Marine Algae and Productivity Quiz 1 PDF

***Marine algae and productivity \ - ***Cell wall*** -- ***layered*** - ***Lack organelles*** - ***DNA circular*** fibrils - ***Peripheral thylakoids*** & ***phycobilisomes*** **Cell structure & Function** **Locomotion** - ***No flagella*** - ***Gliding*** --...

***Marine algae and productivity \ - ***Cell wall*** -- ***layered*** - ***Lack organelles*** - ***DNA circular*** fibrils - ***Peripheral thylakoids*** & ***phycobilisomes*** **Cell structure & Function** **Locomotion** - ***No flagella*** - ***Gliding*** -- ***slow***, ***uniform*** motion, ***parallel*** to long ***axis*** of ***cell*** - Most ***common*** in ***filamentous cyanobacteria*** - Occurs with ***slime*** secretion - Some ***cyanobacteria rotate*** during gliding **Pigments & Photosynthesis** *Major light harvesting pigment is Chlorophyll a* - ***Absorbs*** in ***red*** band *Carotenoids & xanthophylls* - ***High levels*** of ***beta-carotene*** *Phycobiliproteins* - ***Phycocyanin*** and ***phycoerythrin*** - ***Change*** in ***concentration*** with ***light quality*** and ***quantity*** - ***Form phycobilisomes*** - Can ***perform photosynthesis*** under ***aerobic*** and ***anaerobic conditions*** - ***Oldest*** organisms -- with examples found in ***sulfur-rich*** ***ecosystems*** - ***Photosynthesis*** can be ***stimulated*** by ***lowered O2*** - Photosynthesis can be ***stimulated*** by ***H2O*** **Nitrogen fixation** - Many ***prokaryotes*** fix ***N2***, but ***nitrogenase*** is ***responsible*** for ***fixing nitrogen*** and is ***sensitive*** to ***oxygen*** (from photosynthesis). - ***Photosynthesis occur***s during the ***day*** and ***nitrogen fixation*** at ***night*** in order to ***separate*** these two ***processes*** ***Cyanobacteria*** have solved this problem in ***three*** ways: **Nitrogen fixation: 3. *Trichodesmium*** - ***Oceans*** major ***blooming n-fixing cyanobacteria*** - Fix ***¼*** of total ***N*** in the ***world's oceans*** - ***Dominate low O2 tropical waters*** - ***Lack heterocysts***, yet ***fix N2*** in the ***light*** - ***Specialized cells -- diazocytes\**** **Ecology: Where are cyanobacteria found?** - ***Marine*** - ***Freshwater*** - ***Bloom*** formers late ***summer*** - ***Terrestrial*** - ***Primary colonizers*** - ***Extreme*** environments - ***Hot-springs (+70°C!)*** - ***Arctic*** and ***Antarctic lakes*** - ***Hot*** and ***cold arid*** regions - ***Salt*** marshes - In ***Symbiosis*** - ***Lichens*** - ***Root nodules*** **Diversity: Marine Cyanobacteria** *Open Ocean* - ***Picophytoplankton*** - ***Synechococcus*** - ***Prochlorococcus*** - ***Filamentous*** - ***Trichodesmium*** *Littoral* - Encrusting/biofilms - ***Beachrock*** - ***Stromatolites*** **Beachrock** - ***Formed*** through the ***carbonate cementation*** of ***sand*** and ***gravel***, is a ***sedimentary*** rock - Typical ***feature*** of many ***tropical*** and ***subtropical coastlines*** - ***Leads*** to ***intertidal*** rock ***platforms*** - Has ***habitats*** of ***extreme environments*** and ***conditions*** due to ***both high and low tide*** *Black* - ***More*** than ***50%*** ***water loss*** - Complete ***loss*** of ***photosynthesis*** - Fast ***re-activation*** - Typically ***poikilohydric*** - ***Absorbs more heat*** - ***Filamentous*** - ***Heterocystous*** *Pink* - ***Less*** than ***20% desiccation*** - ***Minimal change*** in ***photosynthetic*** activity - ***Atypical response*** of ***desiccation*** tolerant species - High ***reflectivity*** - ***Unicellular*** - ***Non-heterocystous*** **The intertidal** - A ***stressful*** place to ***live*** due to ***desiccation (the removal of moisture)*** - Can ***impact*** their ***growth, development*** and ***metabolism*** - ***Cyanobacterial mats*** are ***poikilohydric*** (can ***withstand desiccation*** by entering a dormant state) - Pink biofilm can hold water better than the black biofilm