OBSERVE / UNDERSTAND / EXPLORE
Field library
Marine organisms, coastal observations, underwater photography and the science behind what you see.
325 readings
Marine life
Comb jellies: eight rows of moving light ↗
Comb jellies swim with eight rows of fused cilia, but the rainbow shimmer in a photograph and a flash of bioluminescence have different causes. Their body forms and feeding structures also vary widely.
Marine life
Hydrozoans: one group, many ways of living ↗
Hydrozoans include attached hydroid polyps, small swimming medusae, and elaborate colonies such as siphonophores. Their varied forms share cnidarian stinging cells, but appearance alone rarely establishes a precise identification.
Marine life
Sea angels and sea butterflies ↗
Sea angels and sea butterflies are pelagic snails whose modified foot helps them swim. Their different adult body forms matter when interpreting shell damage and ocean-acidification research.
Marine life
A siphonophore is a colony with a shared life ↗
A siphonophore is an integrated hydrozoan colony whose connected zooids perform different roles. Its coordinated appearance can resemble one long animal, but colonies vary in form and are not all built alike.
Marine life
True jellyfish: the life behind the bell ↗
A scyphozoan’s familiar swimming bell is one stage in a life cycle that often begins as an attached polyp. Its contractions, feeding structures, and seasonal abundance make sense when viewed as parts of that life history.
Marine life
Tunicates: filter feeders with a chordate connection ↗
Tunicates include attached sea squirts and free-swimming forms such as salps and larvaceans. Their varied adult bodies share a chordate lineage, made especially visible in the larval stage of many tunicates.
Field methods
The sea peach is an animal, not a plant ↗
Halocynthia aurantium is an ascidian tunicate: an attached marine animal with a protective tunic and two siphons. Careful field notes distinguish direct observations from a name that still needs evidence.
Research notes
When video becomes a species description ↗
High-definition underwater video can document anatomy and behavior when collecting a delicate animal is impractical. A video-based species description is a specific evidence case, with clear strengths and limits.
Research notes
A sea slug in the ocean’s midnight zone ↗
Bathydevius caudactylus shows how long-term observation and careful anatomical comparison can reveal an unfamiliar animal’s place in the deep sea.
Research notes
How to map a house made of mucus ↗
Laser imaging can reveal how a giant larvacean’s delicate mucus filters shape water and particle flow, while leaving open questions about where discarded material ultimately goes.
Field methods
One temperature reading, many possible explanations ↗
A temperature difference can prompt useful questions, but repeatable measurements and context are needed before linking it to a coastal process such as upwelling.
Field methods
What makes an underwater image useful to science? ↗
A scientific image records more than appearance: context, scale, lighting, and behavior help readers distinguish visible evidence from interpretation.
Field methods
Where sunlight ends and the deep ocean begins ↗
Ocean light changes gradually with depth, so familiar zone boundaries are useful guides rather than sharp borders. Separating sunlight from animal-made light helps explain what darkness means for life below the surface.
Marine life
Bristle worms: many segments, many lifestyles ↗
Polychaetes share a segmented body plan, but their appendages and habitats reveal a wide range of ways to move and feed.
Marine life
Anemones and corals: life as a polyp ↗
Anthozoans live in a polyp form, using a mouth, oral disk, and tentacles without a free-swimming medusa stage.
Field methods
Plan a shore survey around the tide, not a timetable ↗
A repeatable tide-aware plan starts with the right station and time basis, then treats predictions as context for observation rather than a guarantee of shoreline conditions.
Field methods
Make repeat shore surveys comparable ↗
Consistent boundaries, timing, effort, and gap records help distinguish ecological change from differences in how a shore survey was carried out.
Field methods
Record the field site before recording the animal ↗
A site record captures the habitat and observation conditions needed to interpret detections, tentative identifications, and non-detections later.
Field methods
A week of coastal temperatures: Monterey and La Jolla ↗
A historical comparison of two NOAA station records shows how six-minute water-temperature observations can be summarized while keeping their limits in view.
Water observations
Can a phone photograph document water color reliably? ↗
Phone images can preserve an observation, but exposure, white balance, glare, and lighting need written context before color comparisons are meaningful.
Coastal field trips
Can a short visit produce useful coastal data? ↗
A brief visit can produce useful observations when the question is narrow, the method is consistent, and the record makes its limits visible.
Reading marine data
Can satellite color data measure water quality directly? ↗
Satellite color products are estimates derived from reflected light and processing choices. Calibration, local conditions, and matching in-water observations shape their interpretation.
Seasonal ecology
Can seasonal beach wrack indicate changes offshore? ↗
Repeated wrack surveys can reveal useful changes at the shoreline, while careful notes keep possible offshore causes provisional.
Seasonal ecology
Can seasonal photo comparisons reveal habitat change? ↗
Repeatable photographs can document visible habitat differences when framing, scale, visibility, and camera settings are considered.