Glossary

Amphipod - A small, laterally compressed crustacean (Castro and Huber 2003).

Ascophyllum nodosum - This seaweed creates the seaweed canopy of the mid intertidal, providing other organisms with protection from extreme temperatures, desiccation, waves and bird predation.  Also known as the knotted wrack, Ascophyllum nodosum is a dark green seaweed which grows in long strands and grows air bladders sporadically along its arms.

Ascophyllum nodosum: the long, rope-like green alga seen here

 

Ballast - There have been two general types of ballast in sailing history: rock and water.  Pre-twentieth-century vessels used rocks, sand, scrap iron or other heavy material to weight down the ship for smoother sailing in rough waters.  This material often came from the coastline of one area and was dumped in another for better manuverability into the port.  Any number of coastal species could be transported in such a manner.
            Since the early twentieth century, metal-hulled ships have used water as ballast.  Like rock ballast, this water is accumulated in one port and expelled in another.  Ballast water "teems with planktonic larvae" and provides good conditions for planktonic survival for the voyage (Bertness 1999).

Bivalve - A mollusk with a two valve shell and a single, muscular foot (Castro and Huber 2003).  Examples include mussels and clams.

Cancer sp. - Cancer borealis and Cancer irroratus, otherwise known as rock crabs, are two other crab species found throughout New England shores, including the study site in Nahant, MA.  At the site, both of these crabs were consistently larger than C. maenas and H. sanguineus and colored differently, usually lighter and more reddish brown.  Rock crabs typically live subtidally, most likely to avoid predation from birds that would easily spot them in the dark green seaweeds in the intertidal (Bertness 1999).  A Cancer sp. crab is pictured to the right.

Carapace - The hard, chitinous outer shell which protects the crab.  These are molted from time to time as the crab out grows it.

Chi-square - A statistical test used in science to determine whether numbers are randomly distributed or represent a bias towards a specific distribution.

Chondrus crispus - Also known as Irish moss, this red alga is thinner than the green algae of New England's rocky intertidal and it grows out and upwards in small, branch-like appendages.

Chondrus crispus is the red alga seen here

 

Crab - A predominantly marine crustacean of the order Decapod which also includes lobsters, crayfish and shrimp (Campbell et al. 1999). 

Desiccation - To dry out.

Digital Calipers - A tool yielding a digital readout of fine distance measurements.

Fucus sp. - Also known as rockweeds, these seaweeds are flattened and colored a dark greenish-brown.  They often have small, swollen air bladders and are usually found in the mid to lower intertidal.

Fucus sp. in the lower intertidal

Gastropod - A mollusk with a coiled dorsal shell and a single, muscular foot, such as a snail (Castro and Huber 2003).

Intertidal - The region of shoreline between the high and low tide marks.  The organisms dwelling here are exposed to both aquatic and terrestrial environments with the fluctuating tides.

Mariculture - The farming of marine organisms for commercial purposes.

Polychaete - A segmented worm (Castro and Huber 2003).

Quadrat - A physical square border used to define a small study area for the assessment of the small-scale distributions of plants and animals.  In this study, quadrats were used to measure .5 m² areas in the study site.
       Also, a “quadrat” can refer to the plot of land outlined by the physical quadrat.

Subtidal - The area just below the low tide mark.  This area is never exposed to air.

Transect Line - A line used to measure and record a study area, therefore quantifying physical space.

A transect
 

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