Lecture 10 - Sea Grass systems Flashcards Preview

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Flashcards in Lecture 10 - Sea Grass systems Deck (15):
1

give some details about sea grass systems

These are made up of submerged aquatic vegitation, angiosperms! true flowering plants but no grasses, super high production, low diversity due to narrow range of habitats. These are fragile and fast declining :(

2

Name the three med to tropical families of sea grasses

Posidoniaceae
Cymodoceaceae
Hydrocharitaceae

3

Name the one temperate to med family of sea grass

zosteraceae

4

Name the two tropical families of sea grass

Ruppiaceae
Zannichelliaceae

5

Examples of sea grass species

Eelgrass (Zostera spp.) short growth, they have a rhizome systems which stabilises sediment and allows for growth

6

Tell me about paddle grass (Halophila decipiens)

Different shape, very short with a large surface area for photosynto grows in faster currents

7

Give the 7 points about sea grass ecology

> Strap-like flattened leaves - leaf blades, extensive root and rhizome systems just like grass
> No stomata
> Thin cuticle with waxy layer
> Arenchyma tissue for gas exchange and buoyancy
> Lacunae - continuous channels for gas to roots
> Root hairs (nutrient uptake)
> Halophylic - salt tolerant

8

what is the typical temperature range for sea grass systems

0 to 36oC

9

typical salinity range for seagrasses

0 - 90

10

Explain the movement of oxygen in sea grasses

o2 transported to rhizomes and roots of sea grasses during periods of light when photosynto releases o2 into arenchyma, this then forms an oxidised zone around the roots by night 02 transport ceases and water becomes the source of o2

11

What are the three types of reproduction in sea grass systems

Sexual (classic)
Asexual (through rhizome growth)
Pollination

12

Explain pollination and exceptions

Hydrophillic pollination occurs although there are some exceptions
a) Pollen above water surface
b) on water surface
c) beneath water surface

13

What are Epiphytes

These are a form of algae "epiphytic algea" which cuts down light onto the sea grasses as it grows on them, Some grasses have adapted to grow even when 90% of leaf blade is covered by epiphytic algea.

14

How many fauna are associated with sea grass systems and some key fishys

4000 fish and 50 million invertebrates in a single acre of sea bed grass key species include:
Sea turtles
Parrotfish
Sureonfish
Sea Urchins
Queen conch
Manatees and Dungongs

15

What are potential threats and issues for sea grass systems

Storm damage
Excessive raxing (root and rhizome gets distrubed)
Dredging
Boat damage
Pollution
Wasting disease