Natural History Of Saragssum Article Notes

Question 1

Where was the name Sargassum born from?

Answer 1

From the Fucus of Linnaeus

Question 2

What is the common name of Fucus natans and where is it from?

Answer 2

Common name: Common Gulfweed
Origin: sargasso from the Atlantic Ocean

Question 3

What is the common name of Sargasso fluitans and where is it from?

Answer 3

Common name: Broad toothed Gulfweed
Origin: Atlantic Ocean

Question 4

Why is it problematic to classify Sargassum species?

Answer 4

It is problematic because of their: -polymorphic character
-phenotypic plasticity

Question 5

How are Sargassum traditionally classified?

Answer 5

Based on:
1. Blade Morphology
2. Margins of the blades
3. Blade Midrib
4. Pneumatophores (air bladders)
5. Branching
6. Degree of branching
7. Morphology of receptacles (repro organs)

Question 6

What are the four subgenera of the genus Sargassum?

Answer 6

• Sargassum (most diverse)
• Arthrophycus
• Bactrophycus
• Phyllotrichia

Question 7

What are the 3 sections of subgenus Sargassum?

Answer 7

1. Zygocarpicae
2. Malacocarpicae
3. Acanthocarpicae

Question 8

What is the new way of classifying Sargassum?

Answer 8

Based on:
- Nuclear
- Chloroplast
- Mirochondrial markers

Question 9

What is the classification of the Sargassum found in the western Atlantic Ocean?

Answer 9

Phylum: Ochrophyta
Class: Phaeophyceae
Subclass: Fucophycidae
Order: Fucales
Family: Sargassaceae
Genus: Sargassum
Sub genus: Sargassum
Section Sargassum

Question 10

Q

Question 11

Describe Pelagic Specimens.

Answer 11

• up to 1m long
• yellowish brown color
• cylindrical axis 0.4-1.8mm thick
• smooth or few spines near apex
• well- formed midrib in center
• single layer cortex of cells
• blades with short pedicels
• blades firm
• lanceolate in shape
• pointed apices
• serrate margins with broadly flattened teeth at the base

-Cryptostomatas absent
- Pneumatophores at base of blades
- Unknown receptacles

Question 12

What is a Cryptostomata ?

Answer 12

Sterile cavities with hairs

Question 13

What type of Thallus does Sargassum have?

Answer 13

Diploid Thallus

Question 14

What is the ONLY mechanism of propagation in Sargassum?

Answer 14

Clonal reproduction

Question 15

How does vegetative reproduction occur in Sargassum?

Answer 15

It occurs by fragmentation of old thalli sections, that disintegrate breaking apart ans newly formes fragments grow again.

Question 16

How are oogonia arranged in Benthic sargasso species?

Answer 16

Female oogonia are exposed outside the conceptacle through the ostiole, remaining attached to the receptacle, which is a modified terminal structure of the thallus that contains conceptacles.

Question 17

What is the function of conceptacles?

Answer 17

Produce reproductive cells

Question 18

What is the conceptacle?

Answer 18

It is a cavity (crypt) immersed in the surface of the thallus with an ostiole (opening) to the outside.
- It contains the reproductive structures or gametangia retained by a mucillaginous stalk.

Question 19

What cues allows for the release of the zygote?

Answer 19

Light
Temperature cues

Question 20

Is there sexual reproduction seen in the pelagic Sargassum?

Answer 20

No

Question 21

What kind of temperatures does Sargassum grow best in?

Answer 21

Higher temperatures

Question 22

What degree of water can Sargassum not survive in?

Answer 22

Below 18°C

Question 23

Describe Sargasso in the Sargasso sea?

Answer 23

• Low productivity
• Bright yellow color
• Typical nutrient- depleted populations

Question 24

Describe Sargasso closer to the coast (Neritic Population).

Answer 24

• have greater availablilty of nutrients (mainly Nitrogen and Phosphorus)
• develop a deeper brown color
• higher photosynthetic capacity
• Productivity
• Alkaline Phosphatase activity lower

Question 25

How does Sargasso in the Sargasso Loop system get nutrients?

Answer 25

By passing through the nutrient rich Gulf of Mexico.