Natural History Of Saragssum Article Notes Flashcards
Where was the name Sargassum born from?
From the Fucus of Linnaeus
What is the common name of Fucus natans and where is it from?
Common name: Common Gulfweed
Origin: sargasso from the Atlantic Ocean
What is the common name of Sargasso fluitans and where is it from?
Common name: Broad toothed Gulfweed
Origin: Atlantic Ocean
Why is it problematic to classify Sargassum species?
It is problematic because of their: -polymorphic character
-phenotypic plasticity
How are Sargassum traditionally classified?
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)
What are the four subgenera of the genus Sargassum?
- Sargassum (most diverse)
- Arthrophycus
- Bactrophycus
- Phyllotrichia
What are the 3 sections of subgenus Sargassum?
- Zygocarpicae
- Malacocarpicae
- Acanthocarpicae
What is the new way of classifying Sargassum?
Based on:
- Nuclear
- Chloroplast
- Mirochondrial markers
What is the classification of the Sargassum found in the western Atlantic Ocean?
Phylum: Ochrophyta
Class: Phaeophyceae
Subclass: Fucophycidae
Order: Fucales
Family: Sargassaceae
Genus: Sargassum
Sub genus: Sargassum
Section Sargassum
Q
Describe Pelagic Specimens.
- 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
What is a Cryptostomata ?
Sterile cavities with hairs
What type of Thallus does Sargassum have?
Diploid Thallus
What is the ONLY mechanism of propagation in Sargassum?
Clonal reproduction
How does vegetative reproduction occur in Sargassum?
It occurs by fragmentation of old thalli sections, that disintegrate breaking apart ans newly formes fragments grow again.
How are oogonia arranged in Benthic sargasso species?
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.
What is the function of conceptacles?
Produce reproductive cells
What is the conceptacle?
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.
What cues allows for the release of the zygote?
Light
Temperature cues
Is there sexual reproduction seen in the pelagic Sargassum?
No
What kind of temperatures does Sargassum grow best in?
Higher temperatures
What degree of water can Sargassum not survive in?
Below 18°C
Describe Sargasso in the Sargasso sea?
- Low productivity
- Bright yellow color
- Typical nutrient- depleted populations
Describe Sargasso closer to the coast (Neritic Population).
- have greater availablilty of nutrients (mainly Nitrogen and Phosphorus)
- develop a deeper brown color
- higher photosynthetic capacity
- Productivity
- Alkaline Phosphatase activity lower
How does Sargasso in the Sargasso Loop system get nutrients?
By passing through the nutrient rich Gulf of Mexico.
