Arctic Marine Phototrophic Systems: Functions of Sea Ice Stabilization S
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ARCTIC VOL. 38, NO. 3 (SEPTEMBER 1985) P. 167-173 Arctic Marine Phototrophic Systems: Functions of Sea Ice Stabilization S. APOLLONIO’ ABSTRACT. A forgottennineteenth-century report provides evidence thatthere are twofloras, not one,on thebottom of arcticsea ice, distinguishable in time, speciescomposition, and, perhaps,nutrient condition. A halocline flora isalso noted from recent studiesthat is analogous in habitat to the ice floras.Thus at least three separate autotrophicsystems augment phytoplankton production in arcticseas. These augmenting systems seem to be a function of stability provided by sea ice. Key words: sea ice, ice algae, phytoplankton, halocline flora, ecosystem stability RESUME. Un rapport oublid du 19e sibcle fournit la preuve qu’il existe deux flores, et non pas un seule, au-dessous de la glace marine arctique, et que les deux peuvent Stre distinguds quant it leur Pge, leur composition par esp&ceset parfois, leur condition nutritive. Une flore halocline dont I’habitat est analogue it la flore glaciale est aussi signal6eB partir d’dtudes r6centes.Donc, au moins trois systkmes autotrophes distincts augmentent la production de phytoplancton dans les mers arctiques. Ces systkmes en pleine croissance semblent rdsulter de la stabilitd assurde par la glace marine. Mots cl6s: glace marine, algue marine, phytoplancton, flore halocline, stabilitd de 1’6cosystkme Traduit pour le journal par Maurice Guibord. Microalgae in polar sea ice have attracted attention in the last glefield on the Isabel in the summer of 1852, also as part of the 20 years with the publication ofreports by Canadian, Russian, Franklin search efforts. Thus he had much experience with Japanese, and American researchers on algal species composi- arctic phenomena and he was a careful reporter of many of tion, abundance and productivity, adaptations, and trophic them. Sutherland (1852) wrote a two-volume (1 100page) ac- significance within the polar ecosystems. Grainger (1977)and count of the 1850-5 1 voyage. The account attained such size Horner (1977) have reviewed these contributions; both noted because he included fascinating reports on every conceivable that ice biota - “one of the most remarkable phenomena in natural phenomenon accessible to his study, in addition to a the sea-ice region” (Hoshiai, 1977) - also attracted attention detailed narrative of the voyage itself. At Dickie’s specific re- in the nineteenth and early twentieth centuries and that those quest, Sutherland made collections of and notes on ice flora, earlier reports were primarily taxonomic lists from numerous but the length and detail of Sutherland’s journal, aswell as its locations, in contrast to the quantitative and analytic work of scarcity, may be thereason that all recent reviewers of recent years. Horner’s review concludes with a statement of nineteenth-century work onice biota have overlooked his outstandingunanswered questions concerning these algae, observations. Further, tucked among a numberof lengthy ap- prominent in the list beingtheir origin and their fate when they pendices in his second volume is a report by Dickie (1852) on leave the ice. Sutherland’s collections of ice algae. Dickie’s and Suther- One of the purposes of this note is to bring attention to a land’s reports may thus be the second contribution to this arc- mid-nineteenth-century contribution that has been completely tic literature, preceded only by Ehrenburg (1 84I, as cited by overlooked in the revival of interest in this phenomenon. It Horner, 1977). Sutherland’sobservations clearly predate shows that the early observers did not confine their attentions Nansen’s references (Horner, 1977) to organisms other than to taxonomic lists only and leads us to consider the implica- diatoms being found in sea ice, and his notes on the massive tions of that early work in the context of Horner’s unanswered mucilaginous accumulations of Melosira urcticu predate questions and for future research on ice flora. This in turn pro- Usachev’s (1949). vides an opportunityto point out that there are multiple (prob- Sutherland’s and Dickie’s reports are relevantto current ably at least four) photosynthetic production systemsin arctic research. Because they are rare and hard to obtain, because seas and that future work must encompass all of them if we are Sutherland’s ice biota observations are scattered througha to understand the functioning of that ecosystem. voluminousand discursive narrative andhave been over- The nineteenth-century report to which I refer was written looked, and because they provide an abundance of implica- by the Scottish surgeon and naturalist Peter Sutherland, a stu- tions and food for thought, I present in their entirety in the Ap- dent and friend of G. Dickie, professor of Natural History at pendix all thoseremarks by Sutherland on the phenomenon, as Queen’s College,Belfast. Sutherland made four voyages to the well as the pertinent parts of Dickie’s report. Arctic, the first two on the whaler Advice (Captain William The following few critical notes from Sutherland (found in Penny) in the late 1840s, the third in the company of Captain full in the Appendix) give the basis for the discussion and in- Penny on the Lady Franklin and Sophia in 1850-5 1 in search ferences of the present paper. These observations were made of Sir John Franklin, and the fourth with Captain Edward In- as Sutherland’s vessel, Sophia, was attempting to sail north ‘Department of Marine Resources, State House Station 21, Augusta, Maine 04333, U.S.A. 168 S. APOLLONIO -. through broken and drifting but dense pack ice on the west broken, snow-covered, fast ice. Each has reported insitu coast of Greenland north of Disko Island. On 12 May Suther- growth of ice algae under snow cover andits subsequent land remarked that “ . .the weather was very mild and plea- decline and disappearance as the snow melted. Apollonio sant during the greatest part of the week. The temperature had (1961) also found that artificial snow removal reduced the been rising gradually, and it was up to +34” and +36”. ,” chlorophyll content of sea ice, from 89.6 pg.1-l to 16.6 temperatures clearly indicative of melting snow and thawing pg. 1”. (I have a transparency of the colorless bottom of an ice ice. core thathad lost its chlorophyll content after artificial removal of the snow cover, which contrasts clearly with the May 24th.-The ice which had been turned up during the re- chlorophyll-colored bottom of an adjacent undisturbed, snow- cent pressure was observed to have a number of small cavi- ties. .on its under surface. Each cavity contained a greenish, covered ice core.) Thus these studies demonstrate the termina- slimy-looking substance. .its composition. .a massof in- tion of the cycle of plant development and decline in intact, un- fusory animalcules, and microscopic vegetable forms.. navigable ice as the snow melts and ice deteriorates with the May 3Oth.-. .Wherever the ice hadbeen very much onset of summer. (The observations of Meguro et al. [1967] decayed, a dirty brownish slimy substancewasob- off Alaska seem to be a variation or exception to this cycle in served. .amongst it;. .A beautiful sieve-like Diutoma was that they found an abundant pennate diatom flora in July and very abundent; . .and when the ice disappears for the season, August under ice from which “ . .ablation of the snow the brown slimy substance. .retires from the surface, and ultimately sinks completely out of view, having never tinged cover. .was complete. ”) the water in the slightest degree.. But the nineteenth-century reports of ice algae (Grainger, July 2nd.”. .patches of much decayed ice. .were dirty, and 1977; Sutherland, 1852) are from ships sailing in broken, abounded in the brown slime,. drifting ice from which snow had disappeared and which had July 5th.-. .The sea around usabounded in a brownish suffered surface melt. I have spent hours and days in late sum- slime. .resembling thin mucilage. .it was found to be com- mer - September - on an ice breaker on the east coast of Baf- posed chieflyof filamentous algae (Meloseira) [sic] and fin Island in such conditions watching polar cod stream off the animalcules. deeply colored undersides of ice floes upended or overturned The following note is from Dickie’s report: by the passage of a ship. This is a common experience, fre- quently observed (Bursa, 1961). But the coloration of those Melosira arcticum n. s. .Dr. Sutherlanddescribes it floes cannot be reconciled readily with the documented obser- as. .communicating a brown tinge to the water in Melville vations cited above that such color disappears from unbroken Bay. .in shreds of mucilaginous consistence. ice in the spring as the snow disappears and the ice surface It is nowwell recognized that arctic ice flora and begins to melt. The conclusion seems to follow that there must phytoplankton are separate autotrophic systems. Apollonio be a second algal growth on the ice, a growth documented by (1961), Clasby et al. (1973), and Horner (1977) have shown nineteenth-century reports coming from ships navigating the that arctic ice flora and phytoplankton blooms are floristically, ice but so far overlooked by twentieth-century research on in- spatially, and temporally distinct; thus there are at least two tact ice; a second growth that is characteristic of “summer systems contributing to arctic marine productivity, rather than ice” (snow-free, broken, drifting, partially melting) as distinct one being simply an extension of the other. It is clear that from “spring ice” (snow-covered, intact, not melted). primary production in arctic seas is not dependent solely upon Fortunately, Sutherland allows us to characterize, to a phytoplankton (or upon attached benthic macroalgae in degree, this “summer ice” algal growth as an abundant brown shallow waters). Horner and Schrader (1982) estimated that (not green) mucilaginous slime on the ice or drifting in close ice algae provided about two-thirds and the phytoplankton proximity to the ice.