Critters - from Newsletters

2008 - April
The Ancient Arthropod
     Almost every time you read about the horseshoe crab, the writer is bound to refer to it as a “living fossil ”. Its outer shell design has persisted virtually unchanged over millions of years; the entire body encased in a tough shell, the large crescent head, the hinged mid-section and the maneuverable spiked tail. 
     Until now, the oldest fossil with that distinct body shape dates to 320 million years ago and was found in the Bear Gulch deposits of Montana.  Scientists have recently uncovered the spitting image of a modern day horseshoe crab in Ordovician deposits along the coast of Manitoba. This discovery puts its relatively unchanged body plan back another 100 million years. For the record, this fossil has been named Lunataspis. An expert on fossil arthropods commented that the next step was and its ancestor somewhere in the Cambrian, 500-600 million years ago.

2007 - January
   Sea Sawdust — Science 312 p.1517-9 June 2006
    Tropical and sub-tropical waters make up half of the world ’s oceans.  At one time, these waters were thought to be biological deserts because of the limited amounts of available nitrogen so far from land.  But recent investigations have found that the upper waters are biologically active be-cause of the cyanobacterium, Trichodesmium, known as ‘sea sawdust’ to ancient mariners. This phytoplankter can both photosynthesize and fix atmospheric nitrogen. 
   Trying to assess how much of this is in the water by net sampling doesn ’t work well because its either damaged or destroyed in the process. Sampling via bottles has been used to estimate vertical distribution but isn ’t much good over long distances. 
    Davis and McGillicuddy have recently used a digital microscope towed behind R/V Knorr as it trekked from a point near the Azores to Bermuda, then on to Woods Hole, MA.The ship and the video plankton recorder covered 5500 kilometers in 12 days. The VPR undulated between the surface and a depth of 130 meters.  It also measured conductivity,temperature, pressure, fluorescence, turbidity, and photosynthetically active radiation as well as time and GPS latitude and longitude. 
   Two species of Trichodesmium could be distinguished. The amounts found of both correlated well with warm, salty water. Although patchy in distribution, total numbers were high enough to throw considerable doubt on past estimates. They came up with figures two to three times higher than previous estimates, enough to account for past deficits. The story doesn’t end here because further use of this new technique should clarify a number of questions about open sea productivity. 

2006 - July

Horseshoe Help — Communication from FWRI
     If, in your forays to the beach, you come across horseshoe crabs either mating or not, the Crustacean Fisheries Research Group at the Florida Fish and Wildlife Research Institute would like to know about it. You can send your data to horseshoe@myfwc.com or call 1-800-252-9326. You can see results at www.research.myfwc.com.
     Although horseshoe crabs spawn throughout the year activity peaks around a full or new moon at high tide in April through August. You are most likely to find them on sand flats either in or close to the Gulf in quiet water.  

Red Drum and Sea Trout — Bay Soundings Spring 2006 p.10
     The Florida Wildlife Institute says last years (2005) red tide severely damaged red drum and sea trout populations in the Tampa Bay area. Juveniles of both species have dropped by 50 percent . Oddly, snook and sheepshead young are in much better shape although their adult population was hit hard by the bloom.
     Red drum and trout are near normal in Charlotte Harbor where, scientists say, the red tide outbreak was not as severe during spring spawning.

2006 - April

Light Up Your Life
The bioluminescent world in the sea awaits.  If you have ever made a night dive in the presence of Noctiluca, you know what an astonishing sight it is to be surrounded by thousands of tiny, flashing lights. Many, many other marine critters also light up.  How it works and the way critters use this facility as well as a gallery of them can be found at www.lifesci.ucsb.edu/~biolum/ .

Dermo in the Gulf -  Texas Shores winter 2006
   A major threat to the eastern oyster, Crassostrea virginica, along the Gulf of Mexico coast is a parasite, Parkinsus marinus, commonly known as Dermo (its earlier scientific name was Dermocystidium marinum).  A slow killer, mortality is highest among the largest market-sized oysters.  It does no harm to humans.  Infection, both in intensity and extent, increases in high temperature, high salinity water and conversely decreases in cooler and less saline water.
   From Texas to Florida, major oyster centers are now being regularly monitored.  The data is posted on  www.DermoWatch.org . The data is used both by scientists and oyster fishermen.  Beyond monitoring, oysters can be moved or harvested depending on their size and the extent of the Dermo problem.

A New Bug - Nature 437 pp.1227-8
   Louis Pasteur once commented  “chance favors the prepared mind”.  That seems to have worked in Holland where an awful aroma from the waste of a yeast factory has led to the discovery and use of a “new” bacterium that may change sewer plant operations world-wide.
    To alleviate the odor problem, the engineers at the yeast factory pumped the waste into sealed oxygen-free tanks.  Their microbiologist noted that the ammonia level in the tank was rapidly falling.  Investigating the cause, he discovered a “new” bacterium that will oxidize ammonia and nitrite anaerobically into nitrogen gas.  It has since been named Brocadia anammoxidans.
    How the bacterium does this has been partially worked out and includes processing steps once thought impossible.  Its value in sewage plants is it does the job of denitrifying in one step without aeration or the addition of an additional carbon source such as methanol.  All this leads to a 90% reduction in operating costs and a 50 % reduction in space in waste treatment plants.

2006 - January

Shark Moves

Small Wonder
 

2005
 

Coral Reef Decline - Science 308 pp1740
The world-wide decline in coral reef health has been attributed to four human-related causes: over fishing, land-based pollution, coastal development, and global climate warming.  Among the easily seen degradations are coral diseases and bleaching.
    Pandolfi has set forward the big problem in U.S. reefs, the Florida Keys in particular and engendered strongly worded replies ranging from “right on” to a litany of corrective measures now under way to questions on whether reef declines are due to pollution and over fishing or whether the more likely culprits are weather related.
    The counter reply to these responses points out that only the Florida Keys Sanctuary area is protected  and even that is subject to pollution from waste water systems built long ago and not yet replaced with adequate ones.                                                                       

Jellyfish Glea - J.Exp.Biol.208, 2475 (2005)
As most zoology students know, the jellyfishes have two dermal layers, the ectoderm and the endoderm.  Between the two is an undifferentiated gelatinous mass called the mesoglea.  It provides the critter with some semblance of shape but until recently, that was about all that was known about it.  It turns out that it holds substantial amounts of oxygen, enough to see the jellyfish through large patches of anoxic water for sustained periods of time.
 

Learn about the Horseshoe Crab - with a link on the diagram to a dedicated site.

Killer Jellies

An article about large jellyfish, also with a clickable photo link.

Sighting a Coelacanth - with some risks associated! - Coelacanth

04/27/09 15:26