uptake) integrated to 150 m. Middle: short-term estimates of mass flux at three depths
from traps drifting during BATS operations. Bottom: time-series at 2-week resolution
from sequencing cups on PARFLUX-type traps at 3200 m. Flux includes both organic
and mineral matter, most of both is of biological origin.
(^) (After Conte et al. 2001.)
(^) The seasonality of deep flux of particles and organic matter is similarly pronounced
in the northeast Atlantic, where strong spring blooms occur over oceanic depths, as
shown with time-series traps at 48°N, 21°W by Honjo and Manganini (1993). The
bloom and flux peaks occurred in May of 1989, later than at BATS, which is typical –
the bloom progresses from south to north through spring. When the diatoms deplete
available nutrients, the bloom stock “crashes” to the bottom, forming a flocculent
layer on the seafloor, and the flux at traps below 2000 m is indeed rich in diatoms at
that time.
(^) Tyler (1988) and coworkers have shown that some, but not all, benthic species in
the subarctic North Atlantic respond to this cycling of their food supply with cycling
of growth and reproduction. For example, the protobranch bivalves Ledella and
Yoldiella are strongly seasonal in reproductive activity (Fig. 13.29) as observed in
time-series of oocyte diameter and ovarian state (Lightfoot et al. 1979; Tyler et al.
1992). Some echinoderms (Tyler et al. 1993), brachiopods, and scaphopods show
similar cycling. On the whole, the species with reproductive cycling are those with