Name of microbe: Pennate Diatom

Where sample was found: Bermuda Atlantic Time-series Study (BATS) site, April 18, 2017, surface water

Project: BATS

Photo credit: Rachel Parsons, BIOS

What role does the microbe play in the ecosystem: Diatoms are a major group of algae. They are especially important in oceans, where they contribute an estimated 45% of the total oceanic primary production of organic material.

Interesting facts: A unique feature of diatom cells is that they are enclosed within a cell wall made of silica (hydrated silicon dioxide) called a frustule.

Name of microbe: Chaetoceros

Where sample was found: Bermuda Atlantic Time-series Study (BATS) site, April 18, 2017, surface water

Project: BATS

Photo credit: Rachel Parsons, BIOS

What role does the microbe play in the ecosystem: Chaetoceros is an abundant centric diatom found in the marine environment. It is an important phytoplankton capable of fixing carbon.

Interesting facts: Because of high growth rates and contain high concentrations of lipids, Chaetoceros has been used as a potential alga to harvest lipids for biofuels.

Name of plankton: Thecosome pteropods

Where sample was found: Hydrostation S, Giovannoni Cruise, September 8, 2016, 0-200m

Project: BIOS-SCOPE artistic collaboration

Photo credit: Samantha Newton

What role do these organisms play in the ecosystem: Thecosome pteropods are a type of shelled swimming snail that are part of the zooplankton. With diverse shapes and lifestyles they are part of the diel vertical community, contribute to grazing of the surface community, and make up ~13% of the calcium carbonate export from surface waters to the deep in the Sargasso Sea.

Interesting facts: This photo features five genus of thecosomes (Diacria, Cavolinia, Diacavolinia, Clio and Limacina), all collected at night during two 1-hour tows of the surface waters at Hydrostation S.

Name of plankton: Arietellus spp.

Where sample was found: Bermuda Atlantic Time-series Study (BATS) site, daytime, 450-600m

Project: BIOS-SCOPE zooplankton diel distribution and biodiversity

Photo credit: Leocadio Blanco Bercial, BIOS

What role do these organisms play in the ecosystem: This particular image is a species of Arietellus, a large carnivorous zooplankton that makes a daily migration from the surface waters to great depths during the day. This migration moves carbon from surface waters to the deep sea.

Interesting facts: This photograph was made with a specialized scanner (Zooscan), which allows images to be taken of an entire plankton sample. These can then be run through a set of software tools that, via machine learning, can classify the images into various taxonomic groups and measure their biovolumes, substantially reducing the time it takes to sort and identify zooplankton. This individual was found in a net that contains animals captured from 450-600 m deep!

Name of plankton: Pleuromamma xiphias

Where sample was found: Giovannoni Cruise, September 8, 2016, 0-200m

Project: BIOS-SCOPE zooplankton excreta experiments

Photo credit: Amy Maas, BIOS

What role do these organisms play in the ecosystem: Pleuromamma xiphias is a large zooplankton that makes a daily migration from the surface waters to more than 450 m deep during the day. Consuming surface organisms at night, it then excretes waste carbon and nitrogen at depth, supplying nutrients to the midwater ecosystem.

Interesting facts: This individual was used in an experiment to determine how much and what kind of carbon this species provides to the bacterial community and to determine how the bacterial community responds. It is getting photographed for species validation just before it is weighed.

Name of plankton: Photosynthetic nanoflagellate, Pyramimonas spp.

Where sample was found: Bermuda Atlantic Time-series Study (BATS) site

Project: Microbial Observatory

Photo credit: Rachel Parsons, BIOS

What role do these organisms play in the ecosystem: A flagellate is a cell or organism with one or more whip-like organelles called flagella. Flagella are generally used for propulsion. Some flagellates are autotrophs capable of photosynthesis while others are heterotrophs that capture and ingest bacteria prey.

Interesting facts: The flagellum is constructed of numerous subunits of the protein flagellin, while at the base a system of rings anchors the flagellum in the cell wall and plasma membrane. Surrounding these rings are paired motor proteins, which impart a rotary motion to the filament, and switch proteins, which can reverse the direction of rotation.

This photo and information about the microbe were published in a text book: Helmreich, S. (2009). Alien Ocean: Anthropological Voyages in Microbial Seas. University of California Press, 1-422.

Name of plankton: Oceanic bacterioplankton

Where sample was found: Hydrostation S, 200m

Project: BIOS-SCOPE

Photo credit: Rachel Parsons, BIOS

What role do these organisms play in the ecosystem: Seawater was taken from 200m on the September BIOS-SCOPE cruise. This water was treated with specific carbon compounds to try and promote oceanic bacterioplankton growth. This image shows one of these treatments after 5 days of growth. The specific bacteria that has grown seems to dominate the community and will be identified using DNA sequencing and fluorescent in-situ hybridization.

Interesting facts: The cell morphology shows that a rod shaped bacteria has grown and as a result it is suspected to be Alteromonas, is an opportunistic gammoproteobacteria that often blooms with the addition of carbon compounds to surface seawater.

Name of plankton: Oceanic bacterioplankton

Where sample was found: Hydrostation S, 300m

Project: BIOS-SCOPE

Photo credit: Rachel Parsons, BIOS

What role do these organisms play in the ecosystem: Oceanic Bacterioplankton often attach to particles known as marine snow. These large bacteria are attached to marine snow particles where they are breaking down dissolved organic matter thereby making it available to higher trophic groups via the trophic pathway known as the microbial loop.

Interesting facts: The large bacteria attached to the particles are actively dividing. The DNA is clustered (seen as a yellowish dot) within the cell just prior to cell division.

Name of plankton: SAR11

Where sample was found: Bermuda Atlantic Time-series Study (BATS) site, 80m

Project: Microbial Observatory

Photo credit: Rachel Parsons, BIOS

What role do these organisms play in the ecosystem: SAR11 are heterotrophic bacteria that dominate the euphotic zone of the ocean comprising up to 40% of the total bacterioplankton population. They are known as oligotrophs or scavengers that feed on dissolved organic carbon and nitrogen and are important in the marine carbon and nitrogen cycles.

Interesting facts: The photo shows total bacterioplankton on the left in blue stained with DAPI. The photo also shows SAR11 in the middle targeted using Fluorescent in-situ hybridization with oligonucleotide probes labeled with Cy3. The right hand side shows the two images overlaid with SAR11 positive cells shown in pink.

SAR11 has one of the smallest number of open reading frames of any free living organism, but it still has metabolic pathways for all 20 amino acids and most co-factors. Its genome has been streamlined, thereby reducing the amount of energy required for cell replication.

Name of plankton: Ceratium

Where sample was found: Bermuda Atlantic Time-series Study (BATS) site

Project: Microbial Observatory

Photo credit: Rachel Parsons, BIOS

What role do these organisms play in the ecosystem: The genus Ceratium includes marine dinoflagellates. Species of Ceratium contain two flagella of different lengths. They also contain armored plates that are composed of cross-linked cellulose. These plates can form horns.

Interesting facts: Some species of Ceratium are mixotrophs capable of both photosynthesis and heterotrophic feeding. Ceratium dinoflagellates have a unique adaptation that allows them to store compounds in a vacuole that they can use for growth when nutrients become unavailable.