Diatoms of North America
Mark Edlund
Taxon Contributor Review Board
Content Editor, Centric Diatoms Diatoms of North America, Editoral Review Board
Senior Scientist Science Museum of Minnesota
When in doubt, be like a diatom and help the world breathe more easily... MBE
My research interests have developed around algae, especially the diatoms. Diatoms are microscopic algae characterized by their ornate cell walls made of biologically produced glass. I use diatoms to pursue these research areas:
Because diatoms are made of glass, they accumulate in the bottom of lakes, providing researchers clues to conditions in a lake system in earlier times. Our current research is directed at lakes and National Parks across the Upper Midwest. We use diatoms to determine historical lake response, productivity, and nutrient levels to landuse changes, climate change, damming, and management practices. My earlier paleolimnological research was used to develop nutrient criteria for Minnesota lakes, to drive policy that reduced loadings to the St. Croix River, and to investigate historical climate change on Devils Lake, ND, and Russia's ancient Lake Baikal. Current research is directed at large lakes (Lake of the Woods and the Red Lakes), wilderness lakes undergoing unprecedented change, and lakes suffering from increased salinity. Many of our studies combine modern limnological sampling to determine how lakes and the organisms within them are responding to recent environmental stressors.
The diatom Didymosphenia geminata, or didymo, has become a problem across North America and many places in the world due to its habit of colonizing cold, low-nutrient streams with huge amounts of periphyton that is primarily stalk material. In 2018, the Poplar River on Minnesota's Lake Superior North Shore was invaded by didymo. We are surveying all streams on the North Shore to determine the distribution of didymo, and are intensively monitoring a set of six North Shore streams to determine the seasonality, source, and ecological impacts of didymo on some of our highest value streams.
Conservative estimates set the number of living diatom species at about 25,000, but knowledge of sexuality and life histories is known for only approximately 300 species. This shortfall provides a modern challenge to further a rich scientific history on algal sexuality. My work in this field has centered on description and cytology of sexuality, dormancy strategies, size restitution, and ecology and seasonality of auxosporulation.
Projects
Species contributed
Acanthoceras zachariasii | Achnanthidium minutissimum | Amphora calumetica | Anomoeoneis fogedii | Anomoeoneis sphaerophora | Asterionella ralfsii var. americana | Aulacoseira ambigua | Aulacoseira granulata | Aulacoseira islandica | Aulacoseira italica | Aulacoseira nygaardii | Aulacoseira subarctica | Aulacoseira tenella | Biremis undulata | Chaetoceros muelleri | Craticula coloradensis | Cyclostephanos invisitatus | Cyclostephanos tholiformis | Cyclotella quillensis | Diatoma ehrenbergii | Discostella pseudostelligera | Discostella stelligera | Eunotia bidens | Eunotia bilunaris | Eunotia charliereimeri | Eunotia eruca | Eunotia formica | Eunotia incisa | Eunotia metamonodon | Eunotia pectinalis | Eunotia sarraceniae | Eunotia superbidens | Eunotia tauntonensis | Eunotia zasuminensis | Fragilaria vaucheriae | Fragilariforma constricta | Fragilariforma polygonata | Frustulia bahlsii | Gomphonema freesei | Gomphonema gibba | Gomphonema montezumense | Hannaea superiorensis | Hydrosera whampoensis | Lacustriella lacustris | Lindavia bodanica | Lindavia comensis | Lindavia delicatula | Lindavia eriensis | Lindavia michiganiana | Lindavia ocellata | Luticola ignorata | Melosira dickiei | Melosira normannii | Meridion alansmithii | Navicula aurora | Navicula caterva | Navicula hasta | Navicula rhynchocephala | Navicula vulpina | Neidium sacoense | Orthoseira roeseana | Oxyneis binalis | Oxyneis binalis var. elliptica | Pinnularia turfosiphila | Placoneis amphibola | Placoneis anglophila | Placoneis explanata | Pseudostaurosira brevistriata | Pseudostaurosira microstriata | Pulchellophycus schwabei | Sellaphora auldreekie | Sellaphora fusticulus | Sellaphora laevissima | Sellaphora moesta | Sellaphora schadei | Semiorbis catillifera | Semiorbis eliasiae | Semiorbis hemicyclus | Semiorbis rotundus | Stauroneis bovbjergii | Stauroneis kingstonii | Staurosirella berolinensis | Stephanodiscus binderanus | Stephanodiscus hantzschii | Stephanodiscus hantzschii f. tenuis | Stephanodiscus medius | Stephanodiscus minutulus | Stephanodiscus parvus | Thalassiosira baltica | Ulnaria acus | Ulnaria delicatissima
Species reviewed
Actinocyclus normanii | Aneumastus minor | Aneumastus rostratus | Aneumastus tusculus | Aulacoseira ambigua | Aulacoseira crassipunctata | Aulacoseira granulata | Aulacoseira granulata var. angustissima | Aulacoseira herzogii | Aulacoseira humilis | Aulacoseira newjerseyana | Aulacoseira subarctica | Chaetoceros lauderi | Cyclostephanos dubius | Cyclotella atomus | Cymbellonitzschia diluviana | Cymbopleura stauroneiformis | Decussata placenta | Denticula tenuis | Diadesmis confervacea | Diatomella balfouriana | Diploneis krammeri | Diploneis ovalis | Discostella pseudostelligera | Encyonema latum | Encyonema leibleinii | Encyonema nicafei | Encyonema pergracile | Encyonema reimeri | Encyonema temperei | Encyonema yellowstonianum | Encyonopsis aequaliformis | Encyonopsis albertana | Encyonopsis alpina | Encyonopsis anacondae | Encyonopsis bobmarshallensis | Encyonopsis czarneckii | Encyonopsis dakotae | Encyonopsis descripta | Encyonopsis descriptiformis | Encyonopsis hustedtii | Encyonopsis krammeri | Encyonopsis kutenaiorum | Encyonopsis lacusalpini | Encyonopsis medicinalis | Encyonopsis minuta | Encyonopsis perborealis | Encyonopsis robusta | Eucocconeis alpestris | Eucocconeis flexella | Eucocconeis laevis | Fragilaria recapitellata | Fragilaria vaucheriae | Fragilariforma marylandica | Gomphonema manubrium | Gomphonema sarcophagus | Gyrosigma acuminatum | Iconella tenera | Krasskella kriegeriana | Kurtkrammeria aequalis | Lindavia affinis | Lindavia rossii | Navicula aitchelbee | Navicula caroliniae | Navicula gregaria | Navicula kotschyi | Navicula metareichardtiana | Navicula piercei | Navicula salinarum | Navicula schweigeri | Navicula staffordiae | Navicula subrhynchocephala | Neidium hitchcockii | Pleurosigma delicatulum | Psammothidium obliquum | Reimeria uniseriata | Stauroneis gracilis | Stauroneis heinii | Stauroneis kishinena | Stauroneis lauenburgiana | Stauroneis pax | Stauroneis phoenicenteron | Stauroneis pikuni | Stauroneis rex | Stauroneis smithii var. incisa | Stauroneis subborealis | Stauroneis supergracilis | Stephanodiscus niagarae | Stephanodiscus reimeri | Stephanodiscus yellowstonensis | Surirella striatula | Tetracyclus glans | Tryblionella gracilis
Genera contributed
Acanthoceras | Achnanthes | Achnanthidium | Actinella | Actinocyclus | Adlafia | Afrocymbella | Amphicampa | Amphipleura | Amphorotia | Aneumastus | Anomoeoneis | Asterionella | Aulacoseira | Bacillaria | Biremis | Brachysira | Brevisira | Caloneis | Campylodiscus | Capartogramma | Cavinula | Chaetoceros | Chamaepinnularia | Cocconeis | Cosmioneis | Craticula | Ctenophora | Cyclostephanos | Cyclotella | Cylindrotheca | Cymatopleura | Cymbella | Cymbellonitzschia | Cymbopleura | Decussata | Delicatophycus | Denticula | Diadesmis | Diatoma | Diatomella | Didymosphenia | Discostella | Distrionella | Ellerbeckia | Encyonema | Eolimna | Eucocconeis | Fallacia | Fistulifera | Fragilaria | Fragilariforma | Frustulia | Geissleria | Gomphoneis | Gomphonema | Gyrosigma | Hannaea | Hippodonta | Hydrosera | Hygropetra | Karayevia | Kobayasiella | Lacustriella | Lemnicola | Luticola | Mastogloia | Mayamaea | Melosira | Meridion | Microcostatus | Muelleria | Navicula | Navicymbula | Neidium | Nitzschia | Nupela | Orthoseira | Oxyneis | Pinnularia | Placoneis | Plagiotropis | Planothidium | Platessa | Playaensis | Pleurosigma | Pleurosira | Pliocaenicus | Psammothidium | Pseudostaurosira | Pseudostaurosiropsis | Pulchellophycus | Puncticulata | Reimeria | Rhoicosphenia | Rossithidium | Scoliopleura | Sellaphora | Semiorbis | Skeletonema | Stauroforma | Staurosira | Staurosirella | Stenopterobia | Stephanocyclus | Stephanodiscus | Surirella | Synedra | Tabellaria | Tabularia | Terpsinoë | Tetracyclus | Thalassiosira | Urosolenia