Marine Life and Ecology 2. From phytoplanktons to invertebates
Virtually all primary productivity on land comes from large plants
… seaweeds such as these do exist, but they need shallow water where Sunlight is available and firm substrate for anchorage by their holdfasts.
… whereas microscopic unicellular plants (diatoms, dinoflagellates) and algae account for most of the ocean’s primary productivity.
Phylum Phaeophyta or Brown Algae Phylum Rhodophyta or Red Algae Phylum Chlorophyta or Green Algae Seaweeds are large marine multicellular algae. These non-vascular plants are grouped as green, red and brown algae.
Unicellular Marine Life Skeletal material Size Habitat None None CaCO3 SiO2 SiO2 Cellulose or none SiO2 SiO2 Bacteria Producers (photosynthesizers) Blue-green algae Coccolithophores Silicoflagellates Diatoms Dinoflagellates Consumers (Oxidizers) Protozoans Radiolarians Foraminifera <5 m 5 m 3-10 m 5-40 m 20-80 m 10-50 m 50-500 m 100-1000 m Benthic Surface waters warm open ocean cool open ocean upwelling warm quiet waters Surface waters and sediments
Marsh grass Kelp bed
800 Diatoms Coccolithophores Cell counts per 50 cm3 of water 400 Dinoflagellates 0 0 800 1600 2400 Distance from shore (km)
Spermatophytae (seed bearing plants) Pteridophytae (ferns) Bryophytae (moss) Thallophytae (algae and fungii) Spermatophytae (seed bearing plants) Thallophytae (algae and fungii) Marine plants Land plants
Mangroves thrive in warm tropical waters, kelp prefers cooler waters.
Photomicrograph of tiny marine bacteria (~1 m) attached to the larger diatoms.
Cyanobacteria (x 3000 magnification)
Marine animals • Marine invertebrates • Phylum Porifera (Sponges) • Phylum Cnidaria (Corals, Portugese Man-of-War, Jellyfish) • Phylum Mollusca (Clams, Snails, Octopi) • Phylum Anthropoda (Crabs, Shrimp, Lobsters, Copepods) • Phylum Echinodermata (Sea Stars, Brittle Stars) • Marine worms (Polychaeta, Vestimentifera) Marine vertebrates
As Robert May (Scientific American, October 1992) has argued, most of the species display a predictable relation between physical size and population size: the smaller they are, the moreabundant they tend to be. 1 mm 1 cm 1 m Characteristic size (meters) Implication: More species < 1 mm await discovery than ones > 1 cm.
Jellyfish are cnidarians which lack the polyp stage of the life cycle. Therefore, they are always in the medusae stage. They are considered plankton because they cannot swim on their own--they are dependent upon the current to take them places. They are normally found in the epipelagic layer of the ocean.
Zooplankton concentration shows two peaks in the very productive summertime subarctic or cold temperate waters: • some are feeding at the surface, while • others are resting, or metabolizing what they have consumed, just below the photic zone. In contrast, in the tropics, the zooplankton concentration is on the photic surface waters.
Yellow sponges on a reef. Sponges are filter feeders - they filter their food particles from water that passes through them.
An anemone is a cnidarian, a simple animal consisting of an open gut surrounded by tentacles - stinging cells in these tentacles help paralyze small prey that the tentacles then help bring into the gut.
Is Jellyfish a plankton or a nekton? Different species of jellyfish have different innate buoyancies, so when they are not swimming, some hang neutrally in the water, while others slowly sink when passive; a few float. Some of them are rather small, often less than an inch (or 2.5 cm) and also often found in freshwater as well are subject to the oceans currents, tides and waves for their large-scale movements. But giants like the Lion’s Mane Jellyfish* are known to be excellent swimmers. This is the largest known species of jellyfish, and is mostly found in cold waters north of 42°N (Arctic, North Atlantic and theNorth Pacific) and off Australia and New Zealand. The largest recorded specimen, found washed up on the shore of Massa-chusetts Bay in 1870, had a bell (body) with a diameter of 2.3 m (7 feet 6 inches) and tentacles 36.5 m (120 feet) long. It was longer than a Blue Whale, the longest known animal in the world. * The Sherlock Holmes story, The Adventures of the Lion’s Mane, is centered around a professor who is mysteriously killed. At the end of the story, Holmes discovers the killer is a huge Lion's mane jellyfish.
Bizarre new jellyfish discovered 18:03 07 May 03 NewScientist.com news service A bizarre new species of jellyfish has been discovered in the deep waters off the Californian coast. The bell-shaped creature spans a meter in diameter and has been nicknamed "big red", because of its unusual deep red color. The US and Japanese teams that discovered it say the species deserves its own subfamily. Tiburonia granrojo was discovered using video cameras on deep-diving remotely operated vehicles (ROVs). Its color and shape set it apart from its other gelatinous relatives, but it has another unusual characteristic — a complete lack of tentacles.
Purple and Yellow Tube Sponge Orange Finger Sponge Phylum Porifera
The animals of the class hydrozoa have both a polyp and medusa stage. Siphonophores are a type of hydrozoan with a float for buoyancy. Probably the most famous of these is the species physalia, the Portugese-man-of-war, which is a type of colonial siphonophore.
sea urchin starfish sea cucumber