Download No. 32, March 2003

No. 32, March 2003
TENTH DEEP-SEA BIOLOGY SYMPOSIUM
OREGON COAST, U.S.A. − AUGUST 25-29, 2003
Third Announcement
The 10th Deep-Sea Biology Symposium will be held in Coos Bay, Oregon from August 25−29, 2003. Hosted by the
Oregon Institute of Marine Biology (University of Oregon), the symposium will meet primarily in the performing
arts center on the Campus of Southwestern Oregon Community College. This modern campus lies in coniferous
forest on the shore of Empire Lake, within the Coos Bay city limits and just minutes away from the city of North
Bend and the fishing village of Charleston. Social activities will include a catered banquet on the OIMB campus in
Charleston, an opening night reception, and a trip down the scenic Southern Oregon Coast, terminating in a jet boat
trip on the wild and scenic Rogue River.
Details of the conference, including travel, presentations, housing and registration are available at the
conference website: http://darkwing.uoregon.edu/%7Eoimb/deepsea/frontpage.html
Oregon Institute of Marine Biology, Coos Bay
The deadline for early registration and abstract submission is May 1. Registrations
will be accepted after this date, but with a
slightly higher fee. Students may register at a
reduced rate.
The coast and mountains of southern
Oregon boast some of the most dramatic
scenery in the United States. The spectacular
rocky shores at Sunset Bay, Shore Acres and
Cape Arago are just a few minutes from the
Oregon Institute of Marine Biology. South
Slough National Estuarine Research Reserve, the first protected estuarine watershed
in the United States, is immediately adjacent
to the OIMB campus and offers excellent
canoeing and kayaking. The Oregon Dunes
National Recreation Area, a 50-mile stretch
of enormous sand dunes and beaches, lies
just north of Coos Bay. Scenic rivers popu-
lar with trout and salmon fishermen (the Coquille, Coos, Umpqua, Sixes, Elk, Rogue, Siuslaw) are nearby, and
there are wonderful opportunities for hiking and camping in the Siskyou and Cascade ranges. Crater Lake National
Park is about 4 hours by car from the conference venue and Redwood National Park in Northern California is about
3 hours away.
Organizing Committee
Prof. Craig Young, University of Oregon, chair
Dr. Sandra Brooke, University of Oregon −
[email protected]
Prof. Anna-Louise Reysenbach, Portland State
University − [email protected]
Prof. Emeritus Andrew Carey, Oregon State
University − [email protected]
Prof. Robert Y. George, Univ. of N. Carolina,
Wilmington − [email protected]
Prof. Paul Tyler, Southampton Oceanography
Centre − [email protected]
Registration and payment of fees
It is preferred that delegates register over the
internet by filling out and submitting the form at
Southwestern Oregon Community College
this site. Alternatively, the form may be printed
Performing Arts Center on Empire Lake
out and faxed to Craig Young at:
+1-(541) 888-3250. A hand-copied version is included here. Payment must be made in U.S. funds by check or direct bank transfer. Credit card numbers cannot
be accepted. Details of costs and payment methods are found on the registration form. Registration fees include the
cost of the excursion and river trip, the program, some transportation costs, the opening reception and coffee
breaks. The banquet, which will be an outdoor affair at OIMB with excellent food and drink, is priced separately.
The deadline for early registration and abstract submission is May 1, 2003. Abstracts will not be accepted after
this date. Late registration will incur a slightly higher fee. In the event that a delegate finds it necessary to
withdraw, fees will be refunded in full until August 1; later withdrawals will be dealt with on a case-by-case basis,
with the amount refunded dependent on expenditures that have already been made.
Themes
Oral contributions and posters in any field of deepsea biology are welcome, but we expect to
organize some sessions around the following
thematic areas, all of which have been suggested
by delegates:
Human impacts & exploitation of the deep sea
Reproduction & recruitment
Experimental community ecology
Physiological ecology of deep-sea & midwater animals
Biology of the deep Gulf of Mexico
History of deep-sea biology
Population dynamics & genetics
Benthic-pelagic coupling
Bastendorf Beach, close to OIMB
Please consult the website for instructions on submission of abstracts.
DEEP-SEA NEWSLETTER No. 32, March 2003 – p. 3
10th Deep-Sea Biology Symposium
Registration and Housing Form
Name: ______________________________________________________________________
Title (Dr., Prof., Ms., Mr.): _______________
Institution: ___________________________________________________________________
Mailing Address: ______________________________________________________________
____________________________________________________________________________
Telephone: _______________ Fax: ______________ E-mail: __________________________
Names of accompanying persons: ________________________________________________
Housing Preference (check everything that applies)
I will arrange my own hotel room at SWOCC or OIMB for the following nights:
August
24 ___ 25 ___ 26 ___ 27 ___ 28 ___ 29 ___ 30 ___
On campus housing will be assigned in the order that requests are received. Please rank (1st
choice, 2nd choice, etc.) all housing for which you would like to be considered:
Single occupancy room at SWOCC ___
Single occupancy room at OIMB ___
Double occupancy room at SWOCC ___ Double occupancy room at OIMB ___
Dormitory ”room” at OIMB ___
I have requested double occupancy; please assign me a roommate ___
I have requested double occupancy and will arrange my own roommate ___
My roommate is registering and paying separately; his/her name is: ______________________
Registration and Housing Fees
Early Registration fee before May 1 ($240.00 regular; $200.00 student) $ ___________
Late Registration fee after May 1 ($270.00 regular; $230.00 student) $ _____________
On-campus housing deposit ($50.00 x _____ persons)…………………$ _____________
Banquet ($40.00 x ____ persons) …………………………………………$ _____________
Accompanying person ($70.00 x ___ persons) …………………………..$ _____________
(includes excursion, reception, evening restaurant shuttles)
TOTAL REGISTRATION FEES & HOUSING DEPOSIT ……… $ _____________
Amount paid by check (U.S. funds)
$ __________ Date mailed: _________________
Amount paid by bank transfer*
$ __________ Transfer date: ________________
(sorry… the University of Oregon does not accept credit cards)
*Direct bank transfers should be made in U.S. dollars to:
Umpqua Bank, North Bend, Oregon
Routing Number: 123205054
Account Number: 550000277
Comment Line: make sure the bank includes your name!
Please check for accuracy before sending. Thank you. Your registration and housing will be
confirmed by e-mail.
DEEP-SEA NEWSLETTER No. 32, March 2003 – p. 4
Craig Young’s contact information is below. Please do not hesitate to contact him or another member of the
organizing committee (for e-mail addresses of other committee members, see p. 2) with any questions or
suggestions. The students, postdocs, faculty and staff of Oregon Institute of Marine Biology are excited to welcome
you to our beautiful part of the world.
Craig M. Young
Oregon Institute of Marine Biology
P.O. Box 5389
Charleston, Oregon 97420, U.S.A.
Fax: +1-541-888-3250
Phone: +1-541-888-2581 ext. 299
E-mail: [email protected]
Once again, the Symposium Website:
http://darkwing.uoregon.edu/%7Eoimb/deepsea/frontpage.html
NEW LIGHT ON DEEP-SEA LORICIFERA
The recently discovered phylum Loricifera is still one of the most unexplored meiofauna groups (Higgins &
Kristensen 1988; Kristensen 1991a, b). A total of just 11 species of these microscopic metazoans have officially
been described since 1983 (Todaro & Kristensen 1989). They belong to a taxonomic group with two families and
three genera (Kristensen 1983, Higgins & Kristensen 1986). Virtually nothing is known about Loricifera of the
deep sea. So far, they have mainly been collected from subtidal or littoral habitats. Just one species is described
from the deep sea: Pliciloricus hadalis Kristensen & Shirayama, inhabiting red clay at 8,260 m depth in the IzuOgasawara Trench of the western Pacific (Kristensen & Shirayama 1987, 1988).
Several new findings of Loricifera in the South Atlantic and central Pacific indicate that there are taxa with a
wide distribution exclusively in the deep sea (Gad 2001). Recently, many specimens of Loricifera were sampled
during cruise M 48/1 of the R.V. Meteor. Sampling was carried out during the DIVA I – 2000 project (DIVersity of
the deep sea in the Atlantic), the aim of which was the study of the diversity of the deep-sea fauna in the Angola
A
B
C
D
Figure 1. A, Higgins-larva of a new genus (Pliciloricidae). B, cyst-like instar with unknown status. C, Higgins-larva of a new
Pliciloricus species. D, related adult of the same new Pliciloricus species.
Basin. The 160 samples contained about 280 Loricifera representing 14 new species, most of them belonging to
new genera. More than 95% of the specimens obtained are Higgins-larvae.
The high proportion of larval instars might be characteristic for the deep sea, and also has to do with a newly
discovered life cycle of a new genus. All instars of the life cycle of this taxon are well documented. A hypothetical
DEEP-SEA NEWSLETTER No. 32, March 2003 – p. 5
life cycle contains parthenogenetic Higgins-larvae as a reproductive generation as in the life cycle of Rugiloricus
Higgins & Kristensen, 1986 (Kristensen & Brooke 2002). New species of the genus Rugiloricus are also present in
the deep-sea samples but with fewer specimens than in samples from subtidal or littoral habitats. In their life cycle
there is an aberrant postlarva with protoformations of the adult morphology.
Considering all features, it can be concluded that this postlarva is a cyst-like stage in which metamorphosis to
the adult can be postponed as in the pupa of holometabolic insects, which also does not feed or move. All this
shows that there is an alternation of parthenogenesis and bisexual reproduction (heterogamy) which seems to be
quite common in many taxa of deep-sea Loricifera.
The Higgins-larva of a new genus represents a new type of larva (Fig. 1A) but belongs to the Pliciloricidae all
the same. Compared with Higgins-larvae of the genus Pliciloricus Higgins & Kristensen, 1986 they show clear
distinguishing characters: (1) structure of the mouth cone and prepharyngeal armature, (2) arrangement of scalids,
(3) long thorax with a thin lorica divided into numerous doubly folded plates. Additionally, the trunk is flexible and
can be greatly extended. Also characteristic for this new larval type is the fact that the thorax is only slightly
separated from the lorica or not at all separated.
These complex life cycles are one of the most astonishing characteristics of the Loricifera in general.
Especially in the deep sea the diversity of life cycles with modified instars is surprisingly high. For example in the
life cycle of a new species of Pliciloricus (Fig. 1C and D) there is a postlarva with an “unfinished” adult
morphology similar to that in Rugiloricus. This is the first report of a postlarval instar in this taxon, which was
supposed to have a direct development (Kristensen 1991b).
In addition, a large cyst-like instar lacking an introvert and any kind of sensory or locomotory appendages was
discovered (Fig. 1B). This instar resembles a round capsule with a thick outer cuticle divided into folded plates, and
with one or two thinner layers of inner cuticle. The modified and presumably reduced larva contains around 60
eggs. This instar is not easy to interpret or to fit into a life cycle, but without doubt it belongs to the Loricifera. The
same is true for a more than 1-mm-large new larval type with more then 100 lorica ridges, of which only five more
or less well preserved specimens are available. For Loricifera, which normally have a size from 250 to 500 µm,
these larvae are really gigantic in size and may be an example of deep-sea gigantism. Loricifera, no doubt, have a
high diversity in the deep sea. Further studies may concentrate on the spectacularly modified and complex life
cycles, which may reflect life conditions in the deep-sea environment.
References
Gad, G., 2001: Die Tiefsee als Fundgrube neuer Loricifera Taxa. − Terra Nostra 01/6: 34.
Higgins, R. P. & R. M. Kristensen, 1986: New Loricifera from Southeastern United States coastal waters. − Smithsonian
Contrib. Zool. 438: 1-70.
Higgins, R. P. & R. M. Kristensen, 1988: Loricifera. – Pp. 319–321 in R. P. Higgins & H. Thiel (eds): Introduction to the
Study of Meiofauna, Smithsonian Institution Press, Washington, D.C.
Kristensen, R. M., 1983: Loricifera, a new phylum with Aschelminthes characters from the meiobenthos. - Z. Zool. Syst.
Evolut.-forsch. 21: 163−180.
Kristensen, R. M., 1991a: Loricifera. – Pp. 351−375 in F. R. Harrison & E. E. Ruppert (eds): Microscopic Anatomy of
Invertebrates: Aschelminthes, Vol. 4. Wiley-Liss, New York.
Kristensen, R. M., 1991b: Loricifera − A general biological and phylogenetic overview. − Verh. Dtsch. Zool. Ges. 84:
231−246.
Kristensen, R. M. & S. Brooke, 2002: Phylum Loricifera. – Pp. 179−187 in C. M. Young (ed.): Atlas of Marine Invertebrate
Larvae. Academic Press, San Diego.
Kristensen, R. M. & Y. Shirayama, 1987: Discovery of a hadal representative of Loricifera. − Deep-Sea Newsletter No. 13: 9.
Kristensen, R. M. & Y. Shirayama, 1988: Pliciloricus hadalis (Pliciloricidae), a new loriciferan species collected from the IzuOgasawara Trench, western Pacific. − Zool. Sci. (Tokyo) 5: 875−881.
Todaro, M. A. & R. M. Kristensen, 1989: A new species and first report of the genus Nanaloricus (Loricifera, Nanaloricidae)
form the Mediterranean Sea. - Ital. J. Zool. 65: 219−226.
Gunnar Gad
Biologie, Geo- & Umweltwissenschaften, Carl von Ossietzky Universität Oldenburg
Carl von Ossietzky-Straße 9-11, D-26111 Oldenburg, Germany
E-mail:[email protected]
DEEP-SEA NEWSLETTER No. 32, March 2003 – p. 6
DEEP-SEA DREAMS: DIARY OF A MAD LOPHENTEROPNEUST WATCHER
I made my first dive in the research submersible Alvin in 1975, in the inimitable and jolly company of ichthyologist
Daniel M. Cohen. On the night after that dive, gently rocked to sleep by the lurching motion of the mother ship
Lulu, I dreamed that I was in the Alvin, sitting on the deep-sea floor, and staring through the viewing port at a
nearby rock face. There on the rocks was a group of about 20 little pinkish-red edrioasteroids, all busily feeding.
The edrioasteroids were discoidal, with five food grooves radiating from the central mouth. I should mention here
that edrioasteroids, related to sea stars, have been extinct for 300 million years. I have experienced this powerful
dream hundreds of times, and on every one of numerous subsequent submersible dives, I have half-expected to see
live edrioasteroids. No luck yet!
Two years after this first dive I was with Dan Cohen again, in the Tongue of the Ocean, Bahama Islands. We
had completed Alvin Dive 703 (24°54.9'N, 77°41.1'W, January 12, 1977), a tiring dive during which we ran several
transects across the seabed, and counted thousands of fishes and invertebrates (Pawson 1982). The pilot dropped
the iron weights and we lifted off from the seabed at a depth of about 2,140 meters, to begin our unstoppable ride to
the ocean surface. As we moved upwards, I casually and wearily
looked through my viewing port. Very soon we passed a small, muddy,
gently sloping shelf. I was astonished to see, in the pool of light,
several (about 20?) specimens, perhaps 12−24 inches long, of the weird
worms known as lophenteropneusts scattered on the shelf. I had the
impression that all were more or less U-shaped (as in the illustration
here). Their brightly colored bodies, dark carmine red in the anterior
25% or so, and lighter red posteriorly, were conspicuous on the very
light brown sediment! At that time, I was probably not yet aware of the
1976 paper (issued Dec. 31, 1976) by Henning Lemche and colleagues
(Lemche et al. 1976), and Lemche’s description of “lophenteropneusts”. But, I had seen several sea-floor photographs of these worms
Lophenteropneust (after Lemche et al. 1976) in other publications, and the images were very fresh in my mind. I
suspected that these animals had not previously been seen alive, in situ.
My joy at seeing them was short-lived, for I could not document this discovery. I had packed my camera away as
we ended the transect runs, and I could do nothing but watch helplessly as these gorgeous and exotic worms fell
away from my view and receded into the darkness.
Dive 703 was our last dive on that cruise. We never returned to the Tongue of the Ocean. Later in 1977 the
Alvin was in the Pacific,and hydrothermal vents were discovered. From that moment on, further research in the
Alvin in the Bahama Islands took a back seat. We made scores of dives in the Bahamas in the Johnson-Sea-Link
submersibles, but apparently these worms lived only in great depths, well beyond the range (ca. 1,000 m) of the
Johnson-Sea-Link.
In an excellent and scholarly article, Ole Tendal (1998) has summarized the little we know of these animals.
They and their distinctive spiral fecal trails are known from several seafloor photographs. Have they been seen
alive, or collected, since Alvin Dive 703? I hope so, but I haven’t seen any mention in the scientific literature. In a
brief contribution from 1999, Tendal notes that several readers of his 1998 note question the accuracy of Lemche’s
(1976) reconstruction, which was based on photographs from the SW Pacific (Tendal 1999). I regret that I was
never close enough to see details of the anterior end of the body to be able to determine if Lemche’s (1976)
reconstruction was accurate; all I can recall is that the anterior ends that I saw seemed to lack “fuzziness” that
might have suggested the presence of tentacles.
I have dreamed hundreds of times about those magnificent worms. Sometimes my nocturnal excursions may
seem to possess the double vision of Moliere’s comedies, as images of edrioasteroids and lophenteropneusts swirl
in my fevered imagination. Deep-sea dreams. No doubt everyone who has dived in a submersible has amazing tales
to tell, and has dreamed dreams...
My thanks to Ole Tendal and Mary Petersen for encouraging me to write this note.
References
Lemche, H., B. Hansen, F. J. Madsen, O. S. Tendal & T. Wolff, 1976: Hadal life as analyzed from photographs. − Vidensk.
Medd. Dansk. Naturh. Foren. 139: 263−336.
DEEP-SEA NEWSLETTER No. 32, March 2003 – p. 7
Pawson, D. L., 1982: Deep-sea echinoderms in the Tongue of the Ocean, Bahama Islands: a survey, using the research
submersible Alvin. − Aust. Mus. Mem. 16: 129−145.
Tendal, O., 1998: Whatever became of Lemche’s Lophenteropneust? − Deep-Sea Newsletter 27: 21−24.
Tendal, O., 1999: Lemche’s Lophenteropneust widely known but still an enigma. − Deep-Sea Newsletter 28: 8.
Dave Pawson
NMNH, Smithsonian Institution, Washington D.C.
E-mail: [email protected]
DE PROFUNDIS...
“Out of the depths”... one of us (JAS) got in his detritus sledge something that looked like old nylon fishing line or
pieces of plastic insulation from electrical wire thrown over board from some vessel. This happened in 1978 during
a cruise in the Lofoten Basin off Troms County in northern Norway.
Unfortunately, this “pollution” was not kept. Later, when we, together with Torleiv Brattegard, started to
sample the bottom fauna all over the Norwegian Sea such “nylon strings” showed up again and again. A closer look
made it clear that they were organic, but we could neither put a name on them nor a function.
We are dealing with a tube, open at both ends, 1−2 mm in diameter, sometimes more than 50 cm long, spirally
coiled with at least up to 5 turns, each being about 4 cm in diameter. All have been found empty. The wall material
is whitish grey, with a smooth, silk-like shining surface, and quite resistant to physical damage (Fig. 1).
We do not at present have a full survey of our
records, but in general terms this kind of
object has been found all over the Norwegian
Sea and in the Northeast Atlantic from the
Faroes to the Reykjanes Ridge, at depths of
about 300−1500 m. It occurs on gravelly
bottoms, and has not been found fixed to the
substrate, but may have been broken off.
During the cruises of the Internordic
BIOFAR and BIOICE programmes (Tendal
1998) such strings have been found in gear
types such as Agassiz trawl, detritus sledge
(Sneli type) and hyperbenthic sledge (Brattegard modification). Our cruises took place
from July to September.
We have for a long time discussed the
nature of this hollow string cord, and so far we
thought it to be an egg casing of a kind. However, while we were preparing this letter, Mary
E. Petersen and Torben Wolff called our attention to similar formations described and figured by Aage Møller Christensen in a paper in
the Galathea Report (Christensen 1981), as socalled cocoons of neorhabdocoel, parasitic turbellarians of the family Fecampiidae. After
Fig. 1. A fine example of the cocoon, 47 cm long, from BIOICE
that valuable hint only a brief literature search
Station 3540, 62°00.02'N, 13°33.87'W, 1371 m depth. September
was necessary to establish that our tubes are
2002. Divisions on scale bar are in centimeters.
the cocoons of an undescribed species of deepwater Kronborgia parasitizing the shrimp Pasiphaea tarda Krøyer, 1845 (Christensen & Kanneworff 1967,
Christensen 1988). Comparison with cocoon samples kept in the collections of the Zoological Museum, University
of Copenhagen, confirmed the identification. Such cocoons have been recorded from depths between 275 and 3000
m.
DEEP-SEA NEWSLETTER No. 32, March 2003 – p. 8
Although our mystery was solved before having been brought to the attention of the readers of D-SN, we
nevertheless publish this note because we believe that other colleagues may have found these cocoons without
recognizing them.
The following generalized, brief account of the biology of Kronborgia species is mainly based on Kanneworff
& Christensen (1966): The species parasitize shrimps. They are dioecious, supposedly all with dwarf males. The
females are very large, some up to at about 40 cm long, and develop in the body cavity of the host. After leaving
the shrimp the female constructs the more or less coiled cocoon around itself. In some species this cocoon can
attain a lengh of more than 1 m.
References
Christensen, A. M., 1981: Fecampia abyssicola n. sp. (Turbellaria: Rhabdocoela) and five cocoon types of undescribed species
of Fecampiidae from the deep sea. − Galathea Report 15: 69−77.
Christensen, A. M., 1988: Fecampiidae (Turbellaria, Neorhabdocoela) in Greenland waters. − Fortschr. Zool. 36: 25−29.
Christensen, A. M. & B. Kanneworff, 1967: On some cocoons belonging to undescribed species of endoparasitic turbellarians.
− Ophelia 4: 29−42.
Kanneworff, B. & A. M. Christensen, 1966: Kronborgia caridicola sp.nov., an endoparasitic turbellarian from North Atlantic
shrimps. − Ophelia 3: 65−80.
Tendal, O .S., 1998: The Viking Sea revisited. New investigations into benthic fauna around the Faroe Islands and Iceland. −
Ocean Challenge 8: 32−36.
Ole Secher Tendal
Zoological Museum
University of Copenhagen
Universitetsparken 15
DK-2100 Copenhagen Ø, Denmark
E-mail: [email protected]
Jon Arne Sneli
Institute of Natural History
Museum of Archeology & Natural History
Norwegian University of Science & Technology
N-7491 Trondheim, Norway
E-mail: [email protected]
NOTES ON POPULATION STRUCTURE OF THE SCAVENGER AMPHIPOD
EURYTHENES GRYLLUS FROM THE CENTRAL GULF OF MEXICO
Eurythenes gryllus (Lichtenstein, 1822) is a deep-sea scavenger amphipod (Fig. 1) originally described from the
Pacific Ocean. The species belongs to the family Lysianassidae. Its distribution is cosmopolitan in the world ocean
and it was reported from the north central slope in the Gulf of Mexico for the first time in 1997. The species has
been studied in detail in the northern temperate latitudes, as it is usually attracted in large numbers, together with
necrophagous fishes, to baited traps in the deep ocean.
Eurythenes gryllus occurs on the slope and abyss and is
found in traps from ten to a few hundred meters above the
bottom, suggesting that it uses chemo- and mechanoreception to locate the carcasses in the sea floor. Background information on the species shows that the size
frequency of specimens collected in the northwestern
Atlantic corresponds to a seasonal variation of food input
and that genetic differences are related to the dispersion
capacity of the species in the deep sea. The major predator
for E. gryllus is the cyclopterid fish Paralipiparis bathybius, which exploits its large abundances at food falls.
This note describes the total length-biomass relationship and general environmental conditions in which E.
gryllus occurs in the deep Gulf of Mexico.
Fig. 1. Eurythenes gryllus; specimen captured in baited
Specimens of E. gryllus were collected from six sites on
traps in the Gulf of Mexico abyssal plain. Photograph
the Sigsbee absysal plain within the Mexican Exclusive
courtesy of A. Amons, TAMU. Scale in centimeters.
Economic Zone (EEZ) of the Gulf of Mexico in order to give
DEEP-SEA NEWSLETTER No. 32, March 2003 – p. 9
a basin-wide coverage of the abyssal plain in the tropics. One station was studied during UNAM-TAMU’s first
cruise (Deep Sea Benthic Communities of the Gulf of Mexico research initiative). Five stations were surveyed in
two 15-day cruises, in June and August 2002 (Deep Gulf of Mexico Benthos Study DGoMBS: Joint US/México
Studies of the Sigsbee Deep JSSD research program) aboard the R/V Gyre TAMU.
The sites where specimens were collected (Fig. 2) are located
between 3.4 and 3.7 km depth and have the following
conditions: Station 1 is centrally located and the lowest
biomass values are expected because of its distance from the
basin margins; station 2 is in the vicinity of the Sigsbee Knolls
and is the most distant station from the Mississippi Cone,
which is thought to be a major source of turbidity currentborne sediments from shallow water; station 3 is located at the
base of the Campeche Scarpment and is affected by export
from the Campeche Bank; station 4 is located under the Loop
Current, characterized by strong bottom currents and affected
by the export of the Yucatan upwelling system; station 5 is in
the center of the Gulf of Mexico and shows the least
continental margin influence; station 9 is located to the west
and is affected by translating anticyclone eddies.
Fig. 2. Sites where baited traps at all three cruises (1997 and 2002)
were deployed are depicted with solid circles in the map. From left
to right, top row: stations SIGSBEE-9, DGoMB-1 and 5; bottom
row: DGoMB-2 to 4.
The specimens were collected with baited traps that were deployed in the abyssal plain for time periods of 8 to 12
hours at all three cruises. The specimens were fixed in ethanol or formaldehyde on board. Other specimens were
frozen and used in geochemical analyses. The amphipods were identified and every specimen was measured,
weighed and the measurements recorded. Measures of population structure used to test this hypothesis included the
mean size of individuals, recognition of specific size categories, variations in biomass and abundance from site to
site. The length and biomass values allowed us to obtain the allometric distribution of the species in the Gulf of
Mexico.
Diverse environmental factors were measured in the field to describe the environmental conditions in which
the amphipods were found. A carbon flux model using Stella software is being proposed to describe the potential
interactions of the scavenger amphipod.
A total of 128 specimens of Eurythenes gryllus were collected at the six sampling sites in the abyssal plain of
the Gulf of Mexico. The specimens were inventoried in the data base with the catalogue numbers 20582 to 20590
and 20678 to 20681 The catch per trap varied from 3 to 36 individuals. The total length of the specimens ranged
from 14 mm to 110 mm. The total length-biomass allometric growth relationship obtained from 100 individuals
was expressed by a power curve.
Table 1. The relationship between total length and biomass in Eurythenes gryllus in the Gulf of Mexico compared with
equations described for other locations.
Location
Equation
Reference
2.81
Northeastern Atlantic (45−46°N, 12−16°W)
W = 0.0323L
Charmasson & Calmet 1987
Central North Pacific (28−31°N, 155−160°W)
W = 0.0278L2.81
Ingram & Hessler 1987
Gulf of Mexico (23−25°N, 85−93°W)
2.87
W = 0.0232L
This study
The environmental conditions of the sampling sites include a bottom temperature of 4°C and salinity of 34.8−35.1
in well oxygenated bottom waters of 5.31−5.76 ml per L-1. The sediment is comprised of 92.02−97.17% clay and
DEEP-SEA NEWSLETTER No. 32, March 2003 – p. 10
2.83−7.98% sand. The organic carbon and nitrogen contents in the superficial sediment are 0.9−4.74%C and
0.07−0.17% N, with a C/N ratio of 6.64−67.71. The occurrence of detritus of sea grasses and other coastal plants is
locally common, mainly at station 6.
The conceptual model proposed includes
three boxes, the carcass box, the scavenger standing stock and the biomass of potential predators
on the amphipods (Fig. 3). Arrows arrive at the
carcass and connect the boxes, the arrow that
pulses the carcass availability will be interlinked
with the water column productivity and pelagic
food web length; it is displayed in a separate
water-column section. The arrows that connect the
boxes include the scavenging activity and predation.
Fig. 3. Conceptual model of the scavenger amphipod in
the deep-sea Gulf of México.
Acknowledgements
Projects DGAPA UNAM IN 211200 and CONACyT G-27777B supported one of the cruises and the analyses of
sediment- and water samples. The cruises onboard the R/V Gyre were supported by Minerals Management Service
(Deep Gulf of Mexico Benthos Study DGoMBS: Joint US/México Studies of the Sigsbee Deep JSSD research
program). Thanks are due to G. T. Rowe, TAMUG and R. Avent, MMS as well as M. Wicksten, M. Ziegler, C.
Nunally and A. Ammons, TAMU students and staff, and F. Adame, C. Díaz, A. Salas, B. Salguero and E. Anaya
from UNAM for work in the field.
References
Charmasson, S. S. & D. P. Calmet, 1987: Distribution of scavenging Lysianassidae amphipods Eurythenes gryllus in the
northeast Atlantic: comparison with studies held in the Pacific. − Deep-Sea Research 34: 1509−1523.
Ingram, C. L. & R. R. Hessler, 1987: Population biology of the deep-sea amphipod Eurythenes gryllus: inferences from instar
analysis. − Deep-Sea Research 34: 1889−1910.
Eduardo Nájera
Facultad de Ciencias, Universidad Nacional
Autónoma de México, México, D.F.
E-mail: [email protected]
Elva Escobar
Instituto de Ciencias del Mar y Limnología
Universidad Nacional, A.P. 70-305; 04510 Mexico, D.F.
E-mail: [email protected]
(Corresponding author)
Pp. 11−14: NOTE FROM THE EDITORS:
“Science as Stakeholder”, from “Ocean Challenge” 12 (1) (2002), was sent to us by the author, Hjalmar Thiel. We
regard this article of high importance to all deep-sea biologists and thank Angela M. Colling, the editor of Ocean
Challenge, for granting permission to reprint it in our Newsletter.
For another opinion on this topic, see John Gage’s “Comment from another scientific stakeholder on Hjalmar
Thiel’s concept…” in the article that follows it.
TW & MEP
DEEP-SEA NEWSLETTER No. 32, March 2003 – p. 11
DEEP-SEA NEWSLETTER No. 32, March 2003 – p. 12
DEEP-SEA NEWSLETTER No. 32, March 2003 – p. 13
DEEP-SEA NEWSLETTER No. 32, March 2003 – p. 14
The above article is from: Ocean Challenge, Vol. 12, No. 1 (Special European Issue), 2002, pages 44-47. Thiel (“Approaches
to the establishment …”, in press, see above) should be out in 2003 in A. Kirchner (ed.): Proceedings of the International
Conference on Marine Environmental Law, Bremen, 17−19 April 2002. Kluwer Law International, The Netherlands.