J19 primary production + phytoplankton

Question 1

primary production

Answer 1

Process where organisms turn inorganic matter into biomass using solar energy. Shown by chlorophyll mostly, higher along equator and when there is 24h light in the arctic. Mid ocean gias (like desserts) where there isn’t much phytoplankton.

Question 2

Gross primary production

Answer 2

All energy primary producers create in a given time.

Question 3

Net primary production

Answer 3

What is left after algal respiration

Question 4

Light in ocean

Answer 4

Water glitters because of reflection when light hits the surface, there is a high absorption by water (long wave, red light, that’s why if you could yourself underwater your blood looks black).
Scattering of light is especially a short wave, blue light).
Quantity and quality of light changes throughout water.

Question 5

Mesophotic zone

Answer 5

Fish can see in mesophotic zone (in between photic and aphotic zone. Fish tend to have big eyes), but phytoplankton live in the photic zone (around 200m deep) where they can get enough light for photosynthesis, where 1% of light intensity from the surface is still there. The in deeper water it’s called the Aphotic zone. Litteral zones are shallow water.

Question 6

Phytoplankton

Answer 6

The base of the marine food web, take up carbon that diffuses into the ocean and fix it, these are grazed upon by zooplankton and zooplankton are then eaten by fish. Normally a mix of diatoms and dinoflagellates which are caught in nets, they are the bigger ones, not the most abundant.

Question 7

Dinoflagellates

Answer 7

Typical small dinoflagellates have three points usually to ward off predators. All of the tiny dots surrounding it are smaller plankton cells (they make up the majority and produce 80% of photosynthesis in ocean, and make vitamins, fix nitrogen and produce oxygen).

Question 8

Prochlorococcus

Answer 8

A type of cyanobacterial genus, most abundant photosynthetic (pigments) organism on earth, genome is 4x larger than that in humans (more genetically diverse). A lot of Prochlorococcus in biomass, more than 1000 in 1mm of water, 5% of global photosynthesis comes from them. Very important to life on earth.

Question 9

Phylum Haptophyta: Coccolithophores

Answer 9

-Two anterior flagella and one haptonema
-Calcite skeletons
-Chl a, chl c, carotese and xanthophylls
-Shield like plates may help them reflect light in but they’re not sure
-Are the main oceanic calcium carbonate producers (CaCO3).
-Produce DMSP (climate gas/smell of sea) which works as cloud condensation nuclei in the atmosphere (helps clouds form)

Question 10

Phylum Cyanobacteria: Prokaryotes

Answer 10

35 billion years old, reason the atmosphere is oxygenated. 2000 species. Reason atmosphere and sea became oxygenated.
-Thylakoids have Chl a, carotenoids, phycobilin with some phycoerythrin.
-Carboxysomes are protein complexes which help fix CO2
-Storage product is glycogen, cells often grow in colonies
-Origin of plants through endosymbiosis
-Often occur in chains, sometimes they have heterocysts along them which is an oxygen sensitive enzyme that fixes nitrogen.

Question 11

Nitrogen fixation in cyanobacteria

Answer 11

In certain filamentous cyanobacteria, occurs in specialised cells called heterocysts, where oxygen sensitive enzyme Nitrogenase fixes nitrogen.

Question 12

Opisthokonts

Answer 12

Flagellum is at the posterior part of flagellated cells, examples include 35 phyla, fungi have 7 phyla and both of which are Eukarya.
-Eukaryotes: are flagellated cells which have one or more anterior flagella
-Example = Chromalveolata

9+2 structure of flagella = have rods that transfer energy and allow the flagella to move in a coordinated way. All have different ways of moving.

Question 13

Diatoms: Phylum Ochrophyta

Answer 13

12000 named species
-Mainly built of silica (Si, also glass, transparent)
-Overlapping shells are called frustules
-Pigments are Chl a, Chl c, beta-caroten, fucoxanthin, diato and diadinocanthin
-Storage products are lipids and crysolaminarin
-Related to kelp forest from a systematic point of view
-2 main diatom groups: Pennate, Centric

Question 14

Diatoms

Answer 14

When diatoms divide and grow, they get smaller with each generation, the larger upper frustule is the epitheca, the smaller lower frustule is the hypotheca. There comes a point where they get so small they have to switch tactics, so they form two silica cells within themselves. Have both diploid and haploid cells.

Question 15

Dinoflagellates: Phylum Dinophyta

Answer 15

1700 marine species
-Obtain energy through photosynthesis or phagotrophism
-Chl a and Chl c2 + xanthophylls that give them golden/brown colour
-Store starch and oil
-Endosymbionts called zooxanthellae (corals, nudi’s, giant clams). Form the colours, very important, expelled if the coral gets stressed.
-Big nucleus, 35% of cell. Cellulose in plasmamembrane gives them a rigid structure, in plate form the structures are called theca.
-Most photosynthetic dinoflagellates have light sensitive organelles (kind of eyes, they can also eat other things, mostly phytoplankton).
-Some species have nematocysts or trichocytes which they use to protect themselves or to excrete things they don’t want.
-They can also produce light though bioluminescence (Noctiluca scintillans)

Question 16

Eutrophication

Answer 16

Excess or imbalance of nutrients, mostly nitrates and phosphates
-Problem because were feeding the planet using those chemicals as fertilisers
-Can create hypoxia or anoxia which harms marine organisms and ecosystems
-The excess nutrients can cause a phytoplankton bloom

Question 17

Algal bloom

Answer 17

-Rapid increase or accumulation of phytoplankton. Can sometimes be harmful due to eutrophication.
-Coccolithophore bloom is when the water looks milky and that’s actually from them dying, likely from a virus that has caused the liths (shields) to fall off the dying cells so they reflect more light which can be seen from a satellite
-Dinoflagellate bloom is seen as red/orange in the water, toxins from the dinoflagellates can ill fish and other marine life, can also lead to shell fish poisoning in humans (can even cause amnesia).