`© by Springer-Verlag 1974
`
`The Fatty Acids of Antarctic Phytoplankton and Euphausiids. Fatty Acid Exchange
`among Trophic Levels of the Ross Sea
`
`N.R. Bottino
`
`Department of Biochemistry and Biophysics, Texas A&M University; College Station, Texas, USA
`
`Abstract
`
`The fatty acids of 3 samples of Euphausia superba,
`7 samples of E. crystallorophias, and 12 samples
`of phytoplankton collected in the Ross Sea, Ant(cid:173)
`arctica, during Eltanin Cruise 51 were examined.
`The fatty acid profiles of the samples of E. su(cid:173)
`perba resembled each other closely. The fatty acid
`profiles of the E. crystallorophias samples were
`also similar to each other but different quanti(cid:173)
`tatively from those of E. superba. Phytoplankton
`fatty acid patterns varied with the geographical
`location and species composition of the samples.
`The fatty acids of euphausiids were compared to
`those of the phytoplankton from the corresponding
`locations. Rather similar fatty acid patterns in
`phytoplankton and E. superba corroborate the
`herbivorous nature of this euphausiid. On the other
`hand, phytoplankton and E. crystallorophias showed
`quite different fatty acid patterns. The differ(cid:173)
`ences were mostly due to the presence of waxes
`among the lipids of E. crystallorophias. It is not
`clear whether these waxes are of dietary origin or
`are synthesized endogenously.
`
`Introduction
`
`The study of krill has become intensive in recent
`times, perhaps as a result of its potential im(cid:173)
`portance as food. A variety of organisms is usual(cid:173)
`ly included under that generic name, but in the
`Southern Oceans the name Euphausia superba has
`been considered almost a synonym for krill. How(cid:173)
`ever, due to a quite defined geographical distri(cid:173)
`bution, there are certain areas in which E. su(cid:173)
`perba is replaced by other members of the same
`genus. For example, E. superba is very seldom
`found in shallow waters close to ice, such as the
`Ross Ice Shelf, but the smaller E. crystalloro(cid:173)
`phias predominates in such areas (Marr, 1962;
`Mauchline and Fisher, 1969).
`The chemical composition of Euphausia superba is
`reasonably well known. Its fatty acids, in par(cid:173)
`ticular, have been the subject of several studies
`in the past few years (Nonaka and Koizumi, 1964;
`Tsuyuki et al., 1964a, b; Hansen, 1969; Pierce et
`al., 1969; Hansen and Meiklen, 1970; Sidhu et al.,
`1970; Van der Veen et al., 1971). On the other
`hand, very little is known about the lipids of E.
`
`crystallorophias, except that they increase in the
`late austral summer and decrease gradually during
`the winter (Littlepage, 1964). The present report
`describes studies on the fatty acids of E. superba
`and E. crystallorophias from various locations in
`the Ross Sea. The fatty acid patterns of the two
`euphausiids are compared to each other as well as
`to the fatty acids of phytoplankton from corre(cid:173)
`sponding locations. An attempt is made to deter(cid:173)
`mine the flow of fatty acids through trophic levels.
`
`Materials and Methods
`
`Phytoplankton samples were collected with a 35 ~
`net, by vertical hauls to a depth of 200 m. After
`microscopic examination, samples containing less
`than 80% phytoplankton were discarded. Microzoo(cid:173)
`plankton constituted the major contaminant.
`Euphausiids were collected with a 1 m mid-water
`trawl, at depths varying between 0 and 300 m.
`Shortly after being sorted by hand the samples
`were extracted for lipids with a chloroform:meth(cid:173)
`anol (2:1, v/v) mixt~re (Folch et al., 1957).
`Quantities of 5 to 10 mg total lipids were con(cid:173)
`verted into fatty acid methyl esters by saponifi(cid:173)
`cation, followed by reflux with methanol in the
`presence of boron trifluoride (American Oil Chem(cid:173)
`ists' Society, 1970). The fatty acid methyl esters
`were studied by gas-liquid chromatography on a 6'
`1/8" column of siliconized polyethylene glycol
`succinate (DGSS-X, Applied Science Co., State Col(cid:173)
`lege, Pennsylvania) 10% w/w on Chromosorb (Johns(cid:173)
`Manville, Denver, Colorado) at 17o0 c. A dual-flame
`model GC-5 Beckman gas chromatograph (Fullerton,
`California) was used connected to an Infotronics
`(Columbia Scientific Industries, Austin, Texas)
`digital integrator. Results are expressed as weight
`percent. Fatty acid methyl esters were identified
`by co-chromatography with known standards and by
`plotting relative retention times versus chain
`length before, and in most cases, after hydro(cid:173)
`genation.
`
`Results and Discussion
`
`Fatty Acids of Euphausia superba
`
`Samples of Euphausia superba were collected from
`Stations 8, 9 and 11 of Eltanin Cruise 51 (Fig. 1).
`
`RIMFROST EXHIBIT 1007 page 0001
`
`
`
`198
`
`N.R. Bottino: Fatty Acids of Antarctic Phytoplankton and Euphausiids
`
`Depart lyttelton
`January 17, 1972
`
`. I
`
`Arrive McMurdoStation
`February25,1972
`12
`
`Fig. I. Ross Sea, Antarctica: track of Eltanin
`Cruise 51, showing stations
`
`These stations are located in an area in which two
`currents of water mix (Marr, 1962), thus providing
`the turbulent environment that E. superba seems to
`prefer for a habitat (Ivanov, 1970).
`There is a remarkable similarity in the fatty acid
`compositions of the samples collected from the
`three stations (Table I). In addition, these pat(cid:173)
`terns resemble quite closely those reported by
`Hansen and Meiklen (1970) and by Sidhu et al.
`(1970). The present results, however, differ some(cid:173)
`what from those of Nonaka and Koizumi (1964) and
`of Van der Veen et al. (1971). Of all samples of
`Euphausia superba studied so far, only those of
`the present study were extracted immediately after
`capture. The others were frozen, transported and
`then extracted. This might explain some of the dif(cid:173)
`ferences.
`In two groups of krill (Stations 8 and II), the
`hepatopancreas and stomach were excised and their
`fatty acids were studied separately from those of
`the whole animal. In one case (Station JI), the
`fatty acids of the remaining carcass were also
`studied. Since the stomachs were empty in all
`cases, the values in Table I under the heading
`hepatopancreas and stomach correspond essentially
`to hepatopancreas lipids only. The remarkable simi(cid:173)
`larity among organ, remaining carcass, and whole
`
`Table I. Euphausia superba. Fatty acids (as weight per cent of total acids)
`
`Station 11
`Fatty acid a Station 8
`Station 9
`Whole krill HP+Sb Whole krill Whole krill HP+S Remaining
`carcass
`12.9 13. 5
`22.3 23.4
`I. 4
`I. 3
`8.2
`8.0
`21.8 21. 5
`I. 2
`2. I
`1.0
`3.6
`13.9
`8. I
`
`14. 3
`24.7
`I. 4
`8.9
`21. 7
`0.9
`2.0
`I. 0
`3.3
`11.4
`7.3
`
`I. I
`I. 9
`
`I. I
`3.8
`11. 6
`9.4
`
`14.9
`21. 2
`0.7
`9.0
`18.2
`0.6
`2.6
`
`I. I
`2.2
`16.0
`8.6
`
`10. 7
`21. 2
`I. 2
`6.7
`17. I
`0.9
`2.5
`I. 2
`I. 9
`22.2
`9.4
`
`12.9
`20.9
`0.9
`10. 7
`22.8
`
`I. I
`2.7
`1.4
`2.6
`11. 8
`8.3
`
`14 :0
`16:0
`18:0
`16: I (n-7)
`18: I (n-9)
`20: I (n-9)
`18:2(n-3)
`18:3(n-3)
`18:4(n-3)
`20:5(n-3)
`22: 6 (n-3)
`Minor fatty
`acidsC
`
`4.9
`
`5.0
`
`3.9
`
`3. I
`
`3.6
`
`3.3
`
`aThe number preceding the colon gives the number of carbon atoms in the
`chain, the number following the colon the number of double bonds; (n-x):
`number of c~rbons in the chain minus number of carbons between the methyl
`end and the nearest double bond.
`b Hepatopancreas plus stomach.
`
`cOnly those fatty acids present at a level of 1% or more are included.
`
`RIMFROST EXHIBIT 1007 page 0002
`
`
`
`N.R. Bottino: Fatty Acids of Antarctic Phytoplankton and Euphausiids
`
`199
`
`body composition suggest that there is very little
`differentiation of organ lipids in Euphausia su(cid:173)
`perba.
`
`Fatty Acids of Euphausia crystaZZorophias
`
`In contrast to Euphausia superba, which prefers
`turbulent waters, E. crystaZZorophias is usually
`found in shallow waters in the proximity of the
`Continental Shelf (Marr, 1962; Mauchline and
`Fisher, 1969). We know from Littlepage (1964) that
`E. crystaZZorophias' lipids decrease in amount at
`the end of the austral winter and rise in late
`summer. My own studies (Bottino, in press) show
`that 20 to 40% of the lipids of E. crystaZZoro(cid:173)
`phias are waxes, the rest being mostly complex
`lipids and small amounts of neutral lipids.
`The Euphausia crystaZZorophias collected from
`Stations 11, and 13 through 17 during Eltanin
`Cruise 51 show closely similar fatty acid patterns
`(Table 2). Comparison of the fatty acids of the
`two euphausiids show (Table 3) that E. crystaZloro(cid:173)
`phias contains about twice as much oleic acid
`(average 44% of total fatty acids) as E. superba
`(average 21%). Most of this oleic acid comes from
`the waxes, since about 83% of the wax fatty acids
`is oleic acid (Bottino, in press). The levels of
`highly unsaturated fatty acids (HUFA), mostly
`20:5(n-3) and 22:6(n-3) are quite similar in both
`euphausiids.
`In conclusion, comparison of the fatty acids of
`both euphausiids shows that Euphausia crystaZZoro(cid:173)
`phias lipids are more unsaturated than E. superba
`
`lipids on account of the larger amount of oleic
`acid in the former. This different degree of lipid
`unsaturation might be related to the different en(cid:173)
`vironment in which the two euphausiids live. Where(cid:173)
`as E. crystallorophias dwells near the ice all
`year around, E. superba is probably in contact
`with the ice only during the winter months (Mack(cid:173)
`intosh, 1970).
`
`Phytoplankton Fatty Acids
`
`Phytoplankton samples from Stations 8, 9, 11, 13-
`15, and 18 were studied. According to microscopic
`and macroscopic observations I, the nature of the
`phytoplankton population changes with the stations,
`and this is reflected in quantitative variations
`in the fatty acid patterns (Table 3). Qualitative(cid:173)
`ly, however, the fatty acid patterns showed some
`coromon characteristics: (1) The presence in most
`samples of significant amounts (up to 15%) of Cs
`to C13 fatty acids with both even and odd carbon
`chains (Table 3); most of these acids are not de(cid:173)
`tected or are present at much lower levels in
`euphausiid lipids (Tables 1 and 2). (2) All phyto(cid:173)
`plankton samples contained HUFA, mainly 20:5(n-3)
`and 22:6(n-3) in levels ranging from less than 1%
`to about 23% (Table 3). This suggests that the
`
`1
`Dr. S. El-Sayed provided qualitative and semi(cid:173)
`quantitative microscopic data on the composition
`of the phytoplankton samples.
`
`Table 2. Euphausia crystallorophias. Fatty acids (as weight per cent of total acids)
`
`Fatty acid Station l l Station 13
`Adults Juvenile
`
`Station 14 Station 15 Station 16 Station 17
`
`14:0
`16 :O
`18:0
`16: I (n-7)
`I 8: l (n-9)
`l8:2(n-3)
`J8:3(n-3)
`18:4(n-3)
`20:4(n-6)
`20:5(n-3)
`22:6(n-3)
`Minor fatty
`acids a
`
`2.3
`15.3
`0.3
`8.6
`39.6
`l. 7
`1.0
`0.7
`0.9
`!8. 2
`9.9
`
`I. 5
`
`2.2
`12. l
`0.4
`6.5
`49.8
`2.4
`l. 0
`I. 8
`
`14. I
`7.2
`
`2.4
`13.3
`0.6
`7.9
`48.8
`2.2
`1.0
`I. 5
`
`I 2. 5
`7. 7
`
`2.5
`
`2. I
`
`2.6
`17. 2
`0.3
`7.9
`47.8
`2. I
`I. 0
`I. 2
`0.7
`12. 3
`6.0
`
`0.9
`
`2.6
`15.5
`0.5
`8.4
`49.0
`2.3
`0.8
`l. 3
`0.4
`12.8
`5.3
`
`I. l
`
`2.2
`13. I
`0.5
`9.3
`47.6
`2.3
`0.7
`0.8
`
`14.9
`5.6
`
`3.0
`
`2.6
`16.0
`0.8
`6.5
`40.7
`l. 6
`0.8
`l.O
`1.0
`16.5
`l I. l
`
`I. 4
`
`aExcept for stearic acid ( 18 :0) only those fatty acids present at a level of 1% or more
`are included.
`not detected. See footnotes to Table I for further explanation.
`
`RIMFROST EXHIBIT 1007 page 0003
`
`
`
`!'-)
`0
`0
`
`z
`
`C>j
`
`Oj
`0
`rt
`rt
`
`.....
`0 ..
`
`;j
`
`"'1
`Pl
`rt
`rt
`'<
`
`> n .....
`
`p.
`Ul
`
`0 ......
`> ;j
`
`rt
`Pl
`'1 n
`.....
`rt
`
`()
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`"1
`:::>"
`'<
`rt
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`'rj ,_.
`Pl
`:::i
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`0..
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`trJ
`
`i:: "" ::r
`Pl
`i::
`.....
`Ul
`.....
`0..
`Ul
`
`Table 3. Fatty acids of Antarctic phytoplankton and euphausiids (as weight per cent of total acids)
`
`Fatty acid Phytoplankton at Stationsa
`8
`9a
`I la
`I lb
`
`9b
`
`13
`
`14
`
`!Sa
`
`!Sb
`
`!Sc
`
`18a
`
`18b
`
`Euphausia
`superba
`(average of
`3 stations)
`
`Euphausia
`crystallorophias
`(average of
`7 stations)
`
`0.2
`
`0.1
`0.1
`2.4
`0. l
`14.6
`o.s
`
`- - - - - 7
`
`.9
`0.3
`46.2
`0.2
`-
`
`8:0
`9: ()
`In: 0
`11 :0
`12:0
`13:0
`14: 0
`IS:O
`16: (l
`
`18:0
`IO: 1 (n-?)
`ll:l(n-?)
`12:1(n-?)
`13: I (n-?)
`15: I (n-?)
`16:1(n-?)
`17: I (n-?)
`18: I (n-9)
`20:l(n-9)
`
`18:2(n-6)
`
`-
`-
`-
`0.4
`0.2
`0.3
`2.9
`0.9
`-
`I. s
`-
`I. 7
`-
`-
`-
`0.7
`2.3
`I. 3
`2.3
`1.9
`-
`-
`-
`I. 1
`lS.9
`9.7 22.S 11. S
`I. 9
`0.3
`2.6
`I. 6
`20.4 20. 1 19.9 16.0
`7.0
`2. I
`2.0
`3.3
`-
`0.6
`2.2
`2.S
`-
`-
`-
`0.7
`-
`I. s
`2.8
`I. 6
`-
`-
`o.s
`I. 0
`o.s
`0.7
`0.6
`I. 3
`12.4
`8.3
`6.2
`7.5
`0.3
`0.6
`I. 6
`0.9
`12. I 16.0
`IS. 6 16.2
`-
`0.4
`trace
`0.8
`2. I
`0.1
`0.3
`0.2
`
`-
`-
`-
`I. 0
`I. 2
`I. s
`0.2
`0. I
`2.S
`I. 4
`-
`0. I
`2.4
`4.0
`0.9
`trace
`I. I
`I. 2
`I. 9
`I. 3
`2.2
`2.0
`0.4
`0.4
`2.S
`-
`-
`0.8
`3.0
`0.4
`22.9 2S.S 20.7 17.4 19. 3
`-
`2.6
`I. 7
`3.4
`0.7
`18.8 21. 7 18.S 18.7 17. 2
`2.0
`2.6
`2.2
`I. 9
`I .8
`-
`-
`-
`-
`0.8
`-
`2.0
`0.1
`I. 9
`I. 3
`0.2
`2.4
`0.7
`I. 2
`I. 6
`-
`0.1
`0.6
`1.8
`1.4
`1.0
`0.6
`I. 2
`2.7
`0.4
`S.7
`5.3
`3.4
`7.8
`3.6
`-
`0.3
`0.2
`0.3
`0.3
`16 .3 24.8 11.4 20.2
`18.3
`-
`-
`I. 7
`O. I
`trace
`-
`-
`-
`O. I
`O. I
`
`0.7
`I. 7
`2.2
`0.3
`0.8
`-
`S. 1
`I. l
`16. I
`S.2
`-
`0.9
`0.9
`I. I
`0.7
`3.2
`trace
`12.S
`-
`-
`
`-
`-
`-
`-
`9.S
`-
`
`-
`-
`0.2
`-
`13.0
`0.3
`17. 3 14.9
`I. 7
`1.S
`-
`0.2
`-
`-
`I. s
`0.3
`-
`-
`-
`I. 8
`13. 1 10.3
`1.4
`0.9
`17. 3 18.7
`0.3
`0.3
`3.8
`4. l
`
`-
`-
`0.2
`-
`14.0
`0.4
`22.3
`1.0
`-
`-
`-
`-
`trace
`9.S
`o.s
`20.8
`0.9
`0.2
`
`Continued on page 201
`
`RIMFROST EXHIBIT 1007 page 0004
`
`
`
`z
`?;:I
`
`t:d
`0
`rt
`rt
`>-'·
`~
`0
`
`'Tl
`PJ
`rt
`rt
`'<
`:>
`()
`>-'•
`p.
`
`"'
`0 ,_.,
`:>
`~
`rt
`PJ
`'1
`()
`rt
`>-'·
`()
`
`'i::I ::r
`'<
`rt
`0
`'O ,_.
`PJ
`~
`:>;"
`rt
`0
`~
`
`PJ
`~
`p.
`
`trj c
`'O ::r
`PJ c
`"' >-'•
`
`>-'·
`p.
`Ul
`
`~
`0
`
`18:2(n-3)
`22:2(n-6)
`22: 2 (n-3)
`18:3(n-6)
`18:3(n-3)
`20:3(n-6)
`20: 3(n-3)
`16: 4 (n-1)
`18:4 (n-3)
`20:4(n-6)
`20:4(n-3)
`22:4(n-6)
`22:4(n-3)
`20:5(n-3)
`22:5(n-6)
`22:5(n-3)
`22:6(n-3)
`Minor fatty
`acidsb
`
`RIMFROST EXHIBIT 1007 page 0005
`
`7.9
`
`8.4
`
`5.5
`
`0.9
`
`0.8
`
`0.1
`
`7. 1
`
`2. 1
`16.5
`
`7.8
`
`5.5
`
`1 LO
`
`0.2
`8. 1
`
`3.3
`
`l. 5
`
`4.3
`
`4.6
`
`1.0
`
`3.2
`
`0.6
`
`4.0
`
`2.8
`
`l. 8
`
`0.5
`
`0.9
`
`0.8
`
`7.5
`
`0.4
`
`aMicroscopic examination indicated that the following genera predominated in each station. Station 9: Eudorina, Pando(cid:173)
`rina; Station JO: Thalassiosira, Fragilaria, Nitzchia, Corethron, Silicoflagellates; Station 11: Corethron, Fragilaria,
`Chaetoceros, Silicoflagellates; Station 12: Corethron, Fragilaria, Nitzchia, Tintinnids; Station 13: Complex mixture;
`Station 14: Phaeocustis; Station 15: Phaeocystis, Chaetoceros, Nitzchia, Thalassiosira, Fragilaria; Stations 17 and 18:
`Fragilaria, Nitzchia, Coscinodiscus, Dinoflagellates, Tintinnids.
`
`bOnly those fatty acids present at a level of 1% or more are included. See footnotes to Tables 1 and 2 for further ex(cid:173)
`planation.
`
`3.7
`
`3.3
`
`2.4
`
`3.1
`
`3.3
`
`3.0
`0.8
`
`2.7
`0.9
`
`2. 1
`
`1. 6
`
`7. l
`2.0
`
`12.0
`
`l.2
`
`1.7
`
`2.4
`
`2. 1
`
`l.4
`l.4
`0.2
`0.2
`0.7
`0.7
`trace 0.9
`
`0.3
`0.7
`trace -
`
`0.2
`0.2
`0.1
`o. 3
`2.6
`trace 0.9
`
`6.0
`
`3.0
`
`2.7
`
`3.2
`
`6.2
`
`0.7
`0.3
`0.6
`
`0.3
`0.5
`3.5
`
`0.3
`
`5.2
`0.4
`0.2
`
`o. 2
`0.2
`
`0.3
`0.3
`0.1
`0.2
`
`2.2
`
`2.5
`
`0.3
`0.2
`
`O. I
`1.0
`6.3
`0.9
`4.7
`
`0. I
`
`trace
`
`0.2
`
`0.2
`
`I. 2
`
`0.5
`
`2.7
`0.4
`0.4
`0.2
`
`0.1
`0.9
`
`0.3
`
`I. 2
`0.4
`0.1
`
`trace -
`9.2
`7.0
`
`6.4
`
`1. 7
`
`2. I
`
`trace -
`5.3
`6.0
`
`trace
`trace
`2. I
`
`18.4 23.4
`
`13. I
`
`14 .4
`
`0.6
`0.3
`0.7
`0.2
`0.2
`
`0.3
`0.9
`0.4
`0.2
`
`2.0
`
`3. 1
`
`0.2
`
`l. 3
`11.4
`I. 1
`0.3
`6. 1
`
`4.8
`
`0.3
`4.9
`
`
`
`202
`
`N.R. Bottino: Fatty Acids of Antarctic Phytoplankton and Euphausiids
`
`HUFA of the marine food-chain originate in phyto(cid:173)
`plankton. Holz (1969) has reached a similar con(cid:173)
`clusion from studies on laboratory-grown Protozoa.
`
`Comparison of Trophic Levels
`
`Whereas most euphausiids are considered omnivores,
`there is good evidence that Euphausia superba
`feeds on phytoplankton (Mauchline and Fisher,
`1969). Whether the preferred food is Fragilaria as
`stated by many (Raymont, 1963; Nemoto, 1968), or
`whether E. superba has a wider range of selec(cid:173)
`tivity (Pavlov, 1970), is still in doubt. Although
`generally considered a phytoplankton feeder (An(cid:173)
`driashev, 1968; Knox, 1970), the evidence on the
`food preference of E. crystallorophias seems to be
`only of indirect nature, e.g. the finding by
`Littlepage (1964) of parallel changes in seasonal
`phytoplankton abundance and the lipid content of
`E. crystallorophias, and the study by Mauchline
`(1967) showing striking similarities between the
`feeding appendages of E. crystallorophias and E.
`superba.
`It was of interest, therefore, to compare the
`fatty acid patterns of Euphausia superba and E.
`crystallorophias collected during Eltanin Cruise
`SI with the fatty acids of phytoplankton from the
`corresponding stations. It was hoped that the
`feeding habits would be reflected in similarities
`in the fatty acid patterns of the related trophic
`levels. This obviously assumes that euphausiids
`add very little endogenously-made fatty acids to
`those they acquire from the diet. Since the lipid
`content of phytoplankton is relatively high, be(cid:173)
`tween 2 and 20% of their dry weight (Parsons et
`aL, 1961; Andriashev, 1968), their ingestion by
`zooplankton should markedly diminish the lipo(cid:173)
`genetic activity of the zooplankton. Recent ex(cid:173)
`periments by Jeffries (1972) show that the dietary
`origins of the body lipids of omnivorous fish can
`be determined with a simple budget of fatty acid
`flow from diet to body lipids. The feasibility of
`these determinations is supported by the findings
`of Owen et al. (1972) who, confirming previous
`work by others, have shown that the fatty acid
`composition of fish lipids reflects the compo(cid:173)
`sition of the dietary lipids. Additional support
`is given by experiments in my laboratory (Warman
`and Bottino, 1974) which indicate that, in salt(cid:173)
`water fish-liver the degree of lipogenesis is
`equally low whether the animals are starved, fed
`fat, or fed a fat-free diet. Most probably, the
`same is true for other marine organisms including
`euphausiids.
`It is possible that certain fish-lipid classes
`such as triglycerides may reflect changes in diet(cid:173)
`ary lipids better than other classes of a more
`structural nature. It is shown below that this is
`not true in the present case. Finally, the similar
`fatty acid composition of euphausiid whole body
`and hepatopancreas (shown above) rules out the
`possibility of a preferential incorporation of
`dietary fatty acids into certain tissues. Owen et
`al. (1972) reached the same conclusion while study-
`
`ing the ingestion of polyunsaturated fatty acids
`by fish.
`Table 3 includes in the columns to the right av(cid:173)
`erages of the Euphausia superba and E. crystalloro(cid:173)
`phias fatty acids to facilitate comparisons. Com(cid:173)
`parisons can be made quantitative by determining
`the "distance" between fatty acid profiles with
`the formula (Mcintire et al., 1969; De Mort et al.,
`1972):
`
`where Djh is the degree of difference between the
`jth and hth species and Pij is the percentage of
`the total fatty acid content represented by the
`ith fatty acid in the jth species. For example,
`the distance between the results of two gas(cid:173)
`chromatographic analyses of the same sample of mar(cid:173)
`ine fatty acids is about 2.2 ± 1.8 (average! l
`standard deviation). The average distance between
`the 3 samples of E. superba fatty acids (Table !)
`was 6.3 ~ 1.2. The average distance among the 6
`samples of E. crystallorophias fatty acids (Table
`2) was 7.7 ± 3.5. The distance between the average
`of E. superba and the average of E. crystalloro(cid:173)
`phias (Table 3) was 29.0.
`In comparing the euphausiids with the phyto(cid:173)
`plankton samples of the corresponding stations,
`the distances between the average of Euphausia
`superba and the phytoplankton profiles (Stations 8,
`9a and 9b) ranged between JO and IS, whi~h are
`reasonably low values. The distances between the
`average of E. crystaZZorophias and phytoplankton
`(Stations 11, 13, 14, 15 and 182) were in the 30
`to 40 range. Thus, the fatty acids of E. superba
`compare well both in nature and concentration with
`those of phytoplankton of the corresponding lo(cid:173)
`cations. However, there are marked quantitative
`differences between the fatty acid profiles of E.
`crystallorophias and those of phytoplankton. It
`was mentioned earlier that the lipids of E.
`crystallorophias differ from those of E. superba
`in that they contain 20 to 40% waxes very rich in
`oleic acid (Bottino, in press). Thus, the dif(cid:173)
`ference in fatty acid profiles between the two
`euphausiids and between E. crystaZZorophias and
`phytoplankton may be due to the presence of these
`waxes. To assess this possibility, the average
`fatty acid profile of E. crystaZZorophias was re(cid:173)
`calculated eliminating the oleic acid contributed
`by the waxes, and distances were determined be(cid:173)
`tween the new set of values and those of E. super(cid:173)
`ba and phytoplankton. The distance between the
`corrected average of E. crystallorophias and the
`average of E. superba was 14.J. The distances be(cid:173)
`tween the corrected values of E. crystaZZorophias
`
`.
`2
`Despite the fact that no samples of Euphausia
`crystaZZorophias from Station 18 were analyzed,
`the phytoplankton data from that station are in(cid:173)
`cluded in view of the short distance between
`Stations 18 and 17.
`
`RIMFROST EXHIBIT 1007 page 0006
`
`
`
`N.R. Bottino: Fatty Acids of Antarctic Phytoplankton and Euphausiids
`
`203
`
`and phytoplankton ranged between 22 and 32 for
`Stations II to 15 and between 10 and 15 for
`Station 18. These results indicate that the pres(cid:173)
`ence of waxes in E. crystallorophias is what makes
`the fatty acid profile of this euphausid different.
`It is possible that certain lipid classes such
`as triglycerides may be more susceptible than, for
`example, complex lipids to changes in dietary
`lipids. In fact, it has been accepted for many
`years that depot lipids are more sensitive than
`structural lipids to changes in dietary fats. To
`test this possibility, distances were determined
`between the major lipid classes of both euphausiids
`and the total lipids of the phytoplankton obtained
`in corresponding stations. The results showed that
`the waxes of Euphausia crystallorophias were the
`most distant from phytoplankton (average D = 76).
`The complex lipids of both euphausiids and the
`steroid esters of E. crystallorophias showed an
`average distance of about 30 with respect to phyto(cid:173)
`plankton. The triglycerides of E. superba were the
`closer to phytoplankton with an average D = 17, a
`value which is in the same range as that of E. su(cid:173)
`perba total lipids versus phytoplankton. These re(cid:173)
`sults show that, in the present case, measuring
`distances between diet lipids and individual lipid
`classes is not better than comparing the total
`lipid fatty acids of the diet with those of total
`body lipids. In addition, the data seem to in(cid:173)
`dicate that neither the complex lipids nor the
`steroid esters, and even less the waxes of E.
`crystallorophias reflect very well the composition
`of the dietary fatty acids.
`The similarity between the corrected values for
`Euphausia crystallorophias and some of the phyto(cid:173)
`plankton values suggest that E. crystallorophias
`may be, in fact, herbivorous. Since most of the
`phytoplankton samples contained relatively small
`amounts of waxes, it is possible that E. crystal(cid:173)
`Zorophias may be able to incorporate and concen(cid:173)
`trate dietary waxes. Alternatively, waxes could
`have been synthesized, partially or totally by the
`euphausiid. Holtz et al. (1973) and Sargent et al.
`(1974) have recently characterized wax synthesiz(cid:173)
`ing systems in copepods.
`
`Acknowledgements. The author wishes to acknowl(cid:173)
`edge the identification of the species by Drs. M.
`A. McWhinnie and S.Z. El-Sayed. and the skilled
`technical assistance of Mrs. C. Wiltrout. This re(cid:173)
`search was supported by a grant from the National
`Science Foundation (GV-30413).
`
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`
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`
`204
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`N.R. Bottino: Fatty Acids of Antarctic Phytoplankton and Euphausiids
`
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`
`Dr. N.R. Bottino
`Department of Biochemistry and Biophysics
`Texas A & M University
`College Station, Texas 77843
`USA
`
`Date of final manuscript acceptance: June 28, 1974. Connnunicated by J. Bunt, Miami
`
`RIMFROST EXHIBIT 1007 page 0008
`
`