marine botany test 3

autogenous hypothesis

"self-assembly required" - also known as the endogenous hypothesis; says eukaryotes arose directly from a single prokaryote ancestor by compartmentalization of functions brought about by infoldings of the prokaryote plasma membrane.

complex organelles, two types of chromosomes, and two types of ribosomes spontaneously appear

xenogenous hypothesis

generalized model of primary endosymbiosis! "some components acquired" - phagocytosis allows primitive cells to eat foreign bodies, some inclusions are kept in the cell rather than digested, undigested photosynthetic cyanobacteria "became" plastids, and undigested heterotrophic bacteria "became" mitochondria

Konstantin Mereschkowsky

Russian biologist that first suggested plastids originated as endosymbionts; said:

- plastids are unquestionably reduced cyanobacteria that entered into a symbiosis with a heterotrophic host,

- the host that acquired plastids was itself a product of symbiosis between a larger, heterotrophic, amoeboid host cell and a smaller 'micrococcal' endosymbiont that gave rise to the nucleus,

- autotrophy of plants is an inheritance, in toto, from cyanobacteria

Lynn Margulis

leading figure behind the endosymbiotic hypothesis; her research was the primary support for the endosymbiotic theory, it claims that the origin of mitochondria were separate organisms that originally entered into a symbiotic relationship with eukaryotic cells through endosymbiosis

endosymbiosis

the process by which one organism becomes stably resident within the cell or body of another, known as the host, to form a chimera

what three major forms of endosymbiosis are important in the evolutionary origin of algal plastids?

primary endosymbiosis, secondary endosymbiosis, and tertiary endosymbiosis

primary endosymbiosis

ingested cyanobacterial cells become primary plastids having 2 plastid membranes; seen in red algae, green algae, and glaucophytes

secondary endosymbiosis

eukaryotic cells become endosymbionts within a eukaryotic host cell, resulting in plastids with 3 or 4 plastid membranes; seen in some dinoflagellates, brown algae, and a few other algae

tertiary endosymbiosis

eukaryote cells contain a plastid that has been derived from a eukaryote endosymbiont that possessed a secondary plastid; seen in most dinoflagellates

food web

a model that illustrates the feeding interactions occurring among diverse types of organisms in a particular habitat; concepts of aquatic food webs has changed through time

western rock lobster in ecosystem processes

found in southwestern Australia ecosystems, the western rock lobster consumes a wide variety of plant material like coralline algae, and plays a more important role in shallow water habitat

macroalgae are a more significant food source, though seagrasses can be more important for habitat formation for western rock lobsters

how can algal herbivory be a good thing with climate change?

herbivores help protect the ecosystems from climate change; warming and limpet herbivores restructure marine communities! seaweed proliferates when exposed to ambient temperatures in the absence of limpets, and very little seaweed survives when exposed to warm temperatures and limpet herbivory

- herbivores create space for other plants and animals to move in, meaning more diversity and variety present which helps protect the ecosystem with heat stressors

why are macroalgal microbiomes (MaMs) crucial for the morphological development of seaweeds?

(i.e. thallusin production regulates morphogenesis in Ulva mutabilis)

when grown in sterile conditions, U. mutabilis adopted an uncharacteristic globose morphology with small, thready proliferations, but regained normal morphology when exposed to MaM bacteria from a non-sterile culture.

-Wichard proposed selecting which microbes are introduced in axenic cultures can help create new desired pheotypes

how do marine phytoplankton play a critical role on the global sulfur cycle?

algae excrete substances such as glycolate, amino acids, amino sugars, peptides, carbohydrates, lipopolysaccharides, and DMSP (dimethylsulfoniopropionate) which is converted to DMS (dimethyl sulfide), all of which affects the climate

DMS

dimethyl sulfide; a volatile, gets oxidized to sulfur aerosols which act as cloud condensation nuclei

when airborne, is a volatile antiherbivore and antioxidant metabolite that is released when seaweed is grazed or physiologically stressed (i.e. Ulva fenestrata exposed to airborne DMS)

DMSP as an herbivore defense

a molecule of "keystone" significance, Ulva fenestrata can "eavesdrop", or detect an airborne volatile organic compound released by conspecifics when injured and respond by increasing concentrations of a defensive metabolite

marine snow

amorphous aggregations of detritus from algae and other organisms; plays an important role in the operation of the biological pump!

entire microbial communities may exist upon marine snow

herbivores that depend on algae

herbivorous zooplankton (i.e. ciliates, amoebae, rotifers, cladocerans, and copepods), mesograzers (i.e. dipteran larvae, marine amphipods and pteropods), and conspicuous herbivores (i.e. limpets, mussels, crabs, sea urchins, insects, fish, and some sea turtles)

steller's sea cow (Hydrocamalis gigas)

an extinct relative of dugongs found by Europeans in 1741 in the Bering Sea between Alaska and Russia, extensive distribution during the Pleistocene, grew up to ~30ft in length, fed on kelp.

within 27 years of discovery, the slow moving mammal was easily caught and went extinct by hunting

algae food quality

algal species vary in ingestibility, digestibility, content of mineral nutrients, essential organic compounds, toxin production, and other biochemical constituents (polyunsaturated fatty acids, sterols, mineral ratios, and amino acids)

algal defenses against herbivory

- small cell size and rapid cell division, generates large populations,

- larger cell size, bigger than smaller herbivores,

- predator avoidance for flagellate algal species,

- ability to grow in the cold season when herbivore populations are low,

- structural defenses,

- inducible defenses,

- bioluminescence and chemical deterrents/toxins

structural defenses

protect algae against herbivory; include gelatinous coatings, horns, spiny projections, and tough cell walls that resist digestion

inducible defenses

protect algae against herbivory; i.e. alga will be one to two celled when not exposed to Daphnia, but will be eight celled when exposed to Daphnia

multi-species consortia

mutualisms involving 3 or more partners (types include bacterial, fungal, animal, and plant mutualisms)

bacterial associations with algae

three broad categories:

close associations between microalgae and bacterial cells, macroalgal-bacterial partnerships, and highly structured benthic microbial mats

epibacteria

attached bacteria

fungal associations with algae

lichens (mycobionts with fungi or phycobionts with green algae and cyanobacteria), and cyanolichens; multiple symbioses are more common than previously thought

lichens

stable, self-supporting associations between fungi (mycobionts) and green algae and/or cyanobacteria (phycobionts)

cyanolichens

lichens whos partners include cyanobacteria, of which some produce toxins

phyllosymbia

new fungal-cyanobacterial symbiosis with up-right cyanobacterial sheaths surrounding fungal hyphae; usually, cyanobacteria living in fungi

animal associations with algae

Prochloron (and other algae) within tunicates, and mutualism between sloths, moths, fungi, and algae

E: Prokaryota

K: Bacteria

P: Cyanobacteria

C: Cyanophyceae

Prochloron; has associations within tunicates

sloths, moths, and algae mutualism

the three-toed sloth has one of the most nutritionally poor diets of any mammal species as most of its calories come from jungle leaves which are tough, rubbery, and filled with toxins. moths living in the sloth's fur are thought to help provide additional sustenance by supporting the growth of algae on the sloth's body which the sloth eats

plant associations with algae

plant species associated with nitrogen fixing cyanobacteria like liverwort, hornwort, moss, ferns, and cycads

why are intertidal zones often described as the harshest habitats on Earth?

its fluctuating conditions on the scale of seconds to minutes! emersion/desiccation, temperature, salinity, light (quality, quantity, UV radiation), dissolved inorganic carbon sources for photosynthesis (CO2 & HCO3), nutrient supply (N & P), and wave motion varies

when the ride recedes, macroalgae are subject to terrestrial conditions

community

for terrestrial plants, interdependent assemblages of species that interact with each other both positively or negatively

macroalgal communities

harder to define compared to terrestrial plant communities! "open" systems affected by "supply-side ecology" meaning communities are open to the effects of other benthic communities which supply it with algal and invertebrate propagules via water currents

how are macroalgal communities characterized?

dynamic, patchy (heterogenous) in space and time, shaped by processes like the physiology of the individuals, biotic interactions (competition and facilitation), supply of propagules, biotic and abiotic disturbance

how are tropical seaweed communities characterized?

warm waters that are thermally stratified, surface waters are oligotrophic (low conc of inorganic nutrients), high light levels, deep light penetration (~268m), high rates of productivity with nutrients tightly recycled, and higher rates of herbivory than temperate or polar regions (warmer waters, higher herbivory)

what are examples of tropical habitat-forming communties?

coral reefs with Symbiodinium, seagrass beds mixed with psammophytic macroalgae, Halimeda meadows and beds, and other siphonous green macroalgal beds, nongeniculate coralline algae (glue of the reef), rhodolith beds, algal turf communities (phase shifts), tropical fucoids (Sargassum beds), and foliose macroalgae

psammophytic

sand-dwelling

relative dominance model

predicts which groups will be predominant under the complex interacting vectors of eutrophication and declining herbivory (anthropogenic) on coral reefs

can also be caused by large-scale stochastic (random) disturbances, which coral reefs have recovered from in absences of humans

how are temperate seaweed communities characterized?

progressive seasonal cycles of light and temperature with seasonal stratification, dominated by large, canopy-forming brown seaweeds (i.e. Fucales or Laminariales), canopies modify the local environment, and grazers like sea urchins and amphipods

how do macroalgae (kelp) canopies modify the local environment?

reduce light and create light flecks (increase heterogeneity of the light environment), reduce seawater velocity, and compete for space with invertebrates, but also create habitat for invertebrates and other macroalgae

how are polar seaweed communities characterized?

50% lower annual irradiance than temperate and tropical regions (~8 months of darkness), available light is dependent on thickness of sea ice, melting ice can cause a decrease in salinity, surface seawater temps are low, seawater nutrients are generally high, and is shaped by the physical disturbance of ice scouring and iceberg stranding

how are polar seaweed communities in Antarctica characterized?

33% of macroalgae are endemic (native), extensive canopy-forming brown seaweeds (Desmarestiales), diverse understory of greens, reds, and browns, and is the only continent with no Laminariales

how are tide pool seaweed communities characterized?

stressful environments depending on size and depth, can have rapid changes in temperature, pH, salinity, nutrients, and oxygen concentration

how are estuaries and salt marsh seaweed communities characterized?

horizontal gradients of salinity, typically tidal with a "salt-wedge" of low-density freshwater on top of denser seawater, temperature differences of river versus seawater, periodic exposure with tides, typically turbid with high sedimentation and high nutrients, low light, and soft sediment that is dominated by benthic microalgae (diatoms) and some filamentous branched macroalgae

Chlorophyta

comprises most green algae described and all green marine microalgae

Streptophyta

comprises primarily small freshwater algae and all land plants (embryophytes)

Streptophyte algae general characteristics

predominantly freshwater, though some can be found in brackish conditions, one billion years old, flagellated and unflagellated unicells and filamentous morphologies, most follow zygotic meiosis, cellulose-rich cell walls, plant-like starch used for energy storage, and stellate structure of microtubules at the base of flagella

Streptophycean algal morphologies

branched filaments, unbranched filaments, and unicells

Streptophyte ecology

cosmopolitan distribution and fast growth rates, often ruderal, used to monitor for eutrophication in freshwater systems, and thick mats that trap air bubbles and float, covering the surface and shading out benthos

ruderal

weedy in behavior, growing in disturbed areas, have a quick growth cycle and rapid reproduction

why are all land plants green?

green algae have unique photosynthetic machinery, structural components, genetic components, flagella, and they've been around for over a billion years

Phragmoplastophyta

a proposed clade within streptophyta composed of the lineages with phragmoplasts

phragmoplasts

a specialized structure used in cytokinesis to separate two new cells, builds a new cell membrane starting from the inside and moving outwards to the parental cell wall

found in the Charophyceae, Zygnematophyceae, Coleochaetophyceae, and Embryophyta

Charophyceae

stoneworts; found in fresh and brackish water, biaccumulate calcium carbonate giving them a gritty texture, have well-studied lifecycles, and are historically thought to be the closest lineage to embryophytes (land plants)

Zygnematophyceae

missing link between algae and land plants; multiple molecular, genomic, and proteomic studies have determined that these are significantly more like land plants than Charophyceae

known as conjugating algae, uniseriate filaments or unicells, have stellate, spiral, or axial plate plastids, filamentous taxa form conjugation tubes when sexually reproducing

C: Zygnematophyceae

O: Desmidales

desmids; famous for their "mirror image" appearance of cells, nuclei are located in the isthmus (connection of cells), have two folded plastids per cell

what makes the Zygnematophyceae so special?

high abundance of retrotransposons in the genome of the desmid Penium margaritaceum, which may have allowed ancestral Zygnematophyceae to "customize" their genomes to develop the morphological and physiological traits needed to survive on dry land

retrotransposons

segments of DNA that can "jump" around an organism's genome; can be copied and have the copy inserted elsewhere (class 1), or be excised and translocated (class 2)

allow for rapid modification of entire genomes and genome plasticity (like legos!), high degrees of customization and plasticity in a genome

terrestrialization

the colonization of dry land by previously aquatic organisms; the final frontier for algae

stresses of terrestrialization

dry land is not the same as underwater! early-diverging land plants had to deal with several new stressors like high light levels, less water, less nutrients, and navigating terrestrial reproduction

high light levels on land

increased levels of UV radiation increased risk of desiccation and physical damage; adapted cuticles and flavonoids!

cuticle

waxy, hydrophobic external layer that prevents water loss; adaptation to land after terrestrialization

flavonoids

accessory pigments that can provide protection from photoinhibition from excessive light; adaptation to land after terrestrialization

do not require nitrogen like MAAs, so plants can use the nitrogen for other physiological needs

produced by Embryophytes (land plants)

mycosporine-like amino acids (MAAs)

produced for photoprotection against high light levels on land; require nitrogen which is limited on land compared to water

produced by Zygnematophytes

low water levels on land

early diverging Zygnematophytes needed to prevent themselves from drying out when exposed to air. early land plants likely lived in moist environments where water could diffuse into their tissues (Bryophytes); also adapted cuticles to keep water in tissues

vascular tissue

specialized vessels that transport water and various solutes through the plant (i.e. xylem and phloem!), allowed for more efficient internal transport of water and allowed plants to reach new heights

reproduction on land

early embryophytes relied heavily on water for sexual reproduction (spore transportation, avoiding dessication), while modern basal land plants (bryophytes and come pteridophytes) require constant moisture

desiccation-resistant spores and eventually extremely durable seeds minimized the need for constant water for reproduction

all lineages, except bryophytes, evolved a sporophyte-dominant life cycle

why is the sporophyte dominant?

several hypotheses exist:

1. as sporophytes began to perform more functions, they became more dominant than gametophytes

2. being 2n was advantageous (sporophyte able to asexually reproduce more easily)

how is the Sargasso Sea bounded? where?

called the North Atlantic Subtropical Gyre; bound by rotating currents of the Gulf Stream to the west, the North Atlantic current to the north, and the Canary Current to the east, and the North Equatorial Current to the south

what happened to the Sargasso Sea in 2010?

extreme winds and changing currents from the North Atlantic Oscillation incurred a "tipping point", pushing it to the equatorial Atlantic (between South America and Africa) where it flourished (fueled by favorable light and seasonal nutrient-supply)

where does Sargassum from the Sargasso Sea wash up yearly?

nearly every year since 2011, Sargassum has inundated the Caribbean, the Gulf of Mexico, and Florida coastlines in warm months, June and July peaks

Sargassum Watch System (SaWS)

designed to use satellite data and numerical models to detect and track pelagic Sargassum in near-real time

what's intensifying the Sargassum blooms?

- climate change is warming ocean waters and Sargassum grows faster in warmer waters

- the Amazon River disgorges a plume of sediment in the Atlantic Ocean, which sends an average of 273,361 cubic yards of water into the ocean every second (contains very increased nutrients from the intensive cattle ranching, manure, and soybean farming, fertilizer which increases N and P levels in the Atlantic

- dust clouds from the Sahara that contain iron, nitrogen and phosphorus

- equatorial upwelling and bacterial N-fixation (P from upwelling fuels N-fixation bacteria making it available for Sargassum which grows with constant N supply

Sargassum as a biological desert

the Sargasso Sea was once considered a biological desert due to the very low nutrient concentrations and biological productivity in its surface waters

what is the solution to the Sargassum blooms?

nations must find ways to reduce large-scale nutrient pollution

aquaculture

the rearing of aquatic animals or the cultivation of aquatic plants for food

mariculture

aquaculture in seawater

algal mariculture

~ 221 species of macroalgae are of commercial value, ~ 10 genera are intensely cultivated (64% of the mariculture production is brown seaweeds)

seaweed aquaculture production

most of the world's seaweed supply comes from aquaculture; growing by ~8% per year

over 90% of seaweed production from farming is for human consumption

where is most seaweed farming occuring?

most farmed production is from China, Indonesia, Philippines, South Korea, and Japan

the most important producer of harvested seaweed outside Asia is Chile

Pyropia

E: Eukaryota

K: Plantae

P: Rhodophyta

C: Bangiophyceae

O: Bangiales

F: Bangiaceae

G: Pyropia

one of the most commercially valuable seaweeds; (formerly Porphyra)

Saccharina

E: Eukaryota

K: Chromista

P: Heterokontophyta

C: Phaeophyceae

O: Laminariales

F: Laminariaceae

G: Saccharina

Saccharina japonica is the most commonly grown kelp! it constitutes ~40% of the world's seaweed production

has a sporic life cycle with alternation of heteromorphic generations; gametes need a low temperature and blue light to become fertile

what is Saccharina farmed for?

consumption of iodine and production of alginates and mannitol

Saccharina cultivation

consists of 4 main steps:

1. collection and settlement of zoospores on seed strings

2. production of seedlings

3. transplantation and growing out of seedlings

4. harvesting

Undaria

E: Eukaryota

K: Chromista

P: Heterokontophyta

C: Phaeophyceae

O: Laminariales

F: Alariaceae

G: Undaria

Undaria pinnatifida is an annual that grows in the subtidal, has the same life cycle and cultivation as Saccharina, is processed into food products like seaweed salad, instant soups, and chips

also found in OSEA skincare

Kappaphycus/Eucheuma

E: Eukaryota

K: Plantae

P: Rhodophyta

C: Florideophyceae

O: Gigartinales

F: Solieriaceae

"smothering seaweed" - coral mimic

accounts for over 80% of global production of carrageenans, red alga with triphasic life history with an alternation of isomorphic generations, thalli can double in size within 30 days, bottom and floating monoline methods used (BENEATH THE TIDE)

high growth rate, spreads by fragmentation, outcompetes native algae and coral, grows over coral shading it from sunlight, no native predators in Hawai'i, introduced in 1974 for aquaculture with intentions of cultivating it for carrageenan

causes shifts in ecosystem (was once coral dominated but now algae dominated with low diversity), and habitat loss greatly affects recreational and commercial fisheries

carrageenan

linear sulfated polysaccharides; those of commercial interest are kappa, iota, and lambda

products include instant mix food products, chocolate milk, toothpaste, cottage cheese, ice cream, other dairy products, and fat free products

Gelidium

E: Eukaryota

K: Plantae

P: Rhodophyta

C: Florideophyceae

O: Gelidiales

F: Gelidiaceae

produces the highest quality agar, but grows slowly so natural beds are often over harvested, 35%of the world's agar production comes from Gelidium, also produces bacteriological-grade agar (expensive), acts as a stabilizer and thickener in pie fillings, icings, meringues, gelled fish, meat products, and low-calorie products

Gracilaria

E: Eukaryota

K: Plantae

P: Rhodophyta

C: Florideophyceae

O: Gracilariales

F: Gracilariaceae

G: Gracilaria

also produces agar but of lower quality compared to Gelidium, grows quickly in aquaculture in either tanks or via line/rope farming (like used in brown algae), eaten raw as a sea vegetable in several cultures (i.e. Japan)

how is seaweed farming mitigating climate change?

ongoing: C-sequestration via export of "unseen" production, and food production with reduced CO2 foot print

future: bioenergy production by substituting fossil fuels, reduction of methane emission by using seaweed feed additive to ruminants, stimulation of land-based production by using seaweed biochar soil amelioration and seaweed prebiotic health benefits to live stock, and climate benefit of circular nutrient management by avoidance of CO2 emissions for synthetic fertilizer production

how is seaweed farming adapting to climate change?

adapting to increased storminess and sea level rise with protection via dissipation of wave energy, ocean acidification with high daytime pH in seaweeds to the benefit of calcifiers, and oxygen inputs to coastal waters by avoiding oxygen deoxygenation with warming

integrated multi-trophic aquaculture (IMTA)

used for sustainable and safe food production, seaweeds provide biomitigative services and produce valuable product

describes three trophic levels that should be combined with "fed" fish aquaculture

what are the three trophic levels described in the integrated multi-trophic aquaculture?

1. suspension organic extractive aquaculture with invertebrates like shell fish to recapture the small particulate organic matter from the fish food

2. suspension inorganic extractive aquaculture with seaweeds to recapture the dissolved inorganic nutrients

3. deposit organic extractive aquaculture with benthic invertebrates or grazing fish to utilize the large particulate organic matter that sinks to the bottom

what is the criteria for selecting macroalgae for IMTA?

1. high NH4 uptake and high growth rate

2. tolerance of high NH4 concentrations and capacity for storage of high tissue N

3. ease of cultivation and control of the lifecycle

4. resistance to epiphytes and disease

5. existing or potential market value for the raw material or its derived products

6. commercialization not leading to insurmountable regulatory hurdles

7. ideally native

who is the father of biodiversity?

E.O. Wilson

he said, "On a global basis...the two great destroyers of biodiversity are, first habitat destruction and, second, invasion by exotic species”

diversity

dependent on the richness (# of species in a given area) and evenness (relative abundance) of a species within a community