Spatially explicit estimates of length and biomass of Micromesistius poutassou (Blue Whiting) from acoustic and trawl surveys in the North-East Atlantic in May 2009

Acoustic estimates of herring and blue whiting abundance were obtained during the surveys using the Simrad ER60 scientific echosounder. The allocation of NASC-values to herring, blue whiting and other acoustic targets were based on the composition of the trawl catches and the appearance of echo recordings. To estimate the abundance, the allocated NASC -values were averaged for ICES-squares (0.5° latitude by 1° longitude). For each statistical square, the unit area density of fish (rA) in number per square nautical mile (N*nm-2) was calculated using standard equations (Foote et al., 1987; Toresen et al., 1998). To estimate the total abundance of fish, the unit area abundance for each statistical square was multiplied by the number of square nautical miles in each statistical square and then summed for all the statistical squares within defined subareas and over the total area. Biomass estimation was calculated by multiplying abundance in numbers by the average weight of the fish in each statistical square then summing all squares within defined subareas and over the total area. The Norwegian BEAM soft-ware (Totland and Godø 2001) was used to make estimates of total biomass.

Spatially explicit estimates of length and biomass of Clupea harengus (Norwegian spring spawning herring) from acoustic and trawl surveys in the North-East Atlantic in May 2010

Acoustic estimates of herring and blue whiting abundance were obtained during the surveys using the Simrad ER60 scientific echosounder. The allocation of NASC-values to herring, blue whiting and other acoustic targets were based on the composition of the trawl catches and the appearance of echo recordings. To estimate the abundance, the allocated NASC -values were averaged for ICES-squares (0.5° latitude by 1° longitude). For each statistical square, the unit area density of fish (rA) in number per square nautical mile (N*nm-2) was calculated using standard equations (Foote et al., 1987; Toresen et al., 1998). To estimate the total abundance of fish, the unit area abundance for each statistical square was multiplied by the number of square nautical miles in each statistical square and then summed for all the statistical squares within defined subareas and over the total area. Biomass estimation was calculated by multiplying abundance in numbers by the average weight of the fish in each statistical square then summing all squares within defined subareas and over the total area. The Norwegian BEAM soft-ware (Totland and Godø 2001) was used to make estimates of total biomass.

Spatially explicit estimates of length and biomass of Clupea harengus (Norwegian spring spawning herring) from acoustic and trawl surveys in the North-East Atlantic in May 2012

Acoustic estimates of herring and blue whiting abundance were obtained during the surveys using the Simrad ER60 scientific echosounder. The allocation of NASC-values to herring, blue whiting and other acoustic targets were based on the composition of the trawl catches and the appearance of echo recordings. To estimate the abundance, the allocated NASC -values were averaged for ICES-squares (0.5° latitude by 1° longitude). For each statistical square, the unit area density of fish (rA) in number per square nautical mile (N*nm-2) was calculated using standard equations (Foote et al., 1987; Toresen et al., 1998). To estimate the total abundance of fish, the unit area abundance for each statistical square was multiplied by the number of square nautical miles in each statistical square and then summed for all the statistical squares within defined subareas and over the total area. Biomass estimation was calculated by multiplying abundance in numbers by the average weight of the fish in each statistical square then summing all squares within defined subareas and over the total area. The Norwegian BEAM soft-ware (Totland and Godø 2001) was used to make estimates of total biomass.

Spatially explicit estimates of length and biomass of Micromesistius poutassou (Blue Whiting) from acoustic and trawl surveys in the North-East Atlantic in May 2004

Acoustic estimates of herring and blue whiting abundance were obtained during the surveys using the Simrad ER60 scientific echosounder. The allocation of NASC-values to herring, blue whiting and other acoustic targets were based on the composition of the trawl catches and the appearance of echo recordings. To estimate the abundance, the allocated NASC -values were averaged for ICES-squares (0.5° latitude by 1° longitude). For each statistical square, the unit area density of fish (rA) in number per square nautical mile (N*nm-2) was calculated using standard equations (Foote et al., 1987; Toresen et al., 1998). To estimate the total abundance of fish, the unit area abundance for each statistical square was multiplied by the number of square nautical miles in each statistical square and then summed for all the statistical squares within defined subareas and over the total area. Biomass estimation was calculated by multiplying abundance in numbers by the average weight of the fish in each statistical square then summing all squares within defined subareas and over the total area. The Norwegian BEAM soft-ware (Totland and Godø 2001) was used to make estimates of total biomass.

Spatially explicit estimates of length and biomass of Micromesistius poutassou (Blue Whiting) from acoustic and trawl surveys in the North-East Atlantic in May 2010

Acoustic estimates of herring and blue whiting abundance were obtained during the surveys using the Simrad ER60 scientific echosounder. The allocation of NASC-values to herring, blue whiting and other acoustic targets were based on the composition of the trawl catches and the appearance of echo recordings. To estimate the abundance, the allocated NASC -values were averaged for ICES-squares (0.5° latitude by 1° longitude). For each statistical square, the unit area density of fish (rA) in number per square nautical mile (N*nm-2) was calculated using standard equations (Foote et al., 1987; Toresen et al., 1998). To estimate the total abundance of fish, the unit area abundance for each statistical square was multiplied by the number of square nautical miles in each statistical square and then summed for all the statistical squares within defined subareas and over the total area. Biomass estimation was calculated by multiplying abundance in numbers by the average weight of the fish in each statistical square then summing all squares within defined subareas and over the total area. The Norwegian BEAM soft-ware (Totland and Godø 2001) was used to make estimates of total biomass.

Spatially explicit estimates of length and biomass of Clupea harengus (Norwegian spring spawning herring) from acoustic and trawl surveys in the North-East Atlantic in May 2011

Acoustic estimates of herring and blue whiting abundance were obtained during the surveys using the Simrad ER60 scientific echosounder. The allocation of NASC-values to herring, blue whiting and other acoustic targets were based on the composition of the trawl catches and the appearance of echo recordings. To estimate the abundance, the allocated NASC -values were averaged for ICES-squares (0.5° latitude by 1° longitude). For each statistical square, the unit area density of fish (rA) in number per square nautical mile (N*nm-2) was calculated using standard equations (Foote et al., 1987; Toresen et al., 1998). To estimate the total abundance of fish, the unit area abundance for each statistical square was multiplied by the number of square nautical miles in each statistical square and then summed for all the statistical squares within defined subareas and over the total area. Biomass estimation was calculated by multiplying abundance in numbers by the average weight of the fish in each statistical square then summing all squares within defined subareas and over the total area. The Norwegian BEAM soft-ware (Totland and Godø 2001) was used to make estimates of total biomass.

Spatially explicit estimates of length and biomass of Clupea harengus (Norwegian spring spawning herring) from acoustic and trawl surveys in the North-East Atlantic in May 2007

Acoustic estimates of herring and blue whiting abundance were obtained during the surveys using the Simrad ER60 scientific echosounder. The allocation of NASC-values to herring, blue whiting and other acoustic targets were based on the composition of the trawl catches and the appearance of echo recordings. To estimate the abundance, the allocated NASC -values were averaged for ICES-squares (0.5° latitude by 1° longitude). For each statistical square, the unit area density of fish (rA) in number per square nautical mile (N*nm-2) was calculated using standard equations (Foote et al., 1987; Toresen et al., 1998). To estimate the total abundance of fish, the unit area abundance for each statistical square was multiplied by the number of square nautical miles in each statistical square and then summed for all the statistical squares within defined subareas and over the total area. Biomass estimation was calculated by multiplying abundance in numbers by the average weight of the fish in each statistical square then summing all squares within defined subareas and over the total area. The Norwegian BEAM soft-ware (Totland and Godø 2001) was used to make estimates of total biomass.

Spatially explicit estimates of length and biomass of Micromesistius poutassou (Blue Whiting) from acoustic and trawl surveys in the North-East Atlantic in May 2012

Acoustic estimates of herring and blue whiting abundance were obtained during the surveys using the Simrad ER60 scientific echosounder. The allocation of NASC-values to herring, blue whiting and other acoustic targets were based on the composition of the trawl catches and the appearance of echo recordings. To estimate the abundance, the allocated NASC -values were averaged for ICES-squares (0.5° latitude by 1° longitude). For each statistical square, the unit area density of fish (rA) in number per square nautical mile (N*nm-2) was calculated using standard equations (Foote et al., 1987; Toresen et al., 1998). To estimate the total abundance of fish, the unit area abundance for each statistical square was multiplied by the number of square nautical miles in each statistical square and then summed for all the statistical squares within defined subareas and over the total area. Biomass estimation was calculated by multiplying abundance in numbers by the average weight of the fish in each statistical square then summing all squares within defined subareas and over the total area. The Norwegian BEAM soft-ware (Totland and Godø 2001) was used to make estimates of total biomass.

Temperature proxies of sediment cores from the Sea of Marmara

Reconstructing ocean temperature values is a major target in paleoceanography and climate research. However, most temperature proxies are organism-based and thus suffer from an "ecological bias". Multiproxy approaches can potentially overcome this bias but typically require more investment in time and resources, while being susceptible to errors induced by sample preparation steps necessary before analysis. Three lipid-based temperature proxies are widely used: UK'37 (based on long chain alkenones from phytoplanktonic haptophytes), TEX86 [based on glycerol dialkyl glycerol tetraethers (GDGTs) from pelagic archaea] and LDI (based on long chain diols from phytoplanktonic eustigmatophytes). So far, separate analytical methods, including gas chromatography (GC) and liquid chromatography (LC), have been used to determine these proxies. Here we present a sensitive method for determining all three in a single normal phase high performance LC-atmospheric pressure chemical ionization mass spectrometry (NP-HPLC-APCI-MS) analysis. Each of the long chain alkenones and long chain diols was separated and unambiguously identified from the accurate masses and characteristic fragmentation during multiple stage MS analysis (MS2). Comparison of conventional GC and HPLC-MS methods showed similar results for UK'37 and LDI, respectively, using diverse environmental samples and an Emiliania huxleyi culture. Including the three sea surface temperature (SST) proxies; the NP-HPLC-APCI-MS method in fact allows simultaneous determination of nine paleoenvironmental proxies. The extent to which the ecology of the source organisms (ecological bias) influences lipid composition and thereby the reconstructed temperature values was demonstrated by applying the new method to a sediment core from the Sea of Marmara, covering the last 21 kyr BP. Reconstructed SST values differed considerably between the proxies for the Last Glacial Maximum (LGM) and the period of Sapropel S1 formation at ca. 10 kyr BP, whereas the trends during the late Holocene were similar. Changes in the composition of alkenone-producing species at the transition from the LGM to the Bølling/Allerød (B/A) were inferred from unreasonably high UK'37-derived SST values (ca. 20 °C) during the LGM. We ascribe discrepancies between the reconstructed temperature records during S1 deposition to habitat change, e.g. a different depth due to changes in nutrient availability.

Sable oxygen isotope and Mg/Ca ratios of planktonic foraminifera from DSDP Hole 31-292

This study presents new evidence of when and how the Western Pacific Warm Pool (WPWP) was established in its present form. We analyzed planktic foraminifera, oxygen isotopes, and Mg/Ca ratios in upper Miocene through Pleistocene sediments collected at Deep Sea Drilling Program (DSDP) Site 292. These data were then compared with those reported from Ocean Drilling Program (ODP) Site 806. Both drilling sites are located in the western Pacific Ocean. DSDP Site 292 is located in the northern margin of the modern WPWP and ODP Site 806 near the center of the WPWP. Three stages of development in surface-water conditions are identified in the region using planktic foraminferal data. During the initial stage, from 8.5 to 4.4 Ma, Site 806 was overlain by warm surface water but Site 292 was not, as indicated by the differences in faunal compositions and sea-surface temperature (SST) between the two sites. In addition, the vertical thermal gradient at Site 292 was weak during this period, as indicated by the small differences in the delta18O values between Globigerinoides sacculifer and Pulleniatina spp. During stage two, from 4.4 to 3.6 Ma, the SST at Site 292 rapidly increased to 27 °C, but the vertical thermal gradient had not yet be strengthened, as shown by Mg/Ca ratios and the presence of both mixed-layer dwellers and thermocline dwellers. Finally, a warm mixed layer with a high SST ca. 28 °C and a strong vertical thermal gradient were established at Site 292 by 3.6 Ma. This event is marked by the dominance of mixed-layer dwellers, a high and stable SST, and a larger differences in the delta18O values between G. sacculifer and Pulleniatina spp. Thus, evidence of surface-water evolution in the western Pacific suggests that Site 292 came under the influence of the WPWP at 3.6 Ma. The northward expansion of the WPWP from 4.4 to 3.6 Ma and the establishment of the modern WPWP by 3.6 Ma appear to be closely related to the closure of the Indonesian and Central American seaways.

Miocene planktonic foraminifera of ODP Hole 130-806B

We document the waxing and waning of a "proto-warm pool" in the western equatorial Pacific (WEP) based on a study of multi-species planktic foraminiferal isotope ratios and census data spanning the 13.2-5.8 Ma interval at ODP Site 806. We hypothesize that the presence or absence of a proto-warm pool in the WEP, caused by the progressive tectonic constriction of the Indonesian Seaway and modulated by sea level fluctuations, created El Niño/La Niña-like alternations of hydrographic conditions across the equatorial Pacific during the late Miocene. This hypothesis is supported by the general antithetical relationship observed between carbonate productivity and preservation in the western and eastern equatorial Pacific, which we propose is caused by these alternating ocean-climate states. Warming of thermocline and surface waters, as well as a major change in planktic foraminferal assemblages record a two-step phase of proto-warm pool development ~11.6-10 Ma, which coincides with Miocene isotope events Mi5 and Mi6, and sea-level low stands. We suggest that these changes in the biota and structure of the upper water column in the WEP mark the initiation of a more modern equatorial current system, including the development of the Equatorial Undercurrent (EUC), as La Niña-like conditions became established across the tropical Pacific. This situation sustained carbonate and silica productivity in the eastern equatorial Pacific (EEP) at a time when carbonate preservation sharply declined in the Caribbean. Proto-warm pool weakening after ~10 Ma may have contributed to the nadir of a similar "carbonate crash" in the EEP. Cooling of the thermocline and increased abundances of thermocline taxa herald the decay of the proto-warm pool and higher productivity in the WEP, particularly ~ 9.0-8.8 Ma coincident with a major perturbation in tropical nannofossil assemblages. We suggest that this interval of increased productivity records El Niño-like conditions across the tropical Pacific and the initial phase of the widespread "biogenic bloom". Resurgence of a later proto-warm pool in the WEP ~6.5-6.1 Ma may have spurred renewed La Niña-like conditions, which contributed to a strong late phase of the "biogenic bloom" in the EEP.