Photo by Josie Iselin


Flat-bodied, shrimp-like, crustaceans of the group Amphipoda, including the beach fleas, sand hoppers, etc.


An alga that completes its life cycle, from germination to the production of spores or embryos, within one growing season, and then dies.     


Environmental change caused or influenced by people, either directly or indirectly.   


The flora and fauna found on the bottom, or in the bottom sediments, of a sea, lake, or other body of water.

Biogenic habitat

Habitat provided by living organisms (i.e., kelp, eelgrass, or terrestrial plants). 

Blade or Lamina

The flattened and elongated portion of a kelp or seaweed where most photosynthesis occurs.

The ‘Blob’

A large mass of relatively warm water in the Pacific Ocean off the coast of North America that was first detected in late 2013 and continued to spread throughout 2014 and 2015; It is an example of a marine heatwave. 

Blue Carbon 

The term for carbon captured by the world's ocean and coastal ecosystems.  


Small invertebrates that expand from a party of one to a colony of thousands, which might encrust an entire kelp blade.  

Calcium Carbonate (CaCO3)

A white insoluble solid occurring naturally as chalk, limestone, marble, aragonite and calcite, and forming mollusk shells and stony corals as well as reinforcing the cell walls of some calcified algae (e.g., corallines).


To strip (something) of its covering, possessions, or assets; make bare. 


To remove the moisture from (something); cause to become completely dry.


An animal which feeds on dead organic material, especially plant detritus.


Waste or debris of any kind; organic matter produced by the decomposition of organisms.


microscopic, unicellular, marine or freshwater photosynthesizing algae of the phylum Chrysophyta, having cell walls containing silica (glass). Also see “Plankton”. 


Any species that creates, significantly modifies, maintains or destroys a habitat.   


An alga or animal that grows on another alga as substrate but is not parasitic.   


A recurring period of sexual receptivity and fertility.   


Of, relating to, or formed in an estuary.   


The tidal mouth of a large river, where the tide meets the stream.  

Extirpation (of a species) 

The state or condition of having become locally or regionally extinct.  

Floating kelp

Species that are held aloft either in the water column or at the water surface by pneumatocysts (buoyant bulbs).

Foundational Species

Those that have a strong role in structuring or maintaining a habitat. 


The sexually differentiated, microscopic, haploid, reproductive kelp life stage that produces egg and sperm (gametes).


The complete set of genes or genetic material present in a cell or organism.  


Herbivorous species (usually invertebrates) that feed directly on fresh or detrital kelp material. 

Hapteron (pl. haptera)

A discoid outgrowth or swelling of the stem by which a plant is fixed to its substratum (as in many rock-inhabiting seaweeds); See also “Holdfast”.   


A behavior associated with pinnipeds (true seals, sea lions, fur seals and walruses) temporarily leaving the water, typically occurring between periods of foraging activity. Rather than remain in the water, pinnipeds haul-out onto land or sea-ice for reasons such as reproduction and rest.  


Structure at the base of a kelp stipe that anchors the individual to substrate. 


The phase of a hydrozoan coelenterate that consists of polyp forms usually growing as an attached colony.


The area of a seashore which is covered at high tide and uncovered at low tide.


Without a backbone, of or relating to creatures without a backbone. 


Any of a large order of terrestrial and aquatic crustaceans (such as a sow bug or rolly polly) with a flattened thorax made up of seven segments, each with a leg, and an abdomen with respiratory appendages. A voracious herbivore.   

K-selected species

Those that are larger, have long lifespans, produce few young at a time, and exhibit logistic growth.  


Species of brown seaweed in the order Laminariales. 

Kelp forest

The community and services provided by intact ecosystems dominated by kelp species composed of multiple species and strata (stories) that rise above the benthos (seafloor) and can extend up to 10 to 25 meters to the surface 

Larva (pl. Larvae)

A distinct juvenile form many animals undergo before metamorphosis into their next life stage.


The edge or border of something.  


A predator that occupies a mid-ranking trophic level in a food web, usually medium-sized carnivorous or omnivorous animals, such as raccoons, foxes, or coyotes.   


The community of microorganisms that can usually be found living together in any given habitat  


An old dump for domestic waste which may consist of animal bone, human excrement, botanical material, mollusc shells, potsherds, lithics, and other artifacts and ecofacts associated with past human occupation. 


Black-and-white diving bird of northern seas.


Also known as mother of pearl, is an organic–inorganic composite material produced by some molluscs as an inner shell layer; the material of which pearls are composed; strong, resilient, and iridescent.  


A dried edible seaweed used in Japanese cuisine, made from species of the red algae genus Pyropia.  


A shell-less marine mollusk in the order Nudibranchia ; a sea slug.  

Nutrient Loading

The quantity of nutrients that is washed into a waterbody from its drainage basin, usually expressed as mass per unit area per unit time.  


A complete or impressive collection of things.  


Designating, relating to, or inhabiting that region of the sea which consists of open water of any depth, away from or independent of both the shore and the sea floor. 


An alga that is present at all seasons of the year; persisting for several years usually with new vegetative and reproductive growth. 


The passively floating or weakly swimming usually minute organisms (such as dinoflagellates, diatoms, copepods, radiolarians, and larval crustaceans and fish) of a body of water.   


Buoyant, gas-filled float on some species of brown algae that lifts a portion of the individual off the benthos (bottom). 


An organism or inorganic object or material which takes various forms.  

Primary Producer

The foundation of an ecosystem forming the basis of the food chain by creating food through photosynthesis or chemosynthesis. 

Regime Shift

Large, abrupt, persistent changes in the structure and function of ecosystems, the climate, financial systems or other complex systems.  The shift between kelp-dominated habitat to urchin-dominated habitat may constitute a regime shift if it persists.

R-selected species

Those that have shorter lifespans, are generally smaller, produce many young, and exhibit exponential growth.  

Sea Cow

The Sirenia, commonly referred to as sea cows or sirenians, are an order of fully aquatic, herbivorous mammals that inhabit swamps, rivers, estuaries, marine wetlands, and coastal marine waters; a manatee is an example.  

Senesce (of a living organism) 

To deteriorate with age. 


  1.  Attached directly by the base; not raised upon a stalk or stipe; 
  2.  Permanently attached or established; not free to move about.  

Shifting Baseline

When measurements of a system/habitat/population are established as a baseline by comparison against previous reference points, often without knowledge that those previous points represent significant changes from an even earlier state of the system. 


To shed or remove (a layer of dead tissue).

Sorus (pl. sori)

Reproductive patches on kelp blades composed of sporangia that undergo meiosis and produce zoospores. 


A sedentary aquatic invertebrate with a soft porous body that is typically supported by a framework of fibers or calcareous or glassy spicules.  


The conspicuous diploid life stage in the kelp life cycle that produces haploid zoospores.


The stem of a kelp individual that connects the holdfast to the blades/lamina. Kelp stipes vary between species.


Any of several physical or biological parameters known to affect long-term kelp health and persistence. 


The area where the seabed is below the lowest tide.


A hard internal skeleton composed of calcium carbonate (CaCO3) plates of some echinoderms (urchins and sand dollars).  


A plantlike vegetative body (as of algae, fungi, or mosses) that lacks differentiation into distinct parts (such as stem, leaves, and roots).   

Trophic Cascade

An ecological phenomenon triggered by the addition or removal of top predators and involving reciprocal changes in the relative populations of predator and prey through a food chain, which often results in dramatic changes in ecosystem structure and nutrient cycling.


A group of marine invertebrates that includes sea squirts and salps. They have a rubbery or hard outer coat and two siphons to draw water into and out of the body.    

Turf algae

Small filamentous and foliose algae that form low-growing populations in the intertidal and subtidal.  They are especially prominent and productive in the tropics.

Type Specimen

The specimen, or each of a set of specimens, on which the description and name of a new species is based.  

Understory / non-floating kelp

Species lacking pneumatocysts. These species either lay along the seafloor or held aloft in the midstory by a rigid stipe.


The edible portion of a sea urchin, the gonads.


An oceanographic phenomenon that involves wind-driven motion of dense, cooler, and usually nutrient-rich water from deep water towards the ocean surface.  

Urchin Barren

An urchin-dominated area with little or no kelp.  


The planktonic larvae of many kinds of sea snails and freshwater snails, as well as most bivalve molluscs and tusk shells.

Water Column

A concept used in oceanography to describe the physical and chemical characteristics of seawater at different depths for a defined geographical point.  


In the kelp  life cycle, single-celled, motile, haploid  spores produced through meiosis in the sporangia that form the sorus on the blade of the sporophyte. Once settled on substrate, zoospores quickly germinate into male and female gametophyte.