Lec 12 Flashcards
Holoplankton =
organisms that spend their entire life cycle as part of the plankton
(e.g. most algae, copepods, salps, and jellyfish)
Meroplankton:
organisms that are only planktonic for part of their lives (usually the larval stage), and then graduate to either the nekton or a benthic existence
Phytoplankton =
autotrophic prokaryotic or eukaryotic algae that live near the water surface where there is sufficient light to support photosynthesis - diatoms, cyanobacteria, and dinoflagellates
Zooplankton =
animals that feed on other plankton. Eggs and larvae of larger animals, such as fish, crustaceans, and annelids, are included here
Bacterioplankton =
bacteria and archaea, which play an important role in remineralizing organic material down the water column
Nutrients =
Nitrogen is the most important limiting nutrient, but phosphate and iron are also important
Light =
phytoplankton is limited to the photic zone, also seasonality is going to play an important role, especially near the poles.
The phytoplankton also affects…
the size of the photic zone = (self-shading)
3 Phytoplankton
Diatoms
Dinoflagellates
Cyanobacteria
Diatoms:
Very important primary producers, common in temperate and cold waters
Dinoflagellates:
More common in warm waters, better adapted to low nutrient conditions
Cyanobacteria:
Account for more than half of the ocean’s primary producers
spring bloom
Spring: light no longer limiting, nutrients available as a consequence of winter mixing and upwelling
fall bloom
Fall: storms produce mixing, some light still available, small burst of production
red tides
With stable conditions dinoflagellates can grow explosively into huge numbers, some times causing red tides
diel migration
Many species undergo vertical migrations, going up to feed at night and night and retreating at depth during the day
biological pump =
& is one of the reasons that…
- As living or dead organic material is typically more dense than seawater it tends to sink
- Carbon is transported from surface waters to the deep
- …the oceans constitute the largest (active) pool of carbon on Earth
