms like fish too

• They play a role in carbon controlling atmospheric CO2 and climate, eg the biological pump

What is the euphotic zone?

The euphotic zone is the section of the ocean where primary productivity occurs, and is characterised as the depth at which I% of surface light remains. This is enough for positive growth and productivity. The euphotic zone can extend to around 200m in the clearest water.

What is a key limiting nutrient in coastal environments

Nitrogen

What is a key limiting nutrient of freshwater environments

Phosphorous

What is the primary limiting nutrient in the ocean?

Nitrogen, it is available in lower concentrations in summer and higher concentrations in winter due to the development of the thermocline.

What limits the growth of diatoms?

Silicate, it often becomes depleted after blooms.

What autotrophic groups are represented in the ocean?

• angiosperms

• Lichens

• Fungi

• Algae

What autotrophic group has the highest contribution to marine flora?

Algae (93.8%)

What are algae?

Algae are eukaryotic organisms that are part of the kingdom Protista, making them not plants. Higher plants (kingdom plantae) likely evolved from green algae.

Some defining characteristics of algae are;

• flagella at some stage of their lifecycle (except for the red seaweeds which have mucilage)

• Reproduce by spores

• They dont have roots, instead some have a holdfast

• They are mostly photosynthetic and therefore autotrophic but some are parasitic

• Algae is mostly aquatic and of the aquatic species they are mostly marine

How are algae classified?

• photosynthetic pigments

• Characteristics of flagella (how many, where etc)

• Cell wall material

• Structure (do they occur singly, in colonies, filaments or multicellular)

What are chlorophyta

They are the green algae and their dominant pigments are chlorophyll a and b. Chlorophyta are also characterised through the presence of a cellulose cell wall. They are the ancestors of the kingdom plantae (higher plants/terrestrial plants).

What are ochrophyta?

They are the brown algae including diatoms and brown seaweeds. Their dominating pigments are fucoxanthin.

What are rhodophyta?

The red algae are the oldest and most diverse algal group, although they dont necessarily always look red (sometimes they look brownish). Rhodophyta can be characterised by the absence of flagella on the spores and gametes, the accessory pigments phycoerthyrin and phycocyanin as well as the cell wall that contains agar and carrageenan. They are the deepest known photosynthetic organisms and are dominant high on NZ shores.

What are dinophyta

They are the dinoflagellates, single called phytoplankton with flagella.

What are Macroalgae?

Macroalgae, also known as seaweed, are large multicellular algal organisms. The vast majority of them are photosynthetic and they are key primary producers in coastal oceans.

Draw the Macroalgal reproduction process

What are phaeophyta?

They are filamentous to complicated kelp species, their cell wall was made of alginate (which can be used as an industrial gelling agent) and they can be characterised by the accessory pigment fucoxanthin.

Why is algae important?

• they are major primary producers

  • Around 1% of “plant” biomass

  • Around 40% of the photosynthesis on earth

• They are part of the base of the food web

• They provide habitats for animals

• They can provide food and other products

What is the only marine higher plant?

Seagrasses, there are around 50 species of sea grass worldwide.

What are some contributors to the decline in seagrass

• changes in land use that filter into the sea

• Too much sedimentation can bury the plants

What are some contributors to the decline in kelp forests?

• Some kelp species, specifically some around nz waters, cannot survive in temperatures over 18 degrees Celsius

• Sedimentation increasing

  • Sediment on algal surfaces and in the water column can cause; shading, scouring/sandblasting and burial of organisms

• Decreasing light availability

  • This causes smaller macroalga and less biomass

• Pollution and runoff from the land

• Invasive species

• Dredging

• Habitat degradation

• Erosion

• Port activities

What is a kelp forest?

Kelp forests are usually formed by brown macroalgae of the laminariales order, they provide more 3 dimensional habitat for marine organisms.

What ecosystem services do kelp forests provide?

• energy for food webs, this contributes to the success of fisheries and some tourism industries

• They provide resilience to climate change

• Provide more habitat and protection

• They have important cultural aspects

• They also help facilitate the recruitment of species

• They are important nursery grounds, helping to trap larvae and provide attachment of larvae and spores

What are some benefits of kelp forest habitats?

• macroalgae help provide habitat for sessile animals like bryozoans, Hydrozoans, polychaetes etc

• They also provide habitat for mobile organisms such as isopods, Gastropoda, amphipods, nudibranchs, and fish

• They have less competition for attachment

• They project above the benthic boundary layer

• Seaweeds provide both dissolved and particulate organic matter, which can be food for other organisms

• They alter water flow which can entrains larvae, increases sedimentation and reduces coastal erosion.

• The altered water flow also alters the chemical environment, for example how nutrients n stuff has been taken up.

What is an autogenic ecosystem engineer?

Autogenic engineers are organisms such as corals and kelp that transform ecosystems through their own growth, as they provide the structure to the environment.. They are integral to the environment because without them that certain environment wouldn’t exist eg, without the kelp there wouldn’t be a kelp forest.

What is an allogenic engineer

Organisms that alter the environment and then move on, leaving behind the structure that they made. An example of an allogenic engineer are beavers, they build dams that turn a stream ecosystem into a pond ecosystem.

How does kelp impact fisheries?

• particularly the species Macrocystis is key

• They provide majority of the carbon to coastal fisheries

• Majority of Finnish are found around Macrocystis species

• They provide food for abalone (Haliotis spp.)

• They are also potentially key to the settlement of crayfish larvae (Jasus sp.)

What are picoplankton

• they were discovered in 1986

• They can be found in the tropics and subtropics

• They are the smallest known phototroph

• They contribute to 30-80% of primary production in the worlds oligotrophic oceans

• A prominent species is prochlococcus

What are nanoplankton and haptophytes?

• they are a major transport of carbonate to the sea floor

• Include coccolithophores

• Can be found in sea foam and have major blooms at high latitudes

• Blooms increase albedo in the area and underneath the bloom the water is cooler

• Haptophytes contribute 30-50% of oceanic chlorophyll standing stock

What are microphytoplankton?

• diatoms 50-200 micrometers

  • They can be colonial or form chains up to 2mm long, this helps them to float better and makes them less likely to be predated on

  • They are common in spring bloom in temperate and polar seas

  • They are not motile and so they prefer turbulent waters

  • They form silica frustules

• Dinoflagellates are also in this group

  • They are protists that are either autotrophs with chloroplasts or non-photosynthesising heterotrophs

  • Most are marine but they are also found in fresh water

  • They can be toxic

  • The colour in corals comes from dinoflagellates

What are the main green seaweeds in nz?

1. Ulva

2. Enteromorpha intestinalis

3. Caulerpa germinata