EVSC 4230 Midtertm 1 – Plants, algea, plankton,etc

Cyanobacteria (Phytoplankton)
(Phylum, phytoplankton) “Blue-Green Algae” Prokaryotic, 3 billion years old. Use chlorophyll a. Nitrogen fixers, convert N2 to usable compounds. Some are benthic, some pelagic. Some epiphytic and symbiotic forms.
**Oscillatoria spp** example
Chlorophyta (Phytoplankton)
(Phytoplankton) Green Algae. Two main classes: Chrysophycae and Bacillcriophyceae. Eukaryotic autotrophs, chlorophyll a. Mineralized cell walls of scilia or caco3.
Coccolithophores
(Group, Phytoplankton) Unicellular, contain many calcereous plates called coccoliths in cell walls. Accumulate on the ocean floor when dead.
Chlorophyta -> Bacillariophycae
(Class, Phytoplankton)”Green Algae” Diatoms. Much larger than coccolithophores. Cell wall made of pectin, large amounts of scilia. Frustule contains two halves: epitheca, hyrotheca, connected by gurdle. Centric symmetry or pennate radial symmetry. Can have long scilia spines attached to valves, join together in large groups. Asexual split, secretes new (inside) shell, creates different sizes
Dinophyta/ Alveolates
(Phylum, phytoplankton) A few are not photosynthetic, all are unicellular with 2 flagella. One wraps around the cell, the other extends forward, helps move up and down water column. Abundant in warm seas. Plates on cell wall, contains some coral species.Can weather unfavorable conditions by forming cysts. Higher concentraiton of lipids decreases density, reduction of volume:surface area ratio important to stop sinking.
**Gonyaluax spp**
Chlorophyta (Algae)
(Phylum) Multicellular algae, called “Green Algae”. Appears in flat sheets of tubules, only 15% are marine. Most abundant temperate benthic forms found in intertidal zones. Vegetative and sexual reproduction, often alternating.
Codium – Tubular, fleshy
Ulva- Flattened sheets
Halimaeda – Tubular, attached to sediments
Rhodophyta
(Phylum- Algae) “Red Algae”. Most are filamentous, sheet-like marine and use a holdfast to attach to benthos. Red accessory pigment to chlorophyll a. Tropical waters, low light, deeper waters (more red light). Cell wall made of cellulose or agar.
Phaeophyta
(Phylum – Algae) “Brown Algae”. Largest and most complex group, mostly marine. Distinct accessory pigment masks chlorophyll a. Strong holdfast, stipe and fronds help it reach up to the light. Alternation of generation.
**Sargassium spp**: Most are attached, some can float around as sargassium weed. Floating mats are entire ecosystems.
Seagrasses (Marine Angiosperms)
SAV: Submerged aquatic vegetation. Needs:Salinity, complete submergence in shallow water, anchoring system, hydrophyllic pollination. Most of biomass below seafloor (>85%). High light requirement, can regenerate damaged leaf structures. Asexual and sexual reproduction. Vascular tissue, relatively low species diversity
Seagrass – Thalassia testudinum
“Turtle grass”. Large, flat, straplike leave, most common of the seagrasses. Forms large meadows, allows for high biomass ecosystems.
Seagrass – Syringodium filiforme
Cylindrical “Spaghetti” leaves, sometimes called “Manatee Grass”
Seagrass – Halodule wrightii
“Shoal grass”. Stem erect, subtended by elliptic scales. Very small, rizone, horizontal buried stem that contains many shoots, small hair roots.
Seagrass – Zostera Marina
“Eel Grass”, temperate species,found in Chesapeake. Rhizomous plant, long stems with hairlike green leave, 1-2cm wide, +1m long.
Salt Marsh Plants
Emergent pants, only partly submerged, love between lowest low tides and highest high tides. Very high productivity. Detrius based food web, consumed once dead. Outwelling of nutrients and organic matter to open water.
**Spartina alternialova** common in this area
**Spartina poten**
Mangroves
Flowering plants, tropical equivalent marsh plants, example of terrestrial plants reinvading seas. Procted, shallow shores, like limited wave action. Dominant vegetation in mangrove swamps, saline lagoons. Simple leaf structure, but complex roots which are adapted to loose, anoxic environments. Buffer species, shelter other organisms. Traps sediments, encourages accretion. Signicant carbon sink, mosquitoes love it
Rhizophora mangle
“Red Mangrove” First to be found coming from open water. Prop roots hold trees in place, have vasculatized tissue. Lenticels on surface alllow oxic flow through root canals. Gets rid of salt by concentrating it in certain leaves and dropping them. Propagules start growing embryo before dropping, rubbing motion on bottom stimulates new growth.
Avicennia germainans
“Black Mangrove”. Next zone up from red mangrove, in between high and low tide zones. Salt tolerance and fresh water collection still a problem. Cable roots with anchoring, pneumatophores. Bouyant seeds are produced, can stay put or float to better area.